Call me the "Mandrel Bender " :-)

[TonyL]

Well....I am in in this hobby for two weeks and 14 pens and I have bent two mandrels. Something tells me they are supposed to last juts a little longer than that . There seems to be a fine line (figurative line), between too loose and blanks spinning and too tight and mandrel bending. My first acrylic pen took me almost 3 hours, now I am way down from that, but I am definitely more aggressive with my turning.

Should the blanks spin every once in a while when squaring of the corners or is that an indication to tighten move the tall stock toward the head stock?

Using Easy Tools - if that helps.

Thank you!

 

[walshjp17]

It would appear you may be using too much force from the tail stock. If you have not already invested in a mandrel saver, I recommend buying (or bartering for) one as it will enable you to put just enough pressure on the blanks without bending the mandrel. You can find one here ==> Exotic Blanks :: Tools, Glues & Finishing :: Tools :: Pen Mandrel Saver - choose version

 

[glen r]

I've been turning between centers for a few years now but every once in a while I turn a kit that seems to work better using a mandrel and the bushings. When I first started turning I bought a mandrel saver and found that over tightening the mandrel nut is a problem of the past.

 

[Hendu3270]

What John said. Get a mandrel saver.

 

[TonyL]

"Sadly", I am bending them WITH the mandrel saver. I just must have my tail stock in too close. Thank you for the advice.

 

[Hendu3270]

You're turning with bushings, right? Are you using a bunch of spacers between the blank and the mandrel saver by chance?

Have you looked to make sure your centers line up and something isn't out of whack?

Oh, and if I've not secured the tailstock against the blank enough and it spins, I tighten so it doesn't spin. Not enough to break anything, but to prevent the spin.

 

[kovalcik]

If you are bending mandrels while using a mandrel saver, then I think the issue is too much force from your tools or while sanding. My guess is you are doing mostly 2 barrel pens so the exposed mandrel is fairly long. Keep the working part of the mandrel as short as short as possible (use minimal spacers) and use a light touch with your tools and while sanding.

 

[larryc]

I thought you told me you had a Mandrel Saver?

Well....I am in in this hobby for two weeks and 14 pens and I have bent two mandrels. Something tells me they are supposed to last juts a little longer than that . There seems to be a fine line (figurative line), between too loose and blanks spinning and too tight and mandrel bending. My first acrylic pen took me almost 3 hours, now I am way down from that, but I am definitely more aggressive with my turning.

Should the blanks spin every once in a while when squaring of the corners or is that an indication to tighten move the tall stock toward the head stock?

Using Easy Tools - if that helps.

Thank you!

 

[Dan Masshardt]

What's a mandrel?

 

[Hendu3270]

You're not using a screwdriver to turn these down are you? Might be one reason for too much pressure when turning.:bulgy-eyes:

Definitely only have one blank at a time. Especially when making your finishing cuts.

 

[Edgar]

In addition to a mandrel saver, you might also want to consider an adjustable mandrel. It might just be my imagination, but it seems to me that the adjustable mandrel is more stable & has less of a tendency to flex than a standard mandrel.

I like this one with the adjustment bars, but there are similar models available that use wrenches for adjustment.

#2 Morse Taper Keyless Pen Mandrel System at Penn State Industries

 

[kovalcik]

When you are turning a pen, what all is on the mandrel (assume a slimline)? Start your description at the headstock and work to the tailstock.

 

[TonyL]

I do have a mandrel saver...sorry for not including that.
And I bet I am applying too much pressure when sanding.
I am using bushings.
I am turning two sections at a time, but I am going to stop this practice. B. Gross warn against it.

Thank you.

 

[plano_harry]

Tony, if you are going to only turn one tube at a time, you may as well go between centers. It is quicker than putting blanks on and off a mandrel.

One of the few justifications for a mandrel is that you can see both blanks together if you are working a shape where you would like to visualize the whole pen together.

If you are trying to turn a blank in record time, you may be pushing too hard with your tool or with sandpaper. When squaring, if the tool is not super sharp you may hang a corner and spin the blank a little. That is normal. A sharp skew or carbide on edge with a slicing cut will reduce the tendency to snag from a scraping cut.

 

[hcpens]

It is funny how most if not all of the "How to Turn a Pen" u tube video's, (that I have viewed) seem to never talk about a Mandrel Saver, or TBC bushings. I think it is a conspiracy of the Mandrel manufactures.

 

[gimpy]

Make sure your tools are SHARP
they may be dull and that is forcing you to
push harder to make a cut......

sharp, sharp, sharp......

 

[jcm71]

Tony, if you are bending mandrels you should be able to feel vibration when turning. When you get a new mandrel try this test. Put bushings and tubes only on the mandrel, tighten as you normally do, turn it up to your turning speed (mine is 4000 rpm), and feel along the mandrel for any vibration. You should feel none (assuming your bushings are true). If you do, you have either over tightened or your lathe is out of alignment. Back down on your on your tightening and try again. If over tightening is not your problem, check your alignment. If you don't already have a dead center and a live center, buy them (you'll need them when you advance to Turning Between Centers anyways). Their points should line up exactly when you advance your tail stock to the head stock.

If your alignment is OK and you are not over tightening, you are probably applying too much force to the blank when turning. Remember, sharp tools and a light touch. Don't be in a rush.

When turning, even when using a mandrel, only turn one barrel at a time. The rationale is simple. A full length pencil bends a lot easier and a lot more than one half its length. Mandrels are no different. When you advance to TBC you'll be doing one at a time anyways.

By the way, were your turnings out of round? They should have been with a bent mandrel.

Good luck.

John

 

[OLDMAN5050]

With a mandrel saver there is no way to bend the mandrel unless you are putting so much pressure on the blank while tooling the blank. The mandrel saver provides a means which to not put any pressure on the mandrel.. You should go to home depot and buy a piece of 1/4 drill rod and then cut the rod to be the mandrel.. much cheaper than buying mandrel rods....Just saying......

 

[Cmiles1985]

So, you're using the Easy Wood Tools carbide tool for your turning, and you've turned 14 pens. Are you still using the same edge in the carbide cutter? It may be that after the first five pens or so, it just isn't sharp anymore and needs to be rotated.

 

[Sylvanite]

Are you sure you aren't bending them with your mind? Try putting a new mandrel on the lathe, and just think about turning for a while. Then see if it's still straight.

Sorry :biggrin:, couldn't resist.

Eric

 

[TonyL]

I wish

Are you sure you aren't bending them with your mind? Try putting a new mandrel on the lathe, and just think about turning for a while. Then see if it's still straight.

Sorry :biggrin:, couldn't resist.

Eric

Funny, but I am just getting the hang of bending spoon

 

[TonyL]

Bending mandrels

You're turning with bushings, right? Are you using a bunch of spacers between the blank and the mandrel saver by chance?

Have you looked to make sure your centers line up and something isn't out of whack?

Oh, and if I've not secured the tailstock against the blank enough and it spins, I tighten so it doesn't spin. Not enough to break anything, but to prevent the spin.

I am not using spacers, but I am doing all of the above. I have to go more lightly I guess. Thank you.

 

[TonyL]

Mander bending

If you are bending mandrels while using a mandrel saver, then I think the issue is too much force from your tools or while sanding. My guess is you are doing mostly 2 barrel pens so the exposed mandrel is fairly long. Keep the working part of the mandrel as short as short as possible (use minimal spacers) and use a light touch with your tools and while sanding.

You are right, all two barrel pens. And in the beginning, I was definitely sanding too hard. Thank you.

 

[TonyL]

Mander bending

You're not using a screwdriver to turn these down are you? Might be one reason for too much pressure when turning.:bulgy-eyes:

Definitely only have one blank at a time. Especially when making your finishing cuts.

You would think I was using a hammer Thank you.

 

[TonyL]

Mander bending

What's a mandrel?

The thing that Tony keeps bending

 

[TonyL]

Mander bending

In addition to a mandrel saver, you might also want to consider an adjustable mandrel. It might just be my imagination, but it seems to me that the adjustable mandrel is more stable & has less of a tendency to flex than a standard mandrel.

I like this one with the adjustment bars, but there are similar models available that use wrenches for adjustment.

#2 Morse Taper Keyless Pen Mandrel System at Penn State Industries

Mine is not keyless, but it is adjustable. Thank you.

 

[TonyL]

Mander bending

When you are turning a pen, what all is on the mandrel (assume a slimline)? Start your description at the headstock and work to the tailstock.

head stock, locking nuts, washer, bushing, upper barrel, bushing, lower barrel, bushing, mandrel saver, tail stock . Thank you.

 

[TonyL]

Mander bending

Tony, if you are going to only turn one tube at a time, you may as well go between centers. It is quicker than putting blanks on and off a mandrel.

One of the few justifications for a mandrel is that you can see both blanks together if you are working a shape where you would like to visualize the whole pen together.

If you are trying to turn a blank in record time, you may be pushing too hard with your tool or with sandpaper. When squaring, if the tool is not super sharp you may hang a corner and spin the blank a little. That is normal. A sharp skew or carbide on edge with a slicing cut will reduce the tendency to snag from a scraping cut.

Thank you Harry. I am thinking about going between centers.

 

[TonyL]

Mander bending

Tony, if you are bending mandrels you should be able to feel vibration when turning. When you get a new mandrel try this test. Put bushings and tubes only on the mandrel, tighten as you normally do, turn it up to your turning speed (mine is 4000 rpm), and feel along the mandrel for any vibration. You should feel none (assuming your bushings are true). If you do, you have either over tightened or your lathe is out of alignment. Back down on your on your tightening and try again. If over tightening is not your problem, check your alignment. If you don't already have a dead center and a live center, buy them (you'll need them when you advance to Turning Between Centers anyways). Their points should line up exactly when you advance your tail stock to the head stock.

If your alignment is OK and you are not over tightening, you are probably applying too much force to the blank when turning. Remember, sharp tools and a light touch. Don't be in a rush.

When turning, even when using a mandrel, only turn one barrel at a time. The rationale is simple. A full length pencil bends a lot easier and a lot more than one half its length. Mandrels are no different. When you advance to TBC you'll be doing one at a time anyways.

By the way, were your turnings out of round? They should have been with a bent mandrel.

Good luck.

John

Thank you John...my centers are spot on. I tested them 4 times over two weeks. I just think I need to lighten-up on all and go with one barrel at a time. Thanks again. All of this feedback is outstanding.

 

[TonyL]

Mander bending

With a mandrel saver there is no way to bend the mandrel unless you are putting so much pressure on the blank while tooling the blank. The mandrel saver provides a means which to not put any pressure on the mandrel.. You should go to home depot and buy a piece of 1/4 drill rod and then cut the rod to be the mandrel.. much cheaper than buying mandrel rods....Just saying......

Thanks Dave. I just bought my third mandrel. I am going to HD tomorrow and try your idea.

 

[TonyL]

Mander bending

So, you're using the Easy Wood Tools carbide tool for your turning, and you've turned 14 pens. Are you still using the same edge in the carbide cutter? It may be that after the first five pens or so, it just isn't sharp anymore and needs to be rotated.

Believe it or not, I have completely rotated my 3/8 square blade (just ordered another one from PSI 1 hour ago). I have also rotated my round blade, but not completely yet (ordered a spare anyway). I thought they last longer (probably do my more experienced turners). Thank you for the reply.

 

[scottsheapens]

Come on over to South Carolina Tony. I will show you how I turn pens with a pen mandrel and mandrel saver. I used to live in Roswell off Post Oak Tritt near the Cobb/Fulton Country line (ESL).

Glad to help.

Jim

 

[OLDMAN5050]

You can sharpen a carbide cutter. Buy a diamond stone and take the carbide off the tool use water as a lube turn the cutting edge flat on the stone 15 minutes later you have an edge as sharp as a new one. I have made hundreds from one cutter. There is a YouTube video showing how to do this. Cpt Eddie I believe did the video. Come on up the invite is still on the table.

 

[Hendu3270]

You can sharpen a carbide cutter. Buy a diamond stone and take the carbide off the tool use water as a lube turn the cutting edge flat on the stone 15 minutes later you have an edge as sharp as a new one. I have made hundreds from one cutter. There is a YouTube video showing how to do this. Cpt Eddie I believe did the video. Come on up the invite is still on the table.

That's what I use, except with a drop of oil and it only takes 10-15 seconds for mine.

 

[randyrls]

One thing that no-one mentioned. If you do not use a pen mill on your blanks to ensure the ends are perpendicular to the brass tube, it is possible to bend the mandrel from clamping pressure on the mandrel.

 

[TonyL]

Mander bending

One thing that no-one mentioned. If you do not use a pen mill on your blanks to ensure the ends are perpendicular to the brass tube, it is possible to bend the mandrel from clamping pressure on the mandrel.

That's is true. I do use one (a barrel trimmer...assuming that is the same thing or serves the same purpose).

It is great to know all that can contribute to a bent mandrel. Thank you.

 

[TonyL]

Mander bending

You can sharpen a carbide cutter. Buy a diamond stone and take the carbide off the tool use water as a lube turn the cutting edge flat on the stone 15 minutes later you have an edge as sharp as a new one. I have made hundreds from one cutter. There is a YouTube video showing how to do this. Cpt Eddie I believe did the video. Come on up the invite is still on the table.

Please PM me when I could call you tomorrow or Thursday. Thx!

 

[Paul in OKC]

Can't imagine what would be causing this. I do not follow the thought of the tail stock applying too much pressure. Where is it bending? I turn a few pens still on the mandrel, both barrels. Have used the same mandrel for years. One thought, are you using the original center that came with your wood lathe? If so, the point is not the same angle as what is in the end of the mandrel. The point will stick in the bottom of the center drilled hole causing the thing to run out eventually. If that is the case, you can file off the point about 1/16" so it does not go in too far.

 

[TonyL]

Mander bending

Can't imagine what would be causing this. I do not follow the thought of the tail stock applying too much pressure. Where is it bending? I turn a few pens still on the mandrel, both barrels. Have used the same mandrel for years. One thought, are you using the original center that came with your wood lathe? If so, the point is not the same angle as what is in the end of the mandrel. The point will stick in the bottom of the center drilled hole causing the thing to run out eventually. If that is the case, you can file off the point about 1/16" so it does not go in too far.[/quote

Thanks for your help and questions. I will attempt to answer them; I am not doing this three weeks yet.

Even though I am using a mandrel saver, I may have the tail stock slid too close to the head stock. Perhaps, this is squeezing or causing the mandrel to bow (Again, I am guessing).

As far as the original center. The only original center I use, is the pointed one that came with my jet lathe. And I only use it on my buffing wheel which came with its own mandrel (the Barry Gross Buffing System)otherwise I never use it.

Thank you for offering your help!

 

[lwalper]

I'm afraid I don't understand the problem at all. The mandrel saver applies no pressure on the mandrel at all. What's going to bend? I'm new to all this too and just don't see it. I've been reading here how some folks turn their blanks between centers without a mandrel, but that's essentially what is happening with the mandrel saver -- you've just got a rod running through the middle.

The only problem I can see using the mandrel saver is that whatever slop (sliding clearance between the bushings/brass tubes and mandrel) there is between the mandrel and bushing (or tube), even if it's only a couple thousandths of an inch, will potentially introduce that much runout in your project. The mandrel is not bent -- it's slop in the system. Turning between 60 degree centers, without the mandrel, will eliminate that runout. Try rolling your mandrel on a truly flat surface and see if it's actually bent.

I've been trying to figure out how to turn 7mm tubes between centers because there's no flange on the bushing to go inside the tube and hold everything together. I've also been wondering about the unwanted tool chatter I sometimes get. It might just be that small amount of runout which allows the blank to move slightly (that couple of thousandths of an inch) on the mandrel. Turning between centers would eliminate that.