Today, I made a set-up to grind the inside of the ER-40 Collet holder in the mill that it will run in.
That pretty much ensures accuracy I would think. The jig was an electric powered motor
set up with ways running at the required 8 degrees. Concentricity is pretty good now measuring
a thousandth or so. I also machined off the outside of the holder on the mill so if I need to put it in
the lathe again it will be fairly accurate. Also I ran the grinder over the outside surface along with some
emery cloth for a nice surface. So far I am pretty happy with the results. I made an 8 Degree angle plate with
my rotary table so that I could accurately mount the grinding wheel mounted on ways.
Here are several photos of the set-up if anyone else is contemplating making an ER-40 or other holder.
It was a lot of work to make the jig but it will come in handy for other projects so it wasn't time wasted.
Here are several photos of the jig and one of the inside of the ground ER-40 collet holder.
With this jig, I will be able to grind on any inside or outside surface with good accuracy at various angles so
I can see there will be other uses for this tool.
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