MV Jr, New Owner Questions

[andyhol]

Originally Posted by underthetire Much tighter bearing clearance than a knee mill. Just belt drive with no gear box? Thats a new one on me. If it's a belt drive only, it may not have a oil cooler. Guess I should dig my old prints box out tonight and see if I have any info on that type. See, even I can learn stuff on these things. "First guy that says I know it all, is the first one out the door !"

Thanks, look forward to hearing back from you. My current parts list looks like it might be the wrong one, hoping I can get the right one from the guy I bought the machine from.

[andyhol]

I have replaced bearings in knee mills before, can I replace the spindle bearings myself?
Where can I get specs or instructions?
Where should I get the bearings?

Thanks
Andy

[underthetire]

Well, we need to determin what spindle you actually have. Most Mori's use a hydraulic nut for bearing load. Not sure about yours. All World can get you bearings, but gonna be $$ for those. I'm not saying you can't do it, but I would get quotes from rebuilders first. If the bearing set is 2K, and the rebuilders charge 3K, might be worth it. You can ruin a set of bearings very easy. If it is a hydraulic nut style, you would need the tooling.

BTW, a shop in your area is blowing off a bunch of excess machines. PM me if your interested, i can give you a contact. I have no stake in it at all, so I don't care one way or the other.

[andyhol]

While last night I pulled out the spindle, no gear box, belt drive. All you have is the 4 set screws on the top sides, two each side. You have to move the spindle down to get to the left side ones. No need to mark the spindle it will only go back one way because one of the bolts on the hub is indexed differently. The draw bar just pushes against the spindle to release the tool so nothing needs to be taken out there. Mine came out a little harder then yours do, note, it did come down a little when I loosened all of the bolts, at which time the spindle freed up, so I tightened up one of the bolts a little and it seized again, thought that was kind of strange, everybody was talking about precision bearings and how sensitive they were, so I thought maybe I was torquing the bearing assembly. So to get the spindle started down I used the draw bar cylinder, it pushed me down about 1/2", enough to get the lower oring free. I then stuck to bolts in the threaded holes in the end of my spindle and moved the table and spindle so I could clamp those bolts in the vise. My vise is brand new and have not bolted it down yet, so I took the wheel and raised z up some, my vise promptly lifted up. If I were smart I would have looked around for bolts to tighten my vise down (Which I found later I did not have any t nuts) but instead I pulled out the handy dead blow hammer and started hitting the vise down toward the table, then raised the z up some more, worked slow but it worked. Once I got closer to the end I put boards under the spindle as you said. Anyway sat the spindle on the bench and looked at it, spun great didn't feel any grit or grind, felt great. So my thought was, going back to that bind or torqued thought I now laugh at, maybe there is some contamination in the area that is causing the bind. So I cleaned all of the goo off the spindle and the head and reinserted the spindle noting to see how the spindle felt as it went in. Felt great all the way up to about 0.020 from the end. Again went back to that dumb idea that it might be in a bind, messed with different bolts to see it I could get it to pull in without torquing it and seizing. Finally came to the conclusion that I could not. Sat, thought, looked, sat, thought and looked more, then I saw it, the draw bar was tight against the end of the spindle. This went with more of my idea I had had all along that something must have happened during shipping, so anyway, pulled the spindle back out so I could get to the cylinder rod to adjust the button up on the rod, moved it up about one full turn and put the spindle back in. I have not done any long runs on it but it does seem to work.

Now, the questions is, the button was tight on the end of the cylinder rod, what would have moved during shipping to cause this to start binding?


Thanks for your help and ideas
Andy

[underthetire]

So it is just a belt drive. Never actually seen one in person. Glad you got it out. So, the unclamp cylinder is down too far pushing on the drawbar. My guess is there is air in the oil system. I need pictures of the unclamp assembly at the top of the head. If its the type i'm thinking it is, i've seen this once before. There is a small check valve that is almost not visible, that needs to come out and be re-worked. A little craytex and you be good to go. PM me for my home email. See what I can do.

[andyhol]

Originally Posted by underthetire So it is just a belt drive. Never actually seen one in person. Glad you got it out. So, the unclamp cylinder is down too far pushing on the drawbar. My guess is there is air in the oil system. I need pictures of the unclamp assembly at the top of the head. If its the type i'm thinking it is, i've seen this once before. There is a small check valve that is almost not visible, that needs to come out and be re-worked. A little craytex and you be good to go. PM me for my home email. See what I can do.

Are you implying that it is a hydraulic cylinder and not a air cylinder that pushes the drawbar? I will look but I am about 75% sure it is air.

[underthetire]

They all are air over oil. I've never seen a Mori that wasn't. Should have oil in the unclamp cyl, air actuated on top.