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View Full Version : Cheap gear reduction, in the 20-80:1 range?



Billy Golightly
07-03-2009, 02:44 PM
Does anyone have some ideas on a cheap way to get me anywhere from 20:1, through 80:1 gear reduction? I'd prefer somewhere in the 20-25 range, but I can deal with more. I've got a 5hp 220v input motor turning 1750rpm. I don't have a smaller motor but I wouldn't object to using one if it was cheap. I need about a 3/5 horse, horse and a half max ouput power. The 5 horse on it now is overkill. I've seen the gear reduction boxes on ebay, but for the power i'm needing its just WAAAAAAY to expensive.

Macs
07-03-2009, 03:03 PM
How about the tranny out of a riding lawnmower or tiller. should work nicely and be a bit adjustable to your liking. Maybe find a beat up riding lawnmower somewhere.

Name Brand
07-03-2009, 05:11 PM
Cannibalize the belt drive system out of a big drillpress. The ones made for drilling metal (versus wood) will likely have much slower operating speeds available.

What are you working on?

Billy Golightly
07-03-2009, 06:05 PM
band saw with a 30inch wheel diameter that needs to be able to cut metal. I can do it with shafts and pulley's, but to get the blade speed down to where it needs to be, its going to have to be reduced like 4 times using 4-15inch pulleys.

brapp
07-03-2009, 06:33 PM
i have a big ass horizontal bandsaw ready to roll just requires 5+hp 3 phase converter i dont have the power to run it lol

hondahaulic
07-04-2009, 02:19 AM
if you could find a small gearbox that uses a worm gear to drive a large gear it should work well and be compact. Ive seen them on smaller metal band saws, but cant think of much else where they are used.

Thorpe
07-04-2009, 02:23 PM
http://www.grainger.com/Grainger/wwg/productIndex.shtml?operator=retrieveProdLevel1Inde x&prodLevelList=Pulley%257CPulleys%252C&prod_level_selected=Pulley

Dirtcrasher
07-04-2009, 02:43 PM
I'm thinking riding lawnmower gear box :D

Of course you could make a simple drive with a worm gear and worm wheel, but you'll need some thrust washers or thrust bearings.

Call a bearing shop, give them some shaft sizes you can deal with and a ratio you want and maybe that would help? McMaster sells that crap individually.

Billy Golightly
07-04-2009, 11:50 PM
I can buy pulleys and put them on shafts, I know how to do that. But even with pulley's I'll need a 4 inch to 15 inch wheel FOUR TIMES to get the correct reduction. Thats about $450-$500 in belt pulleys.


Now...a home made worm gear box...that would probably work.

brapp
07-05-2009, 11:39 AM
hell for 500 bucks you cna drive up her ean dbuy my bandsaw i am gonna take a look at the gear reduction set up we have on the electric motor for the pipebender we built.

joshco84
07-05-2009, 11:00 PM
go to surpluscenter.com and look under power transmission. They have lots of gear reduction stuff, and lots under 100 for what you are looking for.