TBC question, why are bushings needed?

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UCLAJediKnight

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Quick question, why are bushings needed when turning between centers? Wouldn't the live and dead centers provide enough pressure to spin the blank well? Are the bushings just for protecting the centers?
 
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Some have success without bushings using just the dead and live centers. If it works for you, do it.

I have tried it, and for my style, I prefer to used bushings. Bushings increase the stability of the blank for me, and avoids "belling" the tube and lowers the risk of cracking blanks.

Entirely turners option -- Other than the on-off switch on electric lathes there are few absolute rules (although many like to make them).
 
They are not. I turn a large variety of my pens without bushings. I set an outside caliper to just over the finished size that I can slide over the blank while it's still spinning then I creep up on the finished diameter stopping every few passes to check it with a digital caliper.

You'll get a much better fit and all but eliminate out of round or eccentric turnings. You can also square up after the fact much easier.
 
I like them so that I know how far down to turn so Im not stopping to measure with calipers and the extra support instead of the centers pressing in the tubes
 
To me I always use bushings because it gets me close to finished size of the blank before I break out the calipers. Also it lessens the possibilities of OOR turning unless your bushings are of poor quality. When supporting the blank on a very thin piece of brass edging makes for possible OOR turning in my opinion. Flaring of the brass and adding stress to the fragile ends of a blank where it is more prone to crack is something I do not need to add when turning a blank.
 
I never use bushings any more . The bit of flaring can be an asset during assembly . Sharp tools and just enough pressure to stop the blank from slipping on the center shouldn`t crack the material . If it does , the material is probably so brittle that the pen will crack the first time it is dropped on the floor .

Contrary to what most probably do , I also turn 4-5 inch diameter pieces directly between centers .
 
Thank you for all the answers so far.

Along the same lines then, do you need special 60 degree bushings? Wouldn't standard bushings do the trick? I imagine they would provide the same horizontal pressure to keep the blank stable and give a final diameter.
 
I have tried the regular bushing and rather the 60* for a better fit. I think there was a tutorial on how to do them your self but I get mine from Brian Nikitas
 
I once tried standard bushings for TBC, and had no luck with my pens being round. There was recently a post about using standard bushings, and modifying them for TBC. I personally do not use bushings. Like Carl said, I'll measure the parts before hand and write the exact measurements on the bag. Then I set my caliper(s) (two if different finished diameters) to a couple thousandths over. Stopping and starting adds minimal amounts of time to final measuring (which you should do regardless whether or not you're using bushings for an optimal fit).
 
If you get a simple cheap set of outside calipers, you won't have to stop the lathe until you are almost down to your finished dimension. They slide over a spinning rounded blank just fine.

I'm talking about this style that can be had for like $10 or less. Then once you can pass these over, you know you're close and can then stop the lathe to check with digital calipers until you hit your mark.

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I use regular Mandrel bushings to quickly / visually get down to almost the bushings then take the bushings of and finish up TBC with 60 degree cones this iliminates the possibility of oor due to not perfect bushings, then a digital caliper from there.
 
Carl Fisher said:
If you get a simple cheap set of outside calipers, you won't have to stop the lathe until you are almost down to your finished dimension. They slide over a spinning rounded blank just fine.

I'm talking about this style that can be had for like $10 or less. Then once you can pass these over, you know you're close and can then stop the lathe to check with digital calipers until you hit your mark.

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I just use these and seldom bother with the digital anymore .
 
As many others have said, you certainly don't NEED bushings to turn between centers. I turn 100% between centers, but only have bushings for the pens i do the most of. My TBC bushings look brand new after dozens of pens, mainly because tools and sandpaper have never come anywhere near them. I ONLY use them to get close to size/shape quickly. Once I'm turned down to a bit over bushings, they come off and it goes between centers for final sizing with calipers. I will say that bushings make the pen go MUCH quicker and I am much more confident turning to round and down close than without bushings (you know, it's REALLY hard to put the wood back on if you take too much off...)

But based on the mandrel bushings I have from back when I started. I would rather turn without bushings than use them. Even with my TBC Bushings, which are head and shoulders higher quality and precision than any mandrel bushings I have ever used, when I take them off and go between centers only, you can tell with the first cut that they are not perfectly concentric. It's minor enough that it likely wouldn't matter, but every little bit is one step higher...
 
Do any of you feel you have "damaged" your live center/dead center by turning without bushings?

What about while finishing? I am pretty liberal with the CA...
 
I come through every so often with a 7mm tube between the centers to turn them both and clean them up with a cutting tool (carbide, skew, whatever)
 
I think the centers can take a little bit of abuse. I clean mine after each pen that takes a CA finish. I have an old crappy skew that I use to clean the CA off of the centers. I just turn the hand wheel or live center by hand while holding that old 3/4" skew flat against it. Every now and then, a little acetone gets the residue all the way off.
 
UCLAJediKnight said:
Do any of you feel you have "damaged" your live center/dead center by turning without bushings?

What about while finishing? I am pretty liberal with the CA...
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I've "damaged" a dead center, as it has had rings on it from the tubes rubbing when they catch and stop spinning (after hundreds of barrels), and like Carl and others, I've used a skew to take CA off, but it's pretty easy to true up the dead center while you're cleaning it up, and I think the ones I bought were $12 at Woodcraft (meaning you should be able to find cheaper other places, but they are convenient for me and the dead center is worth). Carbide centers will last longer, but cost more and will be more difficult to true up. I have 2 dead centers now, one looks rough, and the other looks great, but I can't tell the difference between them when turning... The "rough" one is not good for 7mm tubes, as I use the slimline bushings between it and the live center when cleaning and never bothered turning off the slight raised area that the bushing covers.

Through all of that "damage" to the dead center, my live center is fine, in fact the skew has barely touched it. I did use the skew to take the CA off when I was first starting, but I've gotten a bit neater with my CA lately and haven't needed to clean it in a long time. I would probably use Acetone at this point if it needed it....
 
Simple answer: They're not. BUT ... I do find when reducing the blank to diameter that if I have the bushings installed it reduces sideways breakaway of the material. Definitely don't keep the bushings on if you are finishing with CA - you'll glue the bushings to the blank and then abrade the bushings when you scrape the CA off - not to mention leaving a noticeable ridge on the blank ends where the CA built up over the bushings.
 
I've done both. If I'm in a 'hurry' I tend to use bushings, but that's best avoided anyway....

As far as applying CA when the blank is supported by centers only, just stop and put a thin layer of paste wax before continuing. CA comes right off and you don't have to be afraid of sealing the ends of the tube/blank. Works great.
 
GrahamH said:
So would you only need a set of bushes for each tube size rather than each pen type ?
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One would think that to be the case, but it is more complicated. First, the OD of the bushings' larger diameter would need to be the size of the smallest finish size. That may be way too small for some other style.

But the real kicker is that one brand of cigar style may have a different tube ID than another. Same with other kits. Even though the kit directions may list the same drill bit to use, the tubes may be different. Not a lot, but enough to make it impossible for a bushing for one to be used on another.

I do like the idea of using bushing until the final few light cuts, then take them off.
You need to keep in mind that the simple fact that the bushings need to slide into the tube means there is a small amount of play there, otherwise they would get stuck in the tube.
When I make bushings out of brass, I feel I have done the best I can when I need to use a pliers to gently twist the bushing out of the tube. That's a tight fit and has reduced the out of round as much as possible.
 
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