Dedicated Pen blank drilling Chuck

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reiddog1

reiddog1

Member
Joined
Oct 14, 2011
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Location
Jacksonville, FL
Hey fellas, I just received my PSI Drilling Chuck and has a slight variation in the entry hole. It was a little bigger than the exit hole. I checked my alighnment and locked my tail stock down each time I adjusted it for depth. I think that when I was backing out the drill bit to clear it out that I was pulling the bit completely out of the blank and then back in it went. I think that by doing that it made the entry whole a bit larger. Any advice from you guys that drill on the lathe? Thanks in advance.

Dave
 
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I turn the lathe off after I back out the drill bit, then insert the drill bit to the bottom of the hole, back it off a little bit, lock the tail stock down, hold the jacobs chuck with my hand, turn the lathe on and then continue to drill.

Just the way I do it.
 
whegge said:
I turn the lathe off after I back out the drill bit, then insert the drill bit to the bottom of the hole, back it off a little bit, lock the tail stock down, hold the jacobs chuck with my hand, turn the lathe on and then continue to drill.

Just the way I do it.
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Same, but I have one drill bit that causes the large entry hole no matter what I do. No more pens of that size until I get a new drill.
 
Just the way I do it.[/quote]

Same, but I have one drill bit that causes the large entry hole no matter what I do. No more pens of that size until I get a new drill.[/quote]



I use a dedicated chuck also and I had the same problem with a 3/8" bit - changed the bit out and no more problems.
 
For the hole problem, start with a center drill, then change to the correct drill size. Drill about 1/2 inch, turn the lathe off and back the bit out manually. Then reset the tailstock. Repeat until you reach the other end of the blank. This will give you a more precise hole.
 
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reiddog1 said:
Do u guys think it may be that I'm using a brad point bit?
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Almost all of mine are brad points, and only the 10.5mm gives me problems. My money is on a single bad bit. I have no idea what would make the bit bad, though. I bought my 10.5mm and 12.5mm at the same time from the same place, same manufacturer, but the 10.5mm has started with the large entry holes. I am considering doing another, but gluing some scrap to the entry side because I really want to do a Jr. gent fountain pen this weekend, but won't be able to get a new 10.5mm drill by then.

I do use a centering bit, too. I think it's probably a good idea overall, but no help with this problem for me.
 
PenMan1 said:
For the hole problem, start with a center drill, then change to the correct drill size. Drill about 1/2 inch, turn the lathe off and back the bit out manually. Then reset the tailstock. Repeat until you reach the other end of the blank. This will give you a more precise hole.
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Same here. When I need a really precise hole, I use a center bid. The variation tends to happen as the bit travels slightly on the first entry cut.

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Ya know, the bit I was using was a 10.5mm bit. Kinda makes ya wonder. I do have center bits, so I'll try that. Thanks for your help everybody.
 
I always start with a center bit and for anything over 10mm I pre drill with a bit about half the size of the final bit and no longer have that problem.
 
Here's a 5 second tip that will save material and a lot of heart ache. Before putting ANY drill bit into ANY kind of chuck, roll the bit along a flat and level surface. If the bit wobbles as it rolls, IT WILL NOT DRILL AN ACCURATE HOLE, regardless of how accurate your set up may be.

This proceedure takes less than 5 seconds and identifies defective drill bits BEFORE you drill that $40 piece of Bakelite.
 
I'm pretty new to wood lathes but have been using small metal lathes for years.

From my experience with metal lathes I find this most commonly caused by an angular misalignment of the center line of the drill bit with the piece you're drilling.

This could be caused by several things, the head or tail stock not perfectly aligned parallel with the ways (i.e. center line of one at a slight angle to parallel), slightly bent drill bit (relatively common in Chinese drill bits), if the chuck is mounted on a taper the taper could be defective where it joins to the chuck (usually on another taper or threaded), also if on a taper a surprisingly small amount of dirt can cause this. The chuck itself could be holding the bit slightly angled (there is a way to correct this but I have no idea how to do it without a metal lathe). There are several ways to test these things but the ones I know require the ability to make very precise measurements.

There could also be other causes not related to machine alignment. Again, I'm new to wood lathes and this is only from experience with metal lathes.
 
A numer of things can cause a brad point bit to cut an enlarged entry hole. It could be bent, tailstock and headstock not on same center, not centered properly, etc. In my experience though it is usually a poorly sharpened bit, even BRAND NEW one. If one spur starts cutting before the other, the bit will deflect slightly until both spurs are well into the hole. The brad point is not properly centered. The spurs are not sharpened with the proper relief angle out to the spur tip and one side "drags". I have had to resharpen bits I just purchased to drill for a new kit. It isn't easy but it can be done, and they cut much better. Many of the imported bits have very poor quality control.

For more precise holes i use a center drill and drill the 60 degree cone deep enough that the spurs are about a 1/64 into the cone, this stops some of the problems. Just put the tube in deep enough the tiny cone in removed on truing.
 
PenMan1 said:
Here's a 5 second tip that will save material and a lot of heart ache. Before putting ANY drill bit into ANY kind of chuck, roll the bit along a flat and level surface. If the bit wobbles as it rolls, IT WILL NOT DRILL AN ACCURATE HOLE, regardless of how accurate your set up may be.

This proceedure takes less than 5 seconds and identifies defective drill bits BEFORE you drill that $40 piece of Bakelite.
Click to expand...

Naw, can't be that easy.:biggrin: great advice.
 
Thanks guys. Great advice from all. Come to think of it, I have a 27/64 brad point (my only other brad point bit) that did the same thing when I would use it on the DP. It was also new. I got it, I think that all brad point bits hate me. Before long I'll turn them into chisel point with my drill doctor like I did their friends.
 
When I'm drilling materials with varying hardness, etc.(such as when using African Blackwood, Holly and aluminum accents), I start with a center drill, then use increasinly larger diameter drills to get a good, clean hole. In some cases, I've used 7 drills to get to a 27/64" hole size. Takes time, but the results are worth it.
 
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