Worm Oil Substitutes

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John Hasler
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Worm Oil Substitutes

Post by John Hasler » Mon Feb 12, 2018 2:06 pm

I'm building a power hacksaw. I scored a very nice 24:1 combination worm/spur reduction gear at the local university surplus store for $1.00 (had to make a cover and an input shaft adapter) but it's an unlabeled (and unused) spare part. I know I can buy worm gear oil by the gallon for ridiculous prices considering that I only need half a pint. Any suggestions for cheap substitutes? The worm gear is brass. The worm and the spur gears are steel. The four start worm is about 1" diameter. Worm speed will be 2000 to 3000 rpm. Sealed ball bearings except for the inside end of the worm. Enveloping worm gear, straight worm.

Downwindtracker2
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Re: Worm Oil Substitutes

Post by Downwindtracker2 » Mon Feb 12, 2018 2:29 pm

Differential oil , even the best syn 75/140 is inexpensive compared to a pail of non EP gear oil.
A man of foolish pursuits, '91 BusyBee DF1224g lathe,'01 Advance RF-45 mill/drill,'68 Delta Toolmaker surface grinder,Miller250 mig,'83 8" Baldor grinder, plus sawdustmakers

John Hasler
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Re: Worm Oil Substitutes

Post by John Hasler » Mon Feb 12, 2018 4:28 pm

According to my research worms need ISO 680. SAE 75 gear oil is about 46 ISO.

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wlw-19958
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Re: Worm Oil Substitutes

Post by wlw-19958 » Mon Feb 12, 2018 4:42 pm

Hi There,

You can get ISO 680 from McMaster-Carr for about
$10.66 a quart (plus shipping).

Good Luck!
-Blue Chips-
Webb

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Bill Shields
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Re: Worm Oil Substitutes

Post by Bill Shields » Mon Feb 12, 2018 4:51 pm

considering the load on the gearbox, just use differential oil.

I started using it in my saw about 30 years ago...will probably outlive me.

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warmstrong1955
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Re: Worm Oil Substitutes

Post by warmstrong1955 » Mon Feb 12, 2018 7:27 pm

If any type of gear design screams for EP gear oil (Extreme Pressure) it's a worm & gear. If you add up the contact pressure, contact area, and contact speed, it is one of the worst....with maybe close to it is the hypoid.
EP oil will maintain oil shear when standard gear oils will not. That means it will maintain an oil film between the surfaces under load, rather than the oil yielding and you achieve metal to metal contact.

Only thing to watch for, is the compatibility with the gear or bearing materials. Some EP's will slowly dissolve brass & bronzes.
These days, synthetic oils have taken care of that problem, but it's still important to verify.

I can explain further....but I will avoid being boring....

;)
Bill
Today's solutions are tomorrow's problems.

Downwindtracker2
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Re: Worm Oil Substitutes

Post by Downwindtracker2 » Mon Feb 12, 2018 7:52 pm

For the Radicons at work,, the brand name is used much like Kleenex for worm and wheel angle drives, I used 150wt, 220wt or 320wt.Depending on size. I was the lubrication expert, I had read the specs. On our biggest wire drawing machine which had a 3' wheel, we used the heaviest oil, a black sludge,SWEPCO 460. It's an very expensive moly oil. On the drums it was labeled SAE 140 as well. You'll be safe, you not drawing down 13mm rod.

Worm and wheel are obsolete in industry as they they waste too much power. If you keep oil in them, they do last. The seals fails with age , then you have to rebuild.
A man of foolish pursuits, '91 BusyBee DF1224g lathe,'01 Advance RF-45 mill/drill,'68 Delta Toolmaker surface grinder,Miller250 mig,'83 8" Baldor grinder, plus sawdustmakers

Wolfgang
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Re: Worm Oil Substitutes

Post by Wolfgang » Tue Feb 13, 2018 8:48 pm

John Hasler wrote:
Mon Feb 12, 2018 2:06 pm
"... Worm speed will be 2000 to 3000 rpm. Sealed ball bearings except for the inside end of the worm. Enveloping worm gear, straight worm..."
Another time and another place I did a bit of automation work using commercial worm gear boxes. Found out that typically these had TWO limiting factors: 1) output torque, 2) input speed. The input speed was usually limited to 1800 rpm, and if exceeded, the gearbox would overheat and seize up REGARDLESS of any imposed load!

I found this out the hard way when I fitted a 20:1 worm gear box on my wood bandsaw in order to cut steel. I put a 4 step pulley between motor and gear box to get appropriate speeds for stainless & tool steels, low carbon (mild) steels, brass & bronze, and aluminum.

I turned these pulleys myself so as to get the desired speeds. The pulley step for sawing aluminum raised the motor speed to over 2000 rpm at the input shaft and yes, the gear box overheated and seized up! Fortunately all was well after it cooled back down to room temperature.

For lubrication I used synthetic differential oil us used in limited slip differential for my RX-7.

John Hasler
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Re: Worm Oil Substitutes

Post by John Hasler » Wed Feb 14, 2018 11:45 am

The worm drive reduction ratio is 6:1 (followed by a 4:1 spur gear pair). According to my research that means that the worm drive should be about 90% efficient. The whole gearbox is about twice the size of 1.25hp 2500rpm 7.5:1 worm drives found in various catalogs. Load power won't exceed 400 watts so assuming 80% overall efficiency input will be 500 watts. The brass worm gear is about .5" by 2.25" and the worm about 1" by 1". The worm will be fully immersed in oil (so that oil reaches both spur gears).The gearbox is aluminum. Seems like it should be able to handle 50 watts of losses in the worm drive (100 watts total).

I'm going to try the nearby NAPA store for oil. He should at least have small quantities of 140W gear oil.

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