re:maxnc/sherline (Z axis motor)
Posted by
ballendo@y...
on 2000-10-12 15:01:29 UTC
taus,
Welcome!
Agreed the MaxNC documentation is terrible!
Don't overdrive your motors! Putting 2A in a 1A motor does no good
for anything!
Not likely that the difference between 20TPI and 25.4TPI and .3750
(I've used the stock sherline inch leadscrew) vs. .3937 is the REAL
cause of your problem(s). (There IS more friction loss with the 25.4)
I've used both with similar motors and found no real difference.
BUT:
70 oz.in. is near the bare minimum to use for a Sherline Z axis. And
you are DE-rating the motors by over-driving them! You MAY have even
destroyed the magnetics of the motors at this point.
What I'm saying is that 70 oz. in. motors SHOULD work, even on a
metric leadscrew. But, you may no longer have 70 oz.in.!
Since you have the Sherline CNC mounts You might check the preload on
the bearings(does it turn freely and easily by hand?)
And, I hate to mention this;(but I was a service tech in a past life
and I've seen worse) Is the Axis LOCK OFF?(the little brass lever by
the nut for the z)
Have you used a good lubricant on the screw? Is the Z axis nut
SECURED and well-adjusted? (check by hand-turning "the whole length")
years(IMO) from where you are now.
to help. I've never NEEDED one.
Hope this helps.
Ballendo
Welcome!
Agreed the MaxNC documentation is terrible!
Don't overdrive your motors! Putting 2A in a 1A motor does no good
for anything!
Not likely that the difference between 20TPI and 25.4TPI and .3750
(I've used the stock sherline inch leadscrew) vs. .3937 is the REAL
cause of your problem(s). (There IS more friction loss with the 25.4)
I've used both with similar motors and found no real difference.
BUT:
70 oz.in. is near the bare minimum to use for a Sherline Z axis. And
you are DE-rating the motors by over-driving them! You MAY have even
destroyed the magnetics of the motors at this point.
What I'm saying is that 70 oz. in. motors SHOULD work, even on a
metric leadscrew. But, you may no longer have 70 oz.in.!
Since you have the Sherline CNC mounts You might check the preload on
the bearings(does it turn freely and easily by hand?)
And, I hate to mention this;(but I was a service tech in a past life
and I've seen worse) Is the Axis LOCK OFF?(the little brass lever by
the nut for the z)
Have you used a good lubricant on the screw? Is the Z axis nut
SECURED and well-adjusted? (check by hand-turning "the whole length")
>ANYHOW,You still need a well-adjusted machine, but this setup will be light-
>I am thinking of getting a Camtronics 3 axis 2amp board and getting 3
>180 oz/in 2amp bipolar motors...I feel this should fix all of my
>concerns.
years(IMO) from where you are now.
> What size motors are other people using on their sherline?Everything from 50!! to 225!! oz.in. MOST use 85 to 190 oz.in.
>I saw the page where (I am sorry I forgot who) made a counterspringThere are a few different versions of this "out there". They've GOT
>for the Z-axis and it looked GREAT! I will look into making one
>myself!
to help. I've never NEEDED one.
Hope this helps.
Ballendo