Question about turning between centers.

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J

jojomcdugal

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Jul 18, 2014
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23
Location
Cheboygan, MI
I am interested in trying to turn between centers. The question I have is what type of drive center should be used. I can't seem to find one without spurs on it and using one of those seems dangerous to me. Could someone tell me how to either work around them or find one without spurs? Any help would be greatly appreciated.
 
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volozhin said:
Do you need special bushings for this? If yes, why?
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The whole idea of turning between centers is to avoid bushings in favor of more accurate sizing. You pinch the tube mounted blanked between a dead center (head stock) and live center (tail stock) turn as normal accept you will need to use calipers or another measuring tool to size it.

You will also need to clean up the ends of each blank from CA or finish that rolls over the edge. If not, your finish will chip off when you press them together at assembly time.
 
I like to use bushings to protect the ends of tubes and blanks. Otherwise you can put outward pressure if you tighten too much. I make sure the bushing is centered and the correct angle by drilling the holes with a center drill.
 
I use the standard bushing when I turn between centers. I then remove the bushings to do my CA finish. Personally I have found that any out of round issues are primarily because of the mandrel, not the bushings. On the rare occasion that I think I have an issue I have found the smallest amount of glue in the tube causing the problem. Try experimenting. You can always use the bushing when removing the bulk of the material and then remove them for the final cuts.
 
Both bushings and mandrel can cause out-of-round

My personal view .... I do not use bushings of any kind when doing TBC. I found that the bushings I was previously using, as well as the mandrel, were both contributing to out-of-round issues I was having.
 
I am only doing this a year, but about 300 pens worth. I ditched the mandrel about a month into this, and started TBC. Now, I have even ditched the bushings as I start to get about 10% -5% from the final diameter. I used to think not using bushings was some sort of voodoo, now I like it. Have said that, I just bought a bunch of RBC from lazerlinez (Constant). I do like support bushings provide on the ends..but with a sharp skew or carbide insert, I habe not found to need the bushing. I definitely need calipers. FWIW... :-) PS. when I apply a CA finish. I don't use any bushings (not even the delrin)...thanks to what good friend and IAP member advised me to do.
 
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