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  1. #1
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    Default Colt ( Myford Copy) Lathe Conundrum. Oil or Grease For Back Gear Shaft?

    G'day

    I'm pulling apart a 2ndhand Colt lathe that I bought. It had a couple of issues when I got it that I knew about and one issue that I didn't know about. When I first ran it (high range) it was fine, select low range by engaging the back gears and whoops we've wound off a pulley on the motor side of things. The back gears seemed a little slow but I'd squirted oil on everything that didn't need grease, so I had hopes. But no. So, now it's all apart and cleanish, does anybody know what to lubricate that spindle with?
    It has what looked like a grease nipple near it on the handle that engages the gears and the last person to maintain the lathe thought it was a grease nipple too so there was grease in it. But it's lubricating a plain shaft that the gears run on, there's no ball bearings. So, oil, right? Anybody want to make a good guess as to what sort of oil?

    Not sure how the Myfords are lubricated in this area but the big difference between them and this copy is that this one has tapered bearings and grease nipples on the headstock so no oil to drip down further.


    This is the end that's normally surrounded by a handle.The hole is 10mm in diameter and contains (if you squint) what looks like a grease nipple. The hole in the center is from a center drill. Sorry about the fuzz from the camera phone.





    This shows the hole for whatever lubricates the back gears.



    Thanks, any answers welcome.
    We don't know how lucky we are......

  2. #2
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    Default

    The nipples are for oil, not grease! This will help a long way, it is for the original Myford but I suspect it applies to its clones too:
    http://www.haythornthwaite.com/184%2...ubrication.pdf

  3. #3
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    Default

    Excellent link, thanks. I've been searching for Colt specific stuff so I've (obviously) missed a lot of Myford info.

    Right very, very helpful...all that grease in the v-belt pulley on the spindle has to be cleaned off to.


    I'm now only fairly certain that the tapered headstock bearings are greased...
    We don't know how lucky we are......

  4. #4
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    Quote Originally Posted by cba_melbourne View Post
    The nipples are for oil, not grease! This will help a long way, it is for the original Myford but I suspect it applies to its clones too:
    http://www.haythornthwaite.com/184%2...ubrication.pdf
    I'll second that. I have a Myford ML7L and your back gear shaft looks to be identical. I use straight 30 - 50 motor oil on mine. The Myford lubrication system is "total loss", I always have an oil puddle under the headstock.
    Best Regards:
    Baron J.

  5. #5
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    Quote Originally Posted by seanz View Post
    I'm now only fairly certain that the tapered headstock bearings are greased...
    I think they are more likely to be oiled as grease would cause heat build up. My previous lathe 7x20 (Taiwanese) had tapered roller bearings in the headstock and they were oiled.

    Michael

  6. #6
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    Default

    Yes Michael G, I did a little research and I'm aware of the heating problem with too much grease. So oiling is tempting, now that I'm certain that other parts need (total loss) oiling anyway having a little more oil pooling under the lathe won't be an issue.


    I'm tending towards greased for the headstock bearings...I should be receiving a pom-pom oiler in the mail any day now so I'll be able to test to see weather they can be oiled as they are currently set up.
    Checked the price of sight glass oilers and a pair is just shy of NZD$100. I'll probably just use grease. It wasn't the headstock that was the problem after all.
    We don't know how lucky we are......

  7. #7
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    Quote Originally Posted by seanz View Post
    Yes Michael G, I did a little research and I'm aware of the heating problem with too much grease. So oiling is tempting, now that I'm certain that other parts need (total loss) oiling anyway having a little more oil pooling under the lathe won't be an issue.


    I'm tending towards greased for the headstock bearings...I should be receiving a pom-pom oiler in the mail any day now so I'll be able to test to see weather they can be oiled as they are currently set up.
    Checked the price of sight glass oilers and a pair is just shy of NZD$100. I'll probably just use grease. It wasn't the headstock that was the problem after all.
    Bad idea! If the headstock bearing is a nice hand scraped tapered bronze bearing like in the Myford, it will soon seize up if you try to grease it. Then you may have to learn how to scrape a bearing....

  8. #8
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    Default

    These are tapered roller bearings, steel. Pretty sure they're good for grease. Oil might be better as it will run cooler and easier. The bearings I pulled out were in reasonable condition (all things considered) and don't seem to have suffered from being greased. Spindle shaft is OK too. It's just that shafts using (old) grease instead of oil produced too much drag for the poor old pulleys when the back gears were engaged.


    Been looking at online pics of Colt lathes and there's a range of lube fittings on the headstock from nipples to sight glasses to what looks like a grease cup. Anybody ever seen a manual for one of these things?
    We don't know how lucky we are......

  9. #9
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    Right, where was I? The lube points for the headstock taper roller bearings are M6 grease nipples. Too small for a Myford oiler, so that's out. Grease it is.

    I seem to have got slightly distracted and the lathe is on the backburner at the moment, fingers crossed that the new pom pom oiler for the shafts isn't too excessively oily.
    We don't know how lucky we are......

  10. #10
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    Default Bearing grease

    Hi Seanz,
    Use the grease sparingly. Think of the wheel bearings in your car. They are filled to less than half capacity, assembled and preloaded then run for the equivalent of 1000 hours before a clean and re-pack.. On a lathe you may check pre-load a bit more often to maintain accuracy, but it should be enough to give the bearings a couple of shots of grease every 100- 200 hours. Last thing you need is over filling which causes grease to churn through the bearings causing overheating and leakage.
    A light wheel bearing grease could be suitable, as it remains stable at higher temperatures so tends not to leak. If someone here has an official makers recommendation then follow that. The above are my thoughts after a lifetime among earthmovers, vehicles and workshop gear.
    Combustor.
    Old iron in the Outback, Kimberley WA.

  11. #11
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    I'll check the specs on the grease before I use it, it's just General Purpose (lithium?) stuff. We're pretty cold here right now, please don't tell me what you mean by "higher temperatures". Cheers.
    We don't know how lucky we are......

  12. #12
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    Quote Originally Posted by seanz View Post
    I'll check the specs on the grease before I use it, it's just General Purpose (lithium?) stuff. We're pretty cold here right now, please don't tell me what you mean by "higher temperatures". Cheers.
    Taper roller bearings in a lathe require a MUCH greater preload than a car wheel. The high preload combined with grease churning causes the bearings to get quite warm after a short time running. Typically, after half an hour running the headstock can feel hot to touch. Taper roller bearings would run a lot cooler in oil. However, if the headstock is designed for grease you cannot simply use oil instead, as there will be no suitable seals to keep the oil in.

    Regarding what grease to use, you should be fine with general purpose lithium grease. Because in your case it is not a grease lubrication "for life". Your headstock is fitted with grease nipples to replenish.

    I had no idea that these Myford clones would use taper roller bearings, instead of the Myford typical hand scraped tapered bonze bush at the right and two angular contact bearings at the left.

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