Cam material

[CorRadParticipant @corrad]

I will be machining 4 cams for a twin 31 cc – the Jerry Howell v twin. The plans calls for the use of drillrod ( silver steel). I find machning leaded steel an absolute pleasure due to the easiness and the quality finish that one obtains. Leaded steel is somewhat softer and its resistance to wear is lower. Does anyone have any experience in using leaded steel in place of drill rod for a cam? Seeing that it is a flat surface in contact with the cam follower, is the use of the softer leaded steel really going to have a detrimental impack?

[CorRadParticipant @corrad]

Is leaded steel suitable for a cam ?

[Ian ParkinParticipant @ianparkin39383]

Surely the plans call for the cams to be hardened

That's why the plans call for silver steel (drill rod)

You will be making them twice if you make out of leaded mild steel

[Clive FosterParticipant @clivefoster55965]

Leaded steel will be too soft. Cams and followers do need to be hard as loads are high even on the most modest of engines.

Alternative would be a case-hardening steel. But you need the case hardening compound. Or be prepared to mess around with the various DIY alternatives presented by folk mining old literature. Most of the old methods are such an utter faff to carry out that I find it hard to believe that anyone in the Western world has actually seriously used them in the last 30 or 40 years.

Clive

[Nick_GParticipant @nick_g]

.

I have always found silver steel to be reasonably nice stuff to machine with nice sharp cutters. Having used it a fair bit (including making a cam) it's certainly IMHO nothing to shy away from.

Having said that depending on the supplier some seems to be nicer than others. – Stuff from HPC gears is always nice.

Nick

[duncan webster 1Participant @duncanwebster1]

Just to clarify, leaded steel is not the best for case hardening. The purists would have it that you need EN32, but EN3 will case harden OK

[Martin KyteParticipant @martinkyte99762]

George Thomas suggested that anealing silver steel prior to machining helps. Clock makers use EN32 as and alternative to silver steel as Duncan suggests as it's nicer to machine and doesn't wear your expensive pinion cutters out as fast. Or again as suggested case harden and the compound is readily available despite what people say.

regards Martin

[MichaelRParticipant @michaelr]

I'm prepared to be shot down on this, but I used cast iron for the cams on my Centaur gas engine, the cam followers are stainless steel, after quite a bit of running they seem to be doing the job with no apparent wear. On my Wyvern gas engine I used mild steel case hardened with stainless steel followers, these also do the job Mike..

[JasonBModerator @jasonb]

The V-twin is supposed to be good for 6500+ rpm, bit more than a Centaur or Wyvern. Also without looking at the drawings I think the cams are a lot narrower.

Silver Steel is not too much trouble to mill, I've not had issues with it making cams.

EDIT, actually reasonably wide but drawing does call for them to be hardened as well as the Cam followers

Edited By JasonB on 27/09/2017 15:33:51

[CorRadParticipant @corrad]

Thank you for the good advice. Silver steel it will be.

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