Time factor.. I have some very nice bowl gouges but would like to bore the jars out as large as possible, first.. the largest I see in a quality Forstner is about 3.5 inchesI don't know how big you can find but I am sure that they would be very expensive. Why not just use s bowl gouge?
Jack
Have you considered metal-work style boring bars or fly cutters?Time factor.. I have some very nice bowl gouges but would like to bore the jars out as large as possible, first.. the largest I see in a quality Forstner is about 3.5 inches
Darkmoor is a business and this will be production work
Only a Jet 1642 so far, about to try iti hope you have a gigantic and powerful lathe, trying to use a 4" plus forstner bit takes ALOT of power.....
I think that we are talking a maximum thickness of 5-6". Is that right?
If so maybe just use a Forster Bit say up to 2".
The use carbide square insert tools to widen hole say 1/4-3/8" at a time. Come straight in from the end grain. Should not take too long.
You really have to be tight at the chuck. Seems that the size of the hole would be limited by strength of the wood, how thin, does it have checks, how dry?
I have made hollow columns that 4" long and 5" diameter in such manner.
Alan
Not too mention a large drill press to spin it, a harbor freight belt driven jobber wouldn't do it.....These people http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/forsbit.htm carry a 4" but chucking would present a problem. If you could remove it from the lathe and than bore on a drill press that would be ideal. You would want to run at very low rpm's.
Not too mention a large drill press to spin it, a harbor freight belt driven jobber wouldn't do it.....