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Pm 940v
- Thread starter nighthawkFmobil
- Start date
- Joined
- Oct 14, 2013
- Messages
- 1,291
Btw, if you have shop air you could use an air cylinder as your counterbalance... bigger, but you dont have to worry about it leaking down over time.
Sent from my SM-G892A using Tapatalk
Sent from my SM-G892A using Tapatalk
- Joined
- Dec 23, 2019
- Messages
- 176
Yes mine is exactly like that from what ive seen. Do you have some kind of rear access?
Does the z screw have to be removed in ordet to get that assembly out?
Does the z screw have to be removed in ordet to get that assembly out?
Thanks, Yes, I know James caught it soon enough to trade his in for a knee mill. I doubt that he was seeing all the things I have observed, but he did not like the issues. I did pay for a CNC version, which it PM quit selling. I spoke to Matt, at PM, a year or so ago and I know he has been trying to find a CNC mill that he wants to sell, but there is nothing on his web site yet. Guess he has not found one yet.
I live in Pittsburgh so I have been to his facility several times. The folks are very helpful. I purchased a PM1440GT lathe from them here while back and have posted my VFD conversion documents Saturday. So the lathe conversion has kept me from worrying much about the 940 issues. I have just been living with it.
My machine's side looks like your picture. I took the huge CNC electronics box (~200#s) off the back so I have the same view as @yota picture. However, because of my CNC version I have a small z-axis crank. The nut, washer, and bearings can be reached from the hole in the back but it is tight working. I did not want to take the crank assembly off so have not tried to do so. However, others have. I am not for sure if the lead screw has to be removed to do so, but I doubt it. In my case, I would have to take the mill off the stand to have head room to remove the lead screw so....... The basement joist are just over head. If you want to see the nuts etc more clearly see the start of the post thread I sent. @yota picture with the arrow is the correct location. You can also see my mill. I have it on wheels, but block it when I am happy with the location. I have pulled it out a couple of times. Because of the caster height, I can slip a car jack under the stand to take it on and off the blocks.
By the way, in the CNC version, when the mill goes up and down that crank handle slaps back and forth a short distance, but its very loud and annoying. It sounds like something is broken. Hence others with CNC have removed it. Because my the head on my machine falls, I use the crank all of the time. Before I turn the mill power off I tie a bungie cord to the handle to keep it from turning. After my experience with the way locks/clamps I do not use them.
Thanks. No air cylinder available. No head room to spare either. I have not yet found room to mount cylinder on the front or sides yet. But this is why I am thinking air spring "closers" (not openers) instead of weights. I could mount the closers to the vertical column back with the cables and pulleys going over the top. However, I have not followed up and found the right size closers yet.
the bearing can be removed easily by itself. it looks like the crank handle assembly will not come out with out removing the Z leadscrew. I'm not positive but it looks like the Z leadscrew has to come out from the bottom of the column.
- Joined
- Dec 23, 2019
- Messages
- 176
Is there something up top blocking it? Was thinking it could be possible to move z screw up just enough to get handle assembly out.
- Joined
- Dec 23, 2019
- Messages
- 176
Initial messaging with pm states this is normal behaviour for a mill to unpredictably nod in
the Y and shift or tilt in the X along the z axis. Ill have to look more into this but it seems odd a 5k$ mill cant consistently sit within at least .003 of perpendicularity to the table.
For now ill just have to keep cleaning it up and checking it out. Hopefully it gets better.
the Y and shift or tilt in the X along the z axis. Ill have to look more into this but it seems odd a 5k$ mill cant consistently sit within at least .003 of perpendicularity to the table.
For now ill just have to keep cleaning it up and checking it out. Hopefully it gets better.
the lead screw has a section at the bottom that is threaded to work with the worm gear on the hand crank. It did not look to me like you could get that section through the casting that holds the leadscrew which is above that section. it only looked like it could come out from below but I was not looking hard at it as I did not need to remove it. you will have to look at it.