TBC bushings- Special made or normal

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Richard Gibson

Richard Gibson

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Joined
Sep 24, 2010
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730
Location
Knoxville TN
I understand from reading several post here, that several of you turn between centers just using the regular bushings that are used for mandral turning. Is there any advantage to getting the special bushings that are made for TBC and have the 60 degree tapered hole?
 
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I will on occasion do that, if the "good" bushings aren't available. The problem with the standard bushings is that they are usually out of round and you can't tell if the hole is centered and also out of round. Just MHO of course.
 
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I do not have any of the TBC bushings but I can be pretty dang sure they are on spec. Bushings from the pen companies are almost all off center or have some other flaw. I use my factory bushings and cut my own 60* taper using my 4 Jaw and Drill Chuck but I only use those to get close to finished size then I go directly between center to clean up any out of round from them. Some day I will have a full collection of Corian Bushings that I make myself that are more accurate and some delrin for finishing.
 
I make my own TBC bushings on my metal lathe. As mentioned above the manufactured ones have a problem with run out, either the two diameters are not concentric with each other or the hole is not in the center or all three both diameters and the hole are not concentric to each other.

I make mine 1" long, I turn the pilot diameter (part that goes in the tube), and the register diameter (pen blank finish size) in the same chucking then part it off.
The pilot is 3/4" long, and the register is 1/4" long.

I have a drawing some place if you want it.

I then chuck on the pilot diameter, and check for run out on both the pilot and the register diameters, once adjusted to 0 runout, I face the end square, and drill my 60 degree center in the end.

Been working fine for me.
 
I guess busings have really gone down hill since I got mine. The only set of TBC busing I have are the ones I got from Johnny some years back for slims. Other than that, I've just been using my standard bushings. The only bushing issue I can remember was my first set of Sierra bushings. They were horrible!! And many of us at the time experienced the same problem. The manufacturer fixed the problem and some of got free replacements. I wasn't so fortunate. I had to buy my 2nd set.

But I will agree that Johnny's are by far the best option. You can test your existing bushings for run out easily enough. And I really like Chris' idea of making the stock busihings 60 degrees. I will probably do that with mine now just to make them better.
 
Johnny's bushings are so accurately machined they will make a "Pop" sound when you remove them from the tube. :smile:
Don't let it stop you from trying TBC, but know they are well worth investing in down the road.
You will aslo need a 60 degree dead center and a short tool rest. You should already have the 60 degree live center.
 
The reason I asked is that when I decided to TBC a couple weeks ago, I bought a dead center and live center and then ordered 3 sets of bushings from johnnycnc. But I have about 20 sets of other bushings (some which I will not use again since I didn't like the kits) that I would like to have Johnnys bushings but cannot afford to do so all at one time. I'll just work at replacing them over time. :tongue:
 
Richard Gibson said:
The reason I asked is that when I decided to TBC a couple weeks ago, I bought a dead center and live center and then ordered 3 sets of bushings from johnnycnc. But I have about 20 sets of other bushings (some which I will not use again since I didn't like the kits) that I would like to have Johnnys bushings but cannot afford to do so all at one time. I'll just work at replacing them over time. :tongue:
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Making your own is pretty easy. I will drill a 60* hole in some corian (I laminate two 1" square x 1/2" thick pieces of different colors) then I will run the smallest bit I have (I think 1/64") all the way through the corian. Toss it up TBC and turn it as I see fit. I drill the 1/64" so I can center my live. When I turn I will turn into the second color to go into the tube and leave about 1/4" on the outside and turn it just below the finished size. I do the same steps with Delrin for my finish bushings.
 
Richard Gibson said:
The reason I asked is that when I decided to TBC a couple weeks ago, I bought a dead center and live center and then ordered 3 sets of bushings from johnnycnc. But I have about 20 sets of other bushings (some which I will not use again since I didn't like the kits) that I would like to have Johnnys bushings but cannot afford to do so all at one time. I'll just work at replacing them over time. :tongue:
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That's exactly what I did Richard. As I find new kits to inventory, I get the bushings. And if you don't see them on the site...ask him...easy guy to talk to!
I'm doing our church Men's Retreat again this year; we'll knock out 100 pens in a day. I've been asked to demo BTC stuff and since we are doing Slims...easy!! You're really going to like BTC results.
 
Not taking anything away from Johnny's bushings I am sure they are awsome, and I hope to have the need to make pens that warrant that level of care, but I have only had one bad set of bushing (from woodcraft) from the 50ish models I have bought. The only time I have any issue is when I oversand which alas no bushings will fix, just me in a hurry! The other slight change I made recently is to turn the pen with the nib bushing near the headstock to elminate the mandrel warpage (worked great). The run out most people are experiencing is probably clearance between the mandrel and bushing and flex of the mandrel itself. Having a mfg engineering background, chances are these are turned in one set up from a bars so they are probably pretty accurate.

However for now when I get orders 100 items at a time, I cant make any money doing them 1/2 at a time so I am happily sticking with my mandrel. :-)
 
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