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.

On Thursday, November 16, 2017 at 10:50:08 AM UTC-8, Bob La Londe wrote:
I've decided I need to make some electrical tool height setters for my
machines with a fairly small foot print.
... 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.

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

On Thu, 16 Nov 2017 11:50:03 -0700, "Bob La Londe"
wrote:

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.

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

"Ed Huntress" wrote in message
...

On Thu, 16 Nov 2017 11:50:03 -0700, "Bob La Londe"
wrote:

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.

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.

On Thu, 16 Nov 2017 15:59:07 -0700, "Bob La Londe"
wrote:

"Ed Huntress" wrote in message
.. .

On Thu, 16 Nov 2017 11:50:03 -0700, "Bob La Londe"
wrote:

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.

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.

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

"Ed Huntress" wrote in message
...

On Thu, 16 Nov 2017 15:59:07 -0700, "Bob La Londe"
wrote:

"Ed Huntress" wrote in message
.. .

On Thu, 16 Nov 2017 11:50:03 -0700, "Bob La Londe"
wrote:

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.

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.

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.

On Thursday, November 16, 2017 at 4:39:48 PM UTC-8, Bob La Londe wrote:
"Ed Huntress" wrote in message

See if you can get a small piece of Macor, a machineable glass
ceramic.

Wow! The stuff sure is expensive.

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.

"whit3rd" wrote in message
...

On Thursday, November 16, 2017 at 4:39:48 PM UTC-8, Bob La Londe wrote:
"Ed Huntress" wrote in message

See if you can get a small piece of Macor, a machineable glass
ceramic.

Wow! The stuff sure is expensive.

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.

On Thursday, November 16, 2017 at 6:39:00 PM UTC-8, Bob La Londe wrote:
"whit3rd" wrote in message
...

I'd go with glass

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.

One more option:
Ceramic standoffs (like https://www.mcmaster.com/#94335a151 ) come with
threaded holes, if you want something quick.

On Nov 16, 2017, whit3rd wrote
(in ):

On Thursday, November 16, 2017 at 4:39:48 PM UTC-8, Bob La Londe wrote:
"Ed Huntress" wrote in message

See if you can get a small piece of Macor, a machineable glass
ceramic.

Wow! The stuff sure is expensive.

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.

I bet whats 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 thats 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