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What are you drilling WITH? Drill press? How low a speed can you set it?
You need a very slow speed for a large bit like 15/16.
A Silver and Deming bit, a hole saw or a step drill, will require your work piece be WELL
clamped.
The slower the better. Sharp bit. Cutting oil. Clamps.
Mark Singleton
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10-28-2018, 12:08 PM
(This post was last modified: 10-28-2018, 01:31 PM by Roly.)
Carbide hole saw should work.
LIKE this one. A hole saw or step bit will be much safer than a twist dril for this size hole. Slower speed and cutting lubricant will save the bit. Roly
If you have access to a magnetic drill or can use a drill press we used annular cutters for drilling large I beams. Not for hand held drills.
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(10-27-2018, 08:27 PM)Jason28 Wrote: I need to drill about 24 holes, 15/16" diameter, in 1/8" mild steel for an upcoming project. The largest bit I currently own is 1/2". I'd rather not try to make the step up from 1/2" to 15/16", but I also don't want to buy several large diameter bits I'm not likely to use again. I was wondering if anyone has a recommendation on decent hole saw for steel. I don't expect a regular hole saw would hold up too well, but what do I know? Suggestions?
A step drill bit will probably be the most cost effective and at 1/8" its within the thickness it can handle. The nice think is you'll also get a bunch of other hole sizes with one purchase.
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Jason,
Looks like you have several viable options, thanks to the expertise of those on this forum. I also thank you all for the information as I've learned quite a bit from the information you've brought forward. Nice to know there are cutting tools out there for the average home hobbyist to use to drill large holes in steel thicker than usually worked with in the average woodworking shop.
Someone mentioned it earlier, but slow speed and lots of oil lube will help make it easier and a little safer IMO (learned this from my machinist dad).
Doug
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An annular cutter would make the cleanest holes. but, expensive. You can use a 15/16 bit with just a single pilot hole, no need to step by step. I find that cutting with only the outer edge of a bit is really hard on them. Dull and or chip badly compared to cutting with 1/2 or more of the diameter.
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10-31-2018, 01:33 PM
(This post was last modified: 10-31-2018, 01:34 PM by brianwelch.)
seconding Roly above...May be overkill, but I would consider renting/borrowing a magnetic Hougen drill and purchase a bit. Drilled hundreds of 1" holes in 1/2" steel in seconds/hole...
https://www.hougen.com/
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LIL,
Without knowing how precise to 15/16" you need, I'd suggest a bimetal hole saw.
You can get them in pretty small increments, on line.
I just had a project requiring very close fits on 1/2, 3/4 and 1" pipe.
I tried the saws I had on hand, determined I needed some between what I had.
Ordered them on ebay-had them within a couple days-worked great, drill press, low speed, light feed, a little cutting oil, and done.
Hole saws don't take nearly as much power as a drill-you are only really cutting a small amount of metal, instead of making the entire hole into chips.
If your workpiece is small, make sure to clamp it securely, as someone else mentioned, a small hole for chips to exit really helps.
I've used bimetal hole saws to make 2 1/2" holes, in 1/2" thick steel plate, several times.
The holesaw still cuts like new.
I've used 1" holesaws in a hand drill, when the work was too big for a drill press-just go slow.
I find rocking the holesaw side to side a little seems to help it cut better.
PM me, and I can measure what size cuts closest to 15/16.
Mike
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Knowing the acceptable tolerance for the holes, the size of the workpiece and what the OP has to drive a bit/cutter would help immensely.
Blackhat
Bad experiences come from poor decisions. So do good stories.
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(10-31-2018, 11:44 PM)blackhat Wrote: Knowing the acceptable tolerance for the holes, the size of the workpiece and what the OP has to drive a bit/cutter would help immensely.
Do you mean like an annular bit?
Best choice, but a bit pricey.
Similarly, I use end mills for stuff like this- but a good one would also be perhaps more than what he'd want to spend.
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I would go with the hole saw. I needed some 2-1/8" holes in 3/16" steel. Lenox hole saw made easy work of the task. Like others have suggested: clamp, oil, and slow.
I did make one mistake...did not use the pilot bit on the first try.
"I tried being reasonable..........I didn't like it." Clint Eastwood
