Thread: Big Holes in Thick Plate?

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Denny:

I should have looked first. Maybe I will go back with my print out and get some money back.

Will the hole saw listed at $12.99 do the trick. I have always seen recommendations suggesting the use of a bi-metal saw?

Jay

lots of cutting oil to cool the saw, and blow out the chips as you go and the hole saw will still cut a second hole.

I much prefer using quality tools.... I've never seen much of that Harbor Freight stuff hold up very well. But hey, it's your money. I guess if your just going to use it once and set it on the shelf it's probably fine. Regardless of the quality, with a slow speed and good cutting oil even a cheap hole saw should be able to handle 1 hole.....

A hint from an old timer: After I drill the pilot hole, I take the pilot drill out and insert a piece of 1/4" drill rod. It keeps the hole saw centered, and will not eat out the pilot hole like a drill bit will.

Originally Posted by Henry Rifle

A hint from an old timer: After I drill the pilot hole, I take the pilot drill out and insert a piece of 1/4" drill rod. It keeps the hole saw centered, and will not eat out the pilot hole like a drill bit will.

....hey that's a great idea! I fabricated a plate recently & this would have helped to keep my tolerances closer Bill

that's intresting. I've never noticed any trouble with the pilot bit chewing up the pilot hole... but I have often had the hole saw cut a larger diameter than it perhaps should have... I wonder if that is why? I rarely have to cut any holes so precise that it matters.. just conduit usually. I might just give that a try some time.

Now that is a great tip. I never thought of that. BTW, if you buy quality bimetal hole saws they will last for many holes. We regularly cut through 3/8 plate with them and use them over and over again.

Don

I have been using drill chill ,its a can of stuff to cool down the bits when you are drilling holles like yours,oil lubes and cools ,but gets hot,drill chill ,brings the bit all the way back to cold all the way thru,to help keep the cut cool.
Not manditory ,but it helps you cut the hole faster,by being able to cool it all the way off faster.

Just when you thought you had all the answers:

one other thing I have found about hole saws:

Use 'high speed steel' saws to cut holes with a hand drill. Save the carbide tips for the drill press.

Reason being: If you chatter a carbide tipped hole saw the tips will pop off. The drill press is stable enough to avoid chattering.

All this input has been great and I have now gone yet another direction. I will return the Harbor Freight bi-metal set I bought. Instead I got a quality Ridgid brand hole saw in the two sizes I need right now. It won't give me as many hole sizes but it gives me what I need and hopefully a bit better quality. Although I have had reaosnably good luck with Harbor Freight items, I was hesitant about their hole saws because they never mention metal as one of the materials they are recommended for. The Ridgid ones state clearly for metal or wood. Thanks again, now if I could just find the time to start working on this particular task. I don't remember if I mentioned it, but this whole exercise has been driven by the need to cut a 2 1/2in hole in plate for my under floor brake booster.