PM-727m New mill has arrived!

[TheGov]

I got close to that amount of crud in my first (only) oil change. Have many times you changed it before?

Looking at the pm-727m's blueprints It appears the coarse/fine feed shaft doesn't go into the gearbox. It goes below and to the back of the quill where those teeth are cut in the back of it. If you look under the head behind the spindle, you can see where they engage.

If there is slop up and down on the quill and only during fine feed then there might be an issue with the worm gear engagement. Maybe the clamp knob is not in tight enough? Gunk in the worm gear? To me , part (3) and (21) are worth looking at.
View attachment 232841View attachment 232842

As to the oil change, I did one after the initial break in, then this last one after about 20 hrs run time.
In the pic below is the metalic crud stuck to a magnet.

 

[Sloth2009]

As to the oil change, I did one after the initial break in, then this last one after about 20 hrs run time.
In the pic below is the metalic crud stuck to a magnet.

That is a lot of metal for sure. Is that slop measurement supposed to be 1.6mm? 16mm is over a half inch. Yikes!

This happens when the quill is down. This makes me think the slop is is the top part of the spindle assembly. Because the qill is probably holding the spindle in the correct position when it is up. When the quill drops, I think the spindle assembly may be dropping too causing the slop. If you can confirm that, I would concentrate between the 2 (3) lock rings.

Does it make a difference with the gear switch in high or low. How about with spindle lock on?

With slop in the spindle and those metal shavings, I think you will need to look at the meshing gears (7) (8) and and their counterparts (87) and (89) for wear.

 

[tweinke]

I just had a thought based on my 727, I found that on my mill that if you tightened the draw bar pretty tight that the splines of the quill would have a visible wobble. Upon investigation I found that the draw bar did not center in the quill when tight and I noticed that the quill did not travel smoothly. I would think that might have a tendency to force gear 7 to be pulled out of place but I may be all wet on this theory. I made a new drawbar and a washer that centers into the inside of the quill with a shoulder and that has solved my quill travel smoothness issue.

 

[TheGov]

That is a lot of metal for sure. Is that slop measurement supposed to be 1.6mm? 16mm is over a half inch. Yikes!

This happens when the quill is down. This makes me think the slop is is the top part of the spindle assembly. Because the qill is probably holding the spindle in the correct position when it is up. When the quill drops, I think the spindle assembly may be dropping too causing the slop. If you can confirm that, I would concentrate between the 2 (3) lock rings.


View attachment 232917

Sorry, ment 1.6mm.
With the quill lock snug, no play/slop, same with it all the way up.
With the fine feed engaged, quill lock off, the quill and spindle both move the together.
I stuck a bore scope camera in the housing with no oil to see if the shavings were gone, but couldn't get in that far. (7) prevented this. I will have to find the mirrors that go with the borescope and see if I can see the rings mentioned and gears.

Thank you for your help and suggestions.

 

[Sloth2009]

I just went out and replicated the same conditions on my mill. I was able to get 0.39mm in upward movement on the dro. I ended up tightening the quill set screw behind the quill lock and was able to get rid of the play. In doing this the coarse feed became so stiff it would not return on its own. I put some anti-seize grease on the quill and in the little slot the set screw rides in. Right now there is no play and quill returns itself to the top position most of the time. I could try to tighten the return spring. I also wonder if polishing the end of the set screw might help.

 

[Sloth2009]

There are actually 2 set screws in the hole behind the quill lock! A short allen set screw and a longer slotted one. I took them out and polished up the mating end a bit. Maybe it will help a little. If I had a lathe I would remake the longer set screw out of something with less friction.

I have a suspicion what I am seeing with the quill slop and possibly what you [TheGov] is seeing is just play in the gear on the back of the quill and the quill pinion shaft (1) that comes out of the coarse/fine feed. Tightening the quill set screws forces the quill against the shallow end of the splines on (1) taking up any slack. In the bottom rear of the head you can look through a small gap and see the quill gear teeth. When the set screw is loose the teeth slip up slightly. When the set screw tight, this does not happen. Hopefully that is all it is and not something wrong with your gears. See what you think.

 

[TheGov]

There are actually 2 set screws in the hole behind the quill lock! A short allen set screw and a longer slotted one. I took them out and polished up the mating end a bit. Maybe it will help a little. If I had a lathe I would remake the longer set screw out of something with less friction.

I have a suspicion what I am seeing with the quill slop and possibly what you [TheGov] is seeing is just play in the gear on the back of the quill and the quill pinion shaft (1) that comes out of the coarse/fine feed. Tightening the quill set screws forces the quill against the shallow end of the splines on (1) taking up any slack. In the bottom rear of the head you can look through a small gap and see the quill gear teeth. When the set screw is loose the teeth slip up slightly. When the set screw tight, this does not happen. Hopefully that is all it is and not something wrong with your gears. See what you think.
View attachment 233038 View attachment 233039

You are a god my good man! Finally had some time and checked the set screws. I gave the inner screw a little knudge tighter and the slop disappeared.
Cross that issue off the list. Now to run for a bit and check to see if the metal particulates came after the first oil change. (This last oil change I flushed everything much more than the first time).

 

[Sloth2009]

You are a god my good man! Finally had some time and checked the set screws. I gave the inner screw a little knudge tighter and the slop disappeared.
Cross that issue off the list. Now to run for a bit and check to see if the metal particulates came after the first oil change. (This last oil change I flushed everything much more than the first time).

Yay! Glad it worked. Hope your gear box is in good shape.

 

[TheGov]

Yeah, me too.
I think I just didn't get all the crud out the first time as I only drained the oil.
This last time I drained, flushed with some more oil, blew compressed air, flushed, blew again followed by sucking, (with a vacuum necked down to drain plug size).

 

[Sloth2009]

In a earlier post I showed where I hollowed out a sword scabbard with the mill. Here is result of that project.