Benefit of TBC??

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ramaroodle

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What is the benefit of TBC? I have done both but for the life of me, I don't remember why I first tried it other than it was something different. I don't see a difference in the final product. They are both smooth and symmetrical on the tube. So, what is the benefit other than it's kind of a cool thing to do?
 
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monophoto

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Not sure there is one.

It seems to me that TBC is one of the solutions that are often proposed for instances in which pen turners encounter problems with mandrels - either eccentricity, uneven turning, or excessive wear on the live center. I don't think its any better - its just another way to skin the cat. And probably a fad.
 

ramaroodle

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Not sure there is one.

It seems to me that TBC is one of the solutions that are often proposed for instances in which pen turners encounter problems with mandrels - either eccentricity, uneven turning, or excessive wear on the live center. I don't think its any better - its just another way to skin the cat. And probably a fad.
That's my thinking. "Fad". I have never had a problem with oval pens. Nothing against it. Just don't see a benefit if everything else is working.
 

Curly

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Not sure there is one.

It seems to me that TBC is one of the solutions that are often proposed for instances in which pen turners encounter problems with mandrels - either eccentricity, uneven turning, or excessive wear on the live center. I don't think its any better - its just another way to skin the cat. And probably a fad.
I've been happily following the fad for over 6 years. Let me know when it ends. 😉
 

Edgar

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IMHO, it’s strictly a matter of preference. I use both & I use a mandrel saver when I use a mandrel. Both methods work fine for me.

I think most mandrel warping issues are caused from tail stock pressure or excessive tool pressure, especially when turning multiple blanks simultaneously. The latter can generally be avoided by turning just one blank at a time which is what TBC requires anyway.
 

ramaroodle

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Maybe I've had no issues because I've used a mandrel saver for years and tried TBC last year. Just made me wonder why I did it and if I was missing something
.
 

KenB259

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Here’s my issue, I think most here will agree that bushings are just to get close to the final size. After that, you use a dead and live center, along with a micrometer or a set of calipers to finish up. What difference does it make what method you use to get close? I have used both, both work. TBC bushings are pricey, so is a good quality mandrel. No wrong method here, use whatever floats your boat.
 
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mmayo

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I may be a fad follower too, but I have TBC bushings for all of the pens, seam rippers, razors etc that I sell. I sell quite a few different pens. I get repeatable results. I rarely (read almost never) get oversize or undersized pen bodies using TBC bushings only. The cost of TBC bushings is very reasonable and I highly recommend Nikitas as the goto guy for TBCs.

I use my mandrel with delrin finishing bushings to apply CA, period. I use a mandrel saver instead of the brass nut to save time.

If you wish to use stock bushings, that is your choice. Mine are only used to make delrin copies for sanding and buffing never to turn pens.
 

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mark james

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12 years: Mandrel saver, calipers to measure the components. Rarely have transitions between the blanks and components off.
 

leehljp

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The original reason was different from oval, but I was quick to learn from others that relief from oval turnings was a side benefit.

The original purpose of TBC (and I was calling it "mandrel less" for the first few months) was that I was disgusted with glued on bushings. In particular, oily woods such as ebonies (Japanese persimmon for me) - when breaking the bushings from the blank, the ends of the CA would raise up off of the ebony and look cloudy because of the separation of the CA from the wood. This happened on numerous occasions for me. I asked how this could be prevented. Two guys, mentioned that they had heard of a method from another forum in which the mandrel was not used, and the blank was mounted between centers. After I started using TBC, the CA lifting off the ends stopped for me.

I was living in Japan at the time and did not have quick access to drive centers, so I made my own. I quickly learned that I did not have to fool with dropped nuts rolling under the lathe, nor having to deal with dropped spacers; I also learned that I could take a blank off and inspect it quickly up close far faster than I could take a mandrel off, unscrew the mandrel, take the parts off, inspect closely and then replace all and get started again. The TBC decreased the inspection time by a minute at the least, and I could inspect a delicate segmented blank several times during a turning faster than a single time with a mandrel.
. . . Saying this another way - It is much faster to take a blank off and inspect it with TBC than with a mandrel system. For me, who did segments often, I needed to take a blank off regularly for inspection. TBC saved a lot of time for me.

Also, I found that my accuracy increased as I quit depending on the bushings for sizing and started using calipers.

For others, as mentioned above they found that TBC helped get out of the oval mess.

The original drive center used on this forum and the original TBC blank:
 
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Curly

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When you only turn a few pens a year you don't have to spend anything on bushings of any kind. Turn with the centres only and then stop and put a little wax on the centres before CA finishing.
 

sorcerertd

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I have found that a lot of bushings are not machined very accurately. If I put a bushing between centers, I often find them off center. I should really tune up the old lathe I'm using before being so critical of them. Once in a while, I use a mandrel to rough out a few pen barrelss at a time, but usually I use TBC adapters that I bought from Brian Nikitas. Obviously, that still leaves the problem of inaccurate bushings, but that is solved with TBC (no bushings) and calipers. I'm too cheap to buy custom TBC bushings for every type of pen I make. One thing to be aware of with TBC is that if you don't square off the ends accurately before turning, your barrel will be acentric to the tube, no matter if you use bushings or not.
 

ramaroodle

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I also learned that I could take a blank off and inspect it quickly up close far faster than I could take a mandrel off, unscrew the mandrel, take the parts off, inspect closely and then replace all and get started again. The TBC decreased the inspection time by a minute at the least, and I could inspect a delicate segmented blank several times during a turning faster than a single time with a mandrel.
. . . Saying this another way - It is much faster to take a blank off and inspect it with TBC than with a mandrel system. For me, who did segments often, I needed to take a blank off regularly for inspection. TBC saved a lot of time for me.
Thanks. That really is a reason to consider switching to TBC full-time.
 

MedWoodWorx

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The original purpose of TBC (and I was calling it "mandrel less" for the first few months) was that I was disgusted with glued on bushings. In particular, oily woods such as ebonies (Japanese persimmon for me) - when breaking the bushings from the blank, the ends of the CA would raise up off of the ebony and look cloudy because of the separation of the CA from the wood.
i found that changing the bushings and using hdpe ones (maybe also delrin works) when sanding beyond 600 grit and while applying ca. Also i tend to think that ca coating works much better when i seal the tube ends first and then the body. I suppose most of you already know that.
When talking about tbc is it meant that a mandrel is not used or no bushings (or both)?
 
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leehljp

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i found that changing the bushings and using hdpe ones (maybe also delrin works) when sanding beyond 600 grit and while applying ca. Also i tend to think that ca coating works much better when i seal the tube ends first and then the body. I suppose most of you already know that.
When talking about tbc is it meant that a mandrel is not used or no bushings (or both)?
TBC means no mandrel is used. Bushings can be used or it can be used without bushings. For me, I remove the bushings after the blank is round and near to size. If I am segmenting with metal separators, I get to size using calipers before removing the bushings. I ALWAYS remove bushings before finishing.

I tend to flair the brass ends in the blank if I don't use the bushings to get the blank round, but that is just me.
 

leehljp

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I have found that a lot of bushings are not machined very accurately. If I put a bushing between centers, I often find them off center. I should really tune up the old lathe I'm using before being so critical of them. Once in a while, I use a mandrel to rough out a few pen barrelss at a time, but usually I use TBC adapters that I bought from Brian Nikitas. Obviously, that still leaves the problem of inaccurate bushings, but that is solved with TBC (no bushings) and calipers. I'm too cheap to buy custom TBC bushings for every type of pen I make. One thing to be aware of with TBC is that if you don't square off the ends accurately before turning, your barrel will be acentric to the tube, no matter if you use bushings or not.
True, but this happens with mandrels too, if the ends are not square. Squared ends are a necessity for both Mandrels and TBC
 
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