TBC + Light Sanding + New Lathe still equals out of round on the nib end

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RunnerVince

Member
Joined
Dec 18, 2019
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346
Location
Ogden, UT
Hi all,

I've been making pens for a couple years now, and at first I had a lot of trouble with the blanks not truly fitting with the hardware. I've made quite a bit of progress, but I'm still having issues getting that perfect fit.

The odd thing is that it's really just on the nib end. The clip end of the pen usually has a little more tolerance because the clip goes between the cap and the blank, but even so, I've been getting a really good fit. And I can get a very nice transition between the center band and the blank on two-piece pens. But I'm consistenly getting a poor fit at the nib end. The transition will be great on one side, but rotate 180 degrees to the opposite side and you can feel that the tip is proud of the blank by maybe 1/32" or 1/64". It's not someone who doesn't make pens would think was even a problem, but it's driving me insane. If it were simply my inability to get the size correct, I'd just leave the blank slightly larger and sand/skew in a bevel to meet the tip piece, but it's more than that.

Here's what I've done:
  • I've checked the alignment between headstock and tailstock. With my drive spur and live center, the points line up perfectly.
  • I started with a "mandrel saver" setup that supposedly would put pressure only on the bushings, not the mandrel. I had the same problem with my original MT1 mandrel and the second MT2 mandrel saver I got for my new lathe. I've since moved to a TBC setup from PSI.
  • I've added more patience to my sanding, and I now sand with as little pressure as I can. With the lathe running, I can't "feel" the blank is out of round.
  • I upgraded from my 65-year-old Craftsman monotube to a brand new Rikon. (Not to solve this problem but because it was just time.)
  • I've stopped relying on the bushings and started using calipers to get to the exact dimensions.
  • I've tried turning my pens with the nib end closer to the headstock instead of the tailstock thinking if there was an alignment issue, it'd be less pronounced closer to the headstock.
All of these are things I've gotten as suggestions from reading this message board. Is there something else I'm missing? I'd appreciate any additional advice.
 
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Maybe... When you are at the point where one more pass of the skew will get it. Stop the lathe, loosen the tailstock just enough to rotate the blank 180 degrees and take that last pass. Take it out of the lathe and press in a nib to check it. If it works knock out the nib and finish sanding.
 
Dieseldoc said:
Are you sure your blank is square On both ends?
Click to expand...
Given my current equipment, I'm as sure as I can be. I use the PSI barrel trimmer in my hand drill. I don't have the money/space for a drill press or even a disc sander, but if there's a way to do it on the lathe that would work better, I'm all ears.
 
Charlie already said this, but it is extremely important that the ends of the blank are square to its axis ..... at both ends.

The other thing ..... about your TBC method ..... do you use any bushings at all ?

Mandrel with bushings is the way most of us start off turning pens ..... this method is intrinsically prone to inaccuracy, so we move on to TBC.
But the folks who make bushings still want us to buy bushings .... TBC bushings, now ..... but that method also has inaccuracies.

What I recommend is TBC with NO BUSHINGS at all .... just your dead center, live center and a pair of digital calipers. . Have you tried that ?
 
It's the perfect time! Rick makes a barrel trimmer setup for the lathe! And he is running a discount currently!

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Well, it's that time again! 20% OFF EVERYTHING for the whole month! You can find all my products here... https://www.penturners.org/threads/custom-made-penturning-tools-accessories.92501/ I will also be donating 10% of my sales to the IAP, that means the more you spend with me, the more I...
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RunnerVince said:
Given my current equipment, I'm as sure as I can be. I use the PSI barrel trimmer in my hand drill. I don't have the money/space for a drill press or even a disc sander, but if there's a way to do it on the lathe that would work better, I'm all ears.
Click to expand...

Yes, you can do the end squaring on a lathe .... a metal lathe is best .... but a wood lathe is also a "can-do" if you do it carefully.

Mount your blank (preferrably not longer than 3") in your headstock chuck jaws and VERY CAREFULLY trim your blank end square.
You have to develop the skill to hold and move your cutting tool in such a way as to make the end square. . This will take practice, but well worth it.

MAKE SURE that there is no "wobble", whatsoever, in your blank as it turns.

To ensure this, you can start by aligning the blank very accurately with the lathe axis. . You will need a shallow dimple in the end of your blank.
Use a 60 degree center in your tailstock and bring that up to the exposed end of your blank to get the alignment "spot on".
Then tighten your headstock jaws.
Then, back off the tail stock to give you access to the exposed end of your blank.
 
I used to have the same problem. The answer was given from the responses shown above. I got rid of my barrel trimmer some time back and now use the offset jig from Rick shown above. I made my own face plate, got my disc sandpaper from Amazon and haven't had an out of square blank since. Plus, the jig doesn't tear up your blank ends like the trimmer can.
 
magpens said:
Charlie already said this, but it is extremely important that the ends of the blank are square to its axis ..... at both ends.

The other thing ..... about your TBC method ..... do you use any bushings at all ?

Mandrel with bushings is the way most of us start off turning pens ..... this method is intrinsically prone to inaccuracy, so we move on to TBC.
But the folks who make bushings still want us to buy bushings .... TBC bushings, now ..... but that method also has inaccuracies.

What I recommend is TBC with NO BUSHINGS at all .... just your dead center, live center and a pair of digital calipers. . Have you tried that ?
Click to expand...
I have not tried with no bushings. I have a dead center, but it's home made from pine, so I'm not sure I trust it. :) I'll definitely look into getting a dead center and then I'll try this out if I haven't solved the issue by then.
 
RunnerVince said:
I have not tried with no bushings. I have a dead center, but it's home made from pine, so I'm not sure I trust it. :) I'll definitely look into getting a dead center and then I'll try this out if I haven't solved the issue by then.
Click to expand...

You need a STEEL dead center and a STEEL live center. . . "Home-made" is not good enough, IMHO !!!
 
Thanks all. Sounds like, given my current setup, this is a problem that I'll have to throw some money at.
I'll try the dead center/live center combo first because it's the cheapest and I can use the dead center in other applications.
After that, I'll look at Rick's setup for ensuring my ends are squared, or maybe look at a cheap and small disc sander.
 
It seems that out of round being caused by ends being out of square would require an end mill pilot being insanely loose in the tube. Try the tube on the dead and live center first.
 
RunnerVince said:
Thanks all. Sounds like, given my current setup, this is a problem that I'll have to throw some money at.
I'll try the dead center/live center combo first because it's the cheapest and I can use the dead center in other applications.
After that, I'll look at Rick's setup for ensuring my ends are squared, or maybe look at a cheap and small disc sander.
Click to expand...

I learned a long time ago that throwing money at a cheap tool is just that, throwing money away. Try Ricks tool. The upfront cost far outweighs the amount of money you'll waste on other tools. Rick's not the only guy out there but I've owned mine for about a year now and it's well worth the $50.00 (I think) I spent on it. Trust me, I wasted a ton of blanks by blowing them up with a barrel trimmer. You'll need a few more things, like transfer punches (Harbor Freight-Cheap) and you'll need to make a face plate to attach your sanding discs too. All in all you're probably looking at under $100.00 and you can easily spend that much trying to correct what your experiencing right now. I'm no expert but a lot of what you're seeing above is expert advice (mine excluded), these turners are good at what they do and they won't steer you wrong. Heed their words. Best of luck in your turning adventures!
 
I think the PSI faux TBC device is a bad option. Get real TBC bushings from a Brian Nikitas and never look back. I gave my PSI device away and took the loss. If your dead center and live center line up when viewed from various angles and you use Nikitas's TBC and have carefully squared ends - your issues will be gone. Yes, I understand that you will need bushings for each kit you use (I have them). Manufacturers bushings are suspect and when you add PSI's so-called TBC adapter you add too much slop.

This is my opinion, but I use it and my out of round issues are years behind.
 
IMHO the most cost effective approach to near perfect squaring is to use a scroll chuck or collet chuck on the lathe. The squaring jig might be less expensive initial investment, but a scroll chuck is kind of a mandatory tool that most people will want for other lathe work. A collet chuck is a little more accurate, somewhat versatile but more specialized compared to the scroll chuck. To do the squaring - turn the blank between centers (with brass glued) to a cylinder, mount in chuck, using a sharp pointed skew face the end perpendicular until you barely touch the brass. It takes a little practice, but I feel that I can achieve near perfect squareness without much effort using this method.
 
Not to discourage new tools and Ricks tools but no need for them. If you have a knock punch set or transfer set as they are called then that is a start. This is needed anyway so should bea tool in the arsenal. Then there is a drill chuck which again if you drill blanks on the lathe which is the prefered method by many then you have this tool. Now comes the face plate and all lathes are sold with a faceplate of some sort and size and it does not have to be a specific size. but add a flat piece of either acrylic or metal to it using double sided tape and now you have a disc sander. Rick's tool is just a way to hold the transfer punch and you have that with a drill chuck. Get some sticky back sandpaper and I like to use 120 and sometimes grab the 180 but it depends on the blank. Cut small pieces and insert the proper transfer punch in drill chuck and sand the ends till the brass is shiney and even. If the cut or end is not square just take a sharpie and make a series of marks or actually just color the end of the blank. Now as you sand you will see the marks come off. Untill you get no marks and brass shiney is when you are there. Do this for all ends. Do not use hook and loop sandpaper because it is too soft and will round the ends of the blank if you sand when the blank is at finished size. I do not recommend it. That is my thoughts and have been doing this for many years and have had success. The other point about bushings and yes they can actually be made out of round so that is why people are telling you to do this without them. But what I would do is use you mandrel or other method till you get close to finished size and then put between the centers. I say this because what people forget to tell you it is very possible to flare the ends of those thin tubes if you put too much pressure on them when tightening. Usually when you first turn a blank down it will require a bit more force but when you get to almost finished size your cuts need to be very light to sneal up on correct size and checking with calipers. OK that is all for now.

One thing I forgot to add is you can easily move the sandpaper around the disc to use all areas of it and not waste it. Again this is what I do.
 
jttheclockman said:
Not to discourage new tools and Ricks tools but no need for them. If you have a knock punch set or transfer set as they are called then that is a start. This is needed anyway so should bea tool in the arsenal. Then there is a drill chuck which again if you drill blanks on the lathe which is the prefered method by many then you have this tool. Now comes the face plate and all lathes are sold with a faceplate of some sort and size and it does not have to be a specific size. but add a flat piece of either acrylic or metal to it using double sided tape and now you have a disc sander. Rick's tool is just a way to hold the transfer punch and you have that with a drill chuck. Get some sticky back sandpaper and I like to use 120 and sometimes grab the 180 but it depends on the blank. Cut small pieces and insert the proper transfer punch in drill chuck and sand the ends till the brass is shiney and even. If the cut or end is not square just take a sharpie and make a series of marks or actually just color the end of the blank. Now as you sand you will see the marks come off. Untill you get no marks and brass shiney is when you are there. Do this for all ends. Do not use hook and loop sandpaper because it is too soft and will round the ends of the blank if you sand when the blank is at finished size. I do not recommend it. That is my thoughts and have been doing this for many years and have had success. The other point about bushings and yes they can actually be made out of round so that is why people are telling you to do this without them. But what I would do is use you mandrel or other method till you get close to finished size and then put between the centers. I say this because what people forget to tell you it is very possible to flare the ends of those thin tubes if you put too much pressure on them when tightening. Usually when you first turn a blank down it will require a bit more force but when you get to almost finished size your cuts need to be very light to sneal up on correct size and checking with calipers. OK that is all for now.

One thing I forgot to add is you can easily move the sandpaper around the disc to use all areas of it and not waste it. Again this is what I do.
Click to expand...
Thanks for the advice on a no-/low-cost method.
 
Vince; I will suggest a metal dead center in the head stock, and also; Check the taper to make sure there is NO crud in it. Even a little crud will throw off the center. If you find crdu, clean it out with a brass gun brush.
When and if you order a dead center. They are ~$10 + shipping. Make sure you get the MT taper that matches your lathe. MT1, MT2 and MT3 are common. Most wood lathes have MT2 but some smaller lathes have MT1.
Hope this helps!
 
randyrls said:
Vince; I will suggest a metal dead center in the head stock, and also; Check the taper to make sure there is NO crud in it. Even a little crud will throw off the center. If you find crdu, clean it out with a brass gun brush.
When and if you order a dead center. They are ~$10 + shipping. Make sure you get the MT taper that matches your lathe. MT1, MT2 and MT3 are common. Most wood lathes have MT2 but some smaller lathes have MT1.
Hope this helps!
Click to expand...
Where do you find one for $10 plus shipping? I've needed one a few times for other things, so it's been on my list to get for a while. That and a better drive spur.
 
RunnerVince said:
Where do you find one for $10 plus shipping? I've needed one a few times for other things, so it's been on my list to get for a while. That and a better drive spur.
Click to expand...
Little Machine Shop has all sorts of things that are useful in pen making. They sell things to the metal lathe 7x crowd, but many of the items can be used in pen making. This is an MT2 dead center - $6.80
https://littlemachineshop.com/products/product_view.php?ProductID=1890&category=

This one is hardened and ground for $7.95
https://littlemachineshop.com/products/product_view.php?ProductID=5473&category=

For spur drive, looks like the going price is just under $30 from Wood turning stores, but can be had cheaper.
 
Didn't think I'd be getting a bonus this year, but I did, so I have a little extra money to play with, and I'm thinking of getting Rick's tool and using a faceplate with sandpaper. Any suggestions on a good brand of adhesive-backed paper?
 
RunnerVince said:
Didn't think I'd be getting a bonus this year, but I did, so I have a little extra money to play with, and I'm thinking of getting Rick's tool and using a faceplate with sandpaper. Any suggestions on a good brand of adhesive-backed paper?
Click to expand...


I got my discs off of Amazon. Dura Gold brand, 80 grit and a box of 50 discs. My set up is very similar to Ed's on the video above. I got these from Harbor Freight for $9.99

PITTSBURGH

Transfer Punch Set, 28 Pc.


Check out Ed's video above for the details. Good luck with your project.
 
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