Turning Between Centers - Why?

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Mordi

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Dec 24, 2012
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I am new to pen turning and reading all the posts about TBC and trying to understand what the advantages are and why I should consider TBC?

I have seen some posts that refer to "out of round" conditions from conventional bushings - but I have not really noticed this in my pens so far. I guess I don't really know what I should be looking for or perhaps not looking closely enough? :eek:. Since I have been focusing on single barrel (Wall Street II) styles, I don't really see much of a need?

Is there a writeup or tutorial on this? I like to understand this and try it if it will improve the end product.

Thanks for the help,
Mordi
 
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The out of round issue is very real. I have a set of bushings for the Tycoon that are way out of round, but turning between centers will not fix the out of round issues. I now only turn between centers and now replace my bushings as needed with JonnyCNC's bushings. A mandrel works for starting out but I find that I do get more control and less flexing between centers. I resisted switching but now wish I had done it much sooner. There are lots of turners that don't go between centers too. I hope this helps.
 

lyonsacc

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Try it, you'll like it - to me it feels like I can control the final shape and contour so much better, especially near the ends. I use a mandrel and bushings to get close to the final size than switch to TBC. My "fit" seems to be so much better.

"I'm not gonna try it, you try it"
"No way, I'm not gonna try it"
"Hey, let's get Mikey to try it, he hates everything!"
"He likes it! Hey Mikey!"
(Life cereal commercial from the early 70's)
 

76winger

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I've not yet switch to turning between centers and seem to be one of those that do OK without making the switch.

So long as everything you're making is staying round and not getting to where the final turn pen body is thicker on one side than the other ones, you're probably OK.

So long as you don't get a lot of chattering or vibrations when you're turning you're probably OK without TBC.

So long as you're happy with your current results, then you might want to wait and let the newness of the hobby wear off. And then if you want to raise the bar to the next level, it might be time to think about trying TBC.
 

Jim Burr

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Turning Between Centers - Why?...
Because it's the best fitting pen you will ever make aside from kitless. There is so much info on "Search" that every reason on the planet is easy to find.
 

CoastalRyan

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Dec 12, 2012
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The out of round issue is very real. I have a set of bushings for the Tycoon that are way out of round, but turning between centers will not fix the out of round issues. I now only turn between centers and now replace my bushings as needed with JonnyCNC's bushings. A mandrel works for starting out but I find that I do get more control and less flexing between centers. I resisted switching but now wish I had done it much sooner. There are lots of turners that don't go between centers too. I hope this helps.
Is there a website for those bushings?

When TBC can you use the bushings that accompany most pen kits or do you need specific bushing that match up to the 60 deg. centers?
 

jttheclockman

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The out of round issue is very real. I have a set of bushings for the Tycoon that are way out of round, but turning between centers will not fix the out of round issues. I now only turn between centers and now replace my bushings as needed with JonnyCNC's bushings. A mandrel works for starting out but I find that I do get more control and less flexing between centers. I resisted switching but now wish I had done it much sooner. There are lots of turners that don't go between centers too. I hope this helps.
Is there a website for those bushings?

When TBC can you use the bushings that accompany most pen kits or do you need specific bushing that match up to the 60 deg. centers?


No you can not use the bushing that come with the kits. They do not have the conical ends to fit the live and dead centers.

JohnnyCNC is a member here that sells bushings. Look his name up.

I rarely use them because my mandrel still gives me good results. You can tell if you have an OOR situation if the blank does not fit all the way around the kit parts. It should be a smooth transition all the way around the parts. Many things can cause this and if you do a search you will read tons of info on this.
 

plano_harry

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This question has been asked and answered a lot in just the year+ that I have been a member. I like Mike's answer - if you are happy with what you are getting, keep doing it that way. It is maybe a little faster to do a single setup if you are turning two tubes, maybe.

My best kits/favorite kits I TBC, other kits, I still drag out the bushings because I already have them. I don't buy new mandrel bushings any more. I turn a new kit between centers using calipers with no bushings. If I like it, I will probably order some of JohnnyCNCs or Lazerlinez's TBC bushings. If I don't like it, I didn't waste $6 on bushings. I just like the solid feel -- and I like knowing that my bushings were precision made, not mass produced and maybe out of round.

It is a personal preference with most who have tried it, preferring to stay with it.

Harry
 

Dan Hintz

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I'll TBC for shaping to size. If it's multiple barrels, then I'll slap them both on a mandrel for final sanding and CA coat. It's more accurate to TBC, but faster to use the mandrel for the finishing steps.
 

Justturnin

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I TBC mainly for speed. I was getting good results with my mandrel but I was using a mandrel saver and only turned one barrel at a time. The lath I had at the time had a 9/16 nut head that had to be tightened and loosed to move the Tailstock. So one I got close I had to loosen the TS and slide it off the mandrel to get the piece off to check w/ my calipers. I ended up going TBC because that way I could lock my TS down and just turn the hand wheel a couple of times and the blank would come off. It was a lot faster for checking and saves me time since I check each one after each pass when I am getting close.

As for the mandrel bushings you can use them for TBC. Just get you a cheap set of center drill bits and drill out a 60* hole in the ends and the 60* Dead/Live centers will fit right in, when I did this on my wood lathe I used my pin jaws that came with my chuck to hold them. The catch to that is the bushing are likely off center, even slightly, so only use them to get close. Once you are close lose the bushings and go center to center w/ no bushings being careful not to over tighten and flare the brass and make you final cuts. Once I am done turning on my metal lathe I take it to the wood lathe for polishing between centers.
 

panamag8or

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I'm a recent convert to TBC, and it is miles ahead of turning on a mandrel, at least for me. Granted, it is a pain to just do one barrel at a time, but I use calipers, so it's not that big of a deal.
 

redbulldog

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Before the TBC's came out I was already only turning one barrel at a time, so it was very easy to make the complete change when Johnny CNC made the TBC's available.
to me it is easier in all respects, I am not in that big of a hurry on doing pens also I am not perfect!!
 

Dave Turner

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No you can not use the bushing that come with the kits. They do not have the conical ends to fit the live and dead centers.

I never had good luck using a mandrel, likely due to my poor technique (or poor mandrel). I often got chatter when turning toward the center of the mandrel and it was common to get out-of-round turnings. I soon switched to between centers turning and have never looked back. I routinely use the standard bushings that come with the kits when turning between centers. I find them to work fine with the conical live and dead centers. I only use the bushings to get "close" to the desired diameter. I then take off the bushings and turn with the cones resting directly on the brass tube, using digital calipers to bring it to its final size. It always comes out perfect this way.
 

Chasper

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I turn between centers because it is faster. Yes, faster than turning two or even three sections at once. The load and reload process is much faster and turning goes faster because I can be more aggressive without bending the mandrel and getting excessive chatter.
 

Russianwolf

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Most stock bushings can be use to TBC (as long as they are a stepped design to hold the pen tube, bushings for slimlines won't work). BUT as mentioned the stock bushings can be not quite right and are designed to wear out quickly.

The TBC specific bushings from Johnny (maybe others, but I know Johnny's well) are made from a harder steel and don't wear out unless you are VERY abusive to them. And they fit tight enough in the tubes to make a pressure "pop" when you remove them.

Very good tolerances + harder material = only needing to buy them once.

As mentioned, if you are getting good results, don't worry about it. But mandrels can be bent or bowed, you can apply too much pressure with a dull tube and bow it more, the stock bushing may be drilled off center right out of the bag, too much pressure from the tailstock...... etc. etc. Any of those reasons can lead to a poor fitting pen.

The TBC bushings removes a lot of that.
 

betwisted

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Jan 8, 2013
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I use both the regular bushings (with the steps) and some of Johnny's and get great results from both. with the designed for tbc bushings I can turn barrels faster. With the mandrel bushings I turn the barrels down very close to final then give the light finish cuts with the just the barrel between centers. The final outcome is the same. I prefer using Johnny's bushings, but he doesn't always have what I need in stock. Also, using a caliper to verify final dimensions has worked well.
 
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