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I've been doing a lot of turning lately and just finished a salt shaker yesterday. I used the PSI kit, which is just a cap, a chrome tube, and a plug. The design calls for a 1" through hole. I do have Forstner bit extensions available for my drill press and I do use them. The problem is that a drill press is really not a precision tool and it's hard to ensure no deflection when you have to raise the table so the bit is already in the blank. If I try to drill from both sides, I have gotten slight misalignment. It's not a problem if I don't use the tube, but the chatter or lips or whatever on the inside do block the tube. It wasn't hard to fish some sandpaper inside and clean it up, but I think it would make more sense to just drill from one side and, if there's deflection, just turn it round again.
It seems to me like a 6" extension trying to drill through a 5" blank from both sides is going to lead to deflection with high probability. I would think you can drill through a piece of 1" easily and have them line up, but the thicker you get the harder it is.
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I know that with twist bits, once the drilling starts the hole becomes a drill bushing of a sort, and deflection is less of a problem.
But with some Forstner bits, there is less height there to prevent deflection.
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(01-25-2021, 09:01 AM)FS7 Wrote: I've been doing a lot of turning lately and just finished a salt shaker yesterday. I used the PSI kit, which is just a cap, a chrome tube, and a plug. The design calls for a 1" through hole. I do have Forstner bit extensions available for my drill press and I do use them. The problem is that a drill press is really not a precision tool and it's hard to ensure no deflection when you have to raise the table so the bit is already in the blank. If I try to drill from both sides, I have gotten slight misalignment. It's not a problem if I don't use the tube, but the chatter or lips or whatever on the inside do block the tube. It wasn't hard to fish some sandpaper inside and clean it up, but I think it would make more sense to just drill from one side and, if there's deflection, just turn it round again.
It seems to me like a 6" extension trying to drill through a 5" blank from both sides is going to lead to deflection with high probability. I would think you can drill through a piece of 1" easily and have them line up, but the thicker you get the harder it is.
I am not an expert, but I think most turners use the lathe as a drill press. Also, I suspect you will have more success with an auger-style bit than a forstner.
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(01-25-2021, 01:53 PM)Ridgeway Wrote: I am not an expert, but I think most turners use the lathe as a drill press. Also, I suspect you will have more success with an auger-style bit than a forstner.
Exactly what Ridgeway said.
Mel
ABC(Anything But Crapsman)club member
