Drilling in hardened stainless steel

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gzoerner

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I'm modifying a Harbor Freight caliper to be used as a DRO on my lathe. A couple of 2 mm holes need to be drilled in it so it can be mounted to the cross-slide. The caliper is definitely hardened stainless. A TiN coated HSS drill doesn't do anything to it. What is the best way do drill small holes in this material? Will M35 Cobalt HSS work? Do I need carbide or diamond drills? Brittle carbide that small will probably be pretty tricky.

Thanks in advance for any help.

Glen
 
Try a carbide center drill if you have 1 and see if it will start. I find it hard to believe a HF caliper is hardened. I think you may be trying to drill thru chrome, which would make more sense. If that's the case, just grind off a spot and drill.
 
Try the cobalt but go as slow a speed as you have , but use a heavy feed . Seems I've read or done this before to a hardened steel . Keep it wet with cutting fluid . You might be able to shoot a hole with a plasma cutter . Quick trigger or a pulse .
 
ditto on above - carbide is likely required, but what if you changed the design to clamp the part you are trying to drill through? Making fidgety little clamps isn't fun, but mild steel or even aluminum would be OK.
 
I have drilled HF calipers with carbide drills. Drilling is best done on a mill where you can control the feed and hopefully have less runout. If using a drill press, use a light touch and watch the the chip formation. Those small carbide drills can break easily. Don't attempt drilling with a hand drill.
 
I'm using Guhring HSCO drill bits they are very special and i've use them on stainless steel weld without any problems, HSS is too soft for continues drilling stainless steel or harden stainless steel.
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Thanks for all the quick responses.

The jaws of the calipers and the main body are definitely hardened. Fortunately, the slider where the electronics mounts is relatively soft so my TiN HSS drills work just fine. I don't think my skills (or budget) are good enough for small solid carbide drills. I can break small HSS bits easily enough.

tcarrington's suggestion is where I'll go for mounting the body to the lathe. JB Weld to the rescue.

Thank you all again.

Glen
 
gzoerner said:
I'm modifying a Harbor Freight caliper to be used as a DRO on my lathe. A couple of 2 mm holes need to be drilled in it so it can be mounted to the cross-slide. The caliper is definitely hardened stainless. A TiN coated HSS drill doesn't do anything to it. What is the best way do drill small holes in this material? Will M35 Cobalt HSS work? Do I need carbide or diamond drills? Brittle carbide that small will probably be pretty tricky.

Thanks in advance for any help.

Glen
Click to expand...

I had to drill a couple of holes in a Shars stainless scale to use it for a quill readout on my mill. HSS wouldn't touch it. Cobalt wouldn't touch it. I wound up buying a set of 10 carbide printed circuit board drills for about $7 from Amazon (Prime) that worked just fine.
 
You can use a small grinding bit like a dremel tool. I had the same problem with hf calipers, it defenitely is hardened. I finally was able to use a small diamond grinding bit on it , get one that is round and small 1/8 inch or less...drills wouldnt work for me.
 
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