[yohan]

Has anyone purchased a PM-25MV in the last year or so? If so, how has it performed? Has the motor had any issues? Any issue converting it to CNC? How does it compare to a G0704?

[eman5oh]

I was considering buying one myself and had contacted them about it, he did tell me that any day now they will be releasing a CNC version of the machine. I ended up picking a Bridgeport Boss5 with a bad control that I plan to retrofit with new controls. If I had not got this I was thinking pretty hard about the PM25-MV and converting it or the soon to be released CNC version of it. I asked around to a few people that had tehm and converted them, all liked the machine and said PM was easy to deal with.

[cgo]

I have one, although I am blueprinting the machine for cnc.

Did use it a couple times so far manual but trying not to get it dirty until Im finished blueprinting.
The spindle motor runs very quiet and for its size has good power and regulation, long term cant say anything yet.
It is larger by a small amount compared to the 0704 and maybe a little stronger in the way the column is attached.
There is no oil galleries on the machine but that shouldnt be too hard to add when I have it disassembled.
There is enough room to use (all) 20mm compact ballscrews if you wanted to spend the money for them , stock screws are .97" dia. with 10 turns per inch movement.
Looks like I can add about an inch more to Y (towards column) when I switch to ballscrews without modding the castings.
I havent done any testing for accuracy, not even adjusted the gibs yet.

[arizonavideo]

I have the new one and like it. The belt drive is quiet and will make it easy to mod it to get higher top speed.

I make CNC kits for it and it is a bolt on idea with no mods needed to install it. I only have room in my shop for one more mill and was debating on running the 704 or PM-25. I'm going to put the PM-25 in service mainly because of the motor being better and that there is not much info out there about the mill so people may like to see it run and how it cuts.

It is basically exactly the same size as the 704 with each part the same weight. The only minor flaw is the stock Z ball mount, it is at the bottom of the Z slide which stops the head from going vary close to the table. I fix this by moving the Z ball nut mount to the center hole which gives a little over 2" more travel to the table so you can run a jig plate off the table and still have a small short tool get to your work.

[Redeeman]

i have one which i believe is identical to the new pm25mv, its belt drive/brushless does indeed run super smooth. at very very low rpm i notice a clacking sound, but i think it will be fixed by one of those 3d printed spline "inserts" that hoss made

[AndrewNC]

Is it possible to do any extension of the stock y travel on the PM25mv similar to how people mod the g0704?

[Redeeman]

I believe the amount you will be able to get is very limited

[eman5oh]

The the way column is bolted to base means a different method of extending the y would be needed,

[Soloratov]

I recently aquired one. It's a great machine, but I have a weird issue with the motor. Not sure if it's normal. It seems to need to "warm-up" every time I use it in order to hold a reliable speed and torque as I am cutting. Using a 2 flute 1/4" HSS end mill, 2500RPM taking maybe 1/16" depth full width cut, 6061 aluminum, I'm losing almost 500RPM. If I switch to low speed, run it at the 1200RPM, it dumps about 2-300 RPM. This is with cutting fluid, moving painfully slow. The main thing is this: if I turn the machine on at say Low gear, full speed should be about 1200-1250 RPM. It takes a good 5 minutes for it to actually get there. It starts at about 800 and slowly works it's way there. This effect is multiplied if I am in high gear. It never actually gets past 2300 RPM. I have sent an email to PM and have gotten replies but then things went quite a few days ago. Thoughts?

I run machines all day, but they are full size bridgeports and VMC's so lighter machining is a bit of a curveball. I only know what I have seen done with the G0704, so i am trying to base my results on that.

[AndrewNC]

Can the y-axis stepper motor be rear mounted on the PM-25MV by drilling a through hole? I can't tell from the photos I have seen if the stock screw position is low enough, or otherwise interferes with the column mount.

[phomann]

I have a TM20VL which is the same design but with a gear drive on the spindle (I've converted it to belt drive now).

When I did my conversion, I looked at all the various options for mounting etc, including having the Y motor at the rear. To me it seemed impractical for 2 reasons;

1. You would need to cut through one of the strengthening webs
2. The rear surface of the base is not vertical and it would be difficult to mount the motor in line and parallel with the screw

Have a look at the underside of the base here;
http://www.cnczone.com/forums/bencht...ml#post1151352

If you want to increase the Y-Axis you would be better off to;

1. enlarge the hole that the ballscrew passes through at the front of the base so the nut can pass through
2. Fabricate a spacer on the front to accommodate for the nut extending through the base

On my conversion I have a spacer block on the Y-axis to hold the FK12 bearing block.
http://www.cnczone.com/forums/bencht...ml#post1188299

If I go to a double nut on the Y axis, I'll add another spacer to accommodate the body of the double nut which will extend through the base slightly. That way, I won't loose any travel in the Y-axis.


One thing to keep on mide is that if you extend the Y-axis you also need to put an equivalent spacer behind the spindle head otherwise you can't use the extra travel.(unless the is a fault in the machine design).
You need the spindle to be in the centre of the Y travel. It is no help having more travel in one direction than the other.
Also, the saddle already overhangs the Y dovetail quite a bit when at it's extreme which won't held the rigidity when machining.

Cheers,

Peter