What do you think???

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Interesting, but I think unless your mandrel fits snugly into it there is still a potential for out of round. If the diameter of my mandrel is less than the diameter of the opening then when I tighten it up it will be sitting on the bottom of the live center and be off center by the difference in diameters. May not be enough to notice or it may. I don't know how far off one can be before it becomes noticeable.
 
In reading the material, it says it will fit mandrels of .245 diameter or smaller. This would cause me to think it would only fit the PSI mandrels which are slightly smaller diameter. Mandrels typically used are the 7mm mandrels which equate to .2755 diamter but are slightly less due to the tube wall thickness. I can't measure one exctly but I'm sure someone will help us out.
 
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dalemcginnis said:
Interesting, but I think unless your mandrel fits snugly into it there is still a potential for out of round. If the diameter of my mandrel is less than the diameter of the opening then when I tighten it up it will be sitting on the bottom of the live center and be off center by the difference in diameters. May not be enough to notice or it may. I don't know how far off one can be before it becomes noticeable.
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I see what you mean Dale. There doesn't seem to be a chuck on the end that would tighten and center the mandrel rod.
 
beck3906 said:
In reading the material, it says it will fit mandrels of .245 diameter or smaller. This would cause me to think it would only fit the PSI mandrels which are slightly smaller diameter. Mandrels typically used are the 7mm mandrels which equate to .2755 diamter but are slightly less due to the tube wall thickness. I can't measure one exctly but I'm sure someone will help us out.
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The 7mm is just a reference to the suggested drill size for the tube.
Most all "7mm" mandrels measure around .245-.246.
 
Keeps from bending mandrels?? This is the solution to a problem that shouldn't be there in the 1st place. The tail-center is there to support the end of the mandrel, not drive it through the headstock. If you are having to use so much pressure that the mandrel bends, you have more problems than this thing is going to solve.
 
Saw it in the new catalog...

...and thought it was a damned interesting concept since there's no pressure on the tailstock end of the pen mandrel.

I'm on the waiting list.

t.
 
Well, I'm a tad lost on what it is supposedly doing..the mandrel is laying in the new gizmo..I envisoned a collet chuck arrangement that would grip the mandrel and then PULL the mandrel..thus no kinking the mandrel..but this(from the picture) seems silly...what am I missing? Funny thing is I have been pondering pen mandrels lately and wondered if I could find a collet chuck that was "live" that I could pull a mandrel....
 
Mick

If you look at the end of the item in the picture it is basically a live center with an opening in the end. The opening is for the rod of the pen mandrel to slide into. You have your kit bushings on the mandrel and now this live center slides right up to the back of the bushing. You now lock the tailstock down and turn the quill so that this live center is now snug against the bushing and turn away. Basically you are apply the tailstock pressure against the bushing rather than against the mandrel rod.

This is basically what turning betwen centers is all about when people refer to that. Just in that case there is no mandrel just properly fitted bushings with holes in the outside ends to accept a dead center infrom the headstock and a live center from the tailstock. Hope that clears it up.

The advantage to this over the last point I made is that you do not have to buy all new bushings and you can still turn between centers so to speak.
 
At that price it's worth a try. The only problem I have with turning between centers is I like to have both blanks turned together. My 'eye' can get a better sense of the shape of the entire pen.
 
Rmartin said:
At that price it's worth a try. The only problem I have with turning between centers is I like to have both blanks turned together. My 'eye' can get a better sense of the shape of the entire pen.
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Those were my thoughts exactly... UNTIL I started turning between centers a few times. It feels so much more rigid to me that I stuck to it and got used to turning each piece separately. I haven't had any out of round issues yet, and don't expect to. And I don't even have Johnnycnc's bushings yet!
 
Standard mandrel is alleged to be "D" drill sized at 0.2460 - The PSI mandrels have tended to be a bit under that and Berea perhaps 0.001 over -

I use an 8mm "B" mandrel when ever possible because it has more cross section area (stiffer) and less subject to damage. (Think cigars, El Grande, etc) This is not going to work with that mandrel

If you already have a good live center (I am using one way with penmakers center) you can turn between centers without a mandrel or with mandrels -

Hey John -- This is a good opportunity for tooling junkies - I will pass on this one, but let us know how you like it.
 
The only advantage I can really see in it is that it may stop someone from over tightening the tailstock and bending the mandrel. I like turning between centers but this may be an option for some of my students.
 
Poor mans set up for turning between centers

PSI has been out of stock on these ever since I first saw them advertised. It should be a very inexpensive way to "basically" turn between centers. As soon as these are available, I'll use them and write a review.
 
I just got one from PSI and have turned a couple of pens with it. I think it does a pretty good job, but can't really tell much difference from using the take up nut. The one thing it does do is slightly shorten the mandrel rod between the supports and it makes it a bit more stable. I have a turncrafter Pro and the tailstock does not seem to tighten up on the bushing as much as it should. Then if the blank has much resistance when turning it will slow down or even stop and the mandrel just spins in the tubes. Maybe a Jet or another lathe can put more pressure against the bushings. That is my product report.
Steve
 
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