which hole saw?

I need to cut 2.5" holes in 0.25 plate for my bumper... which would last longer/cut better?
Bi-metal, carbide tooth, or carbide chip?


TIA -r0

I'd go with the "Carbide grit" variety - it doesn't have teeth per se, but it's a metal base with a batch of carbide grains fused around the mouth. Advantage here is that, as the grits break off, they present another sharp edge - while the teeth would just get dull and they're Hell to resharpen.

That, and the carbie grit will hold up better than the teeth - shallower cut. It will take a little longer, but it should also last longer.

Don't forget to keep the cut flooded to clear the kerf and keep the tool cool. Any light machine oil will work (I buy the stuff I use to sharpen knives in job lots.)

Just out of curiousity - are you doing this to add lighting?

5-90

nope... I scored some 2.5 inch 1/4" wall tube at the metal salvage for like 15 cents a pount and I'm getting the 1/4x6 flats from a friend's company (they bought the cheaper plates @ 6" wider than they need). I figure I'll have enough to box the rails and brace the steering box mounts as part of the bumper mount receiver.

btw, I was leaning towards the carbide chip (grit) cutter. thanks

Roll-over said:

I need to cut 2.5" holes in 0.25 plate for my bumper... which would last longer/cut better?
Bi-metal, carbide tooth, or carbide chip?


TIA -r0

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I picked up a milwaukee hole saw specificaly for drilling in steel. I've done 6 2.75" holes and it still is looking pretty good: trick was that the packing said to cool it with oil often and drill at slow speed.

Kejtar said:

trick was that the packing said to cool it with oil often and drill at slow speed.

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Thats the key with any steel cutting. Don't let the tool get too hot. Keep a spray bottle on hand and be very liberal with the coolant.

kid4lyf said:

Thats the key with any steel cutting. Don't let the tool get too hot. Keep a spray bottle on hand and be very liberal with the coolant.

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I ended up using cutting oil and I kept submerging the tip of the hole so in this plate full of it every so often. That worked out great.

Kejtar said:

I ended up using cutting oil and I kept submerging the tip of the hole so in this plate full of it every so often. That worked out great.

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millwaukee tools hole saws, BIMETAL. I avhe cut over 50 tube ends and holes with an 1 3/4" I have now....and by the way PAM non stick spray works much better than cutting oil and a whole lot less messy. I use it for my hole saws and portable band saw.

X2 on the bi metal.

I've had one that's made 50+ cuts in stainless.

The whole secret is slow and oily!!!!

I'm in with the bi-metal crowd. While carbide is awesome for cutting, it's usually way more expensive for something that "could" get caught and destroy the tool. Bi-metals last forever anyhow. I typically run used motor/gear oil for all my cutting needs out in the barn. Up in the shop I use a 50/50 mix of cutting oil and tap magic.

kid4lyf said:

Thats the key with any steel cutting. Don't let the tool get too hot. Keep a spray bottle on hand and be very liberal with the coolant.

Click to expand...

Heat dulls steel.

Abrasion/impact dulls carbide.