[joshuaz2]

I have a Chevalier VS 3hp head on my grizzly mill and it started making a vibration and loud noise when lowering the quill in back gear. When the quill is up it is quiet but as you lower it it gets louder untill about 2 inches down then it gets quieter again. i dissambled the head and inspected all components and all i could find was the bearing on the lower VS pulley has a lot of play. I have ordered a new bearing but was wondering if there were any other things i should look closer at while i have it apart.

thanks in advance.

Roy

[SpindleRepair1]

If you decide to repair the spindle yourself we recommend replacing all of the bearings with ABEC 7 super precision spindle bearings purchased from an authorized dealer. (Counterfeits are not rare) Remember most spindles are configured with multiple angular contact bearings. These have a front and a back and must be reassembled in the exact same configuration. So note how the thing comes apart. Additionally, these bearings are preloaded. Most spindles use a light preload.

The preload can be accomplished in a number of different ways. However, unless you work in a climate controlled shop and can set spacers to micron tolerances you’ll just have to set the preload by feel. That’ll be OK for your spindle; not recommended for a high end CNC spindle. There should be absolutely zero axial play and there should be a very light drag when you rotate the spindle by hand.

The bearings will probably take 15 to 20% grease lubrication fill. Use good stuff and make sure it’s been filtered. When starting up, start slow and let the grease molecules align. If you have a pyrometer, watch the temperature on the bearings. After a temperature rise and slight fall raise the speed up by 500 RPM. Repeat the procedure until you reach full speed. If you cannot measure temperature raise the speed by 500 RPM every ½ hour.

For more information visit our FAQ section or our blog at highspeedtechnologies.com.

I hope it works out well for you.

[joshuaz2]

well I put in a good skf bearing and it is very quiet now. I got this head used because the rear VS pulley made a lot of noise and the owner just replaced the head instead of dealing with it. when i took it apart then i found the set screw loose on the key allowing the key to slide down and start to come out. after repairing that the VS was quiet but the head made a little internal noise which i was living with until. now the head is as quiet as any i have heard. the spindle has no play and is very smooth so i have left that alone for now.