The Case of the Wandering Drill Bit

[Gary Salisbury]

I have run into a problem and need some assistance from you more experienced turners. The problem is that the holes I drill into the blanks are starting centered but are wander off center by the time I have gone through the 2-1/4" blank. I am using my new Jet 17" drill press, a Rockler 7mm brad point bit, and a Craft Supplies pen vise.

The table is level and the drill press is square and running at 200 RPM. The press is clamped down and I releive the build up very frequently but sometimes that bit just wants to wander off center. It has happened on various woods. Is this normal on a 2-1/4" blank or am I possibly doing something wrong?

Gary in San Diego

[Matt Ziegler]

I used to drill with a drill press that was set at a really low speed, and i had the same thing happened. Using a cast iron vise and bolting it down to the table.

I think i figured it out though, I moved to a different system and started drilling at a faster speed. That seemed to help quite a bit. I think that the drill bits that are used now are designed for higher speeds and will track better when used faster

I dunno i could be way off base though, just a thought

[Dave Bartley]

The problem is most likely one of two things if not both. #1. the drill speed is to slow. #2. Your are forcing the bit to much.

Solution, would be to increase your drill speed and to go a bit slower on drilling down through your piece. That is what worked for me anyway! Good luck!

[Matt Ziegler]

haha...great minds think alike dave

[Terry Quiram]

I have used brad point and pilot bits for drilling pen blanks. I believe that pilot bits drift less. One thing I came to realize is that when the drill first enters the wood the action of a spinning member meeting a stationary member causes the spinning member to deflect. My determination is if it starts at an angle it can only get worse. Now I use a small scrap of wood to "push" the drill from left to right just before it enters the wood and hold it to reduce the initial delfection. I get a lot less drift than I did before I started using this technique. When drilling Corian I administer the same "push" but I really wood pecker the bit to keep chips clear cause blowing out a Corian blank is pretty easy.

Terry

[Ed Heuslein]

Howdy Gary:

Well, I've gotta put in my two cents worth. In wood, I find that the pilot or bullet (depends on mfr) point drills work best. In synthetics, a parabolic flute seems to clear the plastic out better. I agree that a little faster speed helps. Something one of our club members just enlightened us with is to put the blank in your chuck with the drill in a jacobs chuck on the tail stock. It really does seem to work a lot better. Our club has recently drilled about 400 blanks in preparation for the FPP and this procedure as drawn the best results.

Ed

[Jim Baker]

If the blanks are thick enough and you use a barrel trimmer, you can "make do" with a little bit wandering. I sometimes have to let the bit enter slightly off center to be sure that it doesn't exit too far to one side.