V O L . 73
\ITISH OULDING ACHINE C° LTD
WITH WHICH IS INCORPORATED T H E I R O N A N D S T E E L I K A D t S J U U K N A U
N o . 1449. M A Y 25, 1944 [“ Single C o p y 6d. B y Po st 8d.
A n n u al S u b s c r ip tio n Hom e Registered at the G.P.O. as a_Newspoper. Offices: 49, W ellington Street, Strand, London, W .C .2. [_ancj O /erseas. 21 - (P re p a id ).
VERSHAM, KENT.
Used by many leading foundries
D I S T R 1B O N D
the PROVEN BRITISH substitute for Bentonite DISTRICT CHEMICAL COMPANY LT \
1 - 1 9 , N e w O x f o r d 8 1 r e e t , L o n d o n , W .C .1
[
Single (A n nual and O vS T E I N
R EF R A C T O R IE S FOR E V E R Y P U R P O S E
JO H N G. ST E IN & C O . LT D . B O N N Y B R ID G E . S C O T L A N D
(LLDAYS & O N IO N S LTD
B IR M IN G H A M II
oufocturers o f
T H E E R I T H R A N G E O F S A N D S
C o m b in e a v ariety oi s e le c t« ! LOAMS a n d SILICA SANDS ol gu aranteed q u a lity , su itab le fo r every ap p ro p riate fo undry req u irem e n t. In a ll fu n d am ental resp e c ts tb ey are th e o u tstan d in g sands for p resent-day p rac tic e , a n d are trie d a n d proved by perform ance, and resu lts.
W r i t e f o r I l l u s t r a t e d B r o c h u r e e n d F r e e S a m p l e s t o : t S I A B L l S H t U lou d --- --- w „ . F R I T H l o s s
P L A N T S
J. PARISH & CO., ERITH, KENT.>R USE AS
'L T D . HEAD OFFICE
rAlbior
tEFFIELD 26511 (15lines) MANSFIEL
W ... ^
eifield.
FO U N D RY TRADE JO U R N A L MAY 25, 1944
THE FORDATH ENGINEERING C? L<
T E L E P H O N E
WEST BROMWICH 0549(zlines)
HAM BLET WORKS WEST BROMWICH
M IX IN G T IM E - - 2 MIN.
D ISCHARG ING T IM E '/:2 MIN.
“ N E W - T Y P E ” F O R D A T H M I X E R S are m ade in F IV E sizes, from 20 lbs. to I ton per batch.
FOR ILLUSTRATED BROCHURE
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L 3
B r i t i s h M o u l d i n g M a c h i n e C o . L t d .
The fact that goods made of raw materials in short supply owing to'jwar conditions are advertised in this paper should not be taken as an indication that they are necessarily available for export
FO U N D RY TRADE JO U R N A L M A Y 25, 1944
n m if t r a i n . . .
R a i l w a y engineers are a lre a d y a t work on the new p o s s i b i l i t i e s . N e c e s s a r y s t r e n g t h w i t h b u t a f r a c t i o n o f the w e ig h t m eans s a vin g in power a n d in m a i n t e n ance too, both o f tra in a n d p e r m a n e n t w a y . So, j u s t when com p etitio n w ith air t r a v e l b e c o m e s k e e n e s t , l ig h t alloys m a y solve the r a ilw a y s' p ro b le m o f h ig h speed a t low cost. Here s a n o t h e r c a s e w h e r e N T A L a s makers o f a l u m i n i u m a l l o y s f o r every conceivable p u rp o se, look fo rw a rd to h e l p i n g .
43
“ V
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L
U/03
COMPRESSORS* PNEUMATICTOOLS• ELECTRICTOOLS• DIESELENGINESVACUUMPUMPSCONTRACTORSEQUIPMENT> ROCKDRILLS DIAMONDDRILLSOILWELLTOOLS*
FO U N D R Y TRADE JO U R N A L M AY 25, 1944
FOR
STEEL FOUNDRIES
To get the most out of your men and equipment
you must have accurate boxes you must have strong boxes you must have durable boxes you must have S T E R L IN G boxes
•
In th e se d ifficu lt t im e s m o r e f o u n d rie s th a n e v e r a r e t u r n in g t o S te r lin g B o x e s to h e lp s o lv e t h e p r o b le m o f in c re a s e d p r o d u c tio n .
Telegram s; S T E R F L A S K * B E D F O R D
M t o
BE
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L 7
^ o r c o r e s
w •
P” “<“ S e o ' S " » » *
l* c“ « <“ ■ » i l l a t i o n i s d e s i g n e d t o P P a ' i o ° ' W h i m “ ' s . * U a r e b o V , ' “ d W * . a l t ,
<” « » ■ « d r y i n g p r i n c i p l e “ ° ” b
P N M
cupolas core and mould jarr rollover sandprepanngU C
^ b k m o u l d £yers Royer sand mixers drying stoves machines plants , • r TvJ R I P M 1 N G H A M P N E U L E C L I M I T E D - M a f e k in g R o a d - S m e lh w tc k - N e a r B I R M L N ^ n ^ iFO U N D R Y TRADE JO U R N A L M A Y 25, 1944
The war has given high-duty iron castings an opportunity not only to play an im portant part in essential production hut to dem onstrate its poten
tialities as a factor seriously to be reckoned with in post
war re-construction plans. It has accelerated the pace of research work on pig iron carried out by BRADLEY &
FOSTER over a long period.
Knocks
BRADLEY & FOSTER have developed grades of pig iron treated by the Bradley spun- refining process and subject to chemical analysis and mechanical tests at every stage of production which satisfy specifications previously con
sidered to be outside the range of cast iron. We shall be glad to discuss the application of refined pig iron to the produc
tion of high-duty castings in your foundry.
B R A D L E Y & F O S T E R ltd D A R L A S T O N • S O U T H S T A F F S
S pun-refined pig irons.
Spun-refined alloy pig irons.
^ MAKERS OF ^ B lended “ All M in e ” pig iron.
H igh ca rb o n steel pig iron.
F ire-resistin g pig iron,
{
(f p p o r t im it y
M AY
BRITISH IN SU LA T ED CA BLE S LTD..
H e a d O f f i c e P R E S C O T . L A N C S . T e l . N o . P R E S C O T 6571.
by th e m ost inexpensive means of mass p roduction moulding—
Production of d ifficult w o rk is rapid and efficient— 100 moulds can be produced for one unit of e lectricity.
D isto rtion of moulds is elim in ated as “ rclling- o v e r” is perform ed before squeezing, thereby ensuring accuracy of finished mould.
W r i t e fo r le aflet describing
ROLL-OVER TYPE
25, 1944 FO U N D RY TRADE JO U R N A L
H IG U E ! M M Y (g®iTÜ _
I n c r ea se mould production
S e le c t e d high g ra d e raw material and careful technical control at all stages of manu
facture from the mine to the loading bank ensure the con
s is t e n t hig h q u a l i t y of N E T T L E (42/44% Alum ina) Firebrick.
CREOSOTE-PITCH FIR IN G : A n u m b e r o f firm s adopting this fuel have e n co u n te red n e w R e fra c to ry Problem s caused by C o r ro s io n and V itr ific a tio n Spailing. B u t. if a s u ita b le design o f b u r n e r is used, the tro u b le can usually b e o v e rc o m e by using a H ig h A lu m in a F ire b ric k such as N E T T L E — a p o in t p ro v e d by the p ractical e x p e rie n c e o fs e v e ra l cu sto m e rs. A n ad d itio n al p ro te c tio n to th e b r ic k w o r k b y w ash co atin g w ith M akslccar II o r S te in S llllm a n ite C e m e n t w ill often be found e co n o m ic. F u r th e r In fo rm a tio n w ill be gladly su p p lied on req u est.
io FO U N D R Y TRADE JO U R N A L M A Y 25, 1944
O b s o le t e M a c h i n e r y _ -
i s P o t e n t i a l S C R J k W /
The bit o f M a c h in e ry w hich we have so u n ju s tifia b ly stu ck in the m id d le o f a great m odern Power Station is “ D r. W ild e's S ep a ra tely ig n ite d D y n a m o i n v e n t e d a n d p a ten ted in 1863/5. F a r be it fr o m us to suggest that y o u r W o rks c o n ta in s a n y p la n t as antique as th is— but y o u m a y possess one or two item s that have o u tlived their efficiency a n d can now be spared fo r sc ra p p in g . I f so, we shall be p le a se d to p u rc h a s e th em a n d ensure that the resultant scrap reaches the c o n su m in g W orks w ith all po ssib le speed.
G e o r g e C o h e n , S o n s & C o m p a n y 9 L t d .
B r o a d w a y C ham bers, H a m m e r s m ith, L o n d o n, W . 6 ( R iv e rsid e 4141) * Q u a d ra n t Street, C a n n in g T o w n, £.16
( A lb ert D ock 3104) * 600 C o m m ercia l R o a d, £.14 (S te p n e y Green 3434) * a n d at S h effield, B i r m in g h a m,___________
M a n c h e ste r, N ew c a stle, B e lfa s t, etc. G R Q (J R
ONE OF THE
nits
may 25, 1944 FO U N D RY TRADE JO U R N A L II
K E IT H B L A C K M A N LTD. M ILL M EA D ROAD. LO N D O N . N J 7 \
T e le p h o n e s : To tte n h a m 4522 (tw e lv e lines) ^ T e l e g r a m s : " K e it h b la c Phone L o n o o n ."
S U P IN O L “ \ “
T H E SEM I-SO LID O IL
is a specialised new ty p e of core b in d e r su ita b le for all ty p e s o f castin g s becau se i t h as
IN T H E G R E E N S T A T E : A ll th e w o r k in g p rop erties o f a s e m i-so lid D U R IN G CA ST IN G : A ll th e a d v a n ta g e s o f a h ig h -g r a d e o il.
O ur p ro d u c t gives freedom from
NOXIOUS FUM ES—METAL PEN ETRATION—KNOCKOUT DIFFICULTIES I n re g u la r use b y leading ferrous an d non-ferrous foundries.
M a n u fa c tu re d and d istribu ted by
& S u p p lie s L td .
2 1 /2 3 , C O L D H A R B O U R , L O N D O N , E .1 4 A lso su p p liers o f F L U X E S , P A R T IN G P O W D E R ,
ETC. o f e x c e p tio n a l q u a lity .
12 FO U N D RY TRAD E JO U R N A L M A Y 25, 1944
S A N D S L I N G E R S
F O R E X P R E S S R A M M I N G
The portable type Sandslinger, illustrated above, will ram foundry flasks up to approx. 8ft. wide, any length, and all
practicable depths.
No foundations or air supply required— an electric connection sets the machine to work— ordinary patterns and core boxes
— ramming capacity 5 cwts. per min. maximum.
F O U N D R Y P L A N T & M A C H IN E R Y LTD. 113 V S . ST'
M A Y 25. 1944 FO U N D RY TRADE JO U R N A L 15
★ The New Refractory
★ A Tremendous Step Forward
HI S E GA R REGD.
HIGH ALU M IN A
PLASTIC FIR E B R IC K
For R am m in g
AND
FLUID REFRACTORY
For Pouring
H IS E G A R is com p letely n eu tral to expansion and c o n tra ctio n .
H IS E G A R possesses a high re fra c to ry valu e Cone 32-1710° C en tigrad e.
H IS E G A R has exceptional hard burned strength and is highly resistant to th e r
mal shocks and abrasive action.
E N G I N E E R S S E R V I C E S A V A I L A B L E O N R E Q U E S T
F o r com p lete in stallatio n o r re p a irs to : Re-heating Furnaces, Soaking Pits, B ille t Furnaces, A n n ealin g and H e at
T re a tm e n t Furnaces, etc.
D o n ’t w a it fo r d e live ry of those special shapes, co n tact U S im m ed iately.
THE MIDLAND MONOLITHIC FURNACE LINING
C O M P A N Y L IM IT E D ,
B L A C K S E A M H O U S E , N A R B O R O U G H , Nr. L E I C E S T E R .
C A R D IF F
P H O N E : N A R B O R O U G H 2228-2229.
Stocks available at Branches in
B IR M IN G H A M M A N C H E S T E R G L A S G O W L O N D O N
14 FO U N D RY TRADE JO U R N A L M A Y 25, 1944
W h a t d o I g et o u t o f it?
Literally or figuratively ? Sir, we have both the answers— if you are considering the use of sodium carbonate in the manufacture of pig iron. First, you get the sulphur out of the iron by operating the blast furnace for maximum production with a less limey slag, and treating for desulphurisation with sodium carbonate in the ladle.
Second ; sodium carbonate not only desulphurises but it refines and produces a better quality cast iron— in other words, it saves you money.
When you consider the low cost of the sodium carbonate process, its easy application, the increased output and the improved quality pig—well, we hope you will agree that you get quite a lot out of it.
I M P E R I A L C H E M I C A L I N D U S T R I E S L I M I T E D
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L 15
r Forget
^ y o u r Rust ^ problems
by remembering
R
A T L A S A f
IRON & STEEL PRESERVATIVE PAINTS
— the Paints o f Stamina !
C o lo u r C ard , particulars and prices from
Sole Mfrs. ATLAS PRESERVATIVE COMPANY LTD J
L U N D E R C L I F F W O R K S , E R I T H , K E N T I
V - Telephone : E R IT H 2255-6 V
T H R E E - M O T O R W A L L C R A N E
P A T E R S O N H U G H E *
E N G IN E E R IN G C O M P A N Y L IM IT E D V B ed ford H o u se, Bed ford S t., Stran d , W . C . 2 T em p le B a r 7274/6 W y n d fo r d W o r k s , M aryh ill, G lasgow , N . W . M a ry h ill 172/3
l i B Ü É É l f r r r i ii 1 1 1 1 1 1 m i
WimwHICH IS INCOHPORATED T H E IR O N A N D S T E E L T R A D E S JO U R N A L
69, W ellin g to n S tre e t, London, W .C .2 .
W A R T I M E A D D R E S S to which all communications should be sent i__
3, A m e r ih a m R o ad , H I G H W Y C O M B E , B u cks.
’Gram s i “ Zacatecas, High W y c o m b e ."
’ Phone t H IG H W Y C O M B E 1792 (3 lines).
P U B L I S H E D W E E K L Y i 21s. per annum (H o m e and O varsea )
O -FICIA L O R G A N O F i
C O U N C I L O F I R O N F O U N D R Y A S S O C I A T I O N S Chairm an i Fltz H erb e rt W rig h t, The B u tte rle y Com pany, R lp le ) , near D erby. Se cretary i V. D e lp o rt, 2, Caxton Stre e t, W e s tm in - te t,
W.l.
Participating Associations : B ritish Bath M anufacturers' A ssociation ; British Iron fou n ders’ Association ; British M alleable Tube Fittings’
Association; Cast Iron A xle b o x Association ; Cast Iron C h air Assoda- lon; Cast Iron Heating. B o ile ra n d Rad iator M anufacturers’ A ssociation ' Cast Iron Segm ent A ssociation ; Greensand Pipe Found ers'A ssociation jf Sco tlan d ; Iron fou n ders’ N atio n al Confederation ; N atio n al Associa
Ion of M alleable Ironfounders ; N atio n al Ingot M ould Association ; N atlnn al Ironfoundlng E m p lo y e rs ’ F e d e ra tio n A ssociation of A u to m obile and A llie d H ig h D u ty Iro n fo u n d e rs ; British Cast Iron Research Association (atf.Hated): British G r it Association faff'llated l:
Flushing C is te rn M ak e rs’ A ssociation (affiliated) ; In stitu te o f British Fou n d rym en (affiliated ). ______
I N S T I T U T E O F B R I T I S H F O U N D R Y M E N P R E S ID E N T , 1943-44 : D . S h arp e . F o u n d ry Plan t & M a c h in e s , L td . 113 W e s t R e g e n t S t r e e t , Glasgow .
Gen eral Secretary l T. Makemson. A ctin g S e c re ta ry , I. Bolto n , Saint Jo h n S tre e t Cham bers, Deansgate, Manchester 3.
B R A N C H E S
Birm ingham , C o ve n try and W e s t Midlands l A . A . Timmins, F .I.C 33, C a r t e r s Lane, Q u in to n . B ris to l and W e s t of E n g la n d : A . Hares, 20, G re e n b a n k Ro ad , Han h am , B ristol. £. Midlands i S. A . Ho rto n “ T h re e ,” Mostyn A ven u e, Little o v e r, D erby. Lancs : H . B u c k ley, Elle sm e re, N o r fo lk A v e n u e , B u rn le y . L o n d o n : V . C . Fau lkn er, 3, Amersham Road, High W yco m b e. M iddlesbrough (pro fern.) : J. A.
Smithson, N orth-Eastern Iron Refining Com pany, Lim ited, Stllllngton, Stockton-on-Tees. Newcastle-upon-Tyne : C. Lashly, S ir W . G . A rm strong, W h itw o r t h & Co. (Ironfounders), Ltd., Close W o rk s , Gateshead.
Scottish : J. Bell, 60, St. Enoch Square, Glasgow. Sheffield : T . R. W a l k e r, M .A ., English S te e l C o rp o ra tio n , L td ., Sheffield. W ales and M onmouth ; A. S. W a ll, 14, Pala ce A v e n u e . Llandaff, Card iff. W e s t Riding of Y o r k s h ir e : D ouglas Je p son , M .Sc., 9, A m bleside A ven u e, B radford.
South A frica : B. P. Sko k, M utual Building, Johannesburg.
S E C T IO N S
B u rn le y i H. Buckley, Ellesm ere, N o rfo lk A venue, Bu rn lev, Lancs.
Cape) T o w n : K . Z w an z i^ e r, P .O . B ox 346, C ape T o w n , S. A frica, cast Anglian l A . N . S u m n e r, 516, N o r w ic h Road, Ipsw.ch F a lk irk : T. R. G o o d w in . ” V le w field ,” Falkirk Road, Bonnybrldge. Lincoln i f . R. W a lte r , P h .D ., The Technical College, Lincoln.
A S S O C I A T I O N O F B R O N Z E A N D B R A S S F O U N D E R S P r e s id e n t : H . Blssell, J. Sto n e & C o ., Ltd ., Lo n d on . S e cre ta rie s : H e ath co te & C o lem an , 25, B en n e tts H ill, Birm in gh am , 2
T H E I N S T I T U T E O F V I T R E O U S E N A M E L L E R S President i W . H . W h ittle , W . H. W h ittle , Lim ited, Eccles, near M anchester. Chairm an i W . To d d , Park in son S to v e C o .. Ltd ., Seech- fo rd , Birm in g h am . Hon. Sec. I W . Thom as, A .I.C ., Ban k House, High S tr e e t, R ick m an sw o rth , H e rts.
F O U N D R Y T R A D E S ’ E Q U I P M E N T A N D S U P P L I E S A S S O C I A T I O N
Presiden t I G . E. France, A ugust’s, Lim ited, T h o rn T re e W o r k s , Halifax. H o n o ra ry S e c r e t a r y : K. W . Bridges. Assistant S ecretary i Miss L. C o x, 52, Surbiton H ill Park, Su rb ito n , Su rrey.
W E L S H E N G I N E E R S ’ A N D F O U N D E R S ’ A S S O C I A T I O N Presiden t i W . E. Clem en t, C .B .E ., Morfa Foundry, N e w D ock. Llanelly.
S e cretary : I- D. D . Davis, I, St. Jam es Gardens, Swansea.
B R I T I S H C A S T I R O N R E S E A R C H A S S O C I A T I O N Alvechurch, B irm in g h am . 'P h o n e a n d ’G ra m s : R e d d ltc h 7 l6 . Scottish La b o rato ries ¡—Foundry T e c h n b a l l- s tlr u r * .M e e k 's Road, F a lk ir k . (Phone i 332,1
16 FO U N D RY TRAD E JO U R N A L M A Y 25, 1944
The need for all p o ssib le co n serv a tio n o f m an p o w er ; th e dem and for th e m ax im u m o u tp u t o f v ital cast m etallic p rod ucts ; th e in sisten ce u p o n the lo w est c o s t o f p ro d u c
tio n ; and th e n ecessity o f m ain tainin g, and even im p rovin g, the q uality o f th o se p ro d u cts.
A il th ese c o n d itio n s co m b in e to p o in t to th e on ly satisfactory so lu tio n to all th ese p rob lem s—
MECHANISATION
b ut it m u st be m ech a n isation particularly con sid ered , d esigned and adapted to the in d iv id u al site c o n d itio n s ; to the particular p rod u ct ; and w ith fu ll regard to
allthe factors, ec o n o m ic , geographical and h u m an , w h ich may have any bearing on the p rob lem .
In oth er w ords co n su lt :—
“ The Specialists in Foundry Mechanisation”
w h ose p rod ucts
“ Set the Standard b y which Foundry Plant is ju d g e d .”
L IM IT E D
' P h o n e s : 6 1 2 4 7 &. 8
H A L I F A X , E N G L A N D
’G ram s : A u g u s t , H a l i f a xSole L icensees a n d m a n u f a c t u r e r s for B ritish E m p ir e ( e x c lu d in g C a n a d a ) o f the S im p s o n S a n d M ixer
Foundry Trade Journal, M a y 2 5 , 1944
WITH which S IHCOÄTOMTEO THE IRON AND STEEL TRADES JOURNAL
Vol. 73 Thursday, May 25, 1944 No. 1449
established ¡902
What is Your Percentage?
An interesting docum ent, published in the U.S.A., has just come into our hands, dealing with the ques
tion of w ater-quenching of steel castings. This summarises a num ber of Papers which were pre
sented at the annual meeting of the Steelfounders7 Society of A m erica, when the opportunity was taken of arranging a symposium on this subject.
The im provem ent in mechanical properties that can be obtained in steel by the process of liquid-quench
ing and tem pering, as com pared with the ordinary commercial process of annealing, has long been known to m etallurgists. The surprising thing is that only recently, either in this country or in America, have these im portant properties been made use of extensively by steel casting users and producers. T he A m erican symposium indicates that, in 1940, the figure of com m ercial steel cast
ings which were w ater-quenched and tem pered was not in excess of 5,000 tons—less than half of one per cent, of the entire castings production. In 1943, it is believed that not less than 250,000 tons of steel castings were given this treatm ent, or 8 per cent, of the entire volum e of castings produced. It may be thought th at this increase is solely due to wartime dem ands, and that ordinary commercial post-war developm ent will result in an abandon
ment of liquid-quenching in favour of the ordinary commercial annealing processes. We believe, however, th at this is a case w here the exigencies of war have brought about a developm ent in the application of m etallurgical research which had been held back more by sheer inertia than by any
thing else. Custom ers’ specifications have often specifically prohibited liquid-quenching. Both users and producers have been inclined to foster the idea that liquid-quenching, and particularly water- quenching, gave rise to unreliable properties, and was therefore to be discouraged. If, in the past, there was any truth in this, the reason was that liquid-quenching, as then conducted, was done by improvised means, and w ithout proper metallurgical control. W artim e experience has refuted the idea that liquid-quenching involves any reduction in the standard of reliability, and has actually proved that the reverse is the case. It has been shown that liquid-quenching gives a control of the most vital
factor in heat-treatm ent, which is the rate at which castings cool down from the soaking tem perature.
Interesting figures are now disclosed, setting out the tensile strengths of cast steel as a result of different treatm ent processes. The yield point of 0.30 carbon steel is increased from 21 to 27 tons per sq. in., by substituting w ater-quenching and tem pering for ordinary annealing. Norm alising (air-quenching) and oil-quenching give intermediate properties. On tempering at lower temperatures, still higher yield points, up to 45 tons per sq. in., are obtainable, though with reduced ductility.
Similarly, ultim ate tensile strengths are improved from 35 tons per sq. in. for ordinary annealing, to 39 tons per sq. in. for water-quenching and tempering. M oreover, quenched and tempered castings are easier to machine than annealed cast
ings o f the same tensile strength.
It is interesting to note that, of the liquids commonly used for quenching steel castings, i.e., water and oil, w ater-quenching gives an appreci
ably greater im provem ent in yield point. There has been some difference of opinion as to whether water-quenching is still to be preferred to oil- quenching over the whole range of compositions which are treated in this way. We can, however, state that the dangers of setting up cracks by water- quenching have been exaggerated. This im prove
m ent in properties can be m ade generally avail
able, and should be a valuable contribution to the advance of m ethods of engineering construction.
There are, however, the following im portant provisos, if this is to be rea lise d :— (1) C ollabora
tion betw een'founder and designer; (2) installation of suitable plant, and (3) development of adequate
(Continued overleaf, col. 1.)
Contents
W h a t is Y our P e r c e n ta g e ? 61.—F ou n d ry In q u ests—V I, 6 2 - H in ts o n M a n g a n e se B ron ze F o u n d ry T echn iq u e, 6 2 - M e ch a n ica l A id s to Core P ro d u ctio n , 63.—C lea n in g and D e s c a lin g S teel b y E le c tr o ly tic P ic k lin g in M olten C austic S oda, 68.—T he Ir o n fo u n d ry o f th e F u tu re, 69.—Iro n fo n n d ry F u e l N ew s—IV , 70.—Z inc F u m e in th e F o u n d ry , 71.—Scrap Iro n a n d S teel T rade, 72.—C o n tr o llin g th e P rodu ction o f M a g n esiu m C a stin g s , 73.—In c o m e T a x A ssessm en ts : S ch ed ule “ D ,” 74.—N ew P a te n ts , 76.—N ew Trade M arks, 76.—N e w s in B r ie f. 78.—O b itu a ry , 78.—T ita n iu m P ig m e n t M a n u fa ctu rers, 78.—C om pan y R e su lts. 80. N ew C om panies, 80.—P e rso n a l, 80.—Raw' M a ter ia l M arkets, 82.
62 FO U N D RY TRADE JO U R N A L M A Y 25, 1944
F O U N D R Y IN Q U EST S— VI. .
By “ C o r o n e r ”
T h e best m eth o d o f m ak in g a p a tte rn is n o t alw ays a p p are n t a t first sight to a p a tte rn m a k e r n o t possessing a large a m o u n t o f fo u n d ry experience. Fig. 1 ;s a p a rt section o f a ro u n d c astin g th a t w as re q u ire d in fairly large size batches periodically. T h e p a tte rn supplied w as jo in te d th ro u g h th e cen tre w ith core p rin ts eac h end as fu ll lines. T h e c o reb o x m p p lie d w as a h a lf bo x w ith a loose boss to fo rm th e recess A.
T h is core w as n o t a n easy one to m ake, an d also n o t positive fo r positioning, as a clearan c e h ad been m ad e a t eac h end o f the co re p rin t. A fte r a p ercen tag e o f scrap, the p a tte rn eq u ip m en t w as r e designed.
T h e im p ro v ed m eth o d is to m ak e the core prints as d o tte d lines in th e sketch, an d m ak in g th e long ro u n d p o rtio n sep arate to suit in p rin ts B. T h e core fo rm in g the b ack can be m ade in one piece a n d tu rn ed o u t o n to a flat p late an d the centre co re placed in it.
T h is m eth o d n o t o nly facilitates corem aking, b u t also gives a b e tte r guide fo r th e core, an d ensures a larger n u m b er o f good castings, a n d elim in a tes F o u n d ry In quests as fa r as this tro u b le is concerned.
W H A T IS Y O U R P E R C E N T A G E ? (iC ontinued fr o m p revio u s page.)
m etallurgical control. T here is an onus on the steel foundry industry to see th at these have adequate attention. T here are possibilities in the w ider application o f liquid-quenching processes for considerably enlarging the field for the use of steel castings. Im provem ent in engineering products depends on im provem ent in the qualities of the m aterials available to the designer. Engineers are constantly searching for m aterials capable of w ith
standing higher stresses and giving improved w ear
ing properties. F or steel founders who are interested in the developm ent o f their post-war m arkets (and w ho is not?), here, surely, is a field w orthy of consideration.
H INTS ON M A N G A N E SE B R O N Z E F O U N D R Y T E C H N IQ U E
A P a p e r, w hich M r. H . E . M c G o w an p re sen te d to the L os A ngeles C h a p te r of the A m e ric an F o u n d ry - m en ’s A sso ciatio n , includes the fo llo w in g n o tes on m ak in g m an g an ese b ro n ze castings.
(1) M elt in a clean cru cib le o r in a cru cib le th a t has b een used p reviously fo r m an g an ese. T h a t is neces
sary to av o id lea d co n ta m in a tio n .
(2) M elt fa st an d b rin g m etal to a b o u t 1,065 deg. C.
a n d flare o r flash strongly.
(3) U se coarse, dry c h a rc o a l o r glass as a cover, or a good flux.
(4) F u rn a c e co m b u stio n sh o u ld be n e u tra l if possible o r slightly oxidising.
(5) S tir th o ro u g h ly b u t av o id flapping the m etal.
(6) F la re zinc fo r a b o u t 1 m in. b u t no lon g er in o rd e r to re ta in th e tensile stren g th .
(7) A dd 1 to 1-j p e r cent, o f electro ly tic zinc for the w eight o f gates o r risers in the h eat. N o n e should be added fo r the o rig in al ingots. T h is re-establishes the c o p p er-zin c ratio .
(8) Skim th o ro u g h ly a n d p o u r the m o u ld s with cru cib le as th o se to the sp ru e as po ssib le an d pour evenly to avoid surges o r splashes. A g itatio n during p o u rin g , o r m o lten m eta l flow ing a g ain st sh a rp angles in the m o u ld , causes an o x id a tio n w ith in th e m ould th at is d etrim en tal. T h is a llo y w ill oxidise easily.
In v erted h o rn gates, stra in e r cores, o r skim an d choke gates should be used, w h erev e r p ractical. C astings sh o u ld be fed a t b o tto m an d a stra ig h t ru n o f metal in the m o u ld is desirable. H eav y risers a n d feeder heads m ust be g en ero u sly used to o v erco m e both e x tern al a n d in tern al sh rin k ag e, w h ich this m etal has.
(9) F o r p o u rin g the test-b a r: (a ) Skim dry the m ould; (6) p o u r at th e te m p e ra tu re fo r best physical p ro p erties; (c) shake o u t a fte r a b o u t 45 m in. Leaving b ars in the sand fo r a lo n g er tim e m ak es the metal b rittle. A lth o u g h the tensile stre n g th w ill n ot be a ltered m uch, the e lo n g a tio n w ill be lost; (d ) w hen the bars are m ach in ed , th e m ach in e sh o p sh o u ld be cau tio n ed against h eav y c uts o r allo w in g the b a rs to get to o hot. M ach in in g can h a rm th e p h ysical p ro perties of an o therw ise good b a r; (e) if th e feeder or riser section o f the test-b a r does n o t show a decided shrink on the to p section, th e b a r sh o u ld be discarded, and (/) one b a r sh o u ld be b ro k e n in a vice before m achining, an d if an y b rig h t yellow sp o ts a re apparent the b a r has n o t been fed p ro p e rly a n d sh rin k areas are p resent w hich rap id ly low er the phy sical properties.
The production o f the U n ited States m alleab le-iro n castings in d u stry w as v irtu a lly th e sam e in Ja n u a ry this y ear, a t 75,247 sh o rt tons, as in D ecem ber. O rder- b ooks, how ever, are well filled.
American production o f m agnesium castings, excluding in cen d iary b o m b bodies, rose from 160 535 tons in 1942 to 290,449 to n s in 1943. I n the sam e p erio d the p ercentage o f die castings rose from 4 5 to n early 10 p e r cent.
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L 63
MECHANICAL AIDS TO CORE PRODUCTION
By J. BLA KISTO N ,A ¡.Mech.E.
(iContinued, fr o m page 56.)
Position o f the foundry industry in the light o f mechanical advancem ent during the last century
Core Stoves
As previously stated, on a cco u n t of the increasing volume of core p ro rata to tonnage th at has been occasioned by m o d ern engineering developm ent, the core shop as a w hole requires carefu l consideration as to its full lay o u t an d planning. Fig. 13 show s the layout fo r the p ro d u ctio n of 50 tons o f jo b b in g cores up to 10 cwts. in in d iv id u al w eight per week. T his section is intended to be o p e rated by fem ale and m ale labour in the ratio of 5 to 1. A n u m b er o f 18-in.
gauge light railw ay bogies are used to tran sp o rt the sand and core p late s to the o p e ra to rs, w hile the finished cores are delivered by gravity ro ller conveyor to the vertical or tow er stove. T his type o f stove de
serves som e co m m en t, as it is a m ech an ical m ethod of drying. A n u m b er of trays a re circu lated up and
down the in terio r of a vertical tow er, taking a time which can be v aried to suit the type of w ork. T he cores to be baked a re placed on these trays, w hich can be u p to 7 ft. by 3 ft. in size. Flot an d cold air currents are then directed on to these trays during their cycle, so th a t th e cores are baked, dried and cooled during this passage. T he cycle can be re
peated fo r larger cores, if necessary.
T he o u tstanding featu res of these types of stoves are small floor space coupled with high o u tp u t, and low fuel co n sum ption w ith high therm al efficiency, also, the fact th a t the stove, on acco u n t o f its basic principle, is alw ays open a t the b o tto m fo r the recep
tion and delivery of cores. T he stove in this section is fitted w ith the charging device previously described.
A jo lte r station w ith tu rn o v er cage is situ ated so th at the larger cores pro d u ced use a different section of the conveyor fro m those used by the sm all cores.
T he core benches have attach m en ts previously de
scribed distributed am ongst them . All the sm aller w ork is allocated to the benches w ith the m ost su it
ab le devices for the type of core required.
A lthough this section has its ow n sand m ixer, it is so situated in re la tio n to the m ain sand p lan t as to be able to draw from it in the event o f peak loads or breakdow ns. A fter the cores have been b ak ed they are inspected, jointed, sorted an d m ade generally ready fo r the m oulders, so th a t no additional w ork h as to be carried out on th em befo re use.
Fig. 14 shows a sim ilar layoqt, only in this case it is of higher capacity specialising on sm all cores. A suspension conveyor fitted w ith altern ate buckets and trays ru n s ro u n d the outside of this section. T he trays take the em pty core plates back to the operators and baked cores to storage and inspection. T he buckets distribute the sand to the benches fro m the sand plant. T he cores are delivered to a three-stage vertical stove by m eans of a steel b an d conveyor and are loaded by hand. T he three-stage vertical stove w orks sim ilarly in principle to the tow er stove pre-
r t n n r m r '
i» ton» to«» hi o hou»»
F i g . 1 4 .— C o r e P l a n t L a y o u t (b).
viously described, but h ad a m uch larger th roughput, generally with sm aller trays.
T his plant w ould pro b ab ly have been m ore com plete if it h ad included a core-blow ing m achine. T his m achine packs the sand into the corebox p neum atic
ally, b u t its use is only justified w here large num bers of specialised cores are required, as each new corebox requires considerable experim ent as to the correct dis
position of the air vents, before successful operation is achieved. T his, coupled w ith m echanical upkeep, cleaning and cap ital cost, gives only a very small m argin over efficient hand m ethods.
Barrel Cores
C ylindrical or barrel cores have long been m ade by hand-driven extrusion m achines and by strickling loam on a b a rre l tu rn ed by m eans of a handle. These m ethods a,re ad d itio n al to the com m on h an d m ethod of m aking cores in h alf-ro u n d s and. after baking, joining together. T h e first two m ethods obviously suggest them selves to pow er-driving, and it is su r
prising th a t this m ethod is seldom used. E x tru sio n
64 FO U N D RY TRADE JO U R N A L M A Y 25, 1944
M e c h a n ic a l Aids to Core Production
m achines, alth o u g h long established, hav e tw o dis
adv an tag es:— (a) T h e q u ality o f oil sand has to suit the m ach in e an d n o t the p u rp o se o f th e co re; a n d (6) w ith the longer cores the p ressu re re q u ire d to force th em alo n g the c o n v ey o r causes bulging, so th at accu racy c an n o t be m ain tain ed to close lim its.
Fig. 15 show s clearly a sim ple m eth o d o f a pow er drive fo r co re b arrels, the co re b a rre l being carried on “ V ” stands in the n o rm a l w ay; a n o ld lath e head- stock is used f o r the drive, the spindle carry in g a sliding sq u are-h o led socket, w hich can be m o v ed by a ro d alw ays in easy re ac h o f the o p e rato r. E very co re b a rre l re q u ire d f o r use on this m ach in e m u st be fitted a t o n e end w ith a sq u a re ta p e r spigot, w hich can be engaged a t w ill w hen the socket is slid f o r w ard. T h e sq u are sp ig o t re q u ire d on th e co re b a rre l
a d a p ta tio n o f a ch aser lath e , o nly a grin d in g fo rm ed to th e re q u ire d th re a d section is su b stitu ted fo r the chaser. T h e draw ing is se lf-ex p lan a to ry , and it will be seen th a t by ch an g in g the pitch screw and w heel ra tio s o f the h ead sto ck , an y p itc h o f in tern al o r e x te rn al th rea d can b e g ro u n d to g re a t accuracy, this accu racy an d finish being tra n s fe rre d to th e final casting tap e r th read s, o r tru ly c y lin d rical cores can also be g ro u n d on this m ach in e if re q u ire d . This g rinding is b ecom ing m ore g en eral fo r all shapes and sizes o f cores, an d Fig. 18 show s a larg e capacity p lan e su rfa ce co re g rin d in g m ac h in e o f A m erican m an u fa ctu re . T h e m ain use fo r this type o f m achine to d ate is fo r cores th a t hav e to be jo in ted .
T he “ P lu s ” F actor
T hese co res a re m ad e “ plus ” to the jo in t an d then g ro u n d to the ex act size, so th a t w h en th e cores are jo in ted exact d im ensions a re o b tain ed .
F i g . 15.—C o r e B a r r e l M a c h i n e .
can be used fo r sub seq u en t c o re setting an d holding- dow n p u rposes. T h e illu stra tio n also depicts the co m plete lay o u t fo r b a rre l core m an u fa ctu re , an d show s a one-leg w all cran e, w h ich tran sfers the cores fro m the m ach in e to the drying-stove bogies.
Fig. 16 show s a fu rth e r a d a p tatio n o f this b a rre l drive. In this case green san d co res are being m ade o n a m ass p ro d u c tio n basis; this o p e ratio n is as follow s:— G re en sand is fed fro m a h o p p e r by a m ech an ical feed, so th a t it flows a t a n even ra te on to a clay w ash w etted ro ta ry b arrel. T h e sand is co m p ressed a n d p a re d to the c o rrect diam eter by m eans o f a m ech an ical re cip ro c a tin g strickle, th e o v er
flow sand being collected u n d e r the m achine an d re tu rn ed in to the system.
P e rh a p s the m o st striking e x am p le o f the a d a p tatio n o f tu rn in g m eth o d s to core m a n u fa ctu re is show n on Fig. 17, w hich show s a m ach in e fo r screw c u tting b ak ed oil sand cores. T h e m achine is re ally an
F i g . 16.—G r e e n S a n d B a r r e l M a c h i n e . T h is is used p a rticu la rly in c o n ju n c tio n w ith the jigging of co res as p ra ctis ed b y th e m otor-vehicle in d u stry ,5 the w hole co re assem b ly bein g b u ilt up m a jig an d lo w ered en blo c in to the m o u ld . T h e jig locates w ith the b o x pins. A fte r th e c o re assem bly has been secured th e jig c an be co lla p sed a n d w ith
d raw n. T h is system c an be e x p lo ited in m o st fou n d ries in a sm all w ay, using plyw o o d jigs in the sim plest fo rm fo r all co re lo catio n s, w ith c o rre sp o n d in g benefit to the finished casting.
T h e tw o m ain c o n clu sio n s to be draw n fro m this P a p e r are, first, th a t the m an y bench tools, m ach in es an d o th e r devices, to g eth e r w ith b e tte r h an d lin g an d tra n s p o rta tio n , a re b o u n d to p ro d u ce, n o t o n ly a c h eap er, b u t m o re ac c u rate a n d b e tte r finished c o re A p a rt fro m red u cin g fo u n d ry w astage, th e benefit has to be passed on a n d ex p lo ited by the m achine shop p articu la rly as fa r as casting w o rk in g lim its are co n cerned.
R E C IP R O C A T IN G S T R I C K L E
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L 65
T h e first q u estio n th a t will be asked is to w hat lim its can castings be expected to be m ade by m odern m ethods fo r a specified purpose. T h e follow ing m ay be taken as a p resen t day guide fo r com m ercial casting tolerances:—
Barrel hole d iam eters up to 2 in. ... ± 0.005 B arrel ho le d iam eters 2 in. to 6 in. ... + 0.01 M ain dim ensions in 6-in. cube ...+ 0.015 M ain dim ensions in 12-in. c u b e ... + 0.025 M ain dim ensions in 36-in. c u b e ... + 0 .1 T he above sh o u ld be easily m aintained, b u t a fu rth er fa cto r sh o u ld be considered. M o d ern p ro duction m ethods d em an d extensive jigging, Fig. 19 shows w h at often ap p ears to the laym an "to be the hall m ark o f jig w ork, this fa u lt being ap p are n t on com pleted c o m p o n en ts su pplied by som e o f the m ost reputable m an u fa ctu re rs. N o m atter how often corrections tak e place, this fa u lt insidiously creeps
back, and, as f a r as cast co m p o n en ts a re concerned, it can be m inim ised, if n o t elim inated, by close co-operation betw een plan n in g of the m oulding m ethods a n d jig designing, the two being inter-related.
T his illu stra tio n also show s a typical g earb o x m ould set up, the co m p o n en t being subsequently jigged for m achining. T h e setting up o f the m ould, o r the jig settings, sh o u ld be fro m the sam e points. In the case of this illu stra tio n re fra c to ry blocks in the fo rm of firebricks are placed in the m ould, c o rresponding with the fu tu re setting po in ts fo r the jig.
N ow it will be n o ted th a t any v ariatio n th a t can accrue in the casting size is in m ost cases plus, and in no case can a to ta l negative e rro r occur. 'I he p attern fo r this co m p o n e n t should be m ade to a co n traction rule, w hich will p ro d u ce a casting to the engineer’s negative tolerance.
A casting alw ays tends to grow , and, as seen from the illu stratio n , this g row th is cum ulative. T h is grow th can occur in o th er directions an d by ad d itio n al causes to those show n in the illu stratio n , nam ely, p attern rap, casting pressure, sand sagging at join ts, etc., but any fa cto r th a t produces a v a ria tio n o th er th a n “ plus ” is m ost exceptional. It is a co m m o n fallacy to think th at the ex tern al red u ctio n of the p atte rn to m ake it fit the jig will rectify these location troubles.
T h e exam ple o f co -o p eratio n o utlined above w ould en ab le th e jig to take a casting 0.02 in. o ver the
fo u n d ry m inim um casting size, w hile the engineer still m ain tain ed his + 0.01 tolerance. E x p laining this in sim ple language, the engineer’s discrepancies are above and below a lim it, w hile the fo u n d ry m an ’s d iscrepan
cies are all above a lim it.
In a sim ilar m anner, w hen two com ponents are m achined fo r jo in in g together, the jig setting should alw ays be such th at the foundry cum ulative erro rs on each co m p o n en t ru n to g eth er an d n o t in opposition.
A nother source of friction betw een the m achine shop an d foundry w hich can be elim inated by co lla
b o ratio n is occasioned by m isalignm ent of core holes in m ultiple w alled com ponents th a t are to be jig bored. Fig. 20 shows the m achine shop set-up for one of these units; the boring b ars m ust pass freely th ro u g h the casting a n d th e extra tim e tak en to bore one hole separately w ould justify the scrapping o f the casting. In the case of this set-up, a time- saving fa cto r on the com ponents of 10 to 1 is shown.
Fi g. 1 8 .— A Mi l w a u k e e Gr i n d e r.
Fig. 21 show s how th ro u g h incorrect coring m ethods there can be a chance that, owing to m isalignm ent of core holes, th e b oring b ar can n o t be threaded th ro u g h the holes, and in som e cases, even w hen the unit can be used, inaccuracies occur in the finish caused by u n e q u al m achining in the bores.
U n d e rn ea th is show n that, by elim inating individual cores and using b a rre l cores, doubly checked by jig cores on e ac h side, and low ering th e w hole core assem bly into the m o u ld a t once, w ill ren d er the foregoing com plaints im possible. T he second co n clusion is th at th e lim its previously enum erated, finish, an d co n fo rm ity w ith th e subsequent processes will becom e m ore exacting as p ro d u c tio n m ethods develop, p articu larly as im proved core-m aking m ethods becom e universal.
M en tio n w as m ade earlier in the P ap er of the m achine grinding of cylindrical cores and m achine grinding o f core faces. T his developm ent m ay well
66 FO U N D RY TRADE JO U R N A L M A Y 25, 1944
M e c h a n ic a l Aids to Core Production
extend an d fo r certain exacting w o rk the core will be com pletely g round to precision lim its befo re being used. Indeed, ju st before the p re sen t w ar, the w riter was privileged to exam ine som e grey-iron castings fo r precision m ach in es supplied into this c o u n try fro m the C o n tin en t, and was convinced th a t only by the above m ethods could these castings have been p ro d u ced to such a degree o f accuracy.
T h e supplies of fo u n d ry accessories an d eq u ip m en t will have to keep pace w ith these ad v an cem en ts, c h a p lets will have to be .m o re accu rate to dim ension;
plates, coreboxes an d p attern s will have to be right a n d k ep t rig h t by co n stan t inspection. T his inspec-
M r . B l a k i s t o n said th a t in case “ A ’ t h e design o f the c o m p o n e n t w as such th a t the casting w ould m ake its ow n core an d strip itself, a n d lend itself to p late m oulding. T h ere w ou ld be no cores u tilised at all. In the case o f “ B,” th e in te rn a l flange w as such th at it co u ld be m ade by utilising loose pieces. T his case depicted co u ld be d e b ata b le , as, sh o u ld a large n u m b er be re q u ire d w hich d e m an d ed a m oulding m achine set-up, th e tim e saved by this set-up m ight outw eigh the in creased cost in cu rre d if a core was used. E x am p le “ A ” in d icate d “ C o reitis. ’
Mr. S i m p s o n said he w as im pressed by the lec
tu re r’s re m ark s on the m ech an ical aids to corem aking.
It w as show n o n Fig. 14 th a t th ere w ere 32 co re
m akers, six inspectors an d eight la b o u re rs h an d lin g 15 to n s per 8 hrs. T h is did n o t a p p e a r econom ical
A
F i g . 19.—C u m u l a t i v e M o u l d i n g a n d
C o r e E r r o r s . Fi g. 2 0 . — Ji g Bo r i n g Se t- Up.
Fi g. 2 1 . — Co r e Po s i t i o n De f e c t s.
lion sh o u ld also ap p ly to m echanical equipm ent, and, lastly, the fo u n d ry supervision should see th at all m ech an ical equipm ent is alw ays exploited to the full extent.
D ISC U SSIO N
Mr.' S. H. R u s s e l l (Past-Presidem t), a fte r c o n g ra tu lating M r. B lakiston on the excellent P aper, said that, ow ing to v arious facto rs, it w as becom ing essential to use su ch ap p ara tu s as h ad been illustrated. In co n n ectio n w ith Fig. 2, w hich show ed two covers, the one on the left w as lab elled “ w rong ” an d the one on the rig h t was labelled “ co rrec t he u n d ersto o d th a t M r. B lakiston w ithdrew the la tte r d escription and stated th a t b o th indicated a w ro n g m eth o d of p ro ductio n . W ould he please indicate w hy he w as of this op in io n ?
fro m the m ech an ical point o f view. W as th is fo r a light fo u n d ry ?
M r . B l a k i s t o n rep lied th a t th is p a rtic u la r illus
tratio n show ed the la y o u t fo r the p ro d u c tio n o f sm all intricate cores used fo r light electrical w o rk o r small valve w ork. T h is re p re se n te d a c o n tin u o u s o u tp u t of 2.2 lbs. o f core per c o rem ak e r every m in u te, which, to the A u th o r, a p p ea red to be q u ite a high ra te of p ro d u c tio n fo r fem ale la b o u r o n in tricate cores.
Core Plates
M r . M e a s u r e s said he w as in terested in the use o f cast-iro n core plates ag ain st steel plates. In a steel plate m uch w eight w as elim in ated . T h e y w ere, how ever, inclined to w arp slightly, b u t th a t co u ld read ily be overcom e by flattening th em o u t again on a surface p late. Steel core plate cam e b e f o r e ^ g
M A Y 25, 1944 FO U N D RY TRADE JO U R N A L 67
cast-iro n plate fq r av era g e w ork, a n d a t his w orks h u n d red s w ere used. M r. B lak isto n re ferred to lim its o f 2 | th o u san d th s. P erso n al experience o f ex tru d ed cores w as th a t long lengths could be o b tain e d to very
■ close lim its of accu racy . F o r the th rea d grinding m achine, w h at so rt o f a w heel did M r. B lakiston sug
gest, a s he h a d n ev er fo u n d one to stand up to the co n ditions? T h ey all w ore o u t extrem ely quickly.
M r. Bl a k is t o n said it was essential th a t the stone used on th e th rea d grinding m ac h in e should be ru n a t a very h ig h speed, an d the abrasive w hich w as chosen fo r this w o rk (som etim es garnet) w as generally of a g rit a n d grade to suit the p a rticu la r sand and core b in d er used. T h e A m ericans h ad developed an excellent ab rasiv e fo r this purpose and, w hen the grinding wheels lo st th eir shape, they w ere re -c u t with a diam ond.
T he ex tru sio n m ach in e w as a very com m on m eth o d of p ro ducing cy lin d rical cores. U n fo rtu n a te ly , in the case o f certain classes of w ork, the type o f sand re
q u ired fo r the satisfacto ry o p e ra tio n o f the m achine was n o t suitable as re g ard s sub seq u en t casting p ro perties. H e h a d experienced a n d talk ed to m any people w ho h a d sim ila r tro u b le as reg ard s bulging.
He agreed th a t the average ex tru sio n m achine could produce a core to 2 \ to 5 th o u sa n d th s lim its, b ut custom ers w ere now asking in som e cases fo r a g reater degree of accu racy .
T h e m ere fa ct th a t M r. M easures stated th a t a steel plate co u ld be straig h ten ed in d icated th a t h e h ad ex
perienced tro u b le w ith core plates bending. H e, p e r
sonally, h a d fo u n d th a t cast-iro n core plates, if su it
ably designed, co u ld be m ad e very light, an d , utilis
ing som e o f the han d lin g devices as described in the P aper, w ere very ra re ly b ro k en . T he th erm al c o n tractio n of cast iro n w as m u ch less th an steel, and this w as a lso a c o n trib u to ry fa c to r to m ore a ccu rate cores.
Mr. P. A . Ru s s e l l, refe rrin g to tolerances, said he did n ot think fo u n d ry m en w ou ld accep t M r. B lak isto n ’s statem ent th a t all fo u n d ry e rro rs w ere plu s an d n o t m inus. F ro m the m o ulding p o in t o f view, he w ould agree th a t m ost of the m o u ld in g erro rs w ere plus errors, a lth o u g h th ere were, o f course, a few m o u ld ing erro rs w hich w ere m inus errors. Som e co n tractio n erro rs w ere m inus erro rs. T h ere w ere also m inus e rro rs due to sand sw elling u n d e r the h e a t o f the m etal and sand sw elling w here ru n n e rs o r risers w ere cut in to th e m ould.
T h e Au t h o r agreed th a t there w ere exceptions to every ru le, an d a m inus e rro r m ight creep in, b u t generally there w ere so m an y possibilities o f plus erro rs th a t the m inus e rro rs w ere generally sw am ped, and, w hen this m inus e rro r did occur, it w as so c o n spicuous as alw ays to call fo r com m ent. F u rth e r, plus e rro rs co u ld creep in o n acco u n t o f w ood p a tte rn ex pansion caused by m o istu re ab so rp tio n .
Pneum atic Clamp
M r. F. Du n l e a v y said M r. B lakiston was certainly doing a good jo b of w ork, a n d to very fine lim its, b ut he h o p e d th a t it w as u n d ersto o d th a t the larg e q u a n tities o f castings th a t w ere re q u ire d m ade this expense
possible. T h e p n eu m atic clam p did n o t m ake any p erso n al ap p eal, an d h e co u ld n o t see an y value in a m achine o f this ch aracter. T h e disadvantages o f this m achine a p p ea re d to outw eigh the advantages and m ade a g reat deal o f tro u b le and d isto rtio n o f cores w hen using w ooden coreboxes. H e ho p ed th a t w hen fo u n d ry m en asked fo r new m achines, w h eth er it be fo r cores o r m oulds, th at they did so fully realising the re tu rn expected fro m them . O ne m u st n o t sug
gest buying m achines fo r the sake o f the m achine.
C o re disto rtio n could be caused by v ario u s m eans, and if the core-sand m ixture was u n suitable or any m ishandling of the core in the green state to o k place, all the m echanical m ethods o f core m an u fa ctu re broke down.
Mr. Bl a k is t o n said the p o in t was th at the m ethods described in this P ap er h a d got to b e used fo r fo b bing w ork as well as fo r re p etitio n w ork if the fo u n d ry was going to keep u p w ith fu tu re requirem ents. As regards to p neum atic clam ps, this w as a standardised m achine an d the p re ssu re »could be adjusted so th a t the co reb o x w as n o t dam aged by excessive load.
Mr. I. Bu t c h e r said he prefe rred the cast-iron p lates to steel fo r accuracy of pro d u ctio n , b u t his fo u n d ry utilised steel plates. T h e ones illustrated in the P a p e r w ere used on a conveyor system an d , th ere
fore, w ere n o t su b ject to the ro u g h usage of a general fo u n d ry . H e considered th at M r. B lakiston’s P a p e r was m o re a p p licab le to m ass p ro d u ctio n th an jobbing.
Mr. Bl a k is t o n said th at w henever cast-iron core plates w ere b ro k en on th e system described, it was generally fo u n d th a t this to o k place w hen they h ad been tran sferre d to the m ain foundry. T h e lay o u t show n in Fig. 14 h a d w orked fo r several years satis
factorily o n jo b b in g w ork, an d the w hole p o in t of this P aper, as previously stressed, w as to indicate the pos
sibilities of these m echanical facilities in jobbing fou n d ries afte r being m ainly used in the p ast in mass- p ro d u ctio n foundries.
V ote of Thanks
Mr. H . Be c k p ro p o sed a vo te of thanks to the A u th o r. A fte r Mr. G . L. Ha r b a c hh a d seconded, Mr. Bl a k is t o n said th at, w hen w riting this P aper, it re q uired a great effo rt n o t to dw ell too m uch on the m an y m ech an ical aids to corem aking, b u t to try and b ring fo rw a rd to the m em bers the necessity of lo o k ing in to th e fu tu re to see w h at the trend of the fo u n d ry industry w as likely to be, so th a t the p rin cipals engaged in iro n fo u n d in g co u ld m ake som e a tte m p t to p la n fo r th e future.
T h ere h a d b een recen tly m any discussions ab o u t this m atter; som e said th a t th ere w as no fu tu re for th e fo u n d ry , a n d o th ers said th a t th e fo u n d ry h a d an ex panding fu tu re. T h e answ er w as entirely in the foundry m an ’s ow n hands, and by doing everything possible in the w ay of im provem ents and m aking them selves ad ap tab le , th ey should be in a strong p osition to cope w ith an y eventuality.
R E F E R E N C E
* G W B r o w n , M .I.M ech.E .,“ Some general remarks on Mechanical Foundries and th e m aking o f Motor Cylinders,” Proceedings of the Institute of Brit ish Fo undrym en, v o l. 28.
