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Mini-lathe lubricants

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Darren:
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.

bogstandard:
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

Darren:
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

Bernd:
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

Darren:
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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