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Tree Journeyman 325 Spindle Bearings: Possible rebuild?

rbmgf7

Aluminum
Joined
Oct 18, 2017
I picked up an old, parted 325 a couple years ago for the home. It was gutted so basically a frame, no electronics. Perfect for me since I dabble with DIY CNC stuff. At the time all I could check was ballscrew tightness. Couldn't test the spindle but it was a gamble and I got it relatively cheap. Movement was good and tight so I went ahead and got it.

Well after a hiatus, I finally got motion to the machine in the past couple weeks. Today I got the VFD going. Rough start getting the parameters set but seemed good after I tuned it. Then throughout the day, the spindle started to sound progressively worse, especially at low speeds (1500ish range).

Took the top plate off and the pulley bearing is definitely no good. I turned the spindle back on slowly and ramped up and listened to the spindle area and it didn't have a feel-good sound either so I'm thinking it needs new bearings. Definitely a dull clunky, dragging rattle sound.

So what am I in for? I've found a few archived threads about the same subject but no follow through. I know there's a few places out there that still service these machines. For a DIY/home use machine, I prefer the economic option. I feel like I have the tools and the capacity at home (also have access to a decent machine shop). If I need to get more tools, that's not a problem either.

My first concern is removing the spindle/cartridge. Please tell me it comes through the bottom? The machine is in my basement and I only have a 7' ceiling. I assume after I get the pulley off the top and unbolt the Z axis ballscrew nut carrier it should slide out from the bottom? Anyone have a service manual they're willing to share/sell? Thanks.
 
There are videos on YouTube posted by Tesla500 that go into detail on his Journeyman 325, including the work he did on the spindle. The guy was very methodical and thorough. You might find them helpful.
Spindle work started around video #3..
 
The quill comes out the bottom. The spindle is pretty easy to work on. You will need a big pair of snap ring pliers to drop the spindle out of the quill.
You will also need the patience of a saint to undo the screws that attach the ball nut to the back of the quill. By the time I had it loose I was ready to pour diesel fuel on it an set it ablaze.. Lol.

The draw bar can be a couple deferent designs. The one we have is the crappy one that does not clamp that well in my opinion.
If you do some searching here you can find some info..

Good luck
 
There are videos on YouTube posted by Tesla500 that go into detail on his Journeyman 325, including the work he did on the spindle. The guy was very methodical and thorough. You might find them helpful.
Spindle work started around video #3..

Oh man, good stuff. That wasn't hard at all. I believe I have everything to do it in-house. Even the tub of peanut butter to repack the bearings! lol. I like how he discovered how out of balance the pulleys were. I'll have to check that too.

Edit: Here's the Dropbox link to manuals from his YouTube page:

Dropbox - Tree - Simplify your life
 
So, been looking for the bearing I do need and I measured it to be 80mm OD x 32m ID x 16mm T. Can't seem to find such a thing. Anyone have any leads on the industry identifier for these bearings?

Edit: disregard. Bore is 50mm. I got it now.
 
Just parted out my 310, sister parts fir me and some to sell. Good machine but had to get it moved. Anyway the spindle drops out the bottom. Remove ball screw, remove 2 bolts that hold ball screw bracket to quill, then the quill will drop
Out the bottom
 
Gosh, anyone know how to get the spindle pulley out? Trying to regrease the bearing underneath the pulley. Fighting the spherical bearing but can't get it to break loose like the top.
 
False alarm. I just had to post about not being able to do it and then it does it. Just gotta wiggle it out I guess.
 
I'm about to take the spindle out of my J325. It is very stiff as if the grease really is peanut butter. I watched Telsa500 video and it doesn't seem too difficult - I just need those huge snap ring pliers...Appreciate the info on the bearing size. Did you find them fairly ea$ily?
 
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No This is the rubber inside the large ring near the tool holder.
View attachment 330115

I found a hydraulic shaft seal wiper from McMaster that was very easy to source. I bored the groove in the seal housing to match and it worked great. I couldn't find a replacement for the odd size polyurethane oring that was originally in there.

Also, there are two substantially different bearing outer race clamp designs. The YouTube video shows the snap ring.
There's also a spanner ring variety. If that's your spindle, the bcd is 81mm with 8x 5mm holes. Some of the spanner nut holes are threaded. Don't thread the bolts too far in as they expand the spanner nut to bind/lock the threads. Pretty unique arrangement.

You can push the spindle out of the quill and leave the quill in place on the machine. I extended my quill and warmed it with a heat gun to help loosen the bearings. I was able to tap it out with a big dead blow hammer, so I didn't shock the bearings.

I was able to find a new old stock matched set of barden bearings on eBay that were perfect and not that expensive. I bought the abec 7 upper radial bearing from a bearing supply place here.

Good luck,
Mike
 
Thanks Mike
I have the snap ring version. I've taken the spindle out and inspected the bearings. They don't seem to be causing the rotational stiffness. I am thinking that the stiffness is coming from something other than the bearings. I see the bearings on the spindle shaft, a top bearing and one that's under the pulley. Is there one more - you mentioned the quill. There seemed to be excessive grease on the top bearing so I wiped away the excess.My plan was to put the spindle back in and see if there is a change - it does spin freely but I haven't put the snap ring back. The cover, that protects the lower bearing pair, has a bit of a wave but before I see about flattening it I wanted to re-assemble. Getting the snap ring out was a pain and now it seems that getting it back in will be interesting , as I have to overcome a spring force. I don't want to force it but when I released the snap ring the spindle did spring out - I'm guessing it's going to have to get pushed back up via the knee. I'm still investigating and learning about the machine so all advice is appreciated.
 
In the 325 that I had, the belt pulley had 2 angular contact bearings that were the same size and contact angle as the main pair in the spindle, 80x50. The pulley bearings had a wave washer to provide axial preload, but it didn't seem like much force.

The spindle itself had a matched pair of those same angular contact 80 x 50 bearings plus a radial bearing close to the top of the quill. On the spindle design that used a retaining ring for the outer bearing races, I'm not clear on where the outer race preload would come from since there is inherent clearance to install a snap ring.

Maybe it's worthwhile to put the upper pulley assembly back in with the belt and run through the speed range to see how the pulley bearings sound on their own.

Two other things to check, There's an elastomer ring on the bottom of the pulley that damps the spline backlash noise. Those degrade and fall apart and let the metal to metal noise ring. I skim coated the spline with some lithium grease to quiet that and it worked well. The other thing to check is your belt from the motor to the pulley. There was a dayco originally and it was quiet. I bought a replacement belt that had the same tooth form and length but was way heavier. That heavier belt would resonate very loudly. I put the dayco back in and the sound went away completely. Luckily the original belt was in good shape so I stuck with it.

When you press the spindle assembly back into the quill, be sure to press on the outer bearing races and not on the spindle itself.
 
I can tell you from experience that the company that owns Tree now has us by the nuts. I don't know exactly what the small Tree mill in the back of the shop is, but I run an 1050 VMC and the minimum bill for each of the dozen fixes I've had to do on it were $500 and up and that is just for getting the parts to do it ourselves.
 
In the 325 that I had, the belt pulley had 2 angular contact bearings that were the same size and contact angle as the main pair in the spindle, 80x50. The pulley bearings had a wave washer to provide axial preload, but it didn't seem like much force.

The spindle itself had a matched pair of those same angular contact 80 x 50 bearings plus a radial bearing close to the top of the quill. On the spindle design that used a retaining ring for the outer bearing races, I'm not clear on where the outer race preload would come from since there is inherent clearance to install a snap ring.

Maybe it's worthwhile to put the upper pulley assembly back in with the belt and run through the speed range to see how the pulley bearings sound on their own.

Two other things to check, There's an elastomer ring on the bottom of the pulley that damps the spline backlash noise. Those degrade and fall apart and let the metal to metal noise ring. I skim coated the spline with some lithium grease to quiet that and it worked well. The other thing to check is your belt from the motor to the pulley. There was a dayco originally and it was quiet. I bought a replacement belt that had the same tooth form and length but was way heavier. That heavier belt would resonate very loudly. I put the dayco back in and the sound went away completely. Luckily the original belt was in good shape so I stuck with it.

When you press the spindle assembly back into the quill, be sure to press on the outer bearing races and not on the spindle itself.

Running just the pulley is a good idea. So far I have not found the cause of the binding. My plan was the put the spindle back in since whatever was causing the binding is not presenting itself. I need to get the snap ring back in - I found some advice for that- and see if I can recreate the binding.
In regards to only pushing on the outer races I was planning on lifting the table with a block pushing on the spindle. It appears,to me, that I am overcoming the preload since the bearings slip into place - I assume the preload is being applied to the outer race...?. I see no other way to get the snap ring back in since the spindle nose is captured by it. The only issue I have found is that the spindle bearing shield has a wave in it. If I find the binding still exists I will remove the spindle bearings and fix/replace the shield, I would inspect the spindle bearings and either replace or repack them.
Prior to starting the retrofit spindle, belt or any other noise was minimal but since everything is apart I will check the rubber damper

Thanks

Bill
 
Spindle is back in, running smoothly. It took some time to figure out how to get the snap ring back in. It's now controlled with a Centroid Acorn and after some clean up the chips will fly!
 
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