ES-L8 Spindle Rebuild

[big_mak]

Anyone have any experience replacing the bearings on this spindle?

We've got it apart, and have the new bearings, we just need all them pesky details to get it all together correctly.

[OKUMAHERO]

This is not for the faint of heart.

Where did you obtain the bearings?

Okuma is VERY particular on bearings. The pick only the best of the best from the manufacturer. Mostly NSK.

Have you ever fit a bearing before? These are questions that need to be asked. Do you have grinding capability once the stack up is calculated and you need to grind the laybrinth?

There were many UPDATES to the ESL-8 spindle. This is why it is highly advised to have an okuma rep rebuild the spindle.

[big_mak]

We got bearings from Alpine NSK of course, and we do have bearing intallation experience.

There are some procedures for the spindle bearings in regards to preloading that we require the details for.

We do have access to grinding so that's not a big deal.

[underthetire]

Being a taiwan Okuma, not sure if its like most of the others. The procedure is very involved, and, I would have someone that has done them before to do them. If you do decide to try it, make sure you get a good themocouple type thermometer for the break in.

[OKUMAHERO]

Its an okuma. Procedure is the same.

[big_mak]

We have it all together, and run out on the face and taper are less than 0.0001"

Anyone have a recommended run in procedure?

[diegojulio]

You need take off the cylinder of the collet.
Then start running the spindle at 50 RPM during 5 min, to make sure the grease are on all the bearing. After that you will need increase the RPM by 500 each 30 min, until the max RPM allowed. The max temp allowed will be 60 Celsius degrees in both sides.

After that, you need check again the run out (radial and axial)

We have it all together, and run out on the face and taper are less than 0.0001"

Anyone have a recommended run in procedure?

[OKUMAGUY]

Remember too that you need to watch the spindle load on the monitor. You'll see it go as high as 6-9% after every speed increase change but it should drop during each increment of speed to 0-1% before moving the speed up to the next level. If you see a sudden increase in the temperature or load you will need to stop the run-in proceedure, let the spindle come back down to ambiant temperature and then start the run in proceedure from the beginning. I've heard guys talk about having to start/restart this proceedure 3-4 times on tightly built spindles. I've always had good luck in getting it done on the first try but you never know...

[Algirdas]

As we do here- we invite someone experienced for that kind a "first time" job. There are lots and lots of details and surprizes in every job. There are "finger feeling" details replacing bearings also.

[big_mak]

Well it's all together, and running well. Banged off some aluminum parts already. Parts are concentric, and surface finish is great.

So far so good.

For us we found getting ht preload the most challenging thing to wrap our heads around.

Lots of patience during the run in! and it's great.

Thanks for all the input.