cutting holes in stainless plate.

I recently acquired some awesome 1/8" stainless steel plate (from a dumpster) Cleaned off the paint and cut out (with a die grinder and cutoff wheel) 2 nice tube monoblock chasis. I mounted transformers and I noticed that stainless really eats up a cheap drill bit quickly. I used my expensive MAC tools drills and had no problem. (at a reasonable speed) I need to drill some much larger holes now for tube sockets, and was wondering what the best tool for doing this is. I own a large drill press with a 5/8 chuck (16mm) but I need to drill or cut a clean 1-1/8" hole (several actually) Want advice on what others have used for this. Maybe something with replaceable cutter heads?
 
Bimetal or carbide grit holesaw would do the job. A Greenlee chassis punch is great for this kind of work and the mechanical ones that bolt together in this size are rated for 10ga (3.5 mm) stainless so should do the job. A bit costly ($48 on Amazon) but best tool for the job. Don't buy the cheap Chinese knockoffs...they are not nearly as well made and you are working fairly heavy metal.
 
Greenlee punches, seem like bad idea...

The material I am working with is very hard. I have my doubts that a Greenlee punch will cut it. The punch you were referencing is rated for mild steel. This is not mild steel. It is harder than heck steel. I think I found a nice Klein tools 1-1/8" cutter with carbide tips for about $30 shipped would this do the trick?
Combined with plenty of cooling, obvously
 
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To use a punch for the holes expect to require just under twenty tons of force behind it. That assumes a sharp punch with proper alignment and back clearances of fifteen mills minimum, a really good lubricant and a cutting fluid at the shear edge. Of course tool alignment should stay within two mills.

So since you have a drill the issue becomes how slow does it go? I would not go faster than 150 RPM for a hole this size in stainless and for a newbie half that. Now if the bit binds the torque may be great enough to slam the work piece into the drill column and damage both.

So very slow feed with a real commercial cutting fluid is best. Now if you have a power feed on the drill press that helps from over feed or grabs. Of course you mostly likely don't. So wood backing and edge blocks, c clamps, gloves, eye protection and of course ear plugs.

I once had my turret press jam when punching a three inch slot in 12 gauge stainless. Bear will vouch for the size and power of the tool!
 
Yeah, what simon says...

...but if I had to do tube sockets on 1/8" stainless, I'd want to use a milling machine with a carbide cutter, and preferably a continuous flow of liquid coolant/cutting fluid.

I'd never try to cut to full size regardless of what sort of drilling arrangement was available, you'd want to step out below final size and then make a light cut for the finishing at the proper diameter...

punching that thickness stainless, especially IF it is hard as a rock, would not be an option I would entertain. One of the problems with punching is that you get a side with a curved in edge and the other side with flat or slightly burred edge.

Truthfully, it's going to be a slow and painstaking task to do it yourself, as you will need to cut slow and start with a small pilot hole and work out in diameter... if you can swing it see if you can find a local machinist who is sympathetic to your situation to help.

Fwiw you can polish that stainless to a mirror finish if you want, or you can do a fine brush finish...

If you look on my now ancient web page you can see the front panel of an amplifier, the cylindrical part of the handles was some random scrap that I had around, like you, from a dumpster dive of some sort or other random source/donation. Big mistake to use that. Cutting the sections off the rod was really tough going, should have bailed then.

But it was like a challenge at that point. So I kept going. It was rough turning that stuff on the lathe, I cherry'd out a few carbide bits there... :(

I weighed the time to finish the job vs. the drive to pick up fresh stock from 25 miles away at the industrial metal supply house... next time I take the drive and get a softer alloy, believe me!

With that in mind, it might be better to get a better alloy to work, weigh the time and effort and the number of burnt up tool bits...

_-_-
 
1/8" SS is a ***very*** tough job.
Normal bit drilled holes (meaning < 1/2") are easy, but .... socket holes !!!
Not forgetting that chassis weight will be murder.

I make all my stuff, including chassis, but use only aluminum, which even if 1/8" thick is relatively easy to cut/punch/drill ... and half as heavy.

I only use SS to make my own metal corner protectors and even so, I provide the cutting and forming dies and hire shop time at a car parts factory who have all kind of presses.

And even then only use 18ga .

Sorry but your free find may prove to be expensive in the end.
 
Of course you don't start at full size on something that thin. Start 1.5 times the thickness or so and increase the diameter by 50% each pass. It should take seven passes or more.

Ok your milling machine is bigger than mine. But either of us could do it quickly.

Punching really should not distort the metal when done properly. We used to do a fair number of 12 gauge stainless panels. Very tough on engraving tips. I recall about 30 characters per bit.
 

Lo_Tse

Member
2006-12-24 4:26 am
The material I am working with is very hard. I have my doubts that a Greenlee punch will cut it. The punch you were referencing is rated for mild steel. This is not mild steel. It is harder than heck steel. I think I found a nice Klein tools 1-1/8" cutter with carbide tips for about $30 shipped would this do the trick?
Combined with plenty of cooling, obvously

For tube amp chasis, you have to cut quite a few holes, large and small.
I was told that waterjet cutting is the best way to go (imagine one has to cut an IEC opening). It can cut almost anything e.g. granite, marble, glass, steel, Hastelloy etc. The cut is clean and precise. There are shops in the Toronto area that will do the cutting for not too much money. Look around your area to see whether you can find one.

Regards,
 
I'd try a hole saw with generous cutting fluid and the appropriate drill press speed. (That's what I used to put an extra hole in a stainless kitchen sink, minus the drill press.)

Plasma cutter? Make a guide from scrap MDF, cut slightly undersize, then sand or file to size.

Or, I'd contact the guy who works at a shop that makes stainless restaurant fixtures and does sheet metal odd jobs after hours.