Handling or Adjusting For Run Out

[Mike Turner]

Hi All,
I turn long thin spindles for making flutes(25 to 30 " long with 7/8 , 3/4 or 1 " bores)....I dont have a modern lathe but an older Craftsman with the tubular bed. I basically take 2 pieces of stock and rout half the bore of the flute in each and glue these together. Then I insert a mandrel which goes through the entire length of the flute .It is a 1/2" rod which is threaded on one (live center end) and it has inserts in each end to fit the size of bore I am turning...The opposite end jams up to the chuck .I noticed when I turn my first piece this way I had some runout.How do you guys deal with runout? Thanks A Bunch !!

[David E Keller]

Sounds a little like making a giant pen. Is the mandrel straight? That's probably the most common reason for slightly oval shaped pens.

Head stock and tail stock aligned?

If the two issues above check out OK, I'd consider some type of steady rest for improving stability.

Also, I'd love to see some photos of the process and finished work.

[Thom Sturgill]

Also check the tail stock pressure. Too much pressure can also cause problems.

[Ken Fitzgerald]

Also check the tail stock pressure. Too much pressure can also cause problems.

I bought 2 pen mandrels because the gorilla operating the lathe overtightened and bent the mandrels.:o

[Mike Turner]

Thanks guys.......You guys gave me the same replies from another forum. I am a flutemaker and have been doing all the operations basically on a router but still have a lot of hand work..Lathe is quicker...Ive got to check the alignment for sure and I do question the mandrel . My machinist friend had a problem making the threads on the rod work the entire run of them which was 8" . I may get another rod made by another guy .

[Michelle Rich]

can you use stock all rod and make bushings like making a pen? ??? Be easy to make sure the all rod is straight by bashing it into submission..then make bushings from plastic of some sort...if the bushings were made well, it would help with the runout. This idea is worth what you paid for it.....

[Mike Turner]

Hi Michelle


Hi Michelle,
My set up is like this
My mandrel 1/2" dia , 32" long with 1/2 " 13 threads on one end and none on the other... I have three bore sizes...The one I use most is 7/8"...The pieces for both ends are turned from 1 1/2" stock down to the bore dia and they both have a shoulder that stops them ..The length of the inserted part is 3" ....Tailstock end is threaded and has a dimple for the live center.....On the drive end the chuck holds the 1/2" rod and the other piece just slides into the bore and jams up to the chuck...

I know my lathe is not the best( actually have 2 older Craftsmans) but it will have to work for now..

I have found part of my problem in the mandrel..back to the machine to have the main rod made over ...More results in a week or so ! Thanks

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[Richard Madison]

Mike,
Sounds like you are using the bushings (1/2 to 7/8 or whatever) only on the ends. Even if the mandrel is straight the wood can deflect in the center. Can you use an additional spacer bushing at the center of the piece? You could drill and tap the spacer and use a short set screw to secure it at the center of the mandrel.

[Jim Underwood]

I'd probably try a dead center in the headstock, and a cone center in the tailstock and leave it at that.

Then you don't have to worry about the mandrel's runout.

[Brad Vaughn]

I'd probably try a dead center in the headstock, and a cone center in the tailstock and leave it at that.

Then you don't have to worry about the mandrel's runout.

That is what I do when making my flutes.

[Mike Turner]

Sounds to me.........Boy I'm gonna be busy soon experimenting ! Luv it !