Blank Ends

[kooseman]

Could you please tell me (novice turner) if the ends of the pen blanks should be flush with the bushings when the pen is completed. That is, when all sanding/finishing is completed. I'm aware that there should be a smooth transition between the bushings and blanks and I just completed a pen that I thought accomplished this. However, when I removed the blanks from the mandrel and assembled it, there was a small lip extending beyond the center ring. Could this have been a dimensional defect of the pen kit? It's very frustrating as a beginner, to painstakingly complete a pen, thinking all steps have been completed, and find out the final fit is not as intended. Thanks again for any and all advice.

 

[srf1114]

A picture would help, but it sounds like your blank is out of round. This can happen if you applying just a bit to much pressure while turning. The center of the mandrel is the most likely place as well, since it has the least support.

 

[ve3bax]

most bushings are good for little more than a rough guide... get yourself a nice set of callipers... i have a few different ones but for 90% of my pens i use a simple OD calliper without a gauge or anything... just a feeler type setup... i then set the calliper to the size of the part that will mate with each end of the barrel and carefully finish until the calliper will just slide over the blank end. on a pen where i want it to be 100% exact fit i will break out the vernier callipers and again, measure each piece and turn/finish/etc until a matching measurement is achieved.

i realize this SOUNDS like a lot of extra work, but with a bit of practice it doesn't really add much time and the fit quality will go WAY up.

--Dave

 

[thewishman]

When turning with a mandrel, stop the lathe periodically and loosen the nut, rotate the bushings in opposite directions to the barrel and then re-tighten nut and turn some more. Do this three or four times and it should help keep your barrels round.

 

[wiset1]

Blank should be flush with brass tube. If not then you run the risk of cracking the final turn under pressure of kit instillation. The tube will support your kit when installed. Hope I understood the question.

 

[kooseman]

Thanks for the great advice about the callipers. As a beginner, I'm still a little cautious of eliminating too much material at the ends of the blanks. The slimline pen I turned looks really attractive even with the small extension, as it looks deliberate. I'm assuming the callipers will help me eliminate these lips. It'll give it a shot. Thanks again Dave.

 

[kooseman]

Blank end is flush prior to turning. I'm having a bit of a task getting the ends to flush with the OD of the center ring to give a clean smooth design line. I'm somewhat leary of removing (turning & sanding) too much and risk any blowout. I'm using an Easy Wood mini finisher and because of its round tip, it's difficult for me to judge how close I am to the tube while turning. Thanks again for your advice.

 

[BSea]

I'm guessing your pens are wood. And depending on the amount of finish, your diameter can change based on the layers of finish. Many people sand slightly below the bushings to compensate for the buildup of their finish. Then they build up their finish till it's slightly proud of the bushing dimension, then lightly sand to get to the correct finished diameter. Yes it sounds like more work, and to do it as described, it does take more time & effort. But when you get it perfect, you'll know it.

PR is easier since you don't have to build up a finish.

 

[arcwick08]

I've had that result in the past -- my culprit was an out of square blank end. There are a million ways to square a pen end; mills, disc sanders, table saws, gnawing, you name it.