Tailstock live center ... Should this worry me? Am I doing something wrong?

[ccharles]

Hello!

I have turned about 13 pens since getting my lathe on 10/27! All have been done using the 7mm PSI collet style pen mandrel w/ standard 60 degree live center in the tailstock.

I was looking at my center today and I have a pretty significant groove that has formed from the pen mandrel end. (See photos attached)

Questions:
1. What is likely causing this? Am I using too much pressure on the end of the mandrel when I snug up the tailstock? Or possibly, not enough pressure?
2. Is it something I should be concerned about? My TBC bushings just arrived in the mail today, so I am going to start doing my turning between centers.
3. Any other recommendations?

Thanks a lot! I love this hobby and this community!

Kind regards,
Chris

 

[Mike]

Does the live center turn freely?

Mike

 

[KenB259]

If you're going to use a mandrel, get a mandrel saver.

 

[Woodchipper]

Had that for years. Goes with the territory. Welcome to IAP.

 

[Mike]

Yeah, I have been using a mandrel saver for a while now. But I didn't have that groove when I was using that live center. My live center is a Nova.

Mike

 

[ccharles]

Does the live center turn freely?

Mike

Yep, smooth as silk and no wobble. Bearings feel good.

If you're going to use a mandrel, get a mandrel saver.

Great idea ... I was planning to move over to TBC, but will keep that in mind!

Had that for years. Goes with the territory. Welcome to IAP.

Thanks, glad I am not alone.

Yeah, I have been using a mandrel saver for a while now. But I didn't have that groove when I was using that live center. My live center is a Nova.

Mike

Hmmm ... mine is just the standard stock PSI center. It is apparently pretty soft steel. I called PSI tech support; they will replace it under warranty, but not unless the tip breaks off.

 

[egnald]

My first live center did the very same thing. I was researching a "true" Carbide Tipped Live Center, but before I bought one, I found the PSI mandrel saver. (They even produced a YouTube video about it where they stated "Are you tired of bending your mandrel and ruining the point on your live center?".

The only thing I didn't like about it was that the through hole was large enough that it allowed a little slop and wobble -- just too much clearance between it and the mandrel shaft. Then I found the Hold Fast Mandrel Saver by TMIProducts. It used to be sold by WoodTurningz. It came with a type of collet insert that tightens down on the mandrel shaft and centers it more precisely than what is achieved by the mandrel savers that just have a clearance hole through them. The mandrel saver also came with a Cup Center insert and a 60-degree Center insert.

Unfortunately it was discontinued (at least by WoodTurningz) and a cursory search on Google didn't turn up anything either. It's too bad because TMI Products offered some really good stuff. For example, they were the first to bring the Hold Fast Non-Stick Bushings to the market (I think anyway).

Not only that, the next best thing, the Woodpeckers Ultra-Shear Pen Mandrel System has also been discontinued. So my only recommendation at this time would be to look for a high quality carbide tipped live center to minimize wear.

Dave

 

[d_bondi]

The only thing I didn't like about it was that the through hole was large enough that it allowed a little slop and wobble -- just too much clearance between it and the mandrel shaft. Then I found the Hold Fast Mandrel Saver by TMIProducts. It used to be sold by WoodTurningz. It came with a type of collet insert that tightens down on the mandrel shaft and centers it more precisely than what is achieved by the mandrel savers that just have a clearance hole through them. The mandrel saver also came with a Cup Center insert and a 60-degree Center insert.

Unfortunately it was discontinued (at least by WoodTurningz) and a cursory search on Google didn't turn up anything either. It's too bad because TMI Products offered some really good stuff. For example, they were the first to bring the Hold Fast Non-Stick Bushings to the market (I think anyway).

Turners Warehouse has a similar setup from Record Power. It is a bit pricy, but well made.

Spur Drives, Lathe Drives, Live Centers | Turners Warehouse

Ensure precise and accurate results every time with our high-quality Spur Drives, Lathe Drives, and Live Centers. Crafted with precision in mind, these headstock and tailstock accessories are perfect for all your turning needs

www.turnerswarehouse.com

 

[ccharles]

Thanks guys, appreciate the feedback.

Now, I am pretty sure my live center is just made of defective material.

I ran my brand new TBC bushings tonight to turn down a single blank. First two pics below show live center and TBC bushing from tailstock end of lathe. Other two pics show dead center and TBC bushing from headstock end.

 

[bugradx2]

Thanks guys, appreciate the feedback.

Now, I am pretty sure my live center is just made of defective material.

I ran my brand new TBC bushings tonight to turn down a single blank. First two pics below show live center and TBC bushing from tailstock end of lathe. Other two pics show dead center and TBC bushing from headstock end.

Sorry to hear that you're having trouble, I'm only a couple years out in front of you and wish I'd gone to turn between centers as fast as you did.

It's tough to tell the wear on your live center, it could be now that it's started it's going to keep going.

When I was looking at turn between center options I had a couple people recommend this one. If you ever replace what you are currently using I'd recommend looking at it.

https://exoticblanks.com/products/turn-between-centers-mandrel-systems?_pos=1&_sid=e95b3560a&_ss=r

It takes regular bushings which is nice.

 

[egnald]

Sorry to hear that you're having trouble, I'm only a couple years out in front of you and wish I'd gone to turn between centers as fast as you did.

It's tough to tell the wear on your live center, it could be now that it's started it's going to keep going.

When I was looking at turn between center options I had a couple people recommend this one. If you ever replace what you are currently using I'd recommend looking at it.

https://exoticblanks.com/products/turn-between-centers-mandrel-systems?_pos=1&_sid=e95b3560a&_ss=r

It takes regular bushings which is nice.

That TBC mandrel system can come in very handy for other things too. Occasionally I drill a 7mm hole in a piece of stock then turn custom jam chucks to put on that mandrel. It works great for all sorts of materials that have odd sized holes in the ends. - Dave

 

[greggm]

I used a 60 deg live center when I first started pen turning. I quickly found out that method easily caused bowing of the mandrel and caused issues with the blanks. I purchased a mandrel saver from Penn State Industries, and never looked back.

 

[BHuij]

My cheap 60° live center has the same issue but even worse. Tip just gets all dinged up whenever I use it to touch anything that isn't wood.

Still works fine though so I'm not sweating it too much. If and when it's time to replace it, I'll probably get a carbide tipped one.

 

[ccharles]

Thanks for all the advice! I really appreciate it!

Here is the plan I have formulated. Please poke holes in it if I am missing something!

1. I turned a blank this morning using the TBC bushings. Wear looks even worse on the live center (it appears like oxidation just under the surface - literally looked like rust when I cleaned out the end of the TBC bushing.) So ... I am going to replace the live center - I just ordered this one from TBC bushings - looks like a good one, and Brian was really good to me on my last order!
2. I am going to order a Mandrel Saver. The one drawback with the TBC setup is that you cannot turn two blanks at once with it - so, for productivity's sake, I want to have the ability to turn two blanks together. As I get more creative in my profiles, I can see that having the blanks in-line on the mandrel will help to get a better visual of what the transition is going to look like from blank to blank.
3. My current mandrel will be set and ready to go for a quick swap on the lathe for my final blank squaring/touchup after finishing (I set up a poor-man's sanding disk for doing a final touch up before assembly - see photo attached) My blank squaring process is: use the trimmer tool on my drill press to make quick work of squaring and getting rid of excess material down to the brass tube, turn blank, finish blank, touch up ever so lightly on sanding disk to get perfectly squared. I was not happy with the fit I was getting from using the trimmer alone - I was just ever so slightly uneven on end of blank and it showed up in assembly.
4. I will keep that TBC mandrel system in my back pocket as a future option!

Thanks again to all! This is a fantastic forum, and I am learning so much from you pen turning veterans!

Kind regards,
Chris

 

[BHuij]

Yeah I'm the same with you on point #2. I will TBC when I can (even got TBC slimline bushings), but if I'm making a 2-part pen, I'll throw both parts on the mandrel for sanding and finishing just because it's way faster than doing them one-at-a-time. And because it lets me use my soft plastic non-stick bushings for CA finish.

 

[egnald]

Just for future reference....

I know of at least one pen kit, the twist version of the Faith, Hope and Love kit, at least at one time (like in 2022-ish), had a problem with a gap at the center band. It turns out that the gap was not due to the squareness of the blank but was caused by the kit's center band itself. The center band was not square with the centerline of the tube which caused an uneven gap where it met the blank. Since it was a known problem/complaint with the kit it might have been corrected by now.

- Dave

 

[ccharles]

Just for future reference....

I know of at least one pen kit, the twist version of the Faith, Hope and Love kit, at least at one time (like in 2022-ish), had a problem with a gap at the center band. It turns out that the gap was not due to the squareness of the blank but was caused by the kit's center band itself. The center band was not square with the centerline of the tube which caused an uneven gap where it met the blank. Since it was a known problem/complaint with the kit it might have been corrected by now.

- Dave

Good to know, thanks Dave!