lubrication of worm gear box
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It's about $24 at Grainger, which is where i last bought some. It was for work, so I don't have any at home, dangit! But it works well enough that I'd certainly buy it for my stuff once I'm ready to run the thing. I do have a Grainger's local to me, so don't have to pay for shipping. That does help.?
Bill in OKC |
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Consensus on what Steve? You've used an old thread but there are no links back to that thread on my screen- jv On Thu, Dec 24, 2020 at 6:20 AM Steven Greenfield AE7HD via <alienrelics=[email protected]> wrote: So is there a consensus on if either is better, or roughly the same? |
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I think he's asking which lube is the best for the gear box. So far as I know, just about any brand that meets specifications is good enough. If you've got brass or bronze gears or bearings, the yellow-metal safe additives are almost a necessity, but otherwise, any lube is better than no lube. Nope, I'm not a Tribologist. Just been doing of bit of mechanicing, on and off, for much of the last 50 years. Automobiles, high-performance fighter jets, home and industrial laundry equipment, and satellite ground terminals. Lots of broad, not much depth.? Bill in OKC William R. Meyers, MSgt, USAF(Ret.) A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. LAZARUS LONG (Robert A. Heinlein)
On Wednesday, December 23, 2020, 02:36:46 PM CST, John Vreede <vreededesign@...> wrote:
Consensus on what Steve? You've used an old thread but there are no links back to that thread on my screen- jv On Thu, Dec 24, 2020 at 6:20 AM Steven Greenfield AE7HD via <alienrelics=[email protected]> wrote: So is there a consensus on if either is better, or roughly the same? |
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I don't have definitive answers on oil yet but here's what I know from literature and the testing I've done. The worm drive gearbox is a high friction device so needs good oil, and enough of it, or it heats up more quickly and wears the gears more rapidly. 1. Type of oil matters: ? ? a) 75W-90 full synthetic Polyalkene glycol (PAG) based oil is probably the best.? ? ? ? ? ?i) Literature indicates full synthetic gear oil reduces the friction?in worm?drives by 30%+ and reduces operating?temperatures by 70degF+ (20degC+) over mineral oils.? ? ? ? ? ?? ? ? ? ? ii) PAG synthetics effectively do not degrade with time (30x as stable as mineral oil) .? Once you change to it you never need to replace it. Synthetic Hydrocarbon? (SHC) based oils, (like Mobil1 SHC 600 series gear oils) are ~10x more stable than mineral oils, but not as good at lubricating nor as stable? as PAG's. ? ? ? ?iii) 75W-140 full synthetic?gear oil (Lucas Oil Products GL5) is too thick and foams.? I've got a clear plastic cover on my gearbox and the 75W-140 oil turned white almost instantly, where the 75W-90 (Red Line MT90 GL4) remained as oil with no entrainment of air.? Air/oil foam does not lubricate well.? Never would have known if hadn't had a clear cover. ? ? ? ?iv) 75W-90 gear oil is the same viscosity (flow when you pour it) as SAE15W to 20W engine oils while 75W-140 is closer to SAE60 engine oil .? There is no sensible reason why the engine oil and gear oil SAE viscosity scales are so different - they just are.? ? ? ? ? v) Red Line MT90 75W90 is the only fully PAG synthetic that I know of, but there are probably others. ? ? ? ?vi)
Red Line MT90
is about the same viscosity as?
Mobil1 SHC 626 or 627? ?? ? ? ? vii) Lucas Oil 75W-140 is about the viscosity of Mobil1 SHC 632 to 634 - so maybe these Mobil grades foam in the gearbox?too?? ? 2. The amount of oil matters.?? ? ? ? ? i) I used to use ~90ml of gear oil (mineral based GL4) and, when doing continuous cutting tests, the wear on the gear set got noticeably worse?
in the space of a day or two
(blade free up and down movement went from?5mm (~3/16") to 7mm), which started me experimenting with other oils and the amount of oil. ? ? ? ? ii) OEM factory fill is about 200ml, so it spills out if you take off the cover with the saw on its legs. To get 200ml in, you need to tip the saw sideways until it just about tips over. Fill to ~1/4" (6mm) below the edge of the gearbox with the rear RHS leg propped up on a dressed 2x4 (90x45mm) - NB Its almost at the tipping point - very unstable - get someone to help if possible. ? ? ? ? ii) It really helps to have a fill and drain plug in the cover? Easy to do with 3/8" (10mm) Lexan, like in the picture. Fill and drain plugs are the button-headed screws.? Fill with a 60ml syringe. ? ? ? ? ii)? I've compared the temperatures with 240ml vs 120 ml of 10W-40 engine oil and the saw
cutting continuously (as close as I could get).? The gearbox heated to 150degF (65degC) in 32min with?240ml of oil , but took only 16min to reach the same temperature with 120ml. (The heat is generated by the cutting - you can run a saw for hours without load and it heats up <10degF (<5degC)). 3. I'm no tribologist?either but I rather suspect the old days of brass-eating oils are over, at least in high spec synthetics.?? ? ? ? ? ?i) GL5 grade gear oils are not supposed to be 'yellow metal safe', where GL4's are. ? ? ? ? ii) I tested the Lucas Oil Products GL5 (which it says is a replacement for GL4 but doesn't mention 'yellow metal safe' anywhere on the bottle), by putting a piece of polished brass in a specimen jar
of oil, inside an insulated housing on top of my hot water?cylinder.? It's been at 100degF (38degC) for the last 9 months and is more tarnished above the oil level than below?it! (see pic).? No corrosion at all under the oil. ? ? ? ?iii) Be careful?about which grade you use, but it's?not all as cut&dried?as it used to be. Hope this helps - jv On Thu, Dec 24, 2020 at 10:35 AM Aaron Brace <abrace@...> wrote:
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David Pidwerbecki
Howdy,
I bought some Redline MT-90 and put it in my gear box.? ?The only issue is that the stuff is much less viscous than the GL5-90-140Wt oil I had in there before so the seal around the gear box lid leaks.? ?I'm going to have to put some permatex gasket sealer on it tonight. I also added a 1/8" NPT plug in my gear box so I could fill it with 7 oz of MT-90 when the saw is in the vertical saw configuration. Dave |
Bill in OKC too
John Vreede
