New Pm 727m Mill

Well guys, it has been a long afternoon. As expected, everything was packaged well. The fit and finish of the machine was great; it was right on par with my 1127vf-lb lathe I got back in January.

Uncrating was they typical chore. They do a really good job at the factory of crating these things. Once I got the crate all stripped down, I took some quick measurements of the stand and approximate height to the table. The stand is 27" tall, and the table sits about 8" above that. That is a little low for me. I whipped up a temporary stand from 4 ×4's and 2×4's, that gave me 5" more height.

I hoisted everything up into position (except the chip pan which I forgot in my excitement) and bolted it all down. The first thing I noticed is that the y axis was almost impossible to move. It was bound up tight. I inspected the tapered gib and it appeared to be a little long. I sanded it some using the mill table as a flat surface. Then I filed the notch for the gib adjustment screw a little deeper as I realized the screw on one end was only about 2 threads in. This gave me more peace of mind that the screw would hold. I also turned a spacer for the other side adjustment screw as it was bottomed out and not engaging. This allowed it to actually make contact and secure the gib.

The only other issues were simple. The t-slot bolts included in the tool box were too wide for the slots, and for the slots in my new 4" vice. Ground those down to fit and filed the slots on the vice accordingly. Then I noticed that the draw bar was not threaded long enough to fully draw the R8 collets into the spindle. I slapped a couple of washers on there for now. I plan to turn a bushing this weekend. At the same time, I found that the collet wouldn't actually go into the spindle. I remembered a thread on here where Matt commented about simply backing out the small screw in the side of the spindle. I found that screw, removed it, cleaned it and the hole, and put it back in with some blue loc-tite and adjusted it so the collets would slide right in.

The left hand knob on the table had a bit of slop in its engagement and every time I turned the right side know, the left knob made a clunking sound as the handle went over the top and the weight shifted. I shimmed that with some aluminum foil folded over a few times. To me, all that is minor stuff. It is a Chinese machine after all.

With all that said, I did mill some bar stock just a few minutes ago just to see what she would do. Man, it is a beast. My frame of comparison is a little X2 mill, so the bar was not set very high. It plowed through the steel at .030 deep with a 7/16" hss end mill at 600 rpm. I know that isn't a massive cut, but the X2 couldn't even dream of that cut.

The thing that will take some getting used to is the sound of the gears. My X2 had a belt drive. But, this mill isn't really loud at all.

I am very happy with my purchase. I think that this size machine is perfect for a hobby guy like me that doesn't have the room for a full knee mill. It should serve my purposes very well.

20150903_210854.jpg 20150903_210759.jpg
 
Last edited by a moderator:
Sounds like you had a few of those 'Chinese things' to take care of, but it didn't sound like you ran into anything major. I've had similar issues with every machine I've ever owned but I was up and running a lot faster than others I've witnessed having to refurbish or restore a used machine. Of any parentage.

My PM25 will easily take a .25" deep DOC with a good quality endmill (I might use a rougher for that, depending upon the material). I had similar experiences when I stepped up from my LMS mill to my PM, and then from my PM to my CO 12z. Have you stopped grinning yet? :)
 
Nope, definitely still grinning!! I have a couple of new cobalt end mills that I got recently and have waited to try out when I got the new machine. I plant to see what a fresh sharp end mill will do this evening. I actually did make myself go to bed last night right after my update. My buddy Lee (lpeedin on here) was teasing me today that he knew I would end up doing some machining before bed, one way or another!!

The big things I have to do now are just to fab up a steel adjustable base, install that, and put my chip pan on and I am all set. I will fine tune the tram over the weekend too as I can tell just by milling that the left side of the end mill is cutting a little more than the right. I will also probably go ahead and do an oil change since I did a spindle break in yesterday and did some milling with it.

So far, it is everything that I thought it would be.
 
I'm trying to decide between this and the PM-25. This will be my first mill and I will be using it mostly for gun related machining and any other small projects. anybody have an opinion? I can't wait to see some more pics.
 
I do mostly pistol/revolver work, with some rifle mixed in. My PM 25 would do most things I need of it, but if the 727 had been available at that time, I would have opted for it instead as it lends a little more mass/rigidity for when you're milling on forged slides and other similar operations.

My experience has shown that much can be done on smaller machines, but if you can afford the space and money, bigger does work better in many cases.
 
Well, I decided today was "tram the mill day" and what a day it was. I noted that when milling, the pattern favored the left side of the cuttet, meaning the spindle was tilted to the left. So, I went to work.

First, I trammed the head to the column. Then, I removed the column from the table with my trusty gantry crane and inspected the mating surfaces. There was no grit, paint, sand, or anything in there, just some hand scraped mating surfaces. I wiped everything down and reinstalled the the column.

After that, I checked the head to table alignment and noted that I was still tilted left about .005" over 7". So, I re-trammed the head to the column, since I just lifted it with the crane. Then I check the head to table again and I was still .0045" off. So, I loosened the 4 bolts on the column mount and tilted it to the side and ended up using a total of 16 pieces of aluminum foil to shim it. I got it to within .00075. I milled a couple passes to check and the pattern was still favoring that left side, but not nearly as severe. I plan to add 2 more pieces of foil tomorrow which will hopefully get it within .0001".
 
Head to column is the same is head to table, except you put your indicator base in the column and use that as your reference point. This insures that you are setting the rotational axis if the spindle in line with the travel of the head up and down the dovetail.

Once you know that is good, then you move your indicator to the table. Now you arw. Heckling the relationship of the spindle relative to the table. This is when you would need to shim the column to correct misalignment. Having the head square to the table is good, but it if the column is moving up and down at a tilt, there will be a shift in dimensions laterally.

I just went out and checked mine again two times amd it appears that I am much closet than I thought. I figured it this morning at less than .0005" to the left. I am going to just bump the head and mill passes until I get that perfect circle pattern in the surface. When I mill in the y axis only, I get those perect circles. Nod is good. But, there is still the slightest lip on the left edge that is visible and can be felt with a fingernail.
 
Yep, you lay awake half the night (after checking for ticks) thinking about the tram on your new toy. Hope to get over there tomorrow to check it out.


Sent from my iPad using Tapatalk
 
Head to column is the same is head to table, except you put your indicator base in the column and use that as your reference point
So,. lets see if I've got this right. You put the magnetic base on a solid, non-moving part of the column (like behind the dovetail, on the side. Then you set the indicator plunger on the side of the head, and run the head up and down, to see if the needle moves. If it shows movement, what would you adjust, to make it right ? Thanks, JR49
 
Back
Top