Oops, exceeded the "Not-to-exceed point"

[dfwilbanks]

While positioning my PM-935TS mill in its final spot in a corner of the shop and making sure there was sufficient clearance for the table and ram I passed the "Not-to-exceed point" on the ram. I was trying to make sure the ram would not hit the wall and forgot about this "feature" of PM knee mills. Matt this is ridiculous. Put a damn hard stop on the ram. You did it on the table. Now I will have to rent an engine hoist to remove presure on the ram ways so it will come forward. I will be installing a hard stop and recomend anyone with one of these mills do the same, before crossing the "Not-to-exceed point"

 

[davidpbest]

There should be no need to rent any kind of hoist to reposition the ram. Put some wood blocking on the XY table with waxed paper under the blocking, and bring the knee up until the wood blocking is pushing up slightly on the bottom of the spindle nose, then you should be able to nudge the ram forward. I have completely removed the head of the machine and the ram/turret several times without the need of any kind of hoist or chain fall. I've posted a video of how to use the knee to assist in dealing with the weight of the head for removing the motor, or the head drive components or the entire head if necessary. You should be able to use the same technique, without even disturbing the tilt of the head to raise the ram just enough to slide forward and back over the "not to exceed area". The video is HERE.

 

[Flyinfool]

And if the ram is to far out the back, either rotate the whole head 180° so that you can use the knee to take the weight off, Or use an automotive floor jack and a length of 2x4 to take the pressure off.

The last time I needed an engine hoist I found that it was only slightly more to buy one from harbor freight than to rent one IF you watch for a sale and then use a coupon. The one from HF sets up and tears down fairly quick for storage for the once every couple of years that I need it. But when I need it, it sure is nice to have hiding in the corner. You can also check your local HF for returned ones, some goofballs will buy it use it the one time they need it and then return it, HF can no longer sell it as new.

 

[matthewsx]

When I worked at Harbor Freight we called those DUI's, (dun usin' it)

 

[dfwilbanks]

There should be no need to rent any kind of hoist to reposition the ram.

Hey, David. David here also. I was hoping someone would chime in and tell me there is a simple way to fix this. After reading this and watching your video (you sure move fast for an old guy), I went out this morning and fixed it in a couple of minutes. Still don't like that the machine doesn't have a hard stop. Easy fix for another time. By the way, where do you park your ram? I guessed that centered on the table with the Y centered would work. Do you move the ram often?

Thanks for your help.

 

[wrmiller]

I set the ram on my 935 just as you describe: Centered on the table that is centered on the knee.

I do mostly small work, e.g. pistolsmithing, so I have not had to move the ram since setting it's initial position. Maybe I should give it a shot of oil and move it a bit to keep it from locking up?

 

[dfwilbanks]

Maintenance is good but don't go past that "Not-to-exceed point" LOL. Thanks again.

 

[davidpbest]

Hey, David. David here also. I was hoping someone would chime in and tell me there is a simple way to fix this. After reading this and watching your video (you sure move fast for an old guy), I went out this morning and fixed it in a couple of minutes. Still don't like that the machine doesn't have a hard stop. Easy fix for another time. By the way, where do you park your ram? I guessed that centered on the table with the Y centered would work. Do you move the ram often?

Thanks for your help.

I have the ram positioned a bit closer to the tombstone than Bill described in an attempt to increase rigidity. You might be interested in the the last four videos in this series. I like the 935 a lot for it's flexibility and size, but it is less rigid than the Rong Fu 45 it replaced. So I position the ram where I have the least amount of overhang and still get the required work envelope for the project in an effort to improve rigidity - and it does help.

 

[ptsmith]

I have the ram positioned a bit closer to the tombstone than Bill described in an attempt to increase rigidity. You might be interested in the the last four videos in this series. I like the 935 a lot for it's flexibility and size, but it is less rigid than the Rong Fu 45 it replaced. So I position the ram where I have the least amount of overhang and still get the required work envelope for the project in an effort to improve rigidity - and it does help.

I'm surprised your FU-45 was more rigid than your 935. I only have experience with my Lagun mill, and not much with that. But just looking at those 2 mills I would have thought the 935 would be much more rigid.

And thanks for the videos. I've never seen that done before. I need to rebuild my Vari-Drive and replace my brake. It will now be a little more doable than I had envisioned.