Michael Moore
Titanium
- Joined
- Jun 4, 2004
- Location
- San Francisco, CA
As you might recall about 5 months ago I bought a Tree Journeyman 425 that appeared to have never been used before it started to undergo a home-brew control conversion. As is not uncommon with these projects for me it took until recently for me to identify all the unusable new or missing parts so I could transfer the Centroid control from my J325. New power supply transformer, 3 new 40 in/lbf DC servo motors, etc etc.
One of the things I did was put a set of new OEM high-speed spindle and motor pulleys on it, changing it from 3500 to 6000RPM top speed. To do that I had to removed the angular contact bearing race on the original pulley and move it to the new one. I read various comments here about working with spindle bearings and I got some recommended grease and applied it sparingly and then broke in the grease by running the spindle in both directions at ever increasing speeds. After that the area around the bearing warmed up a little but was by no means hot or uncomfortable to touch.
I would hear an intermittent squeek from the spindle pulley area (mostly between 500 and 2500 RPM, below that it was quiet and above that there was more noise from the belt and motor and fan) but I couldn't pinpoint a cause. I pulled the top support plate back off (exposing the bearing) which looked fine and I put on a new drive belt for "just in case." The belt I replaced was the OEM and wasn't worn but it was a bit stiff and had a spot with some "wow" to that was probably where it sat wrapped around the small pulley for years. I did the break in again and the squeek was still there. I found mention in some bearing documents that bearing grease can squeek in cold weather so I hoped that was it since I couldn't identify anything wrong.
A couple days ago I was running it at 6K with a 1/16" EM in aluminum and the EM broke after doing OK for several minutes. As I was changing out the CAT40 toolholder I noticed that the spindle wouldn't turn.
I loosened the tension on the belt and it was clear it was the spindle and not the motor so I pulled the support plate off again to reveal a mess.
This shows the top cap and wavy spring washer that applies some pressure to the outer race of the bearing. There are 3 6mm SHCSs that hold that on and you do need to pull the cap down with the screws as the spring has a fair bit of tension:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing17.jpg
This shows the top cap, washer and the upper support plate that holds the outer race of the bearing:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing18.jpg
Here's the pulley and inner race after the plate and the balls and retainer were removed:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing19.jpg
And here are the pieces of the retainer and a couple of the 8.75mm balls that probably don't clearly show the flat spots on them:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing16.jpg
The upper support plate has two tapered alignment dowels for location. Putting it on the bearing seemed pretty straightfoward -- I either put it on straight and it dropped right down or I had it cocked a little and it would knock a couple of balls out and I'd have to collect and clean them and start over again.
I managed to do it OK the first time when I changed the pulley, and it appears that I messed something up the second time when I removed things to change the belt.
Does the debris, like the sawed-in-half retainer, suggest what I might have done wrong the second time? I suspect that once the retainer started disintegrating at max RPM it didn't take long for things to come to a halt. But it had run for at least a good 15-20 minutes before catastrophe visited. As you would imagine I'd like to avoid having this happen again!
These are the markings on the bearing: RHP England 6Z. on the outer race, and 7010C TSUL P4 on the inner race. RHP is now owned by NSK and I found some code information on their website:
7010 is 50x80x16
C is 15 degree contact angle
T is phenolic cage (retainer)
TYN is polyamide cage (but this is TY and I didn't see that listed)
SU is single universal mounting configuration (not a matched set)
L is light preload
P4 is ISO Class 4 (ABEC7)
I didn't see anyting about the "6Z." on the outer race.
NSK 7010CTY P4 seems to be a current bearing per the NSK website though I saw mention of one in the documentation with the extra "SUL" code in the name.
What's a bearing like this likely to cost me? $100, 200 or ? I'd like to have some idea before I start calling around for a replacement as bearing prices seem a bit variable at times.
I was so pleased to finally be working on parts instead of on the tools. Sigh.
cheers,
Michael
One of the things I did was put a set of new OEM high-speed spindle and motor pulleys on it, changing it from 3500 to 6000RPM top speed. To do that I had to removed the angular contact bearing race on the original pulley and move it to the new one. I read various comments here about working with spindle bearings and I got some recommended grease and applied it sparingly and then broke in the grease by running the spindle in both directions at ever increasing speeds. After that the area around the bearing warmed up a little but was by no means hot or uncomfortable to touch.
I would hear an intermittent squeek from the spindle pulley area (mostly between 500 and 2500 RPM, below that it was quiet and above that there was more noise from the belt and motor and fan) but I couldn't pinpoint a cause. I pulled the top support plate back off (exposing the bearing) which looked fine and I put on a new drive belt for "just in case." The belt I replaced was the OEM and wasn't worn but it was a bit stiff and had a spot with some "wow" to that was probably where it sat wrapped around the small pulley for years. I did the break in again and the squeek was still there. I found mention in some bearing documents that bearing grease can squeek in cold weather so I hoped that was it since I couldn't identify anything wrong.
A couple days ago I was running it at 6K with a 1/16" EM in aluminum and the EM broke after doing OK for several minutes. As I was changing out the CAT40 toolholder I noticed that the spindle wouldn't turn.
I loosened the tension on the belt and it was clear it was the spindle and not the motor so I pulled the support plate off again to reveal a mess.
This shows the top cap and wavy spring washer that applies some pressure to the outer race of the bearing. There are 3 6mm SHCSs that hold that on and you do need to pull the cap down with the screws as the spring has a fair bit of tension:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing17.jpg
This shows the top cap, washer and the upper support plate that holds the outer race of the bearing:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing18.jpg
Here's the pulley and inner race after the plate and the balls and retainer were removed:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing19.jpg
And here are the pieces of the retainer and a couple of the 8.75mm balls that probably don't clearly show the flat spots on them:
http://www.eurospares.com/graphics/metalwork/tree425/Tree425bearing16.jpg
The upper support plate has two tapered alignment dowels for location. Putting it on the bearing seemed pretty straightfoward -- I either put it on straight and it dropped right down or I had it cocked a little and it would knock a couple of balls out and I'd have to collect and clean them and start over again.
I managed to do it OK the first time when I changed the pulley, and it appears that I messed something up the second time when I removed things to change the belt.
Does the debris, like the sawed-in-half retainer, suggest what I might have done wrong the second time? I suspect that once the retainer started disintegrating at max RPM it didn't take long for things to come to a halt. But it had run for at least a good 15-20 minutes before catastrophe visited. As you would imagine I'd like to avoid having this happen again!
These are the markings on the bearing: RHP England 6Z. on the outer race, and 7010C TSUL P4 on the inner race. RHP is now owned by NSK and I found some code information on their website:
7010 is 50x80x16
C is 15 degree contact angle
T is phenolic cage (retainer)
TYN is polyamide cage (but this is TY and I didn't see that listed)
SU is single universal mounting configuration (not a matched set)
L is light preload
P4 is ISO Class 4 (ABEC7)
I didn't see anyting about the "6Z." on the outer race.
NSK 7010CTY P4 seems to be a current bearing per the NSK website though I saw mention of one in the documentation with the extra "SUL" code in the name.
What's a bearing like this likely to cost me? $100, 200 or ? I'd like to have some idea before I start calling around for a replacement as bearing prices seem a bit variable at times.
I was so pleased to finally be working on parts instead of on the tools. Sigh.
cheers,
Michael