Shorter bar ends.
Less run-out - *IF* you're turning the OD.
Don't have to buy guide bushings:-)
Just keep in mind that the length of your parts will be limited by the
We sometimes run the cam operated Swiss (sliding head) without guide
bushings. On these machines you can remove the guide bushing holder
and slide the head up into the tool tree. Works great for profiled
material (hex, square), and short parts. Wind up with little 2-3" bar
ends, instead of 6-8" bar ends.
Star used to have what they called a 'Chuck Work' option. It was a
spindle nose extension that fit up into the tool tree (after removing
the guide bushing holder).
A guide bushing-less machine has it's place, but if you plan to run
parts that exceed the length-to-diameter ratio of the barstock, you
won't be happy with it. The only way to make longer parts is to do
multiple chucking's, and then you'll run into concentricity problems.
Tsugami has models that can convert from guide bushing to bushing
less and back so you can do longer pieces if necessary. Not sure
about other brands. Maybe Dan Murphy will followup and tell you
Another advantage of running without the guide bushing is that you
don't need ground stock. But as Matt Stawicki said your length to
diameter ratio is limited
If your parts are over 3x diameter to length ratio then the guide bushing
is the best option. For shorter parts running without the guide bushing
will give you better roundness and runout when using cold drawn stock.
Tsugami machines can be switched back and forth. Machines like the Ganesh
can only be run without, Star and Citizen machines currently can only be
run with the bushing.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.