How do you drill digital caliper jaws?

[compressor man]

Is there an easy way to drill holes in the the jaws of cheap-o digital calipers? I have mounted a set or 2 to my machines to make a poor mans DRO and have had good results from them. But the last set I used seemed to be as hard as glass. I ended up heating up one of the jaws in order to draw down the temper but it had the unfortunate result of burning up an inch or so of the readout strip. Astonishingly it still works. Still though, the jaw remained so hard that I burnt up a couple of bits trying to get through it.

Is there some type of drill bit that will go through one of these things better than HSS or cobalt?

Chris

 

[mklotz]

Try a carbide drill. It may help to spot anneal first using a steel rod in the drill press.

 

[moanaman]

A stellite drill will do it I am sure, seeing that our demonstrations with these drill was to drill holes in files. These are a cobalt drill and the secret is high pressure when drilling as the extreme heat generated will soften locally the item you are drilling. Must be used in a drill press and you really have to hang on the drill press handle. Will not work with a hand held drill.

Barry G

 

[imagineering]

I concur with Moanaman, Cobalt DrillBit with high pressure and LOTS of Lubricant.
In the past, I have created a little Dam with BlueTack or Plastercine around the Hole and filled it with Rocol RTD.
This technique keeps the DrillBit lubricated and a lot cooler.

Murray.

 

[Ken I]

All the above.

You can use an el-cheapo carbide tipped masonry bit - if you resharpen it to a normal metal cutting drill point. Don't allow it to get hot enough to melt the brazing.

Ken

 

[T70MkIII]

An alternative, if you have room, would be to make up small aluminium clamps to fit the caliper jaws and bolt to your machines. I'm thinking of going this way on my lathe.

 

[crankshafter]

All the above.

You can use an el-cheapo carbide tipped masonry bit - if you resharpen it to a normal metal cutting drill point. Don't allow it to get hot enough to melt the brazing.

Ken

Hi Chris.
I second Ken's way to do it.
Have done it many times, just remember plenty of cooling/cuttingoil.

CS

 

[DICKEYBIRD]

I used a 2 flute solid carbide 1/8" router bit in the mill at its highest speed (only 2000 rpm on my X3) using regular cutting oil, frequent pecking and it cut right through.

This was on a HF cheap chinese 6" digital caliper but it was pretty hard stuff. The router bit was the only small carbide bit I had and thought what the heck, let's try it and see what happens. It worked great!

 

[compressor man]

Thanks for the great ideas guys. I found a couple of 3/32 carbide drill bits today that I did not know I had. The next time I need to drill one of these things I am gonna try one out.

Loved the cabide masonry bit idea though, I would never have thought of that one.

Chris

 

[firebird]

Hi Chris

They are hard to drill aren't they.

when I fitted one to the tail stock on my lathe I went the way of clamps. Easy to fit and remove.

You can see it here

http://www.homemodelenginemachinist.com/index.php?topic=3730.0

Cheers

Rich

 

[bentprop]

I simply used a dremel cut-off wheel to remove the pointy bits from the jaws.
I then made up a clamping holder from some type of synthetic plastic.This has been on my milldrill for several years now,and apart from cleaning,has worked flawlessly.I too tried to drill the scale first,but gave up after 2 HSS drill bits.
The bit of the scale i burned was also removed with the dremel wheel.

 

[tel]

Ditto with the Dremel cut-off discs, but I drilled mine with a 3mm carbide drill no trouble.

 

[compressor man]

I have also used dremel cut-off discs to cut a slot in the jaw of a caliper. I then put my mounting screw through the slot.

Chris

 

[mklotz]

Harbor Freight, among others, sells sets of carbide spade drills for drilling tile and glass. I've never tried them but they're cheap enough to warrant a bit of experimentation.