Just started TBC ...what am I doing wrong?

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wrjones224

wrjones224

Member
Joined
Mar 15, 2020
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161
Location
Kentucky
So after 2 and half years of using a mandrel I have started to venture into TBC. Here is my setup. My first question is why is my live center getting destroyed like this? Am I tightening the tailstock too much. I have made about 15 pens like this and they turned out great. I do like TBC better...but definitely need advice on how to not destroy the live center. I did use some bushings to get close to the diameter needed but then I take them off. As always I am grateful for any advice. I have learned so much from this forum and I am grateful.

Ryan
 

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I'm not a TBC turner but my guess would be that your live center isn't turning and the blank is wearing it down. I've had this problem with live centers that wouldn't spin. Not sure why but that would be my guess.
 
I don't really have an answer for you but my eyes are drawn to the fact that all those ridges are at different diameters. Did all this damage occur while turning one pen?
 
I would say that Tom is right ... your live center is "not wanting to spin" !
The live center looks rather large in size compared to the dead center.
Could it be that it IS very large and heavy ?

Maybe it has so much inertia that it is slow to come up to speed, and during the time that it is accelerating (still going slow) the blank and tube are able to cut into it .

What material is the live center ?
 
I am not sure what the exact material is but I believe it is this one. I did use multiple different sized kits so that is what is causing the ridges. I have had it for a very long time so maybe it isn't turning smoothly. I just bought a new one.

www.pennstateind.com

Live Tailstock Center w/ 60 deg point - #2MT

This center is large and strong with precision bearings. It runs very true and is also well balanced and smooth for effective turning. Ideal to support your work at the tailstock end of your lathe. 1-11/16" overall diameter. #2MT.
www.pennstateind.com
 
To Ken's point, it would be interesting to know what pens you have made using TBC.

Some Slimlines ( 7 mm tube ), some Bolt Action ( 3/8" tube ), some Jr Gent or similar ( 10.5 mm and 12.5 mm tubes ) ??

Whatever ..... it is time for you to get a new live center .... that one should not be used any more !

A new live center will cost you around $30 ..... ask for one at a tool store that sells accessories for a metal-working lathe.
You can check the price at ..... LittleMachineShop.com

RE: . Your picture ..... are you sure that's the live center you have been using ? . The one in the latest pic looks much smaller than the first you showed.


www.littlemachineshop.com

Mini Lathe Live Center | Lathe Live Center | LittleMachineShop

This mini lathe live center has a short 2 Morse taper and fits the tailstock of the mini lathe. Shop this lathe live center at LittleMachineShop today!
www.littlemachineshop.com www.littlemachineshop.com
 
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Wow, I've turned TBC with kits (although not as many as you) and not seen that much wear. It looks like your center may not be hardened. I'm guessing a brass tube could put a little groove in the center. But this has material worn away. If you run the corner of a file over the center and it makes a deep groove the center is not hardened.
 
You definitely need a hardened live center. . . any live center you buy from a reliable tool store, such as CDCO, would be hardened .
 
Penultimate said:
Wow, I've turned TBC with kits (although not as many as you) and not seen that much wear. It looks like your center may not be hardened. I'm guessing a brass tube could put a little groove in the center. But this has material worn away. If you run the corner of a file over the center and it makes a deep groove the center is not hardened.
Click to expand...

Great point. Like knife making, your file should skid across the metal and not leave any marks if it's hardened properly. If the file "bites" then the metal is not hardened and will show signs just like the first picture.
 
Hmmmmm ....... I would never do the "file test" on MY live center !!!!!!!!!! . . Nope ..... NEVER !!!!!!!!!! . . . . :mad::mad:
 
I have a live center from Harbor Freight that I've had for years, and used on 2 or 3 different lathes. I have to say, it has really held up well. I've used it for thousands of pens. If you need one in a hurry, and have a Harbor Freight nearby, it might be worth a shot.

www.harborfreight.com

Morse #2 (MT2) Live Center

Amazing deals on this Mt2 Live Center at Harbor Freight. Quality tools & low prices.
www.harborfreight.com www.harborfreight.com
 

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magpens said:
Hmmmmm ....... I would never do the "file test" on MY live center !!!!!!!!!! . . Nope ..... NEVER !!!!!!!!!! . . . . :mad::mad:
Click to expand...

To be honest Mal, it's the only way to determine if the LC is hardened that I know of. If it's not hardened by this test then you'll know and can get rid of it and get a new one. Doesn't take much pressure so you're not going to damage a truly hardened LC with a file. Plus you don't do it on the point but more the area on the flat spot. The whole thing should be hardened, not just the business end. Plus you're not using a Bastard file but a much finer cut file, one like you'd use for Brass.
 
I'll take your word for that, Tom !! . . Your veracity is not in question at all .... being the knife man that you are !!

Gotta run ....... I'll check back on this discussion in a while .....
 
I had a live center that the back plate began to loosen sometimes, resulting in a sloppy bearing fit. It came off once. I cleaned it, tightened it regularly and finally replaced in. A few lines and such but nothing like that. Brass should not chew up steel like that.
 
Ryan, as mentioned you have a few things to check and now that this one is destroyed for this use it may still have value for other things. As mentioned I do not believe this is hardened steel. It may also be possible the bearing is not spinning well and not keeping up with the speed of the lathe and thus maybe it is spinning but so is the tube on it.

Now another thought is can you tell us how you are turning between centers?? Are you using bushings or are you just putting the blank between the dead and live center?? If that is the case no way soft brass will form those grooves in harden steel. If that is so then look inside the tube and see if the tube is worn on the live center side. If it is then that tells you it is spinning on the live center. Now some people try to use standard bushings without the mandrel and place them between live and dead center and think they are turning between centers properly. Well they are not because the standard bushings mandrel hole does not conform to the cone shape of a center. Thus they will spin on a small area of the center creating a groove as you see. This is the same problem when you use a mandrel and do not use 60 degree centers. That dimple on the end of a mandrel is 60 degrees. Hope you figure it out. Let us all know.
 
How is the bearing in that live center? Looks like it had a lot of drag or possibly too much pressure from the tail stock that maybe induced some drag.

Also, that looks more like aluminum or soft steel rather than carbide tipped. AND it looks quite large for a tail stock to be used on pen blanks.

Something doesn't seem right, but then that is why you are asking. Hope we can get the right answers for you.
 
jttheclockman said:
Ryan, as mentioned you have a few things to check and now that this one is destroyed for this use it may still have value for other things. As mentioned I do not believe this is hardened steel. It may also be possible the bearing is not spinning well and not keeping up with the speed of the lathe and thus maybe it is spinning but so is the tube on it.

Now another thought is can you tell us how you are turning between centers?? Are you using bushings or are you just putting the blank between the dead and live center?? If that is the case no way soft brass will form those grooves in harden steel. If that is so then look inside the tube and see if the tube is worn on the live center side. If it is then that tells you it is spinning on the live center. Now some people try to use standard bushings without the mandrel and place them between live and dead center and think they are turning between centers properly. Well they are not because the standard bushings mandrel hole does not conform to the cone shape of a center. Thus they will spin on a small area of the center creating a groove as you see. This is the same problem when you use a mandrel and do not use 60 degree centers. That dimple on the end of a mandrel is 60 degrees. Hope you figure it out. Let us all know.
Click to expand...
Thanks all for the feedback. I think this may be where I went wrong. I was using standard bushings to just get me started and then went to no bushings. I either need to invest in the tbc bushings or just use the calipers. Still wouldn't have thought standard bushings would tear this up so fast. Like others have mentioned this live center might not be hardened.
 
So, Ryan, did you actually use the standard pen bushings between your blank and the live and dead centers ?

Re-reading your last post, I think the answer is yes. . . I think that is a bad idea ... standard bushings were not intended to be used that way.
Those bushings would then have a "corner" against the slope of the dead/live centers.
 
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wrjones224 said:
Thanks all for the feedback. I think this may be where I went wrong. I was using standard bushings to just get me started and then went to no bushings. I either need to invest in the tbc bushings or just use the calipers. Still wouldn't have thought standard bushings would tear this up so fast. Like others have mentioned this live center might not be hardened.
Click to expand...
Steel on steel will tear it up if that is the case.
 
wrjones224 said:
Thanks all for the feedback. I think this may be where I went wrong. I was using standard bushings to just get me started and then went to no bushings. I either need to invest in the tbc bushings or just use the calipers. Still wouldn't have thought standard bushings would tear this up so fast. Like others have mentioned this live center might not be hardened.
Click to expand...
Ryan, I began with an aluminum drive center and used standard mandrel bushings, as TBC bushings had not been invented at that time, and I never had anything like that.
 
There are a couple of options you might have not considered:

1.) Purchase a pair of slimline TBC bushings - these can then be inserted into standard bushings to instantly turn all of your standard bushings into TBC. Probably not the best for final turning, but works pretty good for rough turning to size. Would probably want to finish without bushings using calipers.

2.) Just get one set of TBC bushings for the various tube sizes, then use a calipers without bushings for final turning.
 
My first thought when I saw the pic was standard bushings gouging the center. Don't ask how I know. I'm using the same live center you just bought from PSI and it works fine with the right bushings (or even with none) I do still sometimes use a mandrel to get the blanks rounded off so it doesn't catch and spin the bushings on the centers. It avoids extra wear and tear (read: expense).

As Sam @Dehn0045 said, a 7mm set works to get you most of the way done. These 7mm adapter bushings are top notch and fit right into the standard bushings. Though I don't see him much on the forums, the owner/machinist is a member here. You can always add more specific TBC bushings down the road.

I have a ways to go before I'm as skilled as many pen makers here, but this is what works for me so far. I turn them down almost to the bushings, then set the tube directly on the centers to finish them, using calipers to measure, and very gentle pressure from the tailstock. Since the final cuts are essentially just a light shaving, the tubes shouldn't catch and spin on the centers. I wax the centers before putting tube on directly so I can just apply the CA finish while it's on there without as much trouble cleaning the centers when I'm done.
 
I use standard pen bushing when turning between centers but I alter them before using them this way. This allows me to rough out blanks prior to finish turning without bushings.

I take a larger center drill and put a 60 degree chamfer on them using the metal lathe at work. I should think that could also be done on a wood lathe as well with appropriate chuck.
 
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