Drilling a hole in calipers.

[JimSchroeder]

I have read several recent posts asking about drilling holes in harden steel calipers. The hardened stainless used in these calipers is indeed tough material but it is no match for carbide drills.
















































Photo 1 - a hole I drilled in a 4" caliper used on my tailstock.

There are two choices. You can buy a solid carbide Atrax drill for a little over eleven dollars plus shipping. The other choice is go to your local Home Depot and buy a carbide tipped drill sold for masonry use, price a little over four dollars. The masonry drill will not have the sharp edge that the Atrax has but if you have access to a diamond wheel you can improve the edge on the masonry drill very easily. The drill will easily make a hole in your caliper as is but the sharper edge gives a cleaner hole and requires less pressure.
















































Photo 2 - a masonry drill with an improved edge.


I keep a 1/8” and 3/16” drill close at hand for just these type jobs.

[FONT=&amp]Jim[/FONT]

 

[Ed Hoc]

Nice idea Jim. I also like the clamp on the barrel of your tailstock. Do you have a photo of the mounting on top of the tailstock? Looks like a great setup:thumbsup:

Thanks for the ideas.
Ed Hoc

 

[JimSchroeder]

Hi Ed, you can see from the following photo that the holder for the slider part of the caliper is a thin piece of aluminum sheet that is attached with two screw on the far side of the housing.






































Photo #1 - 4" caliper mounted on tailstock.

I find this a most useful modification to my lathe and certainly worth the ten bucks it cost. I used a Dremel tool with a cutoff wheel to remove the jaws of the caliper.

Jim

 

[vt-biketim]

This is just brilliant. Thanks for the advice on sharpening cheap masonry bits... I wrecked a HSS drill trying to put two holes in some stainless last year.

Tim

 

[kd4gij]

As a side note the Drills sold by tapcon for there screws are a higher quality than standerd bits for not much more money. I use them all the time.

 

[Tony Wells]

If you use the masonry bits, keep them cool. Unlike solid carbide, the carbide is brazed or silver-soldered in place and if it gets overheated it will fall off, possibly getting stick in the hole. Bad news.

 

[Jimbo]

I'll second that Tony. Drilled two holes through a caliper, first one was great but I was in a hurry for the second and the carbide came off just after the tip had broke through. Then I had to finish it with a diamond tool in a dremel.

What is your mounting scheme for the read out on the tail stock?