Newbie Question

[JohnR06]

After I introduced myself a few weeks ago... and the consensus was "just jump in and start making some pens"... I have done so. I've made three so far. My wife loves them... whereas I look at them and say, "I could have done this [insert appropriate part, transition, etc.] better." I'm sure I'll always say that no matter how long I make 'em.

Anyway, I've been making pens with 7mm tubes. Yesterday I attempted turning a larger pen with a 10mm tube. This was done using a 7mm mandrel. When I took the wood off the mandrel... the tube was off center in relation to the wood. Looking at the end of the wood I would normally expect to see two concentric circles. In this case, the tube was off to one side - so one part of the wood was quite thin and the opposite side was rather thick. Looks to me like when I put everything on the mandrel - I locked it down with part of the tube against the mandrel, but the rest of the tube was not against the mandrel, nor was it centered around the mandrel.

The bushings that came with the kit were 7mm... I assumed I could turn it on this mandrel and not have to get a 10mm mandrel.

So, what should I do in the future to do it right? Seems like I need to center the 10mm over the 7mm mandrel - but I don't know the secret. Well, besides holding my tongue just so...

Thanks,
JohnR

 

[dennisg]

If I read you correctly, you didn't have the bushings for the new style pen you were turning? That could be a real problem. I'm not sure how you turned the blank, the 7 mm bushing should have just slid into the 10 mm tube. I need help with the terms, is the 7 mm mandrel you are using the A version. If so it's 1/4 inch diameter, and the 7 mm tube goes on nice a snug. Bigger tubes need bushing to center them or you could try to turn between center. I don't recommend that without bushings of some sort as you can flare the tubes and crack the wood when tightening enough to turn.
Please clarify and someone can help you.

 

[Smitty37]

After I introduced myself a few weeks ago... and the consensus was "just jump in and start making some pens"... I have done so. I've made three so far. My wife loves them... whereas I look at them and say, "I could have done this [insert appropriate part, transition, etc.] better." I'm sure I'll always say that no matter how long I make 'em.

Anyway, I've been making pens with 7mm tubes. Yesterday I attempted turning a larger pen with a 10mm tube. This was done using a 7mm mandrel. When I took the wood off the mandrel... the tube was off center in relation to the wood. Looking at the end of the wood I would normally expect to see two concentric circles. In this case, the tube was off to one side - so one part of the wood was quite thin and the opposite side was rather thick. Looks to me like when I put everything on the mandrel - I locked it down with part of the tube against the mandrel, but the rest of the tube was not against the mandrel, nor was it centered around the mandrel.

The bushings that came with the kit were 7mm... I assumed I could turn it on this mandrel and not have to get a 10mm mandrel.

So, what should I do in the future to do it right? Seems like I need to center the 10mm over the 7mm mandrel - but I don't know the secret. Well, besides holding my tongue just so...

Thanks,
JohnR

You don't need another mandrel and the bushings should center the tube on the mandrel, but you could have drilled the blank at an angle rather than straight through, this will cause that problem.

You could have the tail center not meeting correctly with the head center causing the mandrel to be at an angle rather then straight.

Or you could have over tightened things and bent the mandrel.

 

[sbell111]

Drilling a blank off center will not result in the final product being off center as discussed in the OP. The blank will merely spin off kilter until it is turned down.

 

[Smitty37]

True but

Drilling a blank off center will not result in the final product being off center as discussed in the OP. The blank will merely spin off kilter until it is turned down.

That is true if you turn the blank far enough but it can still be out of round on some pens if you leave a lot of wood.

Using the wrong size bushings can also cause the problem or trying to use slimline bushings with a larger pen.

 

[WoodWorkinthe530]

How do you square the ends of your blanks once the tubes are glued in? If you are using a 7mm shaft on your trimmer with an adapter tube to 10mm then the "cleaning" tip of the trimmer wouldn't have cleared glue from the pen tube. Check to see that there is no glue in the tube, that will cause the blank to sit on the bushing off center. If I use an adapter to trim a blank I always clean up the tube carefully with a small round file.

I still consider myself a newbie with only about 60 pens completed, I learn a little with everything I turn, that's half the fun!

 

[Hess]

I agree with Smithy and make sure you sand long ways!!

I found this will correct it faster at the final sanding spin by hand sanding down to the need depth or bushing where it is high