Tool Setter Materials

I've decided I need to make some electrical tool height setters for my machines with a fairly small foot print. I've figure out my design so they
will have a lot of over travel and good repeatability, but I am wondering about the anvil or touch surface. The analog indicator type I am using now seem to have a steel surface, but they are softer than the tools and they will ding fairly easily if you make a mistake. Because I do a lot of flood machining I was thinking stainless might be the ticket. 304 for the body, and 303 or 416L for the anvil with an acetal insulator. A harder machineable insulator might be better, but I am not sure what.
Definitely NOT something like HDPE since its compressible, and spring pressure over time might cause it to extrude and lose positional accuracy. I don't really have room for an off material setter to to be used all the time. Adding soft buttons and macros to semi automate the tool height set is pretty easy for my controls. It would improve my machine times, and reduce my necessity to deburr between tool changes more easily creating consistent parts.
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On Thursday, November 16, 2017 at 10:50:08 AM UTC-8, Bob La Londe wrote:

Glass is dimensionally stable; the dense fiberglass/epoxy plastics would be good, as well. Available in sheet or tube forms.
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wrote:

See if you can get a small piece of Macor, a machineable glass ceramic. I've machined it on my South Bend lathe, so there's nothing tricky about it.
If you turn it, just cover the bedways with some aluminum foil or oiled paper.
--
Ed Huntress

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"Ed Huntress" wrote in message wrote:

See if you can get a small piece of Macor, a machineable glass ceramic. I've machined it on my South Bend lathe, so there's nothing tricky about it.
If you turn it, just cover the bedways with some aluminum foil or oiled paper.
******************
You are the third person to suggest machinable ceramic, and the second to suggest Macor specifically. McMaster stocks it. I am leaning more and more towards trying it. I'm just concerned about how it will react to the spring loaded anvil returning to position when a mill retracts. I guess one way is to try it and find out.
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wrote:

Yeah, I think you'd just have to try it. It's not really tough, but it's not particularly brittle, either. I have a demo piece that the Corning people machined for me at an IMTS, probably 1980. I've whacked it and given it some rough treatment over the years. It's still intact.
It was the first of those machineable ceramics, but I think there are others out there now. Check them out.
--
Ed Huntress

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"Ed Huntress" wrote in message

Yeah, I think you'd just have to try it. It's not really tough, but it's not particularly brittle, either. I have a demo piece that the Corning people machined for me at an IMTS, probably 1980. I've whacked it and given it some rough treatment over the years. It's still intact.
It was the first of those machineable ceramics, but I think there are others out there now. Check them out.
*******************
Wow! The stuff sure is expensive.
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On Thursday, November 16, 2017 at 4:39:48 PM UTC-8, Bob La Londe wrote:

Yeah; soapstone, slate, pyrophyllite, and other natural products are also machinable, and cheap as rocks.
I'd go with glass, even if I had to visit the crafts store and buy a sixpack of round mirrors and desilver 'em in lye. Or take a diamond blade to a Tabasco bottle.
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"whit3rd" wrote in message
On Thursday, November 16, 2017 at 4:39:48 PM UTC-8, Bob La Londe wrote:

Yeah; soapstone, slate, pyrophyllite, and other natural products are also machinable, and cheap as rocks.
I'd go with glass, even if I had to visit the crafts store and buy a sixpack of round mirrors and desilver 'em in lye. Or take a diamond blade to a Tabasco bottle.
**********
Part of the concept is to be able to make the parts uniform thickness. Even the insulating sleeve. I'm going to give phenolic a try. The stuff is pretty stable, and I use it already for other things like handles on lead casting molds.
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On Thursday, November 16, 2017 at 6:39:00 PM UTC-8, Bob La Londe wrote:

One more option: Ceramic standoffs (like <https://www.mcmaster.com/#94335a151> ) come with threaded holes, if you want something quick.
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On Nov 16, 2017, whit3rd wrote

I bet what?s usually used is glass-epoxy sheet, which one can get from McMaster. If one makes a blank-headed bolt from A2 steel, hardens it, polishes the top flat with diamond film on a sheet of glass, and assembles it with glass-epoxy washers to a ordinary steel body, this ought to make a fine tool setter that?s very durable when touched by cutting tools.
The classic alternative is mica sheet instead of glass-epoxy. This is the most stable material available. The washers are widely used for insulating power transistors from heatsinks. Sheets are available from McMaster. Muscovite type is probably what you want. Washers are available from electronics supply houses like Newark.
Joe Gwinn
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