Author Topic: Mini-lathe lubricants  (Read 6707 times)

Offline jemglen

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Mini-lathe lubricants
« on: March 19, 2009, 10:31:23 AM »
Can anyone recommend a lubricant for the tumbler, leadscrew and changewheel gears on the 7x12 mini-lathe? I'm in the process of prepping mine (after owning it for two years without using it -- long story  :bang:) and rebuilding the left-hand end I stumbled over what to use to lube the gears  :scratch: Also, having constructed a cover for the apron gears what should they be packed with?

White lithium grease is mentioned elsewhere and I do have some but I don't like the way the stuff emulsifies and just kind of sits there appearing not to do very much.

Offline Bernd

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Re: Mini-lathe lubricants
« Reply #1 on: March 19, 2009, 10:49:13 AM »
I've used plain 20w-50w motor oil on my lathe gears. If it works in your car engine it should work fine in your lathe. Another oil I would use would be an oil for manual transmmisions. It's stickeir than motor oil.

As far as grease is conserned I would use any kind of gear grease.

Remember this stuff was engineered for industrial type use so it should work very well for our hobby machines that don't get put through everyday production.

I'm sure if I'm wrong here I'll hear about it from the  :borg::D

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Bernd
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Offline Darren

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Re: Mini-lathe lubricants
« Reply #2 on: March 19, 2009, 10:53:16 AM »
Are your 7x12 changewheels plastic? If so, like mine and I wouldn't use any lube with these. No need and lube gets messy   :wave:
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Offline websterz

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Re: Mini-lathe lubricants
« Reply #3 on: March 19, 2009, 01:22:35 PM »
Can anyone recommend a lubricant for the tumbler, leadscrew and changewheel gears on the 7x12 mini-lathe? I'm in the process of prepping mine (after owning it for two years without using it -- long story  :bang:) and rebuilding the left-hand end I stumbled over what to use to lube the gears  :scratch: Also, having constructed a cover for the apron gears what should they be packed with?

White lithium grease is mentioned elsewhere and I do have some but I don't like the way the stuff emulsifies and just kind of sits there appearing not to do very much.

Are you talking about the aerosol white lithium "grease" or the real stuff that comes in a tube. I tried the spray one time and was not at all happy with it. I switched over to the thicker stuff that comes in a squeeze tube and have been quite satisfied with it. I use it on my my 7x12 lathe as well as my x2 mill with no issues.
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Offline jemglen

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Re: Mini-lathe lubricants
« Reply #4 on: March 19, 2009, 02:00:13 PM »
Thanks chaps.  :wave:

Darren: plastic changewheels and actually, I did wonder if they might be fine unlubed -- it kind of goes against the grain not to lubricate moving surfaces which are in contact and yet oil and plastic doesn't seem like an especialy good mix either (though Bernd, I appreciate your comments on 20w50).

Websterz: the aerosol stuff. It goes on wet but dries out really quickly, emulsifies, traps dirt and chips and..well you can see why I don't like it!  :lol: On the other hand I use the squeezable stuff to lubricate cameras that I'm repairing/CLAing and it works very well, especially for curtain drum gears. Hmm, maybe it's good for lathes too  :doh:


Offline Darren

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Re: Mini-lathe lubricants
« Reply #5 on: March 19, 2009, 02:24:17 PM »
Someone please correct me if I'm wrong......

Gears don't have moving surfaces, they don't slide, they roll.

Or at least they should. So the wear shouldn't be as great as one might think.

Plastic is ductile, so no hard contact and less stress.  Also if you lube them they will pick up dust and swarf etc and this will wear them out very quickly. It will embed into the plastic and grind them away in no time.
« Last Edit: March 19, 2009, 02:25:52 PM by Darren »
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bogstandard

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Re: Mini-lathe lubricants
« Reply #6 on: March 19, 2009, 03:46:59 PM »
Slightly wrong there Darren, they do slide, that is where all the different profiles come in. It is how they transmit the power to each other.

For gears, I always use an anti throw grease, it is very 'sticky' so stays on the mating surfaces. Motorcycle spray on chain lube is the easiest type to obtain, and can withstand the pressures involved in gear meshing.

I think I have mentioned this before, some lubricants can have a detrimental effect on certain types of plastics and nylons, so you should follow the manufacturers recomendations if you have any.

John

Offline Darren

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Re: Mini-lathe lubricants
« Reply #7 on: March 19, 2009, 08:16:25 PM »
I'm not so sure about that John,

Gear teeth as far as I understand it are supposed to roll against each other. If they slide then they are badly designed or made. They will also overheat quickly and wear out in no time.

This was something I learnt many years ago when playing with engines and stuff.
Plenty of ref to this on the net...here's one such page about half way down between two images

http://www.robotgames.net/Resources/Gears/gears.htm
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Offline Bernd

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Re: Mini-lathe lubricants
« Reply #8 on: March 19, 2009, 08:26:39 PM »
Darren,

When I was working I worked for a major gear manufacture. I cut all kinds of gears imagineable. Gears do slide. The spur gear not as much as a hypoid pinion and gear in a cars final drive. To prove this you can take a set of spur gears and blue one gear up and then run it against the other. You will see that they do rub or slide.

Bernd
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Offline Darren

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Re: Mini-lathe lubricants
« Reply #9 on: March 19, 2009, 08:36:40 PM »
In that case Bernd, what's a "roll angle" when talking about gears? ............... :ddb: :ddb: :ddb:


I suppose it all depends on the design of the gear as to whether it slides or rolls. They all slide to some extent, but the better ones are designed to roll over each other.

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Offline Bernd

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Re: Mini-lathe lubricants
« Reply #10 on: March 19, 2009, 08:40:05 PM »
In that case Bernd, what's a "roll angle" when talking about gears?


Could you point me to the place you read that. There may be a difference in meaning.

Bernd
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Offline Darren

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Re: Mini-lathe lubricants
« Reply #11 on: March 20, 2009, 08:46:40 AM »
Sorry Bernd,

It's from something I read many years ago in some publication. It was something to do with the shapes of gear teeth to allow them to roll against each other and lessen the sliding action.
I seem to remember this was critical in transmission gears to reduce wear, noise and heat. It also smoothed the torque delivery and reduce pulsating power transmission as the gear teeth changed angles.

I could be barking up the wrong tree of course, I was hoping you may be able to enlighten somewhat.
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Offline Bernd

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Re: Mini-lathe lubricants
« Reply #12 on: March 20, 2009, 11:22:20 AM »
Darren,

I'll try to find out. It's been a long time since I was involved with cutting gears. The other thing I wish I hadn't done now is throw away all the info I had stored up on gear theory.

BTW the company I worked for had a subsidiary in England called Gleason Limited. I don't remember exactly were they are located. A google search on Gleason Works would probably get you there.

Bernd

Found the address of the company in England:

Gleason Cutting Tools Limited
Plymbridge Rd.,Estover
Plymouth PL 6 7LQ, England
« Last Edit: March 20, 2009, 11:29:31 AM by Bernd »
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Offline Darren

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Re: Mini-lathe lubricants
« Reply #13 on: March 20, 2009, 02:59:13 PM »

Bit more reading up on this and it seems they do both, roll and slide. But it only applies to involute gears. ie most gears today.

http://en.wikipedia.org/wiki/File:Involute_wheel.gif

Involute gears are designed to minimise sliding by adding a rolling action.
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Offline Bernd

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Re: Mini-lathe lubricants
« Reply #14 on: March 20, 2009, 06:10:07 PM »
So Darren, does that let me off the hook?  :D

Bernd
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bogstandard

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Re: Mini-lathe lubricants
« Reply #15 on: March 20, 2009, 06:29:11 PM »
And me  :D


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