Large Forstner Bits.. Exposing the MYTH

[Larry Edgerton]

John, I have to agree with Sonny here, you are making some pretty sweeping generalizations, and you should be called out because that is how misinformation gets its roots.

I think your heart was in the right place but your data was flawed.

The bit size you chose was not particularly large as I showed in my last post, the actual rpm was not established as fact, and the types of wood chosen were not particularly challanging. Add to that that there are many other possible drill press uses, and just this one point does not qualify what RPM a drill press should run at at all.

It would seem better to me to have a drill press that ran too slow than one that ran real fast. But that is just my opinion......

[John Gornall]

There's no doubt that each circumstance is specific in using cutting tools. That's why we did tests rather than just look up drill speeds and feeds in an engineering book. When production showed 4.5 million holes would be drilled in a certain type and thickness of steel our tests were justified because of the potential cost savings should we be able to drill twice as fast and use half as many bits.

The point here is simply understanding that when you drill a big hole in a wood of your choice and it isn't going well there are changes you can make that might lead to better results. Bit rpm, feed rate, a different bit design, lubrication, more chip clearance - give each a try. And of course if all else fails get out a chisel amd mallet.

I mention chip clearance - I find most forstner bits jam up in the chip slots - I grind a bit more clearance with my Dremel - seems to help a lot.