Re: Swiss turning conversion

Smoke,

One of the major drawbacks of roller bearing setups is chips get
pulled in under the rollers, plus they don't give full contact
support. A solid support of the bar is important to getting the
accuracies these machines are capable of.

The "standard" of the Swiss turning business is still the fixed (non-
rotating) carbide bushing. They look similiar to a collet except for
the carbide pads. Some swiss machines use a rotating guide bushing
(basically like the ID of a ball bearing), but those bushings are
incredibly expensive. Of course for hex and other non-round shapes
you would have to use a rotating bushing.

When I first looked at swiss machines I thought there must be a
better way than the fixed bushing. Apparently not, as yet no one has
come up with a workable solution that's better.

Doug

--- In CAD_CAM_EDM_DRO@y..., "Smoke" <gordonr@r...> wrote:
> I like the roller bearing idea Jon , but...I'd use a scissors type
mount for
> the bearings similar to those available for doing knurling. I'd
replace one
> of the knurls with a pair of bearings and the other with a single
bearg.
> this would provide the 3 point contact. I'd also make it spring
loaded like
> the ones we made at school.
>
> Smoke
>
> >Since you just want to support the shaft, what about a pair of
roller
> >bearings opposite the tool with a third bearing heavily spring
loaded
> >into the other two? I made such a setup once, except it mounted to
the
> >toolpost. Had to turn 24" lengths of 1/2" nylon, worked like a
champ.
> >Actually it was a custom tool holder/bearing setup that went into
a tool
> >an Aloris tool holder. If I still have it, I'll snap a pic and
email it.
> >I'd think it wouldn't be too difficult to mount this rig to the
carraige
> >instead of the toolpost. It's easily adjustable, ball bearings
ought to
> >last a long time, and they're cheap. (compared to making throwaway
> >bushings)
> >
> >Keep in mind that you must either turn your part in one pass, or
you can
> >rough in steps roughly equal to something less than the distance
between
> >the support and the tool, and you won't be able to take a finish
pass.
> >
> >Jon
> >