- Joined
- Oct 13, 2014
- Messages
- 9,686
I agree the boring bar / cross slide method would be best for accuracy. Although you can get pretty accurate with a trepan tool; the thing is you have to get it on the first shot, so you need check the set on a piece or pieces of scrap till you have it spot on, then do the bore. I have used it on up to .250" mild steel 3-4" diameter holes without too many issues, I think .500 thick is doable. A couple of pointers if you go this route:
It is best too have a backer or spoil board under the work so the tool doesn't break through too fast and snag, a piece of steel or aluminum would be best but wood or MDF might work in a pinch.
Also on the same note, a medium feed is best, that is enough to get a continuous chip(s) and once going avoid stopping, just keep the same even pressure till your through. Stops and starts are what cause snags as will too heavy a feed. Too little feed may cause rubbing and dull the tool or worse, work-harden the material (depending on what you're cutting).
Keep lube or coolant applied as you go, an oiler with dark cutting oil or a spray bottle with soluble oil, may help to have a second set of hands doing that part.
I used a belt drive 15" Delta drill press slowest speed was 470rpm so it can be done but slower would be better.
One more thing. be sure to tighten the chuck in all three holes and go around twice, it does make a difference. The most common foul up is the tool staging and spinning in the chuck, once that happens the shaft will be chewed up and will likely slip again....
It is best too have a backer or spoil board under the work so the tool doesn't break through too fast and snag, a piece of steel or aluminum would be best but wood or MDF might work in a pinch.
Also on the same note, a medium feed is best, that is enough to get a continuous chip(s) and once going avoid stopping, just keep the same even pressure till your through. Stops and starts are what cause snags as will too heavy a feed. Too little feed may cause rubbing and dull the tool or worse, work-harden the material (depending on what you're cutting).
Keep lube or coolant applied as you go, an oiler with dark cutting oil or a spray bottle with soluble oil, may help to have a second set of hands doing that part.
I used a belt drive 15" Delta drill press slowest speed was 470rpm so it can be done but slower would be better.
One more thing. be sure to tighten the chuck in all three holes and go around twice, it does make a difference. The most common foul up is the tool staging and spinning in the chuck, once that happens the shaft will be chewed up and will likely slip again....
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