Stepper motor for the PM-25MV Z-axis power feed?

[7milesup]

You could utilize the setup RJ mentioned with a pulley, string, and a fish scale or similar to measure force.

I believe a torque wrench would also work just as well. You probably will not find an inch-ounce torque wrench that goes above 150 inch ounces unless you pay big money. I would use a ft-lb torque wrench, convert to inch ounces, and add a multiplier of 3x. This should get you close. It's not really rocket science.

 

[dabear3428]

pm25 I have been told will take 2NM to lift the head so plan for 4nm and you will not need all of the speed so 2 : 1 reduction will get you 4Nm out of a 2 NM stepper, be sure to pay attention to the voltage supplied to the stepper. the stepper you listed is 3NM so with some reduction 2:1 or 3: 1 you should be good but test YOUR MILL to be sure.

 

[javaduke]

Well, folks, I think it's a success! I used the 8Nm stepper motor kit from Stepper Online and ZK-SMC01 controller I bought on Amazon. I connected the motor directly to the shaft with the lovejoy coupler. Here's what it looks like (only temporarily, I will make a proper enclosure for it, I promise!):

 

[dabear3428]

Well, folks, I think it's a success! I used the 8Nm stepper motor kit from Stepper Online and ZK-SMC01 controller I bought on Amazon. I connected the motor directly to the shaft with the lovejoy coupler. Here's what it looks like (only temporarily, I will make a proper enclosure for it, I promise!):

View attachment 500751

so what is the answer how many licks to get to the center errrr Nm to turn the darn thing?

 

[javaduke]

Like I said, I used 8 Nm motor and it's powerful enough. Probably even an overkill.

 

[dabear3428]

Like I said, I used 8 Nm motor and it's powerful enough. Probably even an overkill.

got ya, I was inquiring about any test data you had, so the data point is 8Nm more than does it. can you post photos from the side showing how you mounted the stepper?

 

[javaduke]

can you post photos from the side showing how you mounted the stepper?

Oops, sorry for the delay, here are some pictures. I couldn't mount the motor square to the column because there was simply not enough meat to drill and tap new holes, so I made this abomination of a mounting plate from a piece of aluminum. A couple of screws are missing, as you can see, because I screwed up my math and misaligned the holes, but the remaining screws hold it tight in place, there's no movement or vibration whatsoever, and it's VERY quiet. I know it's ugly, but it works and I don't see it most of the time anyway ))
I'm also going to install an end stop switch, but it can wait.