Thread: Drive gears for an 18" slip roll.

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Drive gears for an 18" slip roll.

Gentlemen,

Please forgive my ignorance on this subject. I need help determining the correct size gears for this roller. Hopefully this can be done without having to turn the shafts down anymore. This is my first time using actual gears to transmit power on something I have built (normally use chain or belts).

Rolls are 1.75" Diameter.
Drive ends are turned down to 1" Diameter with .25" key ways.
Fully closed the shaft spacing is 1.75" center to center.
Max. material thickness will be .125"

S6304788 (Medium) by robg531, on Flickr

S6304789 (Medium) by robg531, on Flickr

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The formula for Center Distance is CD = (N1+N2) / (2 x Diametral Pitch) Using 16 DP to start you get:

So in your case 1.75 = (N1+N2) / (2x 16) = 56 = (N1+N2). Divide 56 by 2 and you wind up with two 28 tooth gears. Of course you can substitute other diametral pitches and rework the formula to use different tooth counts.

Hope this helps.

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I can tell you for sure that I would not make that with two gears. Two gears are fine for sheet metal but if you want to roll e.g. 1/4x1" strap with two gears it won't work because the gears just won't mesh. Big rolls use 3 gears and a banjo arm setup so the gears are always in perfect mesh. I hate the two-gear setup on rollers because just when you open them up to near-max capacity to roll something, the gears start not working right.

I'd love a heavily built 18" roller that can open properly to at least admit 3/16" stock. I know the rolls will flex. I can deal with that. As long as I don't exceed their elastic limit it won't hurt the roll.

metalmagpie

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This thread might give you some ideas.

Regards.

Steve.

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Originally Posted by Errol Groff
The formula for Center Distance is CD = (N1+N2) / (2 x Diametral Pitch) Using 16 DP to start you get:

So in your case 1.75 = (N1+N2) / (2x 16) = 56 = (N1+N2). Divide 56 by 2 and you wind up with two 28 tooth gears. Of course you can substitute other diametral pitches and rework the formula to use different tooth counts.

Hope this helps.
Thank you very much.

Originally Posted by metalmagpie
I can tell you for sure that I would not make that with two gears. Two gears are fine for sheet metal but if you want to roll e.g. 1/4x1" strap with two gears it won't work because the gears just won't mesh. Big rolls use 3 gears and a banjo arm setup so the gears are always in perfect mesh. I hate the two-gear setup on rollers because just when you open them up to near-max capacity to roll something, the gears start not working right.

I'd love a heavily built 18" roller that can open properly to at least admit 3/16" stock. I know the rolls will flex. I can deal with that. As long as I don't exceed their elastic limit it won't hurt the roll.

metalmagpie
This one is strictly for sheet metal less than .125" thick. Already have a chain driven pyramid roll for the thicker stuff.

Originally Posted by rythmnbls
This thread might give you some ideas.

Regards.

Steve.

Wouldn't you know it, while scrounging through a tub of old gang drill parts at work yesterday I found 5 17 tooth gears that looked pretty close to the size needed. After a trip through the solvent tank and bead blaster this is what they looked like.

While boring the first one discovered that they are cast iron. After boring, slid them on the shafts to check tooth engagement. Not as much as I'd like but should be useable up to 16 gauge material.

Broached the keyways and put it all back together. Decided to test it with a piece of 12" wide 20 gauge mystery sheet. This material is leftover die tryout stock from work. It's a little stiffer than normal hot rolled. Ran the rear roll all the way up and snugged the other two on the sheet. Cranked the handle about two turns and ended up with a 2.25" diameter cylinder. I think this will be a nice addition to my tool collection.

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Last one.

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Originally Posted by metalmagpie
I'd love a heavily built 18" roller that can open properly to at least admit 3/16" stock. I know the rolls will flex. I can deal with that. As long as I don't exceed their elastic limit it won't hurt the roll.

metalmagpie
Stay tuned.....I'm sitting on a 9' long chunk of 3 1/2" solid round I purchased to make a set of heavy rolls. I've got other projects to finish first, but it's on my list.

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