OT: Step drill bits

I used to own a "unibit" or step drill bit years ago, but I fear it got lost in one of my moves. I went to Home Depot and they want like 55 bucks for one of them.

I need to drill some holes for 9 pin tube sockets in a fairly thin aluminum chassis - I know little about metalwork. Are there any cheapskate solutions available?

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Reply to
bitrex
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one Greenlee chassis punch is probably cheaper.

Reply to
Wond

As long as it's not too thin, such that it will tear, and you only want one size you can buy metal cutting hole drills. (A cylinder with teeth on one end.)

George H.

Reply to
George Herold

Harbor Fright/Freight sells a low cost step set that is suitable for aluminum etc... If you only need a few holes, its affordable...

Steve

Reply to
sroberts6328

Or a chassis nibbler and an oval file.

Cheers

Phil Hobbs

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Reply to
Phil Hobbs

On Mon, 7 Dec 2015 15:41:18 -0000 (UTC), Wond Gave us:

Probably not, but it is the right way to put a hole in thin sheet metal.

Otherwise, make a plate with the row of holes required machined into it, and open up a huge rectangular hole in the chassis and mount the plate onto it.

Reply to
DecadentLinuxUserNumeroUno

Ugly :-(

(I own a fairly complete set of Greenlee chassis punches... dating back to my Dad's Radio/TV repair shop, some 60+ years ago :-)

...Jim Thompson

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Reply to
Jim Thompson

Sure thing, but no worse than using a step drill or hole saw in gooey

1100-T0 aluminum. You can do a nice job if you're careful, though. I agree that a Greenlee is a good way to go.

CHeers

Phil Hobbs

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Reply to
Phil Hobbs

  • 1

Dan

Reply to
dcaster

Just look elsewhere, step bits aren't expensive at all

NT

Reply to
tabbypurr

So you're in need of 1" ~ 1.25" holes in thin cheesy aluminum, no?

Cheapskate solution is to buy a Harbor Freight version.

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Normally I'm definitely no fan of cheaping out on cutting tools, but they should be okay for the job, based on one that I have.

You could also get a 'Greenlee' type chassis punch but that would cost a lot more and would be slower.

--sp

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Reply to
Spehro Pefhany

Thanks! I actually have Amazon Prime, and I found one as an "add on item" for five bucks, so long as I order some other things totalling $25. Free two day shipping.

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Reply to
bitrex

and it's easy to bend the chassis with them

NT

Reply to
tabbypurr

How thin and what's a tube? The nice feature of the step drill is that it won't turn your work into a potatoe chip, like a chassis punch tends to do. The down side is that you're not removing a thing cricumference of metal, but instead are removing ALL the metal inside the hole with the step drill. If you must drill, be sure to put some plywood backing behind the aluminum.

Harbor Freight has some cheapo step drills:

For the smaller holes, I use a Whitney punch: Punching is much easier and neater than drilling.

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Reply to
Jeff Liebermann

Harbor Freight sells set of 3 different size step drill bits for $9.99 when on sale. Even without sale it is something like $15 or so.

They are of a decent quality and for $55 you would probably get enough those drill bits to last for a very very long time.

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Reply to
Sergey Kubushyn

and when drilling gummy aluminium dip the bit in ethanol, it stops the aluminium "welding" itself to the cutting edge, when that happens things go bad fast

-Lasse

Reply to
Lasse Langwadt Christensen

+2

On sale on the homepage, item #60379

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That's what I use.

Cheers, James Arthur

Reply to
dagmargoodboat

Their open construction also makes them easy to sharpen, though I've never had to sharpen mine.

Cheers, James Arthur

Reply to
dagmargoodboat

WD-40 or any light lubricating oil (eg Marvel Mystery Oil) works extremely well with aluminum as well.

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Reply to
mixed nuts

I've tried WD-40, I don't think it works quite as well as ethanol, and ethanol doesn't leave a mess

-Lasse

Reply to
Lasse Langwadt Christensen

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