Long holes in blanks that don't wander

[Bob Roehrig]

Having a few problems of late in using longer 6" Aircraft 1/8" twist drills for drilling holes deep into long blanks. Most of the time they go in straight. Sometimes as happened today, I was using some Zebra 3/4" blanks and the holes wandered to one side or another and did not stay straight. I'm now attributing this to the drill following the grain pattern but am not sure. I've ruined several long blanks with this happening. Would love to hear a sure fire method of drilling these longer holes using a lathe if anyone would like to comment.

 

[jttheclockman]

There is no sure fire method. Bits that thin and that long can follow grains and thus get throw off course. Probably the best way is to drill from both ends and meet in the middle. Less material to drill and you can use a shorter bit which would be more stable.

 

[mark james]

6" long is pretty 'long' and suspectible to wandering. I would drill a thinner hole, then step up to the final diameter. That being said... I suspect the real culprit is the blank grain. For that, good luck, the bit will go where it has least resistance. I agree with JT: Meet in the middle if possible. Been there...

 

[Drewby108]

6" of 1/8" diameter is a massive amount of chances for flex in the drill bit. If you don't want to try drilling from both ends, I'd try doing the process in steps with shorter bits first. A shorter bit will be more rigid and give the longer bit less chances to deflect for the initial length.

I'd also crank the speed up as much as possible and peck the hole, but I'm not the safest or smartest person in the world lol.

 

[Bob Roehrig]

6" long is pretty 'long' and suspectible to wandering. I would drill a thinner hole, then step up to the final diameter. That being said... I suspect the real culprit is the blank grain. For that, good luck, the bit will go where it has least resistance. I agree with JT: Meet in the middle if possible. Been there...

Have thought about that, but a hole on the opposite end would not be my choice since then I would have to think about trying to Plug such a small hole. Think I'll just avoid "grainy" woods since my other efforts went very well. Has to be the Zebra Wood I believe.

 

[TonyL]

Not disregarding anyone's advice, but see if these folks can help. Drills I would call them. I buy all my bits from them (Norseman).

I would also spray Bostik Blade and Bit coat on the bit before each plunge.