2 most annoying aspects of penturning

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Tiger

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Over my time as a penturner 2 things have not changed much and they both cause some frustration.

1. I generally use the standard mandrel, no matter how much I tighten the knurled nut most times as I apply the tool to the work the tool will catch the pen barrels and the barrels spin. I then have to stop the lathe and tighten the knurled nut, it's almost as though the nut slips and works its way loose. This may happen a couple of times during the turning. I know that you can turn b/w centers and I do that occassionally but when I make a slimline pen I like to turn both barrels simultaneously.

2. You've turned your pen, applied your finish and then assemble your pen and the barrel develop fine cracks.

I'm not expecting a solution to either of these but if you have any helpful suggestions I'd like to hear them.
 
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solution to problem 1:- fit a locking nut behind the knurled nut, works for me, my madrel was supplied with one.
problem 2:- what finish are you applying, is it the finish or actual barrel material cracking?
 
Thanks for the quick replies, that was fast!

Didn't get a locking nut but can probably adapt something. These days I generally use a CA finish, I would say it's the wood cracking. Tools are sharp.
 
I used to have the same issue with cracks developing on the barrel when using a pen press. It is difficult to ensure both pieces are lined up correctly, resulting in the component pieces going in at a angles, which crack the wood.

I took the metal rod out of the pen press and put into my drill press. Since doing this, I no longer have issues.
 
Two of these things have already been mentioned here in seperate posts but I will tell you I had the exact same issues as you.

PSI Mandrel saver....huge upgrade over the knurled knob. It's quicker in use (especially if quantity turning) and also helps prevent warped pen shafts.

Clean tubes...not only do I ensure there is no residue in the tubes prior to assembly but I chamfer the pen tube edges with an X-acto knife. This does two things:

1. Provides a small amount of relief right at the component edge reducing the stress on the sometimes very thin material reducing the cracks from assembly pressure
2. Helps seat the component in the tube preventing misallignment and cracks developing from the component being pressed in at a slight angle

Just my 2¢.
 
I replace the knurled knob on the mandrel with a nut, so I can crank down on it when roughing. Finger-tight is not tight enough. I loosen it up after it's round.

AFAIK, I can't use a mandrel saver on my Taig lathe, because it doesn't have a morse taper spindle or tailstock.
 
Thanks for the suggestions. I will try a nut instead of the knurled wheel and see how that goes.

I always clean out the glue from the barrels before assembly and I use the drill press, I've also noted great variability with pen parts and some are tighter than others.
 
I am curious if the cracks you are referring to are shortly after the fact or a day or two later. I had a problem with cracks forming, which I found to be due to using too much accelerant, or being too close with it, while using CA. I learned to back way off with it. A very light mist, and let it sit a bit longer. That stopped my cracks.
 
To handle the cracking I use a small round file and run it in and out of the tube so the it is just a little looser so I can push the fitting part way in by hand and I use a cotton swab to wipe the tube id clean. Than before I put the fitting in I use a drop of CA to make sure the fitting doesnt fall out.
 
Tiger said:
Over my time as a penturner 2 things have not changed much and they both cause some frustration.

1. I generally use the standard mandrel, no matter how much I tighten the knurled nut most times as I apply the tool to the work the tool will catch the pen barrels and the barrels spin. I then have to stop the lathe and tighten the knurled nut, it's almost as though the nut slips and works its way loose. This may happen a couple of times during the turning. I know that you can turn b/w centers and I do that occassionally but when I make a slimline pen I like to turn both barrels simultaneously.

2. You've turned your pen, applied your finish and then assemble your pen and the barrel develop fine cracks.

I'm not expecting a solution to either of these but if you have any helpful suggestions I'd like to hear them.
Click to expand...

You remind me of me :cool:

Now I didn't read all of the responses, I just figured I would throw my 2 cents - this all may have already been said.


Solution to number 1 for me started with a mandrel saver from PSI. They work great, they slide over the mandrel and push against the bushings. Then just tighten up and go. However, I still had a habit of bending my mandrels from too much pressure from my turning tools or what not. So now I turn between centers. (Still need to get a small tool rest, pain in the neck without my standard one.)

Solution to number 2 - I had this problem a lot, and there are a several things you can do.

1 - most things crack due to expansion of the material as you slide in your hardware. Make sure you have no glue on the inside of the CA tube. Some 180 grit sand paper spun around on the inside a couple times usually eliminates it unless there is a lot.

2 - Make sure the edge isn't coated think with your finish. I had problems when I would have a small build up on the ends with CA. When I assembled it would push the CA (which had no tube or anything inside of it) and cause it to crack off the wood.

3. Be gentle, slow - and push in straight. This is very critical to the survival of your finished product. Also - to ease insertion, consider some linseed oil or something of that sort. A very small amount. It makes it easier to slide the pieces in and doesn't seem to cause them to back out at all, especially if set for a while.
 
Thank you again for your help. I have a mandrel saver and I love using it, however I have cracked some barrels probably from applying too much pressure with the mandrel saver so I solved problem 1 and by solving it I've caused problem 2 :biggrin:.

I think the main reason I have had cracks while assembling is that the pen kits can vary considerably and some of the transmissions are a little oversize.
Rsidetrack I'll give the linseed oil a try to ease assembly, good tip.
 
It seems to me the solution to problem #1 is not the brass nut or the mandrel saver but your tool control. Why the catches? Definitely not the brass nut or mandrel saver! Tightening the brass nut or the mandrel saver too tight can cause problems other than your #1 or 2. Figure out why you get the catches when you start turning and solve that problem and #1 will be solve itself.

What tool are you using?

Do a good turn daily!
Don
 
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taig lathes

GoatRider said:
I replace the knurled knob on the mandrel with a nut, so I can crank down on it when roughing. Finger-tight is not tight enough. I loosen it up after it's round.

AFAIK, I can't use a mandrel saver on my Taig lathe, because it doesn't have a morse taper spindle or tailstock.
Click to expand...


hi goat rider strange name by the way !

enco has adaptors to adapt mt 2 to a straight stem or shank.

also taig offers a mt tail stock.

farmer
 
its_virgil said:
It seems to me the solution to problem #1 is not the brass nut or the mandrel saver but your tool control. Why the catches? Definitely not the brass nut or mandrel saver! Tightening the brass nut or the mandrel saver too tight can cause problems other than your #1 or 2. Figure out why you get the catches when you start turning and solve that problem and #1 will be solve itself.

What tool are you using?

Do a good turn daily!
Don
Click to expand...

I find the blanks just spin when you apply the tool whether it's a gouge or skew which are typically what I use. This is reduced once the blanks have the corners off. Always found it hard to judge just how tight to go with the brass nut, mandrel saver seems to have helped here because you can easily tighten the tailstock while the lathe is running.
 
One more thing that will contribute to both issues if it exists - if the wood is not exactly flush with the tube, it will spin with the slightest of catches, and when you crank down on the knurled knob you are applying compression to the wood and not the tube. This causes hairline fractures all the way to complete splits. It would be the same as putting the drilled and turned wood only in a vise and cranking down. Initially it doesn't manifest itself, but as you turn closer to the tube, the wood gets thinner and cracks easier.
Just a thought.
Scott
 
Just one more idea to keep your chisel from catching. I go to my belt sander and in a matter of a minute I have all those corners rounded off. That means there is nothing to catch and everything spins smoothly. Obviously you could get the mandrel saver, but I only finger tighten my mandrel and never have problems with turning. Hope it helps.
 
I don't want to be arguminitive but many of us use a skew from start to finish and don't have problem #1 you describe. Knocking off the corners with a sander may solve the problem but I still think the problem is with how the skew or gouge are used, especially how they are introduced to the blank at the beginning. I would venture to say that a far more of us do not knock off the corners first. I could be wrong...I may be the only one who doesn't.:biggrin: Good luck with a solution to both #1 and #2.
Do a good turn daily!
Don
 
In part it depends on the hardness of the wood and also the speed, the faster the lathe, the less the problem but I have had the work stop more times than I care for. It doesn't happen with any other woodturning activity unless the drive dogs etc don't engage with the wood.
 
I use a spring washer between the nut and the bush and don't seem to get much slip if I tighten up until the split is compressed.
Regards,
John
 
Looking through the thread, one thing that I did not see mentioned or maybe I missed it was a chamfering too. This will relieve the inside edge of the brass tube and allow the pen fittings to start their slid into the barrel. Another thing that I have seen done is sanding the inside of the barrel so that the parts are a slip fit and use loctite to secure the fittings to the barrel.
 
Make sure you are dressing the ends of the blank with a pen mill or sander untill you see the brass tube. If wood is standing proud of the tube, when the bushings are tightened down the wood will both allow spinning and will crack on the ends.

Steve
 
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