Pilot hole for chamber?

[Sasquatch]

I tried drilling a pilot hole to help guide the chamber bit, and was really put off by the results... I got a much better cut just sinking the chamber bit into fresh wood. It seemed to rattle around a bit with a pilot hole to guide it. So much for that great idea.

Any comments? Do you guys "predrill" your chambers?

[ToddJohnson]

I tried drilling a pilot hole to help guide the chamber bit, and was really put off by the results... I got a much better cut just sinking the chamber bit into fresh wood. It seemed to rattle around a bit with a pilot hole to guide it. So much for that great idea.

Yep.

[Sasquatch]

I suppose it was bound to happen that someday ONE of my ideas wouldn't be so good!

The great chess player Tartakover once lost 5 games in a row in a tournament, and when asked what went wrong, he said something like this: In the first game, I had a headache. In the second game, I had a toothache. In the third game, my rheumatism was acting up. In the fourth game, I couldn't concentrate because of the audience. And the fifth game? Well, no one can be expected to win EVERY game."

[Frank]

I tried drilling a pilot hole to help guide the chamber bit, and was really put off by the results... I got a much better cut just sinking the chamber bit into fresh wood. It seemed to rattle around a bit with a pilot hole to guide it. So much for that great idea.

Yep.

Another one of his lengthy replies.

[wdteipen]

I tried drilling a pilot hole to help guide the chamber bit, and was really put off by the results... I got a much better cut just sinking the chamber bit into fresh wood. It seemed to rattle around a bit with a pilot hole to guide it. So much for that great idea.

Any comments? Do you guys "predrill" your chambers?

I've found this to be true also and now only drill a pilot hole about a half inch to an inch in to get it lined up straight.

[ToddJohnson]

You might want to try a "full size pilot" using a forstner bit. If you're using a 3/4" spade bit, for instance, drill about a 1/2" hole with a 3/4" forstner bit and go the rest of the way with the spade bit. The nice square shouldered hole that you drill with the forstner will sort of contain the spade bit and prevent much chatter. Chatter is also inevitable unless you've got either a very heavy lathe or a very precise drill press that is bolted to the cement floor. You can also reduce chatter significantly by shortening the shank of your spade bit to about 2" long.

Todd

[KurtHuhn]

If I'm using a spade bit, I tend to like a full sized pilot as Todd suggests.

If I'm using a spoon bit or a reshaped S&D bit, I use a pilot of about 3/8" and stop about 4 to 8 mm from the finished depth.

Other things I do that prevent chatter are, as Todd suggested, use short bits, and I drill everything on my lathe since it's a hell of a lot more rigid than my drill press. Also, be sure your bits are sharp. If using a spade bit, clean up the edge once in a while with a diamond hone or a piece of 600-grit sandpaper on a flat surface - similar to the way you might hone a plane iron.

[Sasquatch]

My drill press is not real good, and I will be upgrading that or moving to lathe-oriented drilling real soon.

Thanks for the advice guys.

[Nick]

Todd rocks!