Out of round bushings?

[dalemcginnis]

Is it possible for bushings to become out of round?

Just received my dead center today and decided to try it out. Put both centers in and bought the tailstock up until they were point to point and they aligned perfectly. Proceeded to turn a blank and everything was going fine until I got down to bushing size when I discovered a problem. No matter what I did I could not get one end to match the bushing. It would be absolutely smooth with the bushing on one side, but the opposite side had a ridge you could feel and see. Tried rotating the blank on the bushing and turning some more but it didn't work. Finally got out an old set of bushings and put it on the blank and not only was it round, I had over turned it a bit.
I have used the problem bushing before on a mandrell and never noticed any problems, either turning or when I assembled the pen. When I look at the bushing it does seem as if it might have a flat spot.

 

[ken69912001]

I have the same problem with some Jr.Gent bushing that I using currently. Anybody know why this is? And the bushings are out of stock until the middle of Dec. [xx(]

 

[jhs494]

Just my two cents.. But bushings that are made for use on a mandrel are not intended to be ran on a center.
The bore of the bushing is made to run concentric with the O.D. of the bushing and then it is parted off and usually chamfered on the inside of the fatter end as a secondary operation. This just deburrs the hole on the parted off side, and the small chamfer or edge break does not need to run true. If you look at bushings that are made to run between centers they are drilled like the end of your mandrel, with a 60 degree center drill. These types of bushings are made to run true with the center to O.D.
I hope this maybe helps.
If you do a search and see some postings on BCB turning you may find bushings that show the ends that are just center drilled.

 

[Randy_]

Originally posted by dalemcginnis
<br />Is it possible for bushings to become out of round?

Which kit are the bushings for?? We had a situation a while ago where some bushings were out of round right from the manufacturer. Maybe you got some of those??

 

[cowchaser]

I do know that my recent experience on Sierra's was the same. What was happening was when I pulled up the tailstock the bushing was binding although it was hard to tell. I was able to but some scotch tape on the part of the bushing that inserts into the tube to correct this. Finally just ordered a set of custom bushing from johnnycnc and my worries were over.

 

[Firefyter-emt]

You may well of had a set of bushings that were damaged by loose tubes as well. I have found rather poor fitment of tube to bushing on many kits. As for the bushings not seating properly BCB, you mor than likly would have an issue due to a poorly end milled blank or maybe one that was not perfectly 90-degreed to the tube.

From your own words it points towards that set of bushings. Oh... and if you don't now, use a set of calipers and tend to not even watch those bushings for "final fit" it's the fastest way to ruin a pen when it's all done.

 

[Randy_]

Originally posted by cowchaser
<br />I do know that my recent experience on Sierra's was the same...I was able to but some scotch tape on the part of the bushing that inserts into the tube to correct this...

I had exactly the same problem and solution with/for my Sierra bushings. Told Berea about it; but they didn't seem to care.

 

[Firefyter-emt]

FWIW, I made Stevers a set of Sierra bushings based on the sized given here from other bushings measured. I ended up makin him a new set because I found that they were .010 too small on the tube side. The new size was a trial and error fit of the tubes themself. My set I made for myself are so close that the air displacement from the second bushing will push and pull the first bushing in and out of the tube. (In fact, it was quite the little magic trick for my youngest son!)

 

[Randy_]

Originally posted by Firefyter-emt
<br />You may well of had a set of bushings that were damaged by <b>loose tubes</b> as well. I have found rather poor fitment of tube to bushing on many kits....

A minor point, perhaps; but you should probably be talking about loose bushings rather than loose tubes, as that is where the problem seems to lie. If the tubes were too loose, the fit of the finials couplers, nibs and other pen hardware would be a problem and I have rarely found that to be the case. For some reason, many bushings are undersized and don't fit the tubes as well as I would prefer.

 

[johnnycnc]

Dale,the bushings you have were never designed
to use for turning between centers.Some sets
will work out,some won't.I have checked runout
on several sets,and it's a hit and miss proposition.
I have turned several pens using the factory
bushings between centers,and had acceptable results
around 60% of the time.
Try another set if you have them,might help.

 

[rherrell]

Think you could put them in a Beall chuck and hit 'em with a 60 deg. countersink?

 

[Paul in OKC]

Originally posted by jhs494
<br />Just my two cents.. But bushings that are made for use on a mandrel are not intended to be ran on a center.
The bore of the bushing is made to run concentric with the O.D. of the bushing and then it is parted off and usually chamfered on the inside of the fatter end as a secondary operation. This just deburrs the hole on the parted off side, and the small chamfer or edge break does not need to run true. If you look at bushings that are made to run between centers they are drilled like the end of your mandrel, with a 60 degree center drill. These types of bushings are made to run true with the center to O.D.
I hope this maybe helps.
If you do a search and see some postings on BCB turning you may find bushings that show the ends that are just center drilled.

Well said. You could possibly use the Beall chuck, but you will need to snug up the quill lock to hold it still, and even then it will be tough. Loose bushings also could be the culprit.

 

[dalemcginnis]

Originally posted by Randy_
<br />

Originally posted by dalemcginnis
<br />Is it possible for bushings to become out of round?

Which kit are the bushings for?? We had a situation a while ago where some bushings were out of round right from the manufacturer. Maybe you got some of those??

It was a Cigar kit.
Thanks to all who replied, I have an idea now what the problem was and how to resolve it.