I think I need to go back to the basics

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KMCloonan

KMCloonan

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Jun 13, 2017
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Is there some special technique for seating a MT2 keyless drill chuck into the tailstock, or tightening the bit in the chuck? Here's why I ask.

I have been using a keyed drill chuck for years, and I decided I would treat myself to a keyless chuck, for obvious reasons. The last couple of blanks I have drilled using the keyless chuck have been amazingly bad. The holes end up way too large. I keep looking at the chuck - I don't see any obvious wobble. I don't have a runout gage to actually be able to measure it, and with the bit remaining stationary, it's difficult to eyeball if it is cocked.

Today I needed to drill a large bore hold for an Olympian Elite 2 - the body blank uses a 31/64" bit. I decided to drill an 8mm pilot hole, just to guide the larger bit. I had no trouble drilling the smaller hole. You can see it came out centered and clean.

IMG_1490.jpg

Then I chucked up the 31/64" bit (a PSI bit I have used for many pens, still sharp), and started drilling. About halfway, I had to stop. It was obvious that the hole was too large.

IMG_1491.jpg IMG_1492.jpg

I measured the hole, and the bit - the hole was about .100" larger than the OD of the bit.

IMG_1493.jpg IMG_1494.jpg

Here is the Keyless Drill Chuck I just got a couple weeks ago from PSI

IMG_1495.jpg

I need to get this pen made, as I am about 2 weeks behind schedule, so I reverted back to my keyed chuck - I inserted it into the tailstock with a slight twist (I did the same with the Keyless Chuck) - I cut a new blank, and drilled it using the same 31/64" bit, and the hole turned out normal.

My lathe is new - I got it in October. The MT2 bore in the tailstock looks ok. It seems like my problem is coming from the keyless chuck, Is there a trick to seating it? is there a trick to inserting and tightening down on the bit?

Any guidance or suggestions would be appreciated.

Thanks,
Kevin
 
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It's possible the MT shaft is seated cockeyed. If you have a faceplate, you can mount a scrap of plywood on it, mount it on drive spindle and install keyless chuck with the drill bit mounted. Bring the bit up to touch the faceplate and mark the point of contact. Make a reference mark on the chuck MT. Remove chuck rotate it 90 deg and repeat. Do this four times and if the points make a circle the issue it with the chuck. You can do the same for your keyed chuck.
 
Mr Vic said:
It's possible the MT shaft is seated cockeyed. If you have a faceplate, you can mount a scrap of plywood on it, mount it on drive spindle and install keyless chuck with the drill bit mounted. Bring the bit up to touch the faceplate and mark the point of contact. Make a reference mark on the chuck MT. Remove chuck rotate it 90 deg and repeat. Do this four times and if the points make a circle the issue it with the chuck. You can do the same for your keyed chuck.
Click to expand...
Thanks - Sounds like a solid plan to test the chuck seating. I will try tonight.
 
Well, I ran the test Vic Suggested.

This first picture shows the setup Vic Suggested. Note the reference mark on the top of the chuck, so I could approximate 90 degree rotation of the chuck.
IMG_1498.jpg

The second photo shows the mark on the plywood from the bit, after 4 "pokes" from the drill bit, with a 90 degree rotation of the chuck between each poke.

IMG_1499.jpg

As you can see, the mark is pretty small - the brad tip on the bit basically hit "home" all 4 times.

That said, this was only one test. But I can use this method to check my chuck each time I insert it into the tail stock, to see if it ever goes in crooked... Maybe it's user error, and I didn't always seat the chuck properly when installing it. I'll check the next couple time I set up and see if I learn anything.

Thanks Vic for the suggestion!

Kevin
 
On the 2nd blank did you drill a pilot hole? Trying to keep a brad point bit running true with a pilot hole can have similar results to what you describe.
 
Actually, I did not. On the second blank, I just went in with the 31/64" bit (using the keyed chuck) and the hole was fine. But, on the blanks I drilled yesterday, I did not use a pilot hole either, and they turned out pretty bad (using the keyless chuck). But I get your point about trying to have a brad point bit go straight when there is a pilot hole. Probably was not a good idea.

So, basically I have not drilled any "bad" holes with my keyed chuck (over the past 10 years or so), and I have drilled very few "good" holes with the keyless chuck. As I mentioned earlier, I will use the faceplate/Plywood test to see if I can spot if I am installing either the chuck in the tailstock incorrectly, or the bit into the chuck incorrectly.

Thanks again for the suggestions.

Kevin
 
I would lose the brad point bits. That point could be off center. Have seen this before. Plus it will follow grain lines more-so than a standard twist bit.
 
I agree with jttheclockman that you should not use a brad point drill :

jttheclockman said:
I would lose the brad point bits. That point could be off center. Have seen this before. Plus it will follow grain lines more-so than a standard twist bit.
Click to expand...

I know many pen-turners who would never use a brad point drill bit when making a pen.

jttheclockman said:
I would lose the brad point bits.
Click to expand...
 
If you use a live centre,or even a dead one, in your tailstock does it find centre on whatever is rotating in the chuck?
Guessing so if you're using the same setup for years?
Or does it describe a small circle?
Try the same test with the brad point in the jacobs chuck.Not drilling,just brushing the surface.
Did the same bit work fine in the keyed chuck?
Agree with other comments re brad point possibly not being centred on the bit.
Try putting jacobs with bit into headstock and rotate at moderate speed,does it run true.
Does headstock rotate on the bed?If so is it aligned to the tailstock?
Cheers
 
I purchased a dowel chuck from Craft Supplies. It centers the bit in the chuck. Difficult to get the bit centered when the three prongs of the bit bite into the drill bit. Hardly much of a chance to remount in chuck centered. Easier to identify an out of round drill bit as well. 2cents.
 
There are two possible explanations for this problem.

I read somewhere (don't recall where - must be age) that one should mount the bit in the chuck and tighten it before mounting the in the tailstock. The basis for this recommendation is that it is possible for a bit to be captured between two of the three jaws of a drill chuck which means that it will be off-center; that can cause all sort of bad things to happen. I have a keyless chuck on my drill press and I've experienced this many times. Instead, if you insert the bit with the chuck off the lathe, you can easily look at the end of the chuck to confirm that the bit is actually centered between the three jaws. Obviously, this problem can be especially severe with small bits, but I've experienced it on my drill press with bits in the range that might typically be used to drill pen blanks. By the way, this can happen with both keyed and keyless chucks - I had it happen on my keyed jacobs chuck using a very small bit, and when I tightened the chuck jaws, the bit actually broke.

The other explanation is that the tailstock fitting is loose allowing for some very slight angular rotation of the tailstock. This is a known problem that affects several brands of lathe. The cause is that the rectangular tenon on the bottom of the tailstock casting is very slightly smaller than the spacing between the bedways. The amount of error can be quite small (my Turncrafter can rotate about 0.6 degrees), but it's enough to cause a drill bit to be off-center resulting in an oversize hole. There is no simple fix for a lathe that has this problem, but a workaround is to align the tailstock to a centered dimple on the workpiece before locking down the tailstock and starting to drill.
 
Thanks everyone for your input.

First, I agree with and John about the brad point bit. I usually do not use them, but I have had this bit, purchased from PSI, for years, and have never had a problem with it. I will consider setting it aside, but the problem I am having today happens with regular bits as well. The common denominator seems to be the keyless chuck.

Stuart, I will definitely put the keyless chuck in the headstock and see if there is noticeable wobble. I may also run out (pun not intended) to Harbor Freight and pick up a drop gage kit to measure runout.

Louie, I really like your comments about installing the bit before seating the chuck in the tailstock. I have several times needed to loosen and reposition the bit in the chuck, as it did not seem to be gripped concentrically. I will definitely start doing this today.

Rich, I will look into getting a dowel chuck, if the above actions don't help.

Thanks again all!

Kevin
 
KenB259 said:
Though brad points certainly have their place in woodworking, I generally avoid them for penmaking Here's a informative blog on them. Look what they say about an improperly sharpened brad point bit as well as what the say about enlarging a hole. https://powertoolbase.com/what-are-brad-point-drill-bits/
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Thanks Ken, you must have been writing at the same time I was responding to the others' feedback. I will avoid brad point bits going forward.
 
KMCloonan said:
Thanks Ken, you must have been writing at the same time I was responding to the others' feedback. I will avoid brad point bits going forward.
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I use them from time to time. Funny how if you buy pretty much any starter set of usually three kits, bushings and a drill bit, the bit is usually a brad point.
 
Just a thought, try revolving the bit in the chuck before tightening up the chuck. sometimes a bit of dirt on a jaw or not centred right as you tighten down.
 
KMCloonan said:
The common denominator seems to be the keyless chuck.
Click to expand...

Regardless of whether you can identify the exact problem, your methodology so far does suggest that the issue is with the keyless chuck. You've mentioned it's a recent purchase. Any chance you can replace it at little/no cost under warranty or return policy from PSI?

You've never had the problem before, and it seems to me that the only thing that's changed (including your methodology) is the Jacob's chuck. Unless you've left out something else you changed at the same time that could be the culprit, I'd say either get a replacement keyless chuck from PSI or go back to what was working before.

I can say that I've had that exact chuck for about two years now with frequent use and no issues, but this isn't the first time I've heard about PSI products not being super-consistent in terms of quality.
 
RunnerVince said:
Regardless of whether you can identify the exact problem, your methodology so far does suggest that the issue is with the keyless chuck. You've mentioned it's a recent purchase. Any chance you can replace it at little/no cost under warranty or return policy from PSI?

You've never had the problem before, and it seems to me that the only thing that's changed (including your methodology) is the Jacob's chuck. Unless you've left out something else you changed at the same time that could be the culprit, I'd say either get a replacement keyless chuck from PSI or go back to what was working before.

I can say that I've had that exact chuck for about two years now with frequent use and no issues, but this isn't the first time I've heard about PSI products not being super-consistent in terms of quality.
Click to expand...
I have not had any further issues since the initial post in January, and I have been using the keyless chuck exclusively. I always check to make sure the MT2 is fully seated, and that the bit is properly centered in the drill chuck jaws.

Reflecting on the issue that prompted me to start this thread, I think my mistake was drilling a small pilot hole, and then using a brad point bit to drill the main hole - I think with the pilot hole, the brad point had nothing to sink into to guide it straight, so it wandered, and went off -center.

I am also swearing off brad-point bits wherever possible.

Thanks for the input.

KC
 
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