[Jim27]

Wondering what people think of this mill. Think it would be considered a micro mill? From what I can find it is well made but small so limited in what it can cut (or at least how fast). Found one missing the controller so it looks like I would need to replace the axis motors since they are odd variable reluctance motors. Saw one comment that it was more of a precision drill than a mill. The spindle assembly looks to be on a round post so that would seem to limit the force it could take. Anyone have any experience with these? Model of the spindle assembly is M7405 and uses ww collets.

[CS900]

These are cool little machines for sure. I have one (M7504) I'm currently trying to get running again as well. The head of the mill will swivel front to back as well as side to side. Can't see it being overly rigid, but everything I have found people seem to love them.

I believe the servos are standard DC servos, but the feedback does have a position and velocity encoder.

Either way, i have the manuals for the 75XX series mill if you have any questions on them.

[Jim27]

Cliff,

I tried to send a PM but your box is full.

Jim

[CS900]

just cleaned it out...

[Jim27]

I picked up the mill I was looking at. Lots of parts missing but all the critical parts are there I think and I got it for a good price. The spindle unit looks fine except for needing a belt. A few pieces of the old one were under the cover. One collet came with it. Spindle motor works and sounds good. Spindle spins smoothly.

From pictures I have found on the web it looks like the base plate is missing. What I have looks like it was mounted on spacers above a flat base plate but it still has a good sized, heavy base. No axis control electronics and the covers for the stepper motors/belt reductions are missing - may try to 3d print some. On the plus side it is the ball screw version! And the motors are conventional 1.8 degree hybrid steppers with 512 line encoders. I thought the motors were pure VR steppers from flyers I had located as that's what Servo Products advertised. But they are hybrid PM/VR conventional type NEMA 23. The unit had a complex system of oil lines for the ways and screws. Most of it is still there but a few plastic lines are cut and wherever the lube came from is missing - just a stub line into the manifold that goes to all the points to be lubed.

Thought it had a chuck but it is just a shaft in the spindle with a larger section on the end. Looks to be some custom part that isn't that useful. Probably need to pick up some additional collets but I saw a price near $200 for the Servo Products ones. They are hardened and presumably have extra low runout but that's still a lot. Need to figure out if there is any issue with using ww collets from other suppliers such as Sherline.

It's going to be a while before I can really put time into this so for now I will be collecting information and planning...

[CS900]

your's have steppers? You have any pictures? Not common to have encoder feedback with a stepper.

[Jim27]

your's have steppers? You have any pictures? Not common to have encoder feedback with a stepper.

Yes, 1.8 degree steppers. Compumotor OS series. With HP 512 line encoders (Think Avago is the current name of the company that makes the encoders, HP was the old name). Servo Products seems to have called the system VR servo at around the same time this one was made (around 1998). Would be interesting to find out what other machines have and/or pictures.

Here's a pic. I will try to get some others.

[CS900]

wow, that look completely different than my set-up. Almost looks like it was retrofitted. I'll snap some pictures for you in a bit.

[Jim27]

Maybe so on the retrofit. I will get some better shots of my motors too. Would be very helpful if you were able to note the date codes on the motors or other parts on yours. On these they are like "9804" which is 1998, week 4. Would give me some clue to when your machine was built.

[Jim27]

The more I look at this the more it looks like the motors were retrofitted. Looks like they used a nut for a spacer and removed something from the end of the ballscrew shaft - think it may have been the encoder drive. Here are some pics. Not sure what they had in mind using the encoders with the steppers.

If anyone has pics or info on these machines they can share I would appreciate it.

[Fastest1]

That little mill looks very similar to a Dyna Mechtronics 2000, 2200 or 2400 mill. Well the base machine does and as you said maybe a retrofit too. I had seen this same casting used by a large machine tool company too IIRC.