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1935Hillman
Joined: 06 Apr 2010 Posts: 257 Location: Hampshire
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Posted: Tue Aug 11, 2015 12:59 pm Post subject: Metal grades types for turning |
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Hello all,
I am beginning to get to grips with my lathe now and have successfully cut a few screw threads and made some other round things. However, I am clueless as to metals, particularly steels for certain jobs. As an example I would like to try to make some new tappets/cam followers as they are fairly simple in design and hard to get but have no idea what I should be making them from. If anyone can give me a crash course in such matters I would really appreciate it. I look forward to hearing from anyone who can help.
Tim Green |
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peter scott
Joined: 18 Dec 2007 Posts: 7118 Location: Edinburgh
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Posted: Tue Aug 11, 2015 2:05 pm Post subject: |
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Hi Tim,
I think you could make them out of mild steel but you would need to case harden them on the cam following faces.
Peter _________________ http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon |
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1935Hillman
Joined: 06 Apr 2010 Posts: 257 Location: Hampshire
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Posted: Tue Aug 11, 2015 2:37 pm Post subject: |
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Hi Peter,
Yes, you are probably correct in that. That then leads me to ask the question: what is the best method for case hardening? Presumably a pre-prepared hardening compound.
It will be interesting to see if anyone else has an opinion too
Thanks,
Tim |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Tue Aug 11, 2015 4:11 pm Post subject: |
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You may want to consider silver steel for the tappets, its easier to harden than using a case hardening mixture.
Dave |
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goneps
Joined: 18 Jun 2013 Posts: 601 Location: Auckland, New Zealand
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Posted: Tue Aug 11, 2015 11:11 pm Post subject: |
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I've just checked with my retired Air Force engineer pal, who made oversized tappets for my 'new' engine in 2008. He used EN36, a special case hardening steel (high nickel content), and they were hardened by a commercial outfit. He's adamant that neither mild steel nor silver steel are suitable for case hardening.
If you want to read up on the subject, Google "case hardening EN36".
Richard |
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peter scott
Joined: 18 Dec 2007 Posts: 7118 Location: Edinburgh
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1935Hillman
Joined: 06 Apr 2010 Posts: 257 Location: Hampshire
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Posted: Wed Aug 12, 2015 10:08 am Post subject: |
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Very helpful everyone. I will indeed read the text suggested and see where that takes me too. Clearly there is so much more to the subject than at first meets the eye as is usually the case. thanks all. |
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PAUL BEAUMONT
Joined: 27 Nov 2007 Posts: 1281 Location: Barnsley S. Yorks
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Posted: Wed Aug 12, 2015 12:59 pm Post subject: |
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Almost every company that I have worked for have used Wallwork for heat treatment of steel parts. I suggest that you talk to one of their technical folk. Check here for some basic information http://www.wallworkht.co.uk/content/harden_and_temper/?bk |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Wed Aug 12, 2015 5:49 pm Post subject: |
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goneps wrote: | I've just checked with my retired Air Force engineer pal, who made oversized tappets for my 'new' engine in 2008. He used EN36, a special case hardening steel (high nickel content), and they were hardened by a commercial outfit. He's adamant that neither mild steel nor silver steel are suitable for case hardening.
If you want to read up on the subject, Google "case hardening EN36".
Richard |
I know where he is coming from, and its probably the correct exam answer , I use silver steel to make odd sized taps & dies, (its called drill rod in the US because thats whats its used for) its used on a small scale because its easy to turn on a lathe, and less tricky than mild steel to harden. It wouldnt be a first choice material for tappets, but with classics doing a low millage its not so important.
My attempts at case hardening mild steel were......well pathetic, in a DIY enviroment ts just not possible to get/ control the correct temperatures
Cheers
Dave |
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V8 Nutter
Joined: 27 Aug 2012 Posts: 587
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Posted: Wed Aug 12, 2015 8:07 pm Post subject: |
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En24t is easy to harden,but it is very hard, en8 can also be hardened. Some of the old case hardening compounds contained cyanide and they are only available commercially. I don't know if there is a replacement for private use |
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