Boxford VM30

[Chris Short 1Participant @chrisshort1]

My Boxford seems to be getting a little warm around the area of the spindle bearing

Ive stripped the shaft out, cleaned and inspected the bearing and it’s in pristine condition

I’ve re-greased it and refitted it yet it’s still getting warm

Anyone got any ideas?

thanks

[Chris Short 1Participant @chrisshort1]

Warm Spindle Casing

[Speedy Builder5Participant @speedybuilder5]

Lets assume you have the bearings loaded up about right, then there may be too much grease in the spindle bearings! How much did you put into the bearings as they don't need much plus if you topped up by using the greasers it could overload the bearings and that would cause them to heat up – happened to me on my Boxford AUD.

BobH

[Brian WoodParticipant @brianwood45127]

Chris,

The explanation for the heating comes from the sheer effort involved in useless churning of surplus grease and that action causes heat to be generated. In doing so it also degrades the grease in the process, tries to extrude the excess if it can and in extreme cases it can even lead to the balls or rollers skidding on the surfaces rather than rolling on them as intended; that rapidly leads to bearing failure.

It is a situation to be avoided

Brian

[KWILParticipant @kwil]

Speedy, there are not any greasers on a VM30 Mill

[not done it yetParticipant @notdoneityet]

Posted by Brian Wood on 17/03/2019 16:08:27:

Chris,

The explanation for the heating comes from the sheer effort involved in useless churning of surplus grease and that action causes heat to be generated. In doing so it also degrades the grease in the process, tries to extrude the excess if it can and in extreme cases it can even lead to the balls or rollers skidding on the surfaces rather than rolling on them as intended; that rapidly leads to bearing failure.

It is a situation to be avoided

Brian

An example of differing lubrication needs for the same bearing could be comparison of the Raglan Little John and Loughborough training lathes.

The training lathe, which only turns at up to 600rpm (a special could be ordered for 1200RPM) was grease lubed – while the LJ, which had a possible top speed of 2500rpm (most were 1750rpm), was oil lubed. Really high speed spindles use special lubricants to avoid 'shear' heating.

The usual mantra, for greasing open bearings (in plummer blocks), was to grease with the machine running – presumably so that any excess was thrown out. Most electric motors (1425rpm) are grease lubed.

Too much preload can cause the rolling elements to skid, too.

According to lathesdotco, the bearings were 'sealed-for-life' preloaded Timken roller bearings'. Have they been changed for lesser quality bearings?

[David Hughes 3Participant @davidhughes3]

Hi Chris

What grease did you use.

[Dan MansfieldParticipant @danmansfield84090]

Hi Chris,

Did you manage to resolve the issue with warm bearings? I also have the vm30 milling machine and have noticed that the lower bearing is getting hot even when the machine is running with no load being applied.

Dan

[Rex HanmanParticipant @rexhanman57403]

My VM30 gets very warm if used for long periods. Had it (and it's sibling) since new in 1984. Now and then, when it has been running for a couple of hours or more, I get the odd drop of semi liquid grease drip from the spindle onto the table. I just squirt a bit more grease in once in a while.

I rarely run it at the high speed (3000rpm, later machines were derated to 2000 I believe) as the noise from the straight cut gears is deafening!

Lovely little machines though. Just wish it had a quill.

Edited By Rex Hanman on 12/09/2021 21:15:24

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