Turning below the bushing?

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Haynie

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I have read several times on this forum that folks turn their barrels down a hair below the bushing to accommodate the CA finish.

Having done only a couple of wood pens I thought I would give it a try. I quickly mangled the bushings. How do people turn below the bushing without mangling the bushings?

I have also read that people do not turn below the bushings. As a wood newbie what would you suggest I do?
 
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Justturnin

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as for not hitting the bushing I find that impossible..... but this is what I do. I turn the blank down not below the bushings but .10-.15mm below that actual part. Then I build back up w/ ca to .15-.20mm above the finished size. I then sand it back down as close to 0 as I can get w/out going over. I usually end up .03-.05mm from the finished size and I cant feel that when I run my nail across it.

Building up higher than the bushings helps me be sure that I will get all of the ridges out before I hit the MM phase of sanding.
 

terryf

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With the correct use of a skew, you should be able to get in real close and not do any damage to the bushing. That said, its bound to happen and I have certainly wacked a few bushings, mostly through haste than anything else.

I generally turn down to a smidgen below part size and then sand smooth and build up with CA. What you havent mentioned is the type of material and it will make a difference. I find that the softer the material the less I'm inclined to go below the bushings as sanding can quickly take you well below size. I'd rather stop just over and then sand a tad bit longer than have to apply a half inch of CA. (ok not really half and inch but you get the idea:)
 

Texatdurango

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I have read several times on this forum that folks turn their barrels down a hair below the bushing to accommodate the CA finish.

Having done only a couple of wood pens I thought I would give it a try. I quickly mangled the bushings. How do people turn below the bushing without mangling the bushings?

I have also read that people do not turn below the bushings. As a wood newbie what would you suggest I do?
Mark, I have a tutorial in the library entitled "Turning between centers". If you have a look at the tutorial around photo 12 or 13, you will see where I transition from bushings to centers for the remainder of the turning/finishing tasks. When I made a lot of kits, this is how I turned all of them so it's a proven method that quite a few have taken up.

To save you searching the library, here is the link.... http://content.penturners.org/library/techniques/turningbetweencenters.pdf
 

Haynie

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Read the tutorial. I get it, but now I wonder if all live centers are 60 degree. I need to buy one for the jet mini and metal lathe anyway
 

Texatdurango

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Read the tutorial. I get it, but now I wonder if all live centers are 60 degree. I need to buy one for the jet mini and metal lathe anyway

To turn the way I do, you don't HAVE to use 60 degree centers but I think you'll find they are pretty common and cheap.

After I did the tutorial, a few folks were knocking this method and stated that one would stretch or even crack the tubes/blanks by tightening them on the centers directly.

My answer to them was to use some common sense and not tighten the tailstock with 500 lbs feet of torque! Actually, I use less force tightening the blanks onto the centers than I used to secure the bushings.
 

randyrls

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With the correct use of a skew, you should be able to get in real close and not do any damage to the bushing. That said, its bound to happen and I have certainly wacked a few bushings, mostly through haste than anything else.

To join the thread; My skews have a flat grind on them. When you get very close to the correct size, lay the skew on the bushing and cut toward the barrel. If you do this correctly, you will not ding the bushings and you can get the barrel size exactly the size of your bushing. Now sand lightly and apply the CA finish to rebuild the size up to the correct size.

I often sand the bushings until they are .003" to 005" undersize. Then my build up will get to the exact size.
 

Mariner1

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Read the tutorial. I get it, but now I wonder if all live centers are 60 degree. I need to buy one for the jet mini and metal lathe anyway

No not all have a 60 degree angle, there are others available. Just read the description close and it should tell you if it is 60 or not.

Karl
 

jim_colo

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Turning below the bushings

Read the tutorial. I get it, but now I wonder if all live centers are 60 degree. I need to buy one for the jet mini and metal lathe anyway


I see you have a metal lathe! I make my bushing with a small Unimat lathe to the size I need. :wink:
 

GrantH

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I'm about to a point where I am not going to be using bushings at all anymore. Today I was turning a cocobolo heart/sapwood pen and my bushings somehow ( no idea how) put my off center. I had more material on side than the other...I have absolutely no idea what I did wrong.

That being said, I turned between centers for the first time today and LOVED it! I don't know why people even recommend the mandrels to people. Between center is soooo much easier/studier and much more fun. The only down side being that you can't CA finish both at the same time.
 

terryf

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The problem is that not all pen parts are the same size and very seldom the same size as the bushings we have in their current state! (unless they're new)

With the correct use of a skew, you should be able to get in real close and not do any damage to the bushing. That said, its bound to happen and I have certainly wacked a few bushings, mostly through haste than anything else.

To join the thread; My skews have a flat grind on them. When you get very close to the correct size, lay the skew on the bushing and cut toward the barrel. If you do this correctly, you will not ding the bushings and you can get the barrel size exactly the size of your bushing. Now sand lightly and apply the CA finish to rebuild the size up to the correct size.

I often sand the bushings until they are .003" to 005" undersize. Then my build up will get to the exact size.
 

GoatRider

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I'm about to a point where I am not going to be using bushings at all anymore. Today I was turning a cocobolo heart/sapwood pen and my bushings somehow ( no idea how) put my off center. I had more material on side than the other...I have absolutely no idea what I did wrong.

That happened to me when I didn't square the ends of the blanks perfectly, and/or used too much pressure on the mandrel nut. It bends the mandrel.
 

GrantH

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I'm about to a point where I am not going to be using bushings at all anymore. Today I was turning a cocobolo heart/sapwood pen and my bushings somehow ( no idea how) put my off center. I had more material on side than the other...I have absolutely no idea what I did wrong.

That happened to me when I didn't square the ends of the blanks perfectly, and/or used too much pressure on the mandrel nut. It bends the mandrel.

This wasn't on the mandrel, this was all btw centers. I'm pretty sure I was straight edged though as I trim my excess with my spindle gouge until I hit brass. It actually ended up fine though, not something i'd sell...but it was a pen for me anyways. The Atrix BP pens actually cover the lower "transmission converter" so my flaws are covered!
 
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