Penn State Turning Between Centers Mandrel System

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AJMwoodcrafts

Member
Joined
Oct 30, 2017
Messages
49
Location
Ontario, NY
Contents:
Instructions
Storage Box
TBC Mandrels

2dc6c3fb0ee771e2eb7b41dcb35821a0.jpg


Initial Impressions:
I received the mandrel system today and took it for a test turn. I really enjoyed the increased accuracy of the system. I was able ti get very close to the bushings since the mandrel spins so true.

Pros:
Accuracy Accuracy Accuracy
The mandrel is compatible with all of my standard bushings (that work with a 7mm mandrel). This includes compound (center) bushings (see pic).
It’s simple to use and changing out bushings is very simple.

Con:
Harder to manage 2 tube pen kits (compared to standard mandrel). I’m use to setting up the tubes on the lathe in their final orientation. I’ll use my old standard mandrel for finishing.

Conclusion:
I’ll never go back to a standard mandrel with the exception of finishing.



With cigar center bushing on left
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With finished tube
b34a7d2d133b2f104d978e0b21e1dbd8.jpg




Sent from my iPhone using Penturners.org mobile app
 
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Rockytime

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Jun 3, 2014
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1,074
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Arvada, CO 80003
I don't get it. It looks like you are still using bushings. Are these just a Morris taper with a 1/4" stub on which you still have to use 7mm bushings?
 

KB8JXO

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Joined
Mar 18, 2016
Messages
37
Location
Kewanee IL
Thanks for the report

I got a set for Christmas and waiting for the temperature to get above freezing to try it out. (Nothing runs when the garage is below zero.)
 
Joined
Jan 10, 2013
Messages
208
Location
Howell, Michigan
Not sure what the advantage is. There is still the problem of bushing to adapter size. If the bushing didn't run true (off center) on the mandrel shaft, it shouldn't run true on the adapter, either.
 

Talltim

Member
Joined
Mar 12, 2017
Messages
650
Location
Tennessee
Not sure what the advantage is. There is still the problem of bushing to adapter size. If the bushing didn't run true (off center) on the mandrel shaft, it shouldn't run true on the adapter, either.

Sometimes you can get bushings that are not true but generally it is the fault of a warped mandrel.


The advantages of the psi system depend on what you are comparing it with. If you are comparing it with TBC using 60 degree centers it is cheaper than buying the special TBC bushings. And standard bushing tend to wear the 60 degree centers a little faster.

If you are comparing it to a traditional mandrel set up you do not have to worry about the rod warping.

The disadvantage might be that I am not convinced the quality of the psi system’s bearings are that high so it’s its longevity still remains to be seen.

We have had the psi system long so time might make me totally reverse my opinions later.
 
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woodwurker

Member
Joined
Jan 22, 2017
Messages
1
Location
Albany, Ohio
Am I the only one?

I've had my PSI TBC system for about six months now and have pretty much relegated it to the pile of tools that I wish worked but don't.

The reason I went to TBC was to eliminate the problem of the final diameters being off center (I'm sure there is a term which describes this phenomenon), but after receiving the set from PSI, the piece with the bearing had so much run-out that I called them to ask what was going on. They said it was probably just a bad one so they sent another one right away. The folks at PSI have always been very helpful, I only wish that their products were of the same quality.

After receiving the replacement, and putting it to the test, all I can say is I saw no improvement at all. I can hold the piece in my hand and feel the deflection just by moving it around.

Now, I'm certainly no expert, but I've been making pens for twenty years and can recognize problems with pens (the fingernail click test being my favorite method). Maybe someone here has the fix for this issue. The ability to use standard bushings is very inviting, if I could get it to work.
 
Joined
Aug 2, 2016
Messages
21
Location
Orlando, Florida
I have this mandrel set. I used it for about 10 single, and short tube pens, and it worked great. Now, though, the stub of mandrel on the headstock side, is bent, ever so slightly. The closer to the tailstock, the truer it runs. I have a messed up cocobolo blank, right now, that is waaaay out of round. This almost worked. I'm either getting a Whiteside Pro mandrel, or switching to TBC bushings for the pens I turn. I hate that it was a failure, but I hate worse, that it was a waste of money.
 
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