By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale July 23rd

Mallable Iron

All Topics | Latest Posts

Search for:  in Thread Title in  
John Purdy16/07/2019 17:45:57
avatar
169 forum posts
59 photos

I have a set of original Stuart Turner (not the current Stuart Models) castings for the reversing gear for the #1 engine. The eccentric rods are supplied as mallable iron castings and they are both warped to the extent that they won't clean up to the desired 5/32" thickness as required, as there is minimum machining allowance on them. My question for any one who has worked with mallable iron is, are they ductile enough to hammer strait or are they going to snap like normal cast iron would.

These two appear to be identical castings to the one I have just finished machining for my #1 (castings of the the same vintage). It was only slightly warped and machined beautifully, much like mild steel except that the chips came off as little chunks, much like cast iron or hard brass.dscn3207.jpgdscn3211.jpg

pgk pgk16/07/2019 17:53:16
1396 forum posts
278 photos

Not being knowledgeable on the subject I went and looked it up wikipedia

Apparently malleable cast iron requires annealing after casting and thereafter can be stamped, bent or striaghtened so I suppose that depends on whether what was sold as malleable cast iron did go through that process or can be annealed again to be sure?

JohnF16/07/2019 18:15:47
avatar
839 forum posts
95 photos

John, the clue is in the name "malleable " I believe you should be able to straighten the part sufficiently to machine it to size. If you have a muffle furnace to re-heat-treat the casting you could heat up and bend it straight then heat treat to restore the properties but I believe you can manage without this for such a small adjustment.

Have a look t this link -- very informative particularly look at "Malleable Cast Iron properties" about 1/2 way down **LINK**

John

John Purdy16/07/2019 19:02:56
avatar
169 forum posts
59 photos

John

Thanks for the link, it basically confirms what I thought I knew about mallable iron, and why it is more ductile than cast. I was thinking someone here might have had worked with forming mallable iron and could tell me their experience. I will try and straighten them and if not successful can always carve them out of solid!

John

Brian Oldford16/07/2019 19:03:58
avatar
533 forum posts
4 photos

Assuming they are what they claim to be, the clue is in the word "malleable". The swarf from malleable iron will usually appear somewhere between mild steel and regular grey iron.

John Purdy16/07/2019 19:37:54
avatar
169 forum posts
59 photos

Brian

As I said the when I machined the current one the swarf came off as small little cures more like hard brass and there was none of the black graphite dust you get from normal cast iron. The castings are listed on the Stuart parts list sheet as "mallable iron" as were the con rod, crankshaft, and the piston rod/cross head. The reverse gear parts list lists the eccentric rods, expansion link, drag link, connecting link and reversing lever all in "mallable iron".

John

John Purdy17/07/2019 18:47:57
avatar
169 forum posts
59 photos

Well I attempted to straighten them with a hammer on the anvil and it worked OK but it took a lot harder hits than I thought it would, they definitely weren't soft, the hammer left no marks on them.. They are not perfectly straight but close enough so that they will clean up. Just hope there are no unseen fatigue cracks that will cause them to break when it machine them.  Probably might have been better to put them in the kiln and heat them to red heat and then hammer them straight. Hindsight is great!

John

Edited By John Purdy on 17/07/2019 18:51:00

vintage engineer17/07/2019 21:08:31
avatar
141 forum posts

I would heat them up red hot and clamp to a large section of steel and allow to cool.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric July 5 2018
Warco
ChesterUK
Ausee.com.au
Advertise With Us
TRANSWAVE Converters
Meridienne Sept 2019
Eccentric Engineering
emcomachinetools
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest