Re: are 3/4 shafts good for axis ?

Sir,

I have used another approach for machine ways. If you will contact me at jccinc-at-owc-dot-net I can email pix to you. It appears that we cannot add pictures here!

Regards,
JCC

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Roland Jollivet <Roland.Jollivet@...> wrote:
>
> I'm always amazed at the use of round bar and guides on smaller CNC
> machines. Unless the bearings are pre-loaded by spec., I think they are
> pretty useless. Looking at the gantry style, the whole gantry will rock to
> and fro. They are generally not designed for machining machines, more for
> shifting milk cartons etc.
>
> If you examine the SKF, NSK or other good brand on the default clearance,
> you'll see it's excessive. They are designed to take misalignent.
>
> For the Z axis, anything round is a poor choice, unless you can adjust the
> pre-load.
>
> Regards
> Roland
>
>
> On 19 April 2012 20:09, Brian Worth <electromodeler@...> wrote:
>
> > **
> >
> >
> > Hi Dave,
> > I used 20mm drill rod for mine, 400mm long, supported with one support in
> > the middle, and "open" cheap chinese re-circulating ball type linear
> > bearings. These bearings were so sloppy and such junk, I gutted them,
> > replacing the bearings with home made Delrin "c" bushes in the existing
> > carriages. It puts more load on the steppers, but it is strong as the
> > proverbial brick sh**house. I machine wood and alu with no problems.
> > Support in the middle is crucial in my opinion for anything over say 200mm
> > (8").
> > Regards, Brian
> > --- On Thu, 19/4/12, turbulatordude <dave_mucha@...> wrote:
> >
> > From: turbulatordude <dave_mucha@...>
> > Subject: [CAD_CAM_EDM_DRO] are 3/4 shafts good for axis ?
> > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > Date: Thursday, 19 April, 2012, 16:45
> >
> >
> >
> >
> > Hi all,
> >
> > I am designing a wood router with a 18 inch wide X axis.
> >
> > it looks like 3/4 inch shafts will fit the design really well, floating,
> > connected to the ends, not fully supported along the length.
> >
> > I plan on using a trim router and will do cutting in wood.
> >
> > Anyone have experience with 3/4 inch shafting ? I am on the fence between
> > 1 inch and 3/4 inch.
> >
> > If I was planning on doing anything stronger, I would use linear shafting
> > that would be fully supported along the length, but that would cost more
> > than the rest of this machine !
> >
> > Suggestions and feedback welcome.
> >
> > Dave
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>