Not a Woodworking Question...Machinists Out There?

[David DeCristoforo]

I need to enlarge a 42mm hole in stainless steel to 62mm. The SS is not really thick (maybe like 1/32") and normally I would try and jig something up to use a hole saw. But in this instance this is not practical. I think I'm going to have to do it with a grinder of some sort in a hand held drill. I have tried this in the past with a small sanding drum but that has it's drawbacks. So maybe I need a burr that would cut stainless....

[Bill Brehme]

Depending on the grade of the stainless you may need to cut with cobalt or carbide. Interested myself to see what shape of cutter to use?:confused:

[Ed Peters]

"Greenlee Punch" but that kit would run you about $90.00 for a punch, die and pull stud. (MSC #04224473)

Ed

[Kyle Kraft]

Perhaps a carbide burr 1/8" shank in a zippy tool. I have used this successfully on other sheet metal stuff.

[Mark Hubler]

A hand nibbler would work http://www.aircraftspruce.com/catalog/topages/nibblingtool.php

Might also sneek up to the diameter with a knock-out punch. It would be fairly easy to do overlapping punches and grind to a final hole size.

[David DeCristoforo]

One of these?
http://www.victornet.com/cgi-bin/victor/productlist.html?subdepartments=Cylindrical+Burrs: 470,974
The punches are pretty costly for a one time use. I have a "nibbler" but it seems pretty lightweight for this. I've used it in alum. which is pretty easy to cut. Maybe I'll try it on some hiddesn location and see if it will cut the SS.

[Paul Muhlstadt]

If your numbers are correct (42mm=1.65" and 62mm=2.44") I would lay it out with a scribe, cut close to the line with a variable speed jig saw,fine tooth blade, slow speed and file to the line. 1/32" thick is not hard to file and a burr can get away from you pretty easy. If small enough, you could do this on a scroll saw. Use a blade with the most teeth you have and slow the speed down. Speed heats metal. Heat hardens metal.

[David DeCristoforo]

Ahhh...that's the rub, Paul. I can't get "in there" with a jig saw or much of anything else for that matter. This hole is on the front on an espresso machine and there are a lot of things sticking out that would block things like jig saws. That's why I'm thinking about just grinding it out unless someone has a "magic bullet" for me.....

[Greg Mann]

A bullet! There's the answer. Get one 62mm in diameter and stand back about a foot.

How accurate do you need to be? If you can scribe the circle and use a rotary burr to sneak up to the line you can be pretty accurate, if you can stabilize the machine and your arms. Any hole saw or rotary type tool will grab on exit and cause a real mess. A burr will be tedious but you will have lots of practice by the time you get to finish size.:D

[Jeff Patrick]

If you can fit it in, a small abrasive cutting wheel on a dremel will take out most of the metal. Then use a carbide bit in a die-grinder. If the dremel won't fit, then just use the die-grinder. Get two bits, one course/spiral cut and the other a fine cut. You can have this done in no time. Be aware that you'll have metal shavings all over the place, including inside the machine.

Use an air powered die-grinder rather than an electric one. They are much safer and their speed can be regulated if desired.

[Cliff Rohrabacher]

An adjustable cutting trammel will cut it nice and clean. You can do it by hand or in a drill press. But at 1/32 thick I'd do it by hand

[David DeCristoforo]

"If you can scribe the circle and use a rotary burr to sneak up to the line you can be pretty accurate..."

This is most likely what I will end up doing. I have maybe an eighth of an inch of "tolerance" because the gauge has a flange on the front so it does not have to be "dead on".

But I do like the idea of using a 62mm bullet! Do you know where to get one? And whatever I would need to shoot it? Maybe I could just put it in my vise and wack the end with a hammer?

[Randy Klein]

Not sure if the term is right, but isn't there something called a reamer that is a tapered "bit". It's job is to make small holes bigger.

[David DeCristoforo]

"...but isn't there something called a reamer that is a tapered "bit"

Sure. There are "step drills" and "reamers" (also called, oddly enough, "hole enlargers"). Problem is, I can't find one that will punch a 42mm hole out to 62mm.

[Jim Becker]

Do take care to insure that all the specs of metal are fully "gone" once you get the hole resized...it only takes one tiny piece to bollix up the works, either electrically or mechanically. But you knew that.... ;)

[Bill Brehme]

Plasma cutter!:D Beeooowhipp... DONE!!!:cool:

[David DeCristoforo]

"Do take care to insure that all the specs of metal are fully "gone"..."

Another answer to that post about what to do with that great big compressor?

[Daniel Simon]

I removed my post because I didn't carefully read the size. Sorry.

[Scott Rollins]

Sheet metal snips will do the job quickly and cheaply. They run about $10-20 from the big box stores. I used these successfully to cut out for HVAC piping in plenums. Just cut on the line-carefully.

[Tom Walz]

You might try Practical Machinist

http://www.practicalmachinist.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_daily

That's the link for the daily active topics

[David Epperson]

Harbor freight has an air powered nibbler that would probably make short work of this without generating all the metal chips and powder.

[Roland Chung]

If you haven't already decided on how to do this, check out a forum for computer mods. These geniuses routinely cut up alum and steel cases and turn them into works of art. I think that they use the dremmel tool quite a bit. They do things by hand that look like a machine produced it.

If you use oil to lubricate and cool, try not to get it on the insulation of the wires inside. Oil can degrade plastic.

[David G Baker]

Grenlee punch is the way to go if the front and back of the metal is easily accessible. They can be rented. Depending on the grade of stainless, if the metal gets hot from drilling, it gets real hard very fast and will melt a drill bit like butter. If it is drilled use a very slow speed and lots of pressure and lubricant.

[David DeCristoforo]

Well I dug out my "cheapo nibbler" to see if it would cut stainless the same thickness as what I thought I had to deal with. It did although it took some force. Thinking I could deal with this I took the top off the machine and saw that the front panel where the hole is is actually two thicknesses of steel...the stainless front and a sceond layer of thicker (though most likely much milder) steel. So now I'm looking at a good 1/16 -3/32 of steel to cut through. I really don't want to have to tear this thing down just to enlarge a hole so I am going to try a course grinding bur and see how far I get.