Burr Free Sheet Metal Hole Cutting

I am a one-person company

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I produce a raft frame in several sizes using 1 by 2 by 1/8 wall aluminum tubing for cross braces.

I have yet to find a way to cut burr free holes in this material. I typically need to cut several 1" diameter holes in the 2" wide face of each cross brace.

I currently use a 1" diameter drill bit in my drill press - and then have to spend a great deal of time removing the burrs afterward.

I was hoping someone here would know of a better solution.

BTW Back in the sixties I worked for a company in California who had the greatest boring tool for sheet metal - called a Rotobor, I believe. I haven't been able to find these anywhere so I assume they've gone out of business. So I know there is a way to do it - I just can't find it.

Thanks for any advice.

Reply to
Your PT friend
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You'll probably get the cleanest hole with a punch like the chassis/knockout punches made by Greenlee, but it doesn't sound like you have enough room to use them.

I think the Rotobor you mentioned is sold as a RotaBroach or RotaCut set. Go to

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and enter 2209 in the seach window to go to page 2209 and see if that's what you had in mind.

You can also search for "knockout punch" there to see what they look like.

Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com

"Even if you are on the right track, you'll get run over if you just sit there." - Will Rogers (1879-1935).

Reply to
Keith Marshall

Use google [google.com] to find suppliers. Just type "rotobor" in the search box and you will find several suppliers for this tool. Pat

Reply to
JWDoyleJr

Reply to
Machineman

I like the unibits for any sheet metal work, but I'm not certain they come out 100% burr-free. I also use rotabroaches made by Hougen if I need a super-precise and clean hole. You shouldn't use these in a hand drill.

Make sure the part is clamped. Cutting 1" holes involves large forces, and at break-through a drill can catch and spin the part. If it hits your stomach it could be real bad.

Grant

Your PT friend wrote:

Reply to
Grant Erwin

I also like the unibits. They can debur or even chamfer the hole in the same setup, by feeding until the next size step just starts to cut. Then flip over the work to do the same from the other side. Well, maybe it's not practical in a production setup.

Reply to
Bob Powell

Not quite. I've got two (quite old) sets of Rota-Bors (I would have to go downstairs to check on the spelling), and they are significantly different. (Two sets, to cover a range from 3/8" to 1".) Instead of an arbor, a pilot drill, and a screw-on cutting blade, each of these is a single piece (hollow) shank and cutting blade (two points on the smaller, four points on the larger), with a spring-loaded cone-pointed pilot (not a drill) going through the shank, and it and the spring are retained by a plug screwed into the back end of the shank.

The ones labeled:

Deep Cut High-Speed Steel Sheet Metal Hole Cutters

might do the job, though they are probably a bit more prone to chatter. The price is within reason, however. About $15.45 for the cutter (3789A16), and $6.39 for the arbor (3789A46), plus the pilot drill.

However, I consider using the drill as a pilot to increase the chances of chatter, as the pilot can fairly quickly cut its hole oversized. The real Rota-Bor does not have this problem, and works wonders in aluminum (with proper coolant to prevent chip adhesion). Unfortunately, they appear to no longer be made. You *might* find them on eBay, with sufficient searching.

Good Luck, DoN.

Reply to
DoN. Nichols

None of the ones which *I* found led to anything which I could identify with the tool which I have. The first (after a bunch of (surfboard type) surfing related pages, appears to be for a sharpening service for these among other things. Nothing else seemed to do more than mention them as one of the lines carried (all UK, and what I have is US made), so it may be a different product entirely.

Good Luck, DoN.

Reply to
DoN. Nichols

The name of the company that makes the rotobur is Jancy Mfg.

Reply to
ShakasCaregiver

Try this:

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The type C tool should do the trick. They work great but are pricey. Buy lots of extra blades.

regards, Jim

Reply to
JK

I would second that but a few inches lower hurts even more!

John

Reply to
John Manders

Annular cutter. Try Hougen Manufacturing, and Jancy Engineering Company.

Bill

Reply to
Bill Marrs

Thanks much for all your great advice.

I have ordered an annular cutter to try out and I'm getting product info on several of your other suggestions. When they talk about the amazing productivity increases in the US economy over the last 5 years - they need look no further than places like this.

Best regards, Ray Pelland

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Reply to
Your PT friend

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