tbc slimline bushings.

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Fordwakeman

Fordwakeman

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I know that no one is currently making these. For anyone that is making thier own, does anyone have a schematic (measurements) of ones that work. I have access to a machinist that I'm going to try and get to make me some.

thanks
 
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TBC means turning between centers. You use calipers to measure the fit where the turned material meets the pen parts. At least that's my understanding.
 
Kenny Durrant said:
TBC means turning between centers. You use calipers to measure the fit where the turned material meets the pen parts. At least that's my understanding.
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Well, turning between centers means you turn between centers. Dead center and live center. Whether you use bushings or just measure or use bushings and measure with calipers is another question.

I turn between centers exclusively and use bushings 98% of the time I do so.

I'm guessing that's what the OP wants to do as well.

It is a helpful reminder that you don't NEED bushings.
 
The bushing is solid with just a taper on the barrel end to seat the centers in.

Barrel diameter is 0.335" or 8.5mm

tube section diameter is 0.246" or 6.25mm

overall length 0.875" or 22.2mm

Length of tube section 0.492" or 12.5mm
 
Do be sure he cuts the 60 degree recess on the outboard ends --- the kind of detail I have missed a time or two.
 
sschering said:
The bushing is solid with just a taper on the barrel end to seat the centers in.
Barrel diameter is 0.335" or 8.5mm
tube section diameter is 0.246" or 6.25mm
overall length 0.875" or 22.2mm
Length of tube section 0.492" or 12.5mm
Click to expand...
I make my own TBC bushings and for the Slimline there are only 3 critical dimensions, the two highlighted above and the 60* recesses in the drive ends of the bushings. I find that the longer the "Length of tube section" is the more stable the overall setup is and of course this effects the "overall length". I actually pay very little attention the overall length. I have one set that the OAL is probably 1.5":eek:. I tend to make mine so that the "drive section" containing the 60* drive recess is about 1/2" in diameter and 3/8" to 1/2" long. That "tapers" down to the 0.335 dim which is maybe 3/8". That then "steps" down to the 0.246" dimension which is usually at least 3/4" long. If you add up all the lengths you will see that my SL bushings are pushing 2" and you could do them in 1" if you wanted to so don't get hung up on the length dimensions just make sure the two diameters and the 60* are dead on.

All that being said always verify the slimline parts dimensions, you may find that you have to turn the blank slight plus of the bushings or slightly negative of them. This caveat applies to all styles of pens and their bushings.

Edit: Just noticed that this thread has a little age on it but that doesn't change my comments.
 
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One suggestion. If you are having someone make the tbc bushings for you, take them the pen kit and have them make the bushings using their own calipers and measurements. If there is a problem, it should not cost you to remedy.
 
Fordwakeman said:
I know that no one is currently making these. For anyone that is making thier own, does anyone have a schematic (measurements) of ones that work. I have access to a machinist that I'm going to try and get to make me some.

thanks
Click to expand...

I am surprised to see this. Isn't JohnnyCNC making these any more?
 
dankc908 said:
Fordwakeman said:
I know that no one is currently making these. For anyone that is making thier own, does anyone have a schematic (measurements) of ones that work. I have access to a machinist that I'm going to try and get to make me some.

thanks
Click to expand...

I am surprised to see this. Isn't JohnnyCNC making these any more?
Click to expand...


No, he has not made any for awhile now.


Harry
 
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