RE: [CAD_CAM_EDM_DRO] Drill-Mill CNC conversion design.

Nice layout, with one exception:

I'd recommend using TWO angular contact bearings for the z-axis, spaced a
fair distance apart, for three reasons, in descending order of importance:
(1) it looks like the belt will be applying a side load to the ballscrew
assembly, which has nothing to resist it if you only use 1 bearing. Thus,
you'd need 2 bearings, and they should be spaced apart to increase the load
capacity against the cantilevered belt tension. Standard angular contact
bearings can only take a load in one axial direction, and alone have zero
moment capacity. (2) angular contact bearings are meant to be mounted in
pairs for good reasons, like proper preload, alignment, etc. (3) many forces
are likely to exceed the weight of the headstock, such as those from
drilling, friction of the quill in its bore, vibration, accelerations, etc.

Hope this helps,

Carlos Guillermo
VERVE Engineering & Design

-----Original Message-----
From: cadman@... [mailto:cadman@...]
Sent: Wednesday, May 30, 2001 10:50 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Drill-Mill CNC conversion design.

I have finished drawing up a design using Solidworks. I have placed
some pictures and drawings on my web site. Before I start to make
the parts to do this conversion, I would like to get the groups input
on the design.

I did not show preloaded ballscrew nuts in the design, I figured I
could add them if I was not happy with the tolerance that a single
nut gives. The cost of the preloaded nut scared me away. My use of
this machine will not be for business of any kind, just making parts
for my entertainment.

My web site is http://24.12.163.105/cnc/

CADMAN