Drill bit question

[Dan Forman]

Is there any reason to favorbrad points over standard twist bits when drilling on the lathe, for such things as tool handles and pens? I started a handle fro my P7N roughing gouge, but it seems to have a metric sized shaft, whereas I thought they were supposed to be 1/2". I bought this second hand, though it has never been used, so earlier examples may have been metric. Anyway, I will have to buy a new bit tomorrow, so wondering whether to go twist or brad point. Any suggestions?

Dan

[robert hainstock]

For most wood drilling, I prefer the brad point. it gives a more certain centering point to start the hole. Regular twist drills always seem to wander for me. Do you have any way to measure the shaft? I think most tools come a thosandeth large. They do this to insure a good long lasting grip on the shank. If you caan get the shank started you might try to pound on the butt end and let inertia co the work. anyway, GOOD LUCK! :( Bob

[Steve Trauthwein]

Drillling is a tricky question, with a lot of variables. What type of wood are you drilling, speed of drill, feed rate, size of drill bit. Having said that I find that for most of my drilling a standard twist bit works fine. I always start a bit slowly and break chips frequently until I am cutting at the full diameter of the bit. I find if the bit is going to walk it will start at the entry point. Of course smaller bits can be deflected at any time.

Regards, Steve

[Prashun Patel]

In general, brad points cut cleaner.
It's not the actual brad point, but the flared cutters at the edges that make b-pt bits great. The edges of the hole are essentially scored by the cutters b4 the hole is sliced by the rest of the bit face, which eliminates tearout

If my goal is speed and the occasional tearout is ok, I'll use the cheaper twists. If the goal is clean holes, I'd reach for the b-pt.

[Dan Forman]

I guess I should rephrase my question. I prefer brad points for normal flatwork drilling, but sometimes a large brad point, nearly 1/2" in this case, can have trouble in end grain. The handle I'm drilling is 16" long, and I will be doing it on the lathe, not the drill press. The hole will be just shy of 2" The handle is partially turned, so there is a nice indentation that the live center in the tailstock has made, which should prevent the drill from wandering on entry.

Dan

[David Foshee]

You could start with a Pilot hole. (a small bit that is about the size of the chisel point on a regular twist bit). Mostly it is used when drilling metal but is used to help th larger bit not walk off. I have drilled handles both with a pilot hole and without I really don't think it make any difference in wood. I normally drill my handles a few .010 oversize then epoxy the tool into the handle. I want to slide the handle in and out of the hole then the glue has somewhere to go.

[Chris Fierro]

Dan,

For tool handles, I have been drilling a centered hole (undersized) on the drill press, and chucking up an appropriate sized lag bolt (head removed) in the Jacobs chuck. This ensures 100% that my tool hole will be true to the axis of the handle. Then it is a matter of enlarging the hole by a 1/16" which I feel comfortable doing on the lathe.

Have fun!

[Marvin Hasenak]

If this is 1 or 2 time use bit, I would buy the cheapest bit I could find. Then stick it in a drawer and forget about it. Being a 1/2" bit I doubt if you will have enough wander on the bit that even a engineer could find it.

If it is a size you will use quite a lot that is the time to look at quality and how clean of a cut you will need in the future. Again I would not be concerned with the bit wandering. I also use metal lathe and on a 1/2" bit it would take some real mess up to get the bit to wander.

Marvin

[Bernie Weishapl]

I do like Chris does and drill a hole slight undersized. I use a dowel in the chuck turned down so I have a tight fit. Slip it on there and bring up the tailstock. I complete turning the handle so then the tool is dead center with the handle. Probably don't need to but it works for me.

[Dan Forman]

Bernie and Chris---I'm a bit dense when it comes to mechanical matters, not sure if I'm following you. You drill an undersized hole, put either a dowel or headless lag bolt in the hole, then put that in the chuck on the lathe and turn the handle. Then how do you hold the handle when you drill it out the final time?

I turned a tenon on what would be the far end of the handle, put that in the chuck, used a live center on the tailstock. Then turned a tenon on the business end where the ferrule will end up, and shaped the handle. Then removed the live center, replaced it with the Jacobs chuck from my drillpress. With the handle still in the lathe chuck, I drilled the hole using the crank on the tailstock, withdrawing the bit a couple of time to clear the debris. Unfortunately, the gouge fit a little loose. I think if I use an undersized bit first, then the second time I won't have to pull out to clear the chips, and it should end up tighter. I was a moot point however, because it turns out the stock had some internal cracks, which weren't visible when I started, so the whole thing was just a learning experience. Just as well, as I turned the tenon for the ferrule just a hair too small, so the ferrule wouldn't have added any support to the gouge, which was already loose. Hopefully won't make the same mistakes when I try again tomorrow.

This was on one of the Thompson tools, I never did get a 12mm bit for the P&N, but that's another story.

Dan

[Chris Fierro]

You've got it. The undersized hole is your guide as well as chip clearance for the correct sized hole. I find that it is nearly impossible to wander off course with the correct drill bit once you are following the pre-existing hole. I have done that second drilling on either the drill press or with the Jacobs chuck in the lathe headstock. You may find that you'll want to still be 1/64" undersized for that final hole. Again, depending on wood, the tool, and your preference.

If your original hole was 1/16" undersized and you want the final hole to be 1/64" undersized, your truing cut (that second drilling) is only removing 3/64" of stock from the hole--pretty insignificant in terms of chip clearance and close enough that you should not be able to wander outside of that original hole. Hope that clarifies. (You method seems fine too!)

-CF

[Dan Forman]

The part I'm still not sure about is: if you have the jacob's chuck in the lathe headstock, do you just hold the handle in your hand freestyle, and move it into the drill bit. If you have the jacob's chuck on the headstock, there is nothing left that will hold the handle true.

Dan

[Ben Gastfriend]

I'd put the work in the headstock and the bit in the tailstock. Let the work spin, and then there's no worry that you'll be misaligned.

[Bob Hallowell]

Dan,
When I have been doing my tool handles like that I drill them on the drill press first then run a 60 deg live center in the hole and turn till it's how I want it and put'er together.

Bob

[Richard Madison]

Consider piloting the hole (on the lathe) with a slightly undersized forstner bit, centered in the hole from your tailstock point. Start the hole very slowly until the bit is fully inside the work. Best shot at making the hole centered and straight. Then grind a cheapie spade bit to the size needed, trying to grind each side the same amount, and ream out the hole to the correct size.
I have a spade bit (originally 1") marked 1/2" pipe, cause that's what goes into the handles of my home made tools.

[Dave Rudy]

This was on one of the Thompson tools, I never did get a 12mm bit for the P&N, but that's another story.

Dan

Not to hijack the thread, but would you comment on the Thompson tool(s) after you use them?

TIA

Dave

[Dan Forman]

Here is the first handle finished, I'm pretty happy with how it turned out.

http://i98.photobucket.com/albums/l279/T-Caster/P1010708.jpg

Dave---I didn't use it until the end of the class today, because the instructor wanted everyone to use a standard grind gouge that could be sharpened without a jig. When I did get a chance to use it, it performed well, though I don't have enough experience reall to compare it to any other tools, as today was the first time turning facework for me. Thompsons get fine reviews on this forum, however.