Please believe that I am not being flippant here, but I need to ask "why?" (as in, "why would anyone bother forgoing a mandrel and turning a pen between centers?")
Thanks,
Gary
Gary Below is a long compilation of reasons for mandrel-less as it relates to your question:
Posted from a previous post:
http://www.penturners.org/forum/showthread.php?t=7319&page=2
People hate change. The learning curve of overcoming all the little problems associated with a mandrel is a little high. (OK, quite high for a beginner.) However, once you become proficient enough to recognize just where a problem might be, you don't want to let go (and therefore) learn a new method. Call it the Stockholm syndrome.
. . . Because the mandrel has been around for a good while - if we were to just come out and say - Don't go the mandrel route, it is too complicated - then we would probably be in for a fight and Jeff would throw all of us off! And besides, when you as a beginner see all the catalogs, online store set ups and videos that show "mandrels" - would you believe a few others who said "Don't go this way, Go mandrel-less"? People generally follow the larger crowd or commercial entities as Frank pointed out.
Most people that ask about it on this forum - think that it is complicated! Why? Because mandrels are complicated with their own inherent problems. Why believe that more precision can be more simple? Most people equate higher precision with more complication!
In this case, less IS more!
Another post on
problems related to mandrels:
1. Bent mandrel for one reason on another.
2. Mandrel flex from being too tight against the tail stock.
3. Mandrel flex from too much pressure of the chisel on hard wood, especially for beginners.
4. Mandrel / bushing fittings being slightly loose fitting will cause OOR.
Bushings with the hole drilled off center will cause the same problem on the mandrel-less method as it will for the mandrel, however it will be amplified a bit more on the mandrel.
Tail stock out of alignment will still cause problems.
However, when you eliminate 1, 2, 3 & 4 above, the difficulty in finding an OOR problem is GREATLY reduced.
ADDED BENEFIT: after bringing the blank to size or near size, take the bushings off and finish sanding to size, as measured by calipers. NO Sanding dust! Finish in this set up (no bushings) and no problem with CA/bushings sticking.
Mandrel setup versus Mandrel-less:
Steps for Mandrel:
1. put bushings on the blank
2. put spacer bushing on mandrel,
3. place bushing/blank on mandrel
4. add another spacer
5. place and add nut and tighten
6. pull up tail stock and check as to just right tightening.
Turn
Remove to check and see if it is OOR anywhere, replace and go through the 6 steps again.
For no mandrel/mandrel-less/Turn Between Centers:
1. add bushings to blank
2. put bushing/blank on lathe and hold
3. pull up tailstock and lock
Turn
Remove to see if it is OK
repeat with three steps OR leave bushings OFF and:
1. place on lathe
2. finish sanding to size without bushings and check with calipers
3. Apply finish and sand, wax, buff
Much less steps on single blank pens. DOUBLE for two part pens which makes it come out about the same, but with less chances of OOR from mandrel related issues.
Where this REALLY speeds things up is the quickness with which you can remove and check a blank for size or for how it will look against the pen kit parts, and then replacing. On some pens, I take the blank off two or three times to check something. It takes less than 10 seconds to do this with mandrel-less but 30 - 45 seconds or more (take off and put back) with mandrel set up, and more if you drop a spacer!
__________________
