Hi Stefan
>I would not buy his plans even if i could.
>The hardest for me is not how to make it, but how to get the needed
>material.
>The plans don't do the work for me.
>Making some errors during development i something i risk, but i doubt i
>would be satisfied
>with any plans. (you have to search for the specific parts then also...)
>
>
>I think it is good possible to see from the pictures of his machines which
>principles he
>uses, (e.g. which rail mechanism). For someone with a bit understanding
>of mechanics there are no dimensiones etc. required.
>
>
>Look he too uses the ball bearing on pipes/rods...
>i located a big length of stainless pipe (maybe flag pole or similar)
>at a relatives shed.. have to inspect for surface quality but if it is ok i
>am sure
>i can get it..
>
>another source for good rails is ebay..
>at ebay.de (for markus....) there are always a lot of "linearführungen".
>often ground steel profiles with ball or roller beared carriages. no play.
>also acme threads with ball-beared nuts ("kugelumlaufspindel") are sold..
I already do have all materials I think I need for my machine and also
started construction. I had to cease working on it cause I'm held busy
job wise at the moment. I'm looking foreward to continue the work and
once there is a stage where I can take some picutres I will do so and
post a link to them here.
With regard to John's plans - they most likely will be worth the money
for those also able to organize the parts. He's concept for the
machines seems ok for hobby use from what one can see on the pcitures.
I do agree though that the value of plans is more than questionable if
the parts shown there can't be bought easily. This is of course true
for all these kind of plans. Especially for those that want to build
such a machin "on the cheap" it's very important that they can be
flexible with what parts they use. However, this flexibility actually
then destroys the value of a plan...
>it is not as cheap as pipes or steel profiles but a lot more precise.
>
>
>I was thinking about the cnc for some time now, not really having time to
>build one
>but gathering information..
>
>i initially wanted to make a steady table with the spindle moving all three
>axis..
>now i think it is easier to move the workpiece the one direction (x), the
>spindle y and z on a vertical mount (like seen on many designs, including
>kleinbauers).
>Not sure what's better...
I also will do it like this. I.e. a moving x direction and a stand
with y and z mounted to it. IMHO this is is the simplest aproach also
giving a fairly stable result. I will only used threaded rods that
drive a plastic nut. Surely enough precise and stable for the purpose
of my machine (drilling only).
>I want to use the machine not only for pcb making (and there maybe only for
>drilling)
>so i have dome extra requirements.
Mine will be restricted to drilling only. That's what I need most at
the moment - well, it's the only need I had so far. Based on the
experience made and provided the need arises here I then may build
another machine for milling.
>if i make "ball bearing" slides (and not buy good oned from ebay) they need
>to be steel.
>a ball bearing only conacts the rail on one small point (ok a lne with a
>flat rail).
>if you use aluminium bearings and want to mill aluminium this may not be
>sturdy enough.
>ball bearing rails have the disadvantage of small contact points. (i think
>because of this
>on other tools like lathes/mills dovetails are preferred).
My (drilling only) machine will be equiped with those special
drawerslides I mentioned earlyer. They have no play at all, are stable
in all directions (as oposed to standard drawer slides) but of course
have a limitted stiffness because they are just drawer slides. Again,
for the sole purpose of drilling PCB's they are perfect. I'm also sure
that they are sufficient for light milling jobs like wood or plastics
etc. Experience will show.
>i have a lot of other ideas.. but i don't want to bore you...
Instead of using a redy made drill for the motor (I.e. proxxon) I will
build one on my own based on a cheap electro motor as it's used for RC
racing cars. This motor delivers a high enough RPM and torque. An
extra spindle made of a silver steel rod then will be centerd / held
with ball bearings and the motor is then driving this spindle over a
cardan. Like this the motor can be mounted in a way to avoid
virbrations being transported to the machine frame thereby reducing
noise. The home made spindle will be threaded on it's end so as the
Proxxon keyless chuck can be monted to it.
So far the materials I bought are way below $100 - including the
stepper motors bought from e-bay. I will most likely also build my own
controller cirquit cause I don't intend to use a DOS based PC but a
microcontroller for controlling the machine. The drill / mill data
then will be transfered to the machine over a standard ethernet
connection. I happen to have a working single computer network enabled
design I made for another purpose that should be up to the task to
form the base of this controller unit. The machine then can be
controlled using a built in webserver. The costs for the controller
therefore are also within strict limits - I don't expect them to raise
above $80.
Markus