Testing your bushings

[Tiger]

Just recently bought some Cigar pen bushings and they worked out ok for the first 2 or so pens. I then began to notice that the blanks I was producing were not concentric, couldn't work out why. First I thought that some glue had seeped onto either my blanks or the bushings, made sure that both were ok, same result. Cigar pen bushings have a double-ended bushing which I tested on my metal lathe and sure enough it was out of true, not significantly but enough to ruin my blanks. How often do people check their bushings and how do you do it? I do often turn between centers and use digital calipers but must admit when under time pressure I'll use bushings as a guide to get close.

 

[Artisan iron designs]

I was the same and my barrels were not lining up. I now use a starrett caliper for the final few thou. I turn on a 9" south bend. Also I started using a reamer to true my bore and make the brass tube a press fit.

 

[magpens]

You say ...

"Cigar pen bushings have a double-ended bushing which I tested on my metal lathe and sure enough it was out of true, not significantly but enough to ruin my blanks."

I'd say that was pretty darn significant !!!

Most bushing sets are 1 to 2 thou undersize where they fit into the brass tubes.

Doesn't sound like much, but I found that to be the reason why I was frequently disappointed with my turned results.

Now, I don't use bushings and rely on caliper measurements ... much better !!

BTW, I do my turning on my metal lathe, with the tubed blank held between 60 degree cones mounted in the headstock and tailstock.

 

[randyrls]

TC; To test your bushings, mount the bushings and bare tubes on the mandrel. Gently tighten the nut. Turn the lathe on at about 500 RPM. Now hold a lathe tool at both ends and rest it across the bushings and tubes. Any vibration means it is out of round.

Use extreme caution when doing this! You do not want the lathe tool to contact anything that will cause it to fly.

Some time ago, I switched to Between Center Bushings (TBC). I make my bushings on a metal lathe, but it takes an hour or two to make a set of bushings.

 

[farmer]

Metal lathe

Just recently bought some Cigar pen bushings and they worked out ok for the first 2 or so pens. I then began to notice that the blanks I was producing were not concentric, couldn't work out why. First I thought that some glue had seeped onto either my blanks or the bushings, made sure that both were ok, same result. Cigar pen bushings have a double-ended bushing which I tested on my metal lathe and sure enough it was out of true, not significantly but enough to ruin my blanks. How often do people check their bushings and how do you do it? I do often turn between centers and use digital calipers but must admit when under time pressure I'll use bushings as a guide to get close.

If you have a metal lathe you can make your own .

 

[Tiger]

Just recently bought some Cigar pen bushings and they worked out ok for the first 2 or so pens. I then began to notice that the blanks I was producing were not concentric, couldn't work out why. First I thought that some glue had seeped onto either my blanks or the bushings, made sure that both were ok, same result. Cigar pen bushings have a double-ended bushing which I tested on my metal lathe and sure enough it was out of true, not significantly but enough to ruin my blanks. How often do people check their bushings and how do you do it? I do often turn between centers and use digital calipers but must admit when under time pressure I'll use bushings as a guide to get close.

If you have a metal lathe you can make your own .

And I have, but I really need to get a reamer to do a good job on them.