Knowledge You Can Build On — Est. 1998
Drilling End Grain
Don Emmerling
>Hi Folks,
Whenever I try to drill the end grain using a Forstner bit I get a lot of heat and sometime smoke and make little progress in getting a hole. I run the lathe at its lowest setting (~450 rpm) and I feed the bit in slowly but it doesn't help.
While it seems common for turners to do this I must be missing something.
Any thoughts out there?
Regards,
Don
Re: Drilling End Grain
Ron in Drums PA
>How sharp is the bit?
FWIW - I drill at about 1000 rpms and only get "smoke" when I drill green wood.
Re: Drilling End Grain
RevDoug
>Speed kills. Fostner bits need to spin a around 250 or less to be most effective. Slow down the speed and I believe your trouble will go away. We were drilling chunks for clocks a couple of years ago and took the bits back after drilling one or two pieces, thinking that they bits weren't holding an edge. Somebody finally asked about speed. We were drilling with a Shop Smith in the verticle press position at the slowest speed, approx. 500 rpms. Way too fast. Bought a drill press that we could get down to 125 and found we had no dull bit issues.
Turn 'em round,
RevDoug
Re: Drilling End Grain
RonZ
>Sharpen the bit or replace it.
Sharpening Forstner Bits
Rick Allen
>Hi Don
There was a nice article in the December issue of the "Woodworking at Home" DVD magazine. Sharpening is easy enough and the DVD shows how a lot better than I could explain.
Basicly you use a diamond hone on the flats of the bit. Think of the cutting edge having two surfaces to form a sharp edge. Just like we sharpen one side of the cutting edge when we sharpen a gouge you only need to sharpen one side of the edge to yeild a sharp forstner bit.
Good Luck
Richard
Re: Drilling End Grain
Barry Turner
>Make sure you have good quality Forstner bits. Some of the Chinese imports may look good, but that's about as far as it goes.
Make sure the bits are sharp. Sharpening a Forstner bit takes a special set of skills. If you can't do it properly, either replace any dull bits or have them sharpened professionally.
Re: Sharpening Forstner Bits
John Lucas
>I use a diamond hone on the flats and a dremel to dress up the round inner edge. If you use a gentle touch it works great.
Feed faster the bit
Jorge Castaneda ~ Downeast Maine
>Don,
Been there done that, my solution was to feed the bit faster, you need to get shavings, not saw dust, that is why your bit is getting hot, and back off and clear the shavings frequently.
Jorge
