Drilling on the lathe...

[Steve Paxman]

I frequently drill holes on the lathe. I make and sell pens, so all my blanks are drilled on the lathe, holes of various sizes, using the pen drilling jaws of the supernova2 chuck.

It drives me crazy that sometimes the bit doesn't enter the wood centered! Sometimes it is wobbling just a bit right from when it touches the wood, even with a forstner bit. But not always - sometimes it goes through smooth and clean. What would cause it? If it's bad enough, by the time it gets through a blank the whole tailstock is getting shaken around because the bit is being forced to wobble off center.

Any ideas? Does this ever happen to anyone else?

[Harry Robinette]

When you put your center lines on the blank put a small starter hole in with an awl.
Also you need to check your center on your lathe head stock to tail stock center. But it's probably just the need for a starter hole.

[Kyle Iwamoto]

For pens, I drill on my drill press. 2 reasons, the one you stated, and the other is on the drill press, you can have a sacrificial wood under the pen blank preventing a blow out. Could be your centers are off too. A brad point should help. I do get wobble from a "regular" metal twist drill almost all the time. A split point helps starting a nice centered hole.

For other than pen blanks, I use a spade bit. Yes, those toss out when dull cheap spade bits. I drill with 1 bit size smaller, then use my more expensive Forstners. The spades cut way fast, but as everyone knows, leaves a terrible not really round hole. Finishing with the Forstner leaves a pretty much perfect hole. Saves wear and tear on the hard to sharpen forstners. If you're really cheap, like me, the spades can easily be sharpened.

[Thom Sturgill]

Another option would be to get a machinists center bit. http://ecx.images-amazon.com/images/I/41mbeuk06OL._AA160_.jpg A set is less than $10 from Amazon. Harbor Freight sells an inexpensive jabobs chuck mounted on a MT2 taper for less than $15. Dedicate the jacobs to the center bit - its easier to switch out the entire assy. Becaus eof its short length and diameter of the shank relative to the size of the starter it is very stable.

[Dick Mahany]

Another option would be to get a machinists center bit. http://ecx.images-amazon.com/images/I/41mbeuk06OL._AA160_.jpg A set is less than $10 from Amazon. Harbor Freight sells an inexpensive jabobs chuck mounted on a MT2 taper for less than $15. Dedicate the jacobs to the center bit - its easier to switch out the entire assy. Becaus eof its short length and diameter of the shank relative to the size of the starter it is very stable.

Thom's suggestion is an excellent one and I've gone this way as well. Another very handy use for those machinist's center drills is if you want to make "between center" type of pen bushings out of Corian or something similar. They drill perfect 60 degree profiles for the drive centers used in that method of pen turning.

[Steve Paxman]

Another option would be to get a machinists center bit. http://ecx.images-amazon.com/images/I/41mbeuk06OL._AA160_.jpg A set is less than $10 from Amazon. Harbor Freight sells an inexpensive jabobs chuck mounted on a MT2 taper for less than $15. Dedicate the jacobs to the center bit - its easier to switch out the entire assy. Becaus eof its short length and diameter of the shank relative to the size of the starter it is very stable.

Thom, as I did more research yesterday, I stumbled upon this exact idea. I already have one of the Harbor Freight jacobs chucks, and have been thinking at that price, a couple more would come in handy. And luckily, I have a HF close by, so I think today I'm headed there after work for some center drill bits and a couple of chucks. And of course, that will solve all of my problems forever, no doubt. Until I find another thing I can sink some more money into... This vortex is very real!

Thanks for suggestions, all!

[Brian Ashton]

Wood has variable densities through out so the bit will naturally take the path of least resistance. This is lessened when the bit is at it's sharpest. With small bits cranking up the rpms can also help and don't push to hard.

Sometimes I position my tool rest under the shaft of the bit so it's just touching to support it close to the work. This has the effect of countering the bits tendency to wander and wobble. Works well to get foresters and spade bits tracking accurately but only if they're mounted in the tail stock.

[Jon McElwain]

I just use a small sharp bowl gouge and create a divot in the center to start the bit. Same idea as the others but no extra tools needed.

[Russ Denz]

Have experienced the same problem and after thinking "go slow" the problem solved itself. It's very easy and does NOT require anything additional except for maybe 30 seconds of drilling. Here goes: With the pen blank chucked up LOOSELY (but enough to hold it in place), EASE the drill bit up to the blank and let it start its own hole. Next, with the bit still in place turn off the lathe and tighten up the chuck: pressure from both ends centers the blank with your equipment and that's the key! Now advance the drill bit as you would normally; you will love the results. Try it...and have fun.

[Peter Fabricius]

Hi Steve,
Two things, plus all the above comments....
Very important to have the head and tail stocks line up perfectly or the drill starts in a little circle. I have a .003 low tailstock live centre and when doing precise drilling I slide a .003" shim under the front edge of the tailstock, this really works well.
Also, if the end of the blank is not square it is difficult for the drill to find a good centre, the pilot bits help with this.
Peter F.

[Dave Paine]

Good replies. I recently purchased the centre drill set. Very useful on the drill press or lathe, especially if the entry surface is not horizontal. The centre drills do not flex and make a nice pilot hole.

I had similar issues to yourself. I checked the headstock to tailstock alignment with pointed pieces in a chuck in the headstock and a Jacobs chuck in the tailstock. I still had problems. I replaced the Jacobs chuck thinking this was contributing to the problem. No difference.

I finally realised that although my headstock and tailstock appeared to align, I had not ensured the headstock axis was aligned to the middle of the ways on the lathe. The last time I had rotated the headstock, I foolishly assumed the detent would get it back on centre. Not so. The root cause of my problem. The headstock was out perhaps 1/16in.

I re-aligned the headstock axis to be centred on the ways, then re-aligned the headstock to tailstock. I can now drill a centred hole.

FYI, many tailstocks have some play. Mine is one. I have to pull the tailstock toward me as I lock down to get good alignment. The plates under the tailstock are designed for side to side mounting and are a bit shorter than the distance between the ways. Hence the slop in my lathe.

[Thom Sturgill]

Dave, they make a piece with a double MT2 to help align those swivelling heads. I have heard of several people having issues when they did not align them and needed alignment for drilling or reversing a piece. One of the reasons I did not buy a model with a swivel head.

[Dave Paine]

Yes, I found out about this item after I solved my issue. I have looked at buying one. At the moment I am leaving the headstock locked in the present place.

I now appreciate why a rotating headstock is a mixed blessing.

[Steve Paxman]

So, I got those center drill bits. They work miracles, I swear. I drilled a ton of holes today, just because it was finally working so nicely. So much better!