Author Topic: Mini lathe bearing lube  (Read 3969 times)

Offline John Rudd

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Mini lathe bearing lube
« on: December 28, 2011, 04:32:18 AM »
There's been many an article written on changing out the spindle bearings on the m-l.
The original bearings are sealed for life types, the replacement taper rollers are greased prior to boxing up the machine..However over time I guess the grease would eventually be lost...?

The head bearings on my 9*20 lathe are oiled via little brass oil ports...Obviously the m-l doesnt have these ports.

So what would be the preferred method of ensuring the bearings are periodically lubricated?

Your thoughts appreciated.
« Last Edit: December 28, 2011, 05:09:24 AM by John Rudd »
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Offline ketanswali

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Re: Mini lathe bearing lube
« Reply #1 on: December 28, 2011, 09:51:51 AM »
Options:

My guess is that you strip, clean and re-grease. Depending on bearing and lubricant, how good/how long before re-grease is like asking how long is a piece of string.

Option A:
I personally prefer LM - General Purpose grease inside the taper roller bearings 30206. This does mean that your maintanance program needs to be regular. How regular, depends on use. Also, "less is more" principal means I would pack in about 25% to 30% of internal volume of bearing with LM grease. More grease results in higher heat generation and not really needed.....in my opinion.

Option B:
If you dont run a regular maintanance program or you dont want to, than 30206s to be packed with 20%~25% of internal volume with Moly grease. If used in place of LM, it should be used in less volume than LM...to allow the bearings to bed in...This comment changes depending on who you talk to and who you prefer to go by. Moly sticks to the bearings like S...., so, chances of it coming off are far lower than LM.

Option C:
Hopefully to be introduced in January sometime...7206B-2RS angular contact ball bearings with rubber seals. So these bearings will be pre-greased.."sealed for life"...(no such thing really, but a standard statement used). These will be same dims as 6206-2RS bearings currently in place. But, you can pre-load the 7206s. they will be freer/fast running than the 30206s, but with lower load carring capacity than the 30206s, but then again, this is not an issue for this application. Key benefit will be that they will be sealed.
Ketan @ ARC

Offline John Rudd

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Re: Mini lathe bearing lube
« Reply #2 on: December 28, 2011, 10:12:40 AM »
Ketan,

Thanks for that just what I needed to hear..

I understand the issues around over packing bearings...( We've had major equipment damage where I work due to over greasing of bearings.. :Doh: ) and the consequences of under lubrication..

I thought it better to canvass opinion rather than rely on my own experience of bearing changes made on my mini mill ( same bearings..)
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Offline Chazz

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Re: Mini lathe bearing lube
« Reply #3 on: December 29, 2011, 12:08:53 PM »
I just replaced the spindle bearings on my 9 x 20, (haven't had the time yet to post the project) I drilled out the 'oiler caps', cleaned out the holes and 'loctite'ed in two proper grease nipples.  As for grease, I used 'Red Tacky' general bearing grease and perpacked the 'chuck' end to about 30%, the gear end was filled through the grease nipple after final assembly, I just kept hand turning the spindle whilst pumping the grease and stopped when there was a slight increase of resistance in spindle.

Happy New Year,
Chazz
Craftex CT129N Mill & Craftex 9 x 20 CT039 Lathe

Offline John Rudd

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Re: Mini lathe bearing lube
« Reply #4 on: December 29, 2011, 12:55:06 PM »
Chazz,
Thanks for sharing  your experience of the 9*20 brg change...Look forward to the piccies... :D

My new bearings arrived today, I've fitted the outer races into the headstock but need to acquire some grease..
Think I'll start a new thread detailing the rebuild...
HNY to you too.
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