Drilling stainless steel

Hi Fellas...I made a vertical DRO (poor mans) on my drill/mill today from an old digital vernier gauge to get a bit more accuracy on my hole depths and light milling,this involved drilling a 5mm hole top and bottom of the gauge to fix to the brackets.Now i had a real mare of a time getting these holes through this stuff and took the edge off about 8 bits to get through...My question is whats the best method for drilling really hard grade SS???

Yes, this has been covered a few times. The issue is that the stainless is actually hardened. I have had success with a small diamond burr in the Dremel.

Though I am seriously considering building a Spark Eroder.

graham.

Edited By Oompa Lumpa on 14/09/2014 20:09:42

Yea i was leaning towards something that involved grinding instead of cutting....Cheers Graham.

In my job my company works only in Stainless, 316 and 306, To drill a hole you need lots of pressure but slower revs than mild steel and a sharp bit, start small and gradually increase the drill size.

Martin P

Get some Cobalt drills and do it at slow revs. and a bit more pressure to maintain the cut, take care as it breaks through!

Clive

I have drilled 10mm holes in stainless and found 316 stainless steel quite tricky as it tends to work harden, after taking the edge off a few 10mm Cobalt drills opted to buy a couple of solid carbide drills these did the job a lot better than the others although it is important to maintain the feed rate and a slow ish speed.

This is all very well, I drilled half a dozen holes myself in some stainless 316 today, it isn't difficult, but the OP is drilling through a vernier caliper which is induction hardened stainless. And it really is drill resistant. Far easier to grind through the stuff because you will quickly spend real money replacing some quite expensive cobalt drills if you go down that route. The other alternative is a Carbide Plate drill (NOT dinner!) John Moore showed me some very useful examples, maybe he will come by in a bit and remind me.

graham.

I posted the following comments recently on the forum. The MAFord drills have done many a hole in calipers for homemade DRO's. They work, no nonsense:

For drilling stainless or other hardish steel up to 65 Rc the drills at the link below work really well. I bought a 1/8" one and have used it to drill calipers for mounting (among other things). If the 1/8" hole size is used, a #4-40 UNC screw passes easily, and a 1/8" 'c' style roll pin fits with tension in the hole to locate the jaws to mounting brackets with zero backlash.

http://www.maford.com/products/index.aspx?series=200

Good luck, JD

PS you need PLENTY of drilling downforce to make these drills cut. Push them hard and they work great.

I have successfully drilled through tool steel and taps with an easy to make drill made from

either a broken carbide tool or round carbide toolbit . If there is any interest , I will post a sketch.

Roy.

If there is any interest , I will post a sketch.

I'm interested, always nice to see a proven idea

When it is a one off i generally sharpen up a masonry bit. Use coolant on it as you do not want to loosen the tip in the steel shank.

Bri

Edited By Boiler Bri on 15/09/2014 05:23:15

.

+1

MichaelG.

Jeff, very useful, where do you buy them from?

Thanks
graham.

A sharp HSS Drill run slower than you would for mild steel and a fairly strong down pressure on it will help keeping it cutting rather than skating and work hardening the piece, if it happens it is so quick you often have to resharpen.... sometimes doing this several times between melt downs. sometimes there is no problem at all other times it can be a real bear to work with it depends on the grade. Ease up the pressure when it breaks through.

Also

The liberal application of strong language can help drilling tough stainless steel. Well it helps the driller anyway LOL

Regards
John

Cheap spear-point TCT tile drills ought to do the job.

I've drilled HSS toolbits this way but it requires plenty of pressure and coolant.

HTH

Jon

It may be easier to make some little clamps and clamp it to the machine ?

BobH

Jeff, very useful, where do you buy them from?

Thanks
graham.

Hi Graham, I get them from www.kbctools.com, and Travers Tool in USA have them. Not sure if they ship to UK. If you contact MAFord at the link by email, they should be able to put you in touch with their UK distributors if they have them.

They do list a European sales office email on their website- [email protected]

Good luck JD

There is another way of doing it, a suitable size bit of tube, some grinding paste, a bit of putty to make a dam around the area, some cutting lubricant. Use a drill press at low speed, and light pressure, I made a spring loaded arraignment, and for a trial cut I drilled/ground a 1/4" hole through the face of an aero- engine hydraulic valve lifter. Next I drilled a hole through a bit of plate glass. It is a slow process but it works.

Ian S C

Some great posts chaps...thankyou

Three weeks ago I'd have had no answer for you but making replacement buffer beams for my Dart rebuild all I could get hold of was 5mm stainless for the beams and brackets. I was given some brown gloop by one of the club members. It was magic, 270 holes later, no breakages and only one drill bit for each of the hole sizes

It was Rocol RTD

Pete

Edited By Doubletop on 18/09/2014 11:55:21