Off center

[DFerguson777]

I finished up the lower barrel of a cigar pen and pressed the piece that the recever screws into and the wood was noticably off center.

Any ideas why? This has happened to me one time too many

Thanks

-Denny- NC

 

[NewLondon88]

Ah.. the Eccentric Pen! I make lots of those.

There's lots of reasons it can happen. Bad bushings, blank not squared
to the tube (always square to the tube, not to the sides of the blank)
overtightened nut on the mandrel, overtightened tailstock, CA buildup
on the bushings, bent mandrel, stock mandrel withOUT a 60 degree live center,
dirty spindle, dirty morse taper

Oh, I have LOTS more ways of making my eccentric pens, but I don't
want to give away all of my secrets.

You can buy my book "Crooked Man's Pens" at any good bookstore
or proctologists office. :tongue:

 

[leehljp]

Hey Charlie,

Don't you mean "mandrel withOUT a 60° live center?" :wink:

You nailed the reasons. I will add one more that John (JohnnyCNC) passed on to me: Stock bushings are usually "loose" inside the tubes. Last week, I pulled out some of my older commercially bushings that I have not used in a while and sure enough they were LOOOOOOOSE in the tubes as compared to the custom machined bushings. I could wiggle them. Several allowed that

I never thought much about that because I just figured that when I tightened them for turning, they would hold tight.

 

[johnnycnc]

Denny, you have a pretty common problem.we could use some more info about your setup, tools, etc...we can help you out more that way.

 

[NewLondon88]

Hey Charlie,

Don't you mean "mandrel withOUT a 60° live center?" :wink:

Of course. That's what I wrote.
Can't you see it? :tongue:

 

[DFerguson777]

When I get back to the shop I'll take a picture of my set up.
I am using stock bushings. They are loose fitting, infact. Where do you get custom bushings?
You mentioned a bent mandrel. I did notice that my blanks don't slip right onto the mandrel...they snag in the middle and need a push to ge tthem on.....that may mean it's bent.

Thanks for your input. I'll post the pictures and let you look a little further into my problem.

-Denny- NC

 

[rjwolfe3]

Where do you get custom bushings?

You can make them if you have a metal lathe or do what most of us do, buy them from Johnnycnc!

 

[DFerguson777]

Thanks
-Denny- NC

 

[DFerguson777]

It's official....my madrel was bent!
Thanks guys...something so obvious......but such a pain.
-Denny- NC