Help cutting big hole

I need to cut ~7" diameter hole in 3/8 aluminum plate. It doesn't have to be perfect or even close as it can be .25" bigger as it is only a hole for clearance.

What would be the best way to cut this? How about a jig or hand-held sabre saw?

I have a mill but no fly cutter.

Thanks

Reply to
nonono
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Depending on the saw you have, you could make this work. Might be hard to get this tight a radius unless you have a real narrow blade.

Do you have a rotary table? Then this is a piece of cake.

If not, you could just mark out your circle with a compass. Then mill a slot by hand following the line. It would be rough looking but quick and get the job done. Of course, a CNC mill makes this a piece of cake.

If you want pretty, this would be a good time to yourself a trepanning tool for your mill.

Karl

Reply to
Karl Townsend

Simple approach: Scribe the circumference, drill a bunch of holes along the scribe line, and use a hacksaw blade to connect them.

The result will look even cruder than it sounds.

Al Moore

Reply to
Alan Moore

Reply to
Machineman

AND - Wear a full-face shield unless you like to say 'ouch' as hundreds of suprisingly hot aluminum chips bounce off your face. And - variable speed saw *not* optional. Regards. Ken.

Reply to
Ken Davey

Reply to
Thomas Kendrick

Drill a starting hole and use a router with circle attachment, preferably variable speed.. To prevent galling use wd40 as a lubricant, you should be able to do it in 2 passes. It's a bit messy but if you have a vac attachment that helps.

Bernard R

Reply to
Bernard Randall

Apologies, wasn't paying attention, thought I was on a different NG.

Bernard R

Reply to
Bernard Randall

Thanks to all for the suggestions.

I will try the sabre saw with fine toothed-blade.

Reply to
nonono

I have had miserable experiences with a jig saw. The teeth on the blade keep gumming up. I've tried wood and metal in a good Bosch jig saw, I've tried fast and slow, I've tried it dry and with friction stick wax.

For really superior, clean cuts I have had excellent results with carbide router bits in a good router and a template.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG

Reply to
DanG

I wouldn't use anything finer than 8 to 10 TPI. A blade meant for wood will work just fine. Some wax or WD-40 applied to the blade will prevent the alum clogging the teeth. A good variable speed saw would make the job more pleasant, but just about anything will get it done.

Ned Simmons

Reply to
Ned Simmons

I have done this connect the holes appoach on a PC case for 120mm case fan on rear. Steel is hard and almost 1mm thick. Scribed with a disassembled fan body as outline and used cordless drill and dremel for cutting out and cleaning up those jaggies.

That takes long time!

Cheers,

Wizard

Reply to
Jason D.

NO!!!!!! You will simply fill the fine teeth up with melted alum. Course blade!

And as another poster said..face shield or at the least, safety glasses.

Gunner

No 220-pound thug can threaten the well-being or dignity of a 110-pound woman who has two pounds of iron to even things out. Is that evil? Is that wrong? People who object to weapons aren't abolishing violence, they're begging for the rule of brute force, when the biggest, strongest animals among men were always automatically "right". Guns end that, and social democracy is a hollow farce without an armed populace to make it work. - L. Neil Smith

Reply to
Gunner

Coarse tooth wood cutting blade! Fine tooth will load up fast. Ken.

Reply to
Ken Davey

||On Mon, 26 Apr 2004 02:34:23 GMT, snipped-for-privacy@nospam.com wrote: || ||>Thanks to all for the suggestions. ||>

||>I will try the sabre saw with fine toothed-blade. ||>

||NO!!!!!! You will simply fill the fine teeth up with melted alum. ||Course blade! || ||And as another poster said..face shield or at the least, safety ||glasses.

You will be amazed at the quanity of chips that get everywhere doing this. Use WD40 as you cut with a wood-cutting (low tooth/inch count) blade.. Rex in Fort Worth

Reply to
Rex B

I've done that job - cutting a two foot dia circle in aluminum plate.

The blade should have about three teeth in the material at all times, and he should use a spray can of WD-40, spritzed at the blade periodically. This keeps the cut clean.

It took me five minutes to buzz though it. Face shield and ear protection are required for this.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Reply to
jim rozen

I'd do it with my plasma cutter and clean up the hole with a coarse file.

Ted

Reply to
Ted Edwards

Maybe some sort of gun would do the trick. A few closely grouped projectiles might get ya within a quarter inch. Usually the drill it and file way works pretty well depending on your filing profieiency.

Reply to
dann mann

What works good here is to find a piece of Styrofoam that is a little thicker than the length of the saber saw blade and put this under the plate you are cutting.

Reply to
Roger Shoaf

On Sun, 25 Apr 2004 17:53:23 GMT, snipped-for-privacy@nospam.com vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

You need to talk to Tom Gardner.

**************************************************** The Met Bureau is LOVE!
Reply to
Old Nick

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