Drilling stainless

[RaisedByWolves]

Please stop sacrificing carbide drills on the alter of drillpress.

They are for the most part just not meant for that machine.

 

[Jake M]

Please stop sacrificing carbide drills on the alter of drillpress.

They are for the most part just not meant for that machine.

I've had some good "saves" doing that with my drill press I keep at work. It's "pretty tight, for a drill press. On the other hand, you haven't quite lived until you get, at least one time, that feeling in your guy when realize you've got a carbide drill bit broken off half way into your "easy out" extractor.

Carbide drills do kinda prefer a stout machine.

 

[projectnut]

I used a Drill Doctor for many years. In the beginning it did an adequate job. Later in its life as it started to wear it became a Royal PITA. It took more time to adjust the drill to get the proper relief than it did to actually sharpen it. I finally gave up on it and started looking for something that would do a better job.

About 8 years ago I ran across a Black Diamond drill grinder originally purchased by a local National Guard repair depot. It was built in 1974, but never used since the depot didn't have 3 phase power. I bought it when the shop closed, and the contents were auctioned off.

It's a dream to use. It can sharpen number dills from #1 to #60, fractions from 1/16" to 3/4", and letters from A to Z. It takes less than a minute to do a drill. They are fantastic machines, but outrageously expensive if you want to buy one new. Last I checked they listed from $8,000.00 to $10,000.00 depending on the model, and accessories you need.

They do show up occasionally on eBay. Most are still asking outrageous prices, but occasionally a nice one comes with a reasonable asking price.

 

[Jake M]

I ran across a Black Diamond drill grinder ...

Count me jealous.

I've got a lot of advice about drills (and other things) that are based on the premise that between the dedicated space, and the actual cost to have a functional unit in one's own hands, these, and others of that quality/functionality range, that these are just not on the table for these discussions. Those that have them aren't asking about sharpening drills. For most of us, those are hypothetical.

If you ever want to sell it for the price of a Drill Doctor though... Call any time. I'll sit right by the phone.

 

[MikeInOr]

I have had good luck with these 3 flute cobalt bits in stainless:

Amazon.com

 

[projectnut]

Count me jealous.

I've got a lot of advice about drills (and other things) that are based on the premise that between the dedicated space, and the actual cost to have a functional unit in one's own hands, these, and others of that quality/functionality range, that these are just not on the table for these discussions. Those that have them aren't asking about sharpening drills. For most of us, those are hypothetical.

If you ever want to sell it for the price of a Drill Doctor though... Call any time. I'll sit right by the phone.

Actually I did buy this one for not much more than the 750X. It’s a bit of an odd duck (model 65) that was built exclusively for the military. It has a 1/3 hp three phase motor. All the commercial models I am aware of have single phase motors.

 

[Reddinr]

Please stop sacrificing carbide drills on the alter of drillpress.

Agreed, sort of. I've taken to doing most drilling on my RF-45 mill. The drill press sees mainly wood these days. But, if a drill press was all I had, I would use it on stainless too. Sometimes you just have to make holes.

 

[RaisedByWolves]

Agreed, sort of. I've taken to doing most drilling on my RF-45 mill. The drill press sees mainly wood these days. But, if a drill press was all I had, I would use it on stainless too. Sometimes you just have to make holes.

True, but I would go with cobalt over carbide, especially in the drill press.

I used cobalt to open the front sight holes to align the front site on my WASR AK.

I wanted to use carbide as I had then but I was strongly cautioned against it even in the mill as it was a canted interrupted cut.

I did it free hand with a cordless drill using the cobalt bit and the bit was still sharp with no chips afterwards.

 

[Ultradog MN]

Yesterday, I wanted to drill through 2" pipes several 3/8" holes. It didn't work with HSS drill bits, even I cool it well (with stream of water). I resorted to carbide, and it worked, but I only have smaller size bits. After I maxed out the size, I used a carbide grinding bit to make it bigger.

It took a long time for the first hole, and a lot of noise. I also noticed the chattering due to drill press's low precision causes the carbide bits to chip at the cutting corners.

So I decided to try HSS again, since I drilled stainless before with them. I checked my bit for sharpness, and they are. I reground again with drill doctor, but it failed again.

I was a bit frustrated. But I thought to give it another try. So I hand grind it. That worked!

I think the drill doctor does not have a good relief angle at all. I knew this for smaller bit sizes. These are larger size drill bits and also the angle is not good for stainless.

What is the slowest speed of your drill press. Most hobby drill presses turn too fast to adequately drill stainless.

 

[455dan]

What is the slowest speed of your drill press. Most hobby drill presses turn too fast to adequately drill stainless.

That is the killer, too high of speed and the stainless work hardens right where the bit is trying to cut, and at the same time it can also take 'the bite' out of the bit, It really is n almost a requirement to be able to resharpen bits and best to have a few of the size needed when doing multiple holes in stainless.