PM-30 Z-axis power feed?

[alfaspider]

That video shows lower left for PM-727, as does the site for the PM-727, PM-932, and PM-940. The PM-833T has lower right. PM-25 and PM-30 are upper right. I don't see any PM bench mills that have Z crank on upper left; that seems to be the only option that is not used! ☺



I'm guessing that the quill DROs and spindle motor control boxes are the same between the PM-25 and PM-30, which would mean the PM-30 head is substantially larger. At this point I've never seen either mill in real life, so I'm just going by the pictures. But compare the following two images:

View attachment 274983View attachment 274984
Note that the electrical control boxes are very similar other than the speed control markings, and the DROs look almost identical, yet on the PM-25 the electrical control box is nearly as tall as the head whereas it's about ¾ of the height of the PM-30 head, and the DRO scale is about 17% of the width of the head on the PM-25 but only about 13% of the width of the head on the PM-30, which would make the head wider as well as taller.

The spindle travel on the PM-25 is 2 inches, and the spindle travel on the PM-25 is 3 inches. More head height, more spindle material.

The motor on the PM-25 is advertised at 1HP (at 110V), and the motor on the PM-30 is advertised at 2HP (at 220V) so I expect that contributes more weight to the PM-30 head as well.

I expect Matt could fill in more precise information! ☺

yes- crank handle is on upper right side-- my typo mistake. I used this gear drive set up as the hand crank interfered with the factory installed DRO monitor

The wiper motor I used has no trouble with upper travel, so not sure what is the limit-- Tin Barn did a "flintstone" lift on one video and could calculate the weight that his motor could lift. Wiper motor I used was a $19 ebay auto product, so I figured it was worth a try without major re-testing. And, it did work-- If you can get a weight figure for the head on the 30 let me know. If you also can get a weight for the 25 as well, I can add some metal bars to top of my housing and see if this VW wiper motor can lift it.. I bought 2 more of these motors incase one craps out in the near term...

 

[mcdanlj]

Didn't mean to be annoying about the typo, it was just funny! ☺

It's really a question of torque. I can just measure torque with a wrench whenever the mill arrives and figure speed and mechanical advantage as needed. I don't even know whether the PM-25 and PM-30 use the same internal gear ratio so weight isn't the only factor. I was wondering more about mechanical concerns for attachment than motor torque honestly, and it looks like PM-25 and PM-30 are indeed similar there. Hearing that the DRO really does interfere with the handle (I had wondered) means I'm likely to get to this sooner than I would otherwise. Thanks all!

 

[alfaspider]

Didn't mean to be annoying about the typo, it was just funny! ☺

It's really a question of torque. I can just measure torque with a wrench whenever the mill arrives and figure speed and mechanical advantage as needed. I don't even know whether the PM-25 and PM-30 use the same internal gear ratio so weight isn't the only factor. I was wondering more about mechanical concerns for attachment than motor torque honestly, and it looks like PM-25 and PM-30 are indeed similar there. Hearing that the DRO really does interfere with the handle (I had wondered) means I'm likely to get to this sooner than I would otherwise. Thanks all!

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30-----
https://www.precisionmatthews.com/wp-content/uploads/2017/05/Front-Left-nostand.jpg

25------
https://www.precisionmatthews.com/wp-content/uploads/2016/10/PM-25-nostand-web.jpg

The hand crank mounts on the "upper left side" of these mills (if looking from the back side) -- also appear to be a bit different? The 25 has a larger more flush mounted plate with a round "boss" while the 30 has a square mount that protrudes from the column.

 

[mcdanlj]

Finally got my PM-30MV into the shop, thanks to 5 friends who came to help and stayed for pizza. ☺

I still have to run power, so I haven't turned it on, but it's clear that the DRO monitor really gets in the way of Z, so power feed will be a must-have early project. I gave up on the awful PM stand and replaced it with a toolchest which moves the mill higher which I find generally a lot more comfortable, but it makes the Z handwheel even less convenient, so one more reason.

 

[mcdanlj]

I shouldn't have said "awful" and wanted to edit it this morning, but it was too late. Awful for my purposes I meant. If you bolt the mill to the floor it's probably fine, but I don't have that option, and the leveling pads left the whole machine rocking when I turned the Z handle. I work all day at a standing desk so I'm used to a higher working position, and I don't plan to work with lots of super-heavy stuff that's hard to lift up to a higher table. But with the table now 45.5" off the floor, I might decide that this is too high and make my own stand, taller than the PM stand, and shorter than the workbench I'm using right now. If I do that I'll probably use the leveling pads for my stand.

Anyway, I'm about 5' 10", and with the table at 45.5" off the floor I can just barely crank Z by hand from the front of the machine. Just as a point of reference for the next person thinking about this...

 

[Bill Kahn]

I am waiting for the next shipment of PM-30MVs to arrive, which I understand is any day now, for my order to be filled. I ordered the X-axis power feed, but there is no Z-axis power feed available from QMT/PM. I searched on this site and more generally with google, and I don't see any discussion of any Z-axis power feed for the PM-30, just other people asking. Maybe my powers of search are weak today, in which case I would appreciate a pointer, and maybe this post will help the next searcher find what they are looking for!

Otherwise, do any PM-30 owners have shop-made Z power feed solutions they can share? Pictures, ideas, warnings, anything? Anyone who thought they would want one and then discovered that they just didn't care after all? If so, ideas why?

Thanks!

I have the PM25. I powerfeed the Z axis with a little battery hand-held drill and a 19mm socket. Works great. Fast. Still can hand crank. Clutch in drill ensures nothing strips. Not that elegant but very functional.

 

[mcdanlj]

I finally measured: 20 in/lb to lift the head on my PM30.

 

[acruxksa]

I'm about halfway through a z axis power feed for my PM-30 using a wiper motor. I originally purchased a powerfeed from a source online and it lasted 3 days. The internal plastic gear stripped out despite having my gib backed all the way out (not an ideal situation for any machining equipment). In any case, it was clear to me based on the components that it would never be reliable long term. Thus, I spent the last couple days putting ideas to metal and trying to use whatever I had on hand and could find locally. I'm not sure it's the best way to do it and when I finally get the motor dis-engage done, it will require two hands to disengage, but the rest is pretty simple .

I already had the power feed lever because it was intended to be fwd/rev for my old Craftsman 6" Lathe, but I ended up selling it when an Atlas 10" dropped in my lap. The wiper motor was also on hand for an intended lead screw mod for the same lathe. the 24v PSU was from an old MPCNC project I had.

In any case, here are some pics. It's not done, I intend to add a spring/lever actuated motor disengage, variable speed potentiometer and fast move button (debating this for a number of reasons, but might just add it because I can) , but the basics are in the pics.

I will also add, that the mounting plate is probably a bit large, but I'm not sure how I'm going to do the disengage mechanism yet, although have some ideas and might need some of the extra length. Also, it's far taller than it probably needs to be, but the coupler with the rubber interface makes everything operate extremely smooth, so I want to leave it.

 

[jwmelvin]

Looks like a nice start. I’m guessing the disengage mechanism will be required to use the hand wheel? How will the rapid work?

 

[acruxksa]

Looks like a nice start. I’m guessing the disengage mechanism will be required to use the hand wheel? How will the rapid work?

Currently running at 18v (turned down voltage on 24v psu). When I get the speed adjustment pot installed I will turn the psu back up to 24v. Then I will just install a button that bypasses it and gives the motor the full 24v.

That's the idea anyway. The motor is being over volted, but since it's not running for extended periods, 24v should be fine. I'm just not sure I need a rapid on the z lift. I will definitely want it on the x axis though, so I might as well see how it works now.

Yes, I will need to disengage drive to easily turn hand wheel.

Plenty of "clean up" items to do as well. I have some 12gauge 4 conductor wire that I will use to replace the old extension cord currently in use and need to tighten the bolts holding the lever to the side so it's not sitting crooked. May have to add a 3rd hole to keep it square.

**Update**
I managed to get the speed control setup and turned the psu back up to 24v. 50% on the speed control readout is about 11.5v, so it's fairly accurate. Motor stops moving around 6v-7v, but needs 8v-9v to restart after stopping. 24v moves everything just slightly faster than my video above at 18v. Should actually work pretty smooth to just set the speed to %50 or so and then use the rapid button. I haven't gotten that far yet, have a lot of work to do to cleanup what I've got already. Need to extend the potentiometer leads and the LED leads so I can mount the speed control unit somewhere out of sight. It's currently double sided taped to the side of the control box. I may look around for something a bit better than the cheap one I'm using at the moment. I've got several of them left over from other projects, so it was easy to at least prove I'm on the right track.

I'm waiting for some thrust washers and an assortment of springs to arrive before I can tackle the motor disconnect.

Also, got side tracked today and replaced the quill "dro" with an iGaging Absolute scale and connected it to my touch dro.

All for now, heading to TX later tonight to visit the in-laws for a week.

I apologize for the crappy video below, Only two hands and I was paying more attention to my multimeter and where the probes were than what was on the camera.