"Morris Dovey" wrote in message
...
mike hide wrote:

| Last time I followed one of your posts you were spouting robotics.
| a subject totally alien to me . This is what I have been piddling
| with since ......mjh

As you've probably figured out, robotics are an important part of my
work life - and I'm sufficiently fascinated with the possibilities to
talk about the stuff whenever I can.

I especially like your box beam, heavier rails, and the rail supports
for the y-axis - and your router/spindle mount is much more elegant
than my (rather primitive) band clamp setup that surprised even me
with its rigidity.

How did you handle the linear bearings - and are you satisfied with
their performance?

I used Delrin slides on round rails and they work well at low to
moderate speeds, but are prone to chatter when I try to move the
spindle around at speeds higher than about 5"/sec. I'm planning to try
another approach (mounting ordinary ball bearings to machined aluminum
blocks) to see if I can push the speed up a few more notches. I'd
really like to be able to run the steppers flat out.

Please post more pictures as you progress - and let the rest of us
learn from your experiences...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html



Morris I am in the middle of building "joe's machine " as shown in
http://www.cnczone.com/ There is a wealth of info in particular routers. I
have basically only completed the router gantry section ,this being the most
complex part of this design. The cradle runs on gas pipe from HD or Lowes
and uses inexpensive skate bearings readily available on ebay. The
driveshafts are 1/2" acme threaded rod available at enco again inexpensive .

Many people on the group, cnczone , are building the same machine using
parts made on Joes router . Basically being a pauper I could not go this
route and had to produce using basic woodworking equipment and drawings from
the site . One runs into problems here and there such as getting a close
fitting for the gas pipe housings and othere odd sizes easily done on a cnc
router but who has odd sized drill bit in their shop .

The gantry runs on a bed using two larger gas pipes on each side they are
supported in housings on either side of the box beam and the whole thing
runs on 16 skate bearings . The amazing thing to me is this piece of
equipment is producing stuff within a couple of thousandths .

I do have a few problems with the design in that the bearings running on the
gas pipes result in a point contact and thus very high contact pressures. So
I am going to try using an inverted 1 1/4" leg angle iron on a laminated mdf
beam. we will see mjh