About Lead?

[graham-xrf]

It's soft goopy stuff, but I see from YouTube videos it can be (carefully) machined.
Would the cutting tool for turning have the same conventional clearance and rake angles one would use for steel, or does it need something a bit different?

 

[GeneT45]

Most soft materials use lots of clearance front and side and little to no rake - that's where I'd start.

GsT

 

[francist]

And be very wary of how it will suck your tool into the work before you can realize what's going on. Do not get cocky with it -- behind it's softness is a devious material!

 

[graham-xrf]

Thanks guys. The plot behind it is because we are getting to that stage in the xrf material identification thread. There seems no choice but to use a lead part to mount the smoke detector elements.

 

[pontiac428]

I think it will machine well enough. I'm not sure if it would be best fast or slow, though. Probably self-lubricating... Don't eat the chips and keep your fingers out of your mouth while working. No dust to inhale, so I'm not worried about your health this time!

 

[Suzuki4evr]

Just my 2cents. I think when you talk rpm and feed rate,I would say maybe high speed and low feed. It's kind of trial and error I think.

 

[pontiac428]

I'm sure the answer is in the Machinery's Handbook. On one hand, we think of aluminum as kinda gummy and run it fast, but aluminum alloy with silicon is pretty hard compared to lead. Too fast might make a mess. I agree feeds should be slow. It might not be that far off from machining plastics. I want to see pics when the time comes, @graham-xrf!

 

[Suzuki4evr]

I want to see pics when the time comes, @graham-xrf!

So would I. Would be interesting to see how it plays out.

 

[Illinoyance]

I would expect holding the lead in a chuck or collet would be a bigger problem than the turning. Pressure of the jaws will deform the lead causing it to loosen in the chuck.

 

[graham-xrf]

I would expect holding the lead in a chuck or collet would be a bigger problem than the turning. Pressure of the jaws will deform the lead causing it to loosen in the chuck.

Yes - that is what happens. It is possible to let that happen initially while the support mandrel hole is drilled. Once it is an a more grip-able shaft, with a couple of pressure discs, one each end, then you turn away the chuck dents, and make the part in that setup - at least that is how the explanation went.

I have, of course, asked everybody I thought might have any idea, but it seems, as often happens, I am up to doing stuff nobody else knows about. The proof will be in the attempt. There may end up being more than one of those.