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Need to drill a hole digital caliper

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Blue Heeler07/06/2019 13:11:58
189 forum posts

G'day all,

I need to drill a small hole in a Chinese stainless steel digital caliper.

Whatever its made of is super hard and a drill will hardly scratch it let alone drill a hole.

Any ideas on how to do it?



AJW07/06/2019 13:18:10
277 forum posts
117 photos

I've encountered similar material although not a caliper and managed to drill through with a masonry drill.


John Haine07/06/2019 13:23:45
2781 forum posts
140 photos

Look for cobalt drills. I bought this set from Toolstation and they are excellent - went straight through my Dickson toolholder block. Use moderate speed, quite a lot of pressure, lubricate.

SillyOldDuffer07/06/2019 13:39:35
5006 forum posts
1061 photos

Stainless I hate it. Some varieties work-harden if you breath on it.

Now you've tried and failed thus creating a hard spot, an extra hard drill as advised above will be essential, and even they might struggle.

Otherwise, if you can start again where the stainless is still virgin, an ordinary sharp drill has a good chance provided you attack vigorously from the get go with lots of pressure and some cutting fluid. If you can keep the drill cutting all will be well, but any hesitation or insufficient pressure, and the tool rubs, hardens the steel, which promptly blunts the drill. Work-hardened stainless is harder than most materials, which is why they make knives and scalpels out of it.

You stand a better chance with a pricey drill in the first place.

Some stainless steels machine well, they're not all evil.


Brian Oldford07/06/2019 13:41:18
596 forum posts
4 photos
Posted by SillyOldDuffer on 07/06/2019 13:39:35:

. . . . . . . .

Some stainless steels machine well, they're not all evil.


The swarf usually is!

John Paton 107/06/2019 13:42:29
189 forum posts
6 photos

I faced similar problems and used the Frei toolbit which looks much like a masonry bit. I imagine a carbide drill with flooded coolant is best bet for small holes but I always seem to end up breaking those drills.

Ian P07/06/2019 14:24:08
2280 forum posts
93 photos

Whilst the Chinese caliper steel is hard and is stainless it can definitely be drilled with HSS bits.

I have converted several (different makes) of calipers to simple DRO's using normal hacksaw blades and drill bits and not encountered any problems. The important thing is to have a rigid setup so you can apply lots of pressure to the drill and keep it cutting. It will work harden if the drill spins, so best to run at a low (lowest) speed so you can see what's happening and have some feel.

If you get part way through and it work hardens I find the best way to overcome it, is to change drills (or slightly regrind the same one) so that the very slightly different cutting edge profile cuts in a slightly different position. Most holes I have drilled were 3mm and 4mm, smaller is possible but its harder to put a lot of pressure on say a 2mm bit.

Drills, hacksaws and files do cut this stuff as long as long as pressure is applied and not allowed to skid.

Ian P


Edited By Ian P on 07/06/2019 14:24:27

John Haine07/06/2019 14:27:42
2781 forum posts
140 photos


Sorry, I forgot the link.

Stuart Smith 507/06/2019 15:10:03
54 forum posts
10 photos

I had the same problem. I used a tungsten carbide drill bit from this range: - **LINK**

I tried a masonry drill and it did sort of work but not as well as the tungsten carbide bit.


old mart07/06/2019 15:51:57
975 forum posts
104 photos

The best way short of investing in solid carbide drills is to get a set of Bosch multiconstruction drills from Screwfix (95958). I keep a set for drilling hard steel, rather than masonry, their sharp tips are not brittle like solids and they are much cheaper.

mechman4807/06/2019 15:58:16
2531 forum posts
379 photos

Masonry drills do work but you've got to alter the cutting edge; more akin to the 118* of a ordinary drill, I have used these to drill same Chinese S/S callipers for dro's, & glass mirrors, only with the glass drilling I built up a small ' bund wall' filled with WD40 & on slow rpm.


mechman4807/06/2019 15:59:19
2531 forum posts
379 photos
Posted by mechman48 on 07/06/2019 15:58:16:

Masonry drills do work but you've got to alter the cutting edge; more akin to the 118* of a ordinary drill, I have used these to drill same Chinese S/S callipers for dro's, & glass mirrors, only with the glass drilling I built up a small ' bund wall' filled with WD40 & on slow rpm.


No doubt carbide will work just as well.

Rik Shaw07/06/2019 17:06:50
1313 forum posts
352 photos

Make a d-bit from stelllite. High speed, no coolant and lots of welly.


Richard Marks07/06/2019 17:47:46
184 forum posts
8 photos

Diamond burr in a dremel to start the hole then cobalt drill bit to size.

Neil Lickfold07/06/2019 20:48:34
579 forum posts
102 photos

If you get a chisel point tungsten carbide drill, run it at around 800 to 1000 rpm, take peck cuts and have compressed air or the vacuum cleaner hose close to the hole, will work just fine. When it breaks out the other side, is when you want to use the feed stop , and adjust it 0.1mm at a time or so, will give a clean exit hole as well. The stub carbide drills are not too badly priced if it is under 5mm diameter.

Chris Evans 607/06/2019 22:21:39
1526 forum posts

Not a problem when I modified a calliper to use as a tailstock readout. just used a 3 flute carbide slot drill.

XD 35108/06/2019 01:23:49
1384 forum posts
118 photos

Bunnings sell a carbide tipped drill set that will drill metal ,i bought a set out of curiosity and they were not expensive .

if you want to try again with a HSS drill slow speed , cutting fluid and lean on the drill a little so it doesn’t rub .

Blue Heeler09/06/2019 00:28:34
189 forum posts

Hi All,

Thanks for the replies, much appreciated.

Yes, I am making some 'poor man's DRO's for the lathe'.

I bought a set of carbide drills yesterday and they made short work of drilling through.

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