New Pen. 2 Problems.

[Todd in PA]

Here is my latest pen.

I like it but it has two problems.

1.) It is out of round at the nib. I've read about out of round and this is the first time I've experienced it. Could someone explain what causes it, exactly. Is it somewhat preventable by taking more care with centering my bushings. I usually just slide everything on the mandrel and snug it up. It is going to have to happen more than one or two times out of 40 for me to dispense with the bushings and TBC. But I'll take advice and follow instructions if I need to adopt this new practice.

2.) The band is loose. All of my bands are loose, so this is not a new problem with this pen. I read here that if I don't like the band spinning and rattling, I can CA it to one of the barrels. But I'm not clear which one— if it matters. It seems likely that some glue will come out or get inside and adhere to the transmission. A or B?

 

[Dan Parr]

Could be that your mandrel is bent

 

[MPVic]

It's OK to use your bushings/mandrel to rough out your blank, but trying to finish turning is a no-win situation, IMHO. The only way to avoid out of round is to learn to finish turning between centers & using calipers. The only other reason for out of round that I can speculate is that you may have something inside the brass tube, glue/adhesive or even a small distortion or nick in the tube. You won't realize the problem until you go to assemble the hardware. Good luck.

 

[magpens]

Make the transition to TBC ..... without any bushings at all . . . It really is quite easy and very rewarding. . . This should overcome your off-center prob.

As for your center-band prob. . . . This is going to depend on what kit you are using, is it not ? . I don't recognize the kit that you show.
Gluing is not necessary if you can live with a loose centerband and don't lose it when changing refills.

But, for myself, I prefer to have the centerband fixed.
A TINY, TINY bit of epoxy should work. . If you are doing this on slimlines, I suggest you glue the center-band to the UPPER BARREL.
That would be "B" in your picture above (which is not a slimline ??)

Be very careful to NOT get the centerband glued to the transmission, so do the gluing with the two barrels separated.
When glue is dry, clean out any glue residue on the internal surface.
Yes, gluing is messy and you have to do it very carefully using the glue very sparingly

 

[1080Wayne]

Very nice looking pen . One possible cause has not been mentioned above . The wood grain at the nib end approaches cross cut . That can easily cause some out of round as the wood will be very slightly softer along the grain than across the end grain . Dull tools will magnify the problem , as may the sanding operation . And , as one who has only turned between centers for over 10 years , I highly recommend it , BUT , it will not prevent a small amount of out of round on cross cut pieces .

 

[sorcerertd]

I started putting single bushings between centers and spinning up the lathe just to check them. I was amazed how many of the bushings are actually out of round, even brand new and fresh out of the package. There are people who will machine very high quality (precision) bushings, but ultimately the TBC will save you money and frustration. I purchased a TBC adapter set from tbcbushings.com (The owner, Brian Nikitas, is also a member here) to do away with the mandrel altogether. They hold the "kit" bushings without a mandrel, which I use to round and rough the barrels, but then use no bushings at all for the final "truing" and finishing work.

I don't know near as much as most of the active members here, but here are some things that I have learned can cause out of round issues. Someone can probably add to this list.

1. Poorly made bushings
2. The ends of the blank/tube not being perfectly square (even if you TBC, this is still a problem)
3. Bent mandrel (possibly from too much pressure from the tailstock with your live center)
4. The PSI mandrel saver (It is a great idea, but there's a bit too much wiggle room around the mandrel shaft for my taste)
5. Debris inside the morse taper (which can make it seem like your mandrel is bent)
6. Obviously, bad bearings on your lathe, but I think you'd know if that was the issue

@1080Wayne, Thank you for that tip! I will remember that (probably right after swearing a bit but, hopefully, before throwing something).

The loose band is a "feature". It's a built in fidget spinner!

 

[Todd in PA]

1. The ends of the blank/tube not being perfectly square (even if you TBC, this is still a problem)

Thank you for all your suggestions.
I think in this case #1 is my culprit.

im having a hard time trimming the ends square. I was doing it on the disk sander using the square, but then I'm really squaring to one corner and not to the tube.

I bought a barrel trimmer for the lathe, and a dedicated pen blank chuck, every which way I set them up, it vibrates. Not every time, but 50% of the time. I drill the centers in the exact same way, with the tail drill chuck and pen blank chuck so I'm puzzled. The vibration has knocked out tubes before. Squaring the blank seems like a small task, but it remains a struggle for me.

 

[leehljp]

It never cease to amaze me for a preference to complications and and then seeing simplicity as something to be avoided.
Mandrel problems:
1. bent mandrel
2. too tight of tail stock will introduce wobble on the mandrel
3. too tight brass nut on the mandrel can force things out of alignment.
4. loose spacers - spacers can wobble on the mandrel.
5. using the wrong tail stock Live Center with the mandrel (needs a 60° live center on a mandrel) It can work well for a while on non-60° live centers and then suddenly it does not. The point on non-60° centers balls up, causing wobble.
Next two are not specific to mandrels only
6. sanding the blank down to size can often cause softer wood to sand down faster than harder size.
7. non square blank ends

The first 5 are not applicable to the simplicity of TBC.
There is another problem with mandrels - bushings sticking to blank when CA'ed; Snapping the bushings off can and often does the cause the CA to lift off the turned blank.

 

[sorcerertd]

As far as squaring, if I know the blank is solid and stable, I start with a classic barrel trimmer in a hand held drill, but this is my real squaring setup.

1. Sink cutout mounted on a faceplate with a PSA disc. That one is either 120 or 150 grit.
2. Cheap transfer punches from Harbor Freight. Easy to find a good fit for any tube size
3. Drill chuck to hold the transfer punch, and now the shiny new...
4. Offset sanding jig from Rick Harell. You'll see this mentioned by a lot of folks here.

My order of operations was to square the blank with the barrel trimmer, rough it down part way, square it again on the lathe setup, complete shaping and CA finishing, then one more final squaring (very, very carefully) to clean up any CA before assembly. Rick's jig allows the transfer punch to be used off center on the sanding disc to make use of more sanding surface and really speed things up. That jig is new to me, and has only been used 2 or 3 times, but I think the barrel trimmer will be almost completely unemployed now. I plan to stick with the punch centered in the chuck for the final step since it is much less aggressive than the offset.

 

[Todd in PA]

It never cease to amaze me for a preference to complications and and then seeing simplicity as something to be avoided.

Hi, Hank!

I think it is more of a sunk-cost issue than a preference for complications or a refusal to adapt. I am a type who reads a lot on this forum, watches videos and I am earnestly trying to build upon and improve my skillset. There is a part of me that feels particularly wasteful if I don't use a tool I purchased or if I don't learn one technique to my satisfaction before adopting a better one. For example, I learned to use and sharpen the HSS chisels that I already had, before buying the carbide set.

I bought a mandrel (because I was told I needed one at PSI). And it has produced pretty good results over the short term. I'm already bumping into it's limitations in my first 50 pens. I'm interested in advice about the equipment that I have, and on making these tools produce better results.

Having said that, I'm sure that I will be turning between centers before too long. Todd Moore has a pretty sweet setup for trimming. I'll probably abandon my method for trimming pretty soon too and get some of these items.

 

[cmiller]

Hi Todd, I was having this same problem--after making 100 pens suddenly the blanks were very slightly out of round. Not much, but noticeable. I bought a new mandrel, still the same problem. Long story short, I bought one of these: https://www.rockler.com/nova-pen-ma...MItr6TjPPE7wIVUuTICh2I-AfSEAQYASABEgLhM_D_BwE
This thing tightens everything up in a different way, it's too hard to try and explain, but it worked. No more blanks out of round.
As far as the center bands go, on some kits I use CA to glue them down to the end of one blank or the other. It's terrifying, I've ruined a few pens this way. But if you're careful, you can glue them down. Someday someone here will come up with a solution for this...

 

[cmiller]

Sorry, that link above didn't work. Try this one: https://www.teknatool.com/products/lathe-accessories/nova-pen-mandrel-saver-2mt-sku-9048/
I got mine at the local Woodcrafters

 

[cmiller]

It never cease to amaze me for a preference to complications and and then seeing simplicity as something to be avoided.
Mandrel problems:
1. bent mandrel
2. too tight of tail stock will introduce wobble on the mandrel
3. too tight brass nut on the mandrel can force things out of alignment.
4. loose spacers - spacers can wobble on the mandrel.
5. using the wrong tail stock Live Center with the mandrel (needs a 60° live center on a mandrel) It can work well for a while on non-60° live centers and then suddenly it does not. The point on non-60° centers balls up, causing wobble.
Next two are not specific to mandrels only
6. sanding the blank down to size can often cause softer wood to sand down faster than harder size.
7. non square blank ends

One more thing: while I'm happy with the item I purchased above, I also may be guilty of #2, 3, and 5 on this list. So fixing those things will work too, I bet. Especially #5, I did notice that the little nib on my live center was getting chewed up. I was at the store trying to replace it when the employee recommended the new mandrel saver piece.

 

[leehljp]

Just a bit of information: most everyone who uses a mandrel should already have a 60° live center in their tail stock to use with the mandrel, so no price increase there. Any salesman who tries to steer anyone to use the common wood stock fine point is not worth listening to. (Sorry about ending with a preposition.) And all that is need is a dead drive center for the head stock - $12 - $20 depending on where.

I got started without even having to purchase a drive center and made my own (I was living overseas at the time: https://www.penturners.org/media/imported-photo-from-leehljp.3521/

• Much less parts,
• Cheaper (more money left in the pocket)
• Much more precision
• Faster to take off the lathe to check and put back on than with a mandrel.