Re: Re: Spindle motor drive belts MAXNC 10 UPDATE

hansw <hansw@...> wrote:

...looks a

> lot
> sturdier than the crap MAXNC puts out.

Andrew Werby wrote:

>
> [Come on, Hans, MaxNC makes the least expensive CNC mill on the
> market, and
> they make them in the US. Sure, there are lots of features we could
> dream
> up that would be nice additions or modifications, but these mills work
> (admittedly, not 24/7 ) and they are the way a lot of us - even Jon,
> apparently- got our start with CNC.]
>

Yep! that includes me... But when the person tells me the motor mount
was designed ot be flexible I think he's full of it.. First he blamed
Gates for making a poor quality belt....

[Sounds like somebody there was improvising a bit...]

> The guy had the nerve to tell me " we designed it to be flexible" ...I
> also notice the carcass of the MAXNC electronics hanging on the back
> of
> the mill.... I purchased a complete MAXNC -10 because I needed a mill,
> I
> did not want to build one....
> What kind of electronics are you using to drive the motors ?
>
> Well I'm in the middle of making a new motor mount. it will be a four
> point mount and will allow full adjustment... I'll post the results at
> my web site when I done...
>
> [Great- how much would you charge to make these for others? Maybe I
> could
> refer people to you who want a better arrangement.]
>

Just like my Stepper motor driver designs. I don't want to market them,
That's why I posted the artwork and schematics at my web site free for
any individual to use ( not commercial )
However if you are interested I can post the Acad drawing...

[That would be nice. It looked like your 4-point mount plate (if I'm seeing
it right) would be studier than the 2-point system currently used.]

> Sure it's a deal, and now that I've re-built over half of it, I regret
> not doing it from the beginning, the regrets are about $500.- worth of
> motors and electronics and software.. I ordered 70oz-in motors and
> realized after a while that they could not be that powerful. My tests,
> (
> see my web site how I do it ) tested the so called 70oz-in motors at
> 42oz-in.....
>
> [Steppers start out at their rated torque, but it drops rapidly once
> the
> motor starts going. Mid range torque is lower. MaxNC does sell 145
> oz/in
> motors, and they just came out with a servo system. I haven't had a
> chance
> to try it yet, but I'll keep you all posted.]
>

Well then it's a question of what is advertised and what is delivered.
They are advertised as 70 oz-in HOLDING TORQUE

[They shouldn't have said that- one would expect "holding torque" to be
torque at speed.]

I measure them as 42oz-in... And the motor in the brochure is not the
motor they delivered to me.
Check my web site for a simple accurate method of measuing holding
troque...

[Looks okay to me.]

Well I would not touch any MAXNC product again... once burned .... If
they do "cheap and nasty" becasue they hang on to the excuse that the
only way they can do it is by poor quality... That's no excuise at all,
and in many cases they are simply silly ( I would use a different term)
Look at the original spindle motor speed control control as delivered by
factory, the consider the amount of labor cst to assemble such a mess.
Compared to a simple 1" x 1.5" $0.50 circuit board assembly. My
re-ybuilt version of the controller would be more cost effective to
produce and that's how prices are driven down...

[It doesn't look like it would fit in their box, though. How much would
these cost to make?]

> When I asked to see the manufacturers data sheet on the
> motor I was told it was not available and I could get a refund... I'll
> keep the motors as a reminder that I should not be so dumb fat and
> happy
> with everything that's fed to me in brochures... I'm not flaming
> anyone.
> I'm just stating the plain honest facts...
>
> [You might try Pacific Scientific, which makes the motors.]
>

Well these motors have been sprayed black, and MAXNC put their own label
on them, and I was told that the motors i the brochure picture is no
longer being delivered. There was no data available on the motors
delivered to me.

> Would I buy a MAXNC again.... Well no... I do learn from my
> mistakes...
> would I recommend it to anyone... Well NO...
>
> [What would you recommend for someone who wants a CNC mill, including
> software, for under 1300 bucks?]
>

Taig... It looks like a bulldog but i have only heard good stuff about
it...http://www.primenet.com/root/minimill.htm
If not a retrofit of a Sherline...
These may not be in that price class. but when you buy crap you buy
crap....
There is no excuse to not mount the motor in such a manner that it's
stable. the two 6-32 screw studs coming out of the motor are not made to
take this kind of a side load. The motor is clearly mad to be panel
mounted, and as such it will tolerate the side load much better...

>
> [As far as your original problem with the belts is concerned, one
> thing
> (that nobody else mentioned) that might be causing it is taking too
> heavy a
> cut- this can cause belt slippage too.]
>

Right that was what I found out after studying it carefully. In fact
with a bad belt and very slow speed the motor vibrated about 1/8 inch
and the belt tension was directly altered because of this, and mad eit
possible for the belt to twist..

As I said in my earlier reply "Sure it's a deal, and now that I've
re-built over half of it" and that means I could have had a much higher
better quality mill for the extra money and time I've spent making that
one work... I mad a mistake and I learn from them...MAXNC never again...

Accepting poor quality with the excuse that it's cheap, is no excuse at
all.

[Every product made represents a balance between cost and quality. They
wanted to come up with a design that was simple to construct and would meet
most people's needs, while coming in at a lower price-point than anything
else on the market. If you asked, they should have told you that taking
heavy cuts in dense materials at slow speeds would be a problem. It is best
suited for light cuts in light materials at high spindle speeds. ]

I just wish I had seen this list before I started into this venture, I'm
sure it would have saved me $$$$$

[I thought we liked learning experiences in this group? Just out of
curiousity, what would you do if you had it to do over again, start from
scratch? Save up for a Taig? ]

Thank you Andrew, it's always a pleasure to hear someone else's point of
view...

[Likewise, I'm sure.]

Just in case you don;t already have it my web site
http://home.swbell.net/hans_w

regards
Hans Wedemeyer
"Only the Truth will set you free" ...... by someone I don't know who...

[I like your modifications- have you shown them to MaxNC? Mind if I do?
Meanwhile, if I run into someone interested in a slightly used and somewhat
modified MaxNC, should I send them to you? How much do you want for it? ]

Andrew Werby

Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com