Bushing and center band fit(or not)

[papNal]

The last 4 pens I finished didn't fit flush to the center band,close but you can feel a slight edge.I made sure the finish was even with the bushing before taking off mandrel,using a slimline Woodcraft kit,just a plain band,is this normal or am I not doing something to get that last smooth fit?I'm not turning a flat barrel but have a slight slope(convex) on upper and bottom wood. As usual thanks for any help.pap

 

[bitshird]

Pap, are you using a 60 degree live center or the one that came with your lathe? using the center that comes with a wood lathe won't work well in the end of any mandrel. the stock centers have a very sharp point and a cup and are designed to hold wood, where as the mandrels have a 60 degree center hole, so the mandrels can move around a bit and give a bad fit, or you might also be over tightening the tailstock this too will cause fitment problems.

 

[Wheaties]

Had some of the same problems but now I don't trust any bushings. I turn very close to the bushings, then measure the parts of the kits with a caliper, and turn to that size (stopping to measure the barrels frequently). It's a tad more work, but I haven't had a bad fit since I started doing that not too long ago.

 

[Robert Taylor]

getting a good fit

ditto what zach said.

 

[papNal]

Pap, are you using a 60 degree live center or the one that came with your lathe? using the center that comes with a wood lathe won't work well in the end of any mandrel. the stock centers have a very sharp point and a cup and are designed to hold wood, where as the mandrels have a 60 degree center hole, so the mandrels can move around a bit and give a bad fit, or you might also be over tightening the tailstock this too will cause fitment problems.

Yes,matter of fact I just got one last week,it works great.

 

[papNal]

Thanks everyone,I'll go the caliper route and see what else rears its ugly head.pap

 

[papNal]

One other question that I keep forgetting to ask and I haven't seen it posted anywhere.Some of the kits I have uses a stepped drill looks like from a 7mm to about 5/16" or smaller.What do you use to square the small end with,the pen mill is too big and I haven't seen a small pilot for it?Just wondering,guess I could sand it square if necessary. pap

 

[Wheaties]

One other question that I keep forgetting to ask and I haven't seen it posted anywhere.Some of the kits I have uses a stepped drill looks like from a 7mm to about 5/16" or smaller.What do you use to square the small end with,the pen mill is too big and I haven't seen a small pilot for it?Just wondering,guess I could sand it square if necessary. pap

If I understand correctly, I would turn a solid piece of wood to "hold the place" of the metal mill bar and use it as normal. But I may not be understanding you correctly. If not, let me know.

 

[Mac]

Have learned in the past that some factory bushings are out of round,so I turn close to bushings (not to close) then rotate bushings on blank then I know if my bushings are out of round . If thats the case I either throw away or mark then out of round. Then I always finish with calipers between centers, as I do ca finish on most of my pens.
As for your other ? I just bought some Aero kits and none of my mills worked ,so I drilled 7mm hole in blank turned down to fit inside of correct pen tube, using calipers. Marked it for aeros ,another tool made.
After rereading your 2nd ? the kits that are talking about if I'am understanding correctly have shoulders that need to be turned down on the lathe.I made a letter opener that I had to do that to. hope some of this helps.
Maybe if I knew what kit????

 

[DurocShark]

Did this bushing work in the past and only recently seem to make the blank too thick?

That happened to me. Took me forever to figure out why. Then I realized that I had CA buildup on the bushing making it larger. Now I have a jar of acetone near my lathe and when I do a CA finish when I'm done I toss the bushings in there overnight. Takes the CA right off.

 

[papNal]

Sorry for the confusion.I'm not sure what the kit is with the stepped tube,but it looks simular to the PSI mini designer twist pen.the upper tube is 7mm, the lower tube is stepped down. Also on the bushing problem,they have only been used on 4 pens so more than likely they are not sized correctly.I'll go with measuring from now on .Thanks