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BigBoy1
05-12-2009, 12:47 PM
I’m building a small grain grinder for my brother (the farmer). My design has two rollers, powered by a hand crank, spinning at different speeds to provide a shearing action on the grain between the two rollers.

I was looking at buy two gears but a price check cancelled that idea. I can make the gears if I have to but before I go to all that work, I thought I might ask if anyone had a few old spur gears lying around collecting dust. The two gears I need are shown below. The two rollers are 3” in diameter so the two gears have a center distance of 6”. The diameters of the larger of the two gears needed can be in the 7” to 10” diameter range while the smaller of the two gears in the 2” to 5” diameter range. When the gears mesh, the center distance is to be 6”.

I would like the gears to have a thickness of 0.5” or less. There will be no load on the gears so they came be in a well used condition, just as long a no teeth are missing. I'll gladly pay any shipping costs for the gears. Thanks.

http://i163.photobucket.com/albums/t308/i422twains/Millcopy-1.jpg

BigBoy1
05-12-2009, 01:07 PM
I don't have a clue why the drawing is not posting correctly in above. The drawing can be viewed when in photobucket but when link is posted in it not visible.
This the photobucket link:

IMG]http://i163.photobucket.com/albums/t308/i422twains/Millcopy-1.jpg[/IMG

I removed the front and back [,] so the link will not "automatically" work. Maybe someone who can actually drives on the information super highway can figure out why it doesn't work. My name line says it all!!!

Fasttrack
05-12-2009, 01:25 PM
I can only see the thumbnail of the picture - the large one doesn't even show up on photobucket. Maybe try uploading it again or ... ?

I don't have any gears that big just lying around but I'll keep my eyes open. What about making a set of gears? It seems like this might be a good project to learn on since it sounds like you have some wiggle room on the accuracy and the gear ratio.

(Or maybe you already know how to cut gears and just don't want to spend the time - which I understand!)

JABautsch
05-12-2009, 01:34 PM
I don't know if it would work or not. But have you considered using two bicycle sprockets with a chain to drive them. They come in a lot of different sizes to give you the ratios you are looking for and should be cheap enough to use. They should also be strong enough to drive two 3" rollers. Just a thought.

ckelloug
05-12-2009, 04:13 PM
Hi BigBoy1,

I opened your picture by saving it in gimp and having gimp rewrite it.

Here it is.

http://i161.photobucket.com/albums/t202/ckelloug/Millcopy-1.jpg

camdigger
05-12-2009, 04:36 PM
What you're looking for is a +/- 2:1 ratio. Very much like crank shaft/cam shaft ratio in a detroit auto engine. HINT HINT

I ripped the transmission out of a wringer washer that had gears roughly that size, but helicals.

An el cheapo hand winch from the local chinese discount house will yeild roughly 4:1 ratio out of pressed steel. An idler train can be used, but even #s of gears will need to be used for counter rotation.

If the rolls are already built, it will limit the gear size selection considerably.

BigBoy1
05-12-2009, 07:05 PM
Hi BigBoy1,

I opened your picture by saving it in gimp and having gimp rewrite it.

Here it is.

http://i161.photobucket.com/albums/t202/ckelloug/Millcopy-1.jpg


I don't have a clue what you did or how you did it but thank you. I'm sure glad you are a highway driver!!

Evan
05-12-2009, 08:22 PM
Why bother with gears? It isn't critical that the two rolls stay synchronized. Use a knurled metal roller for the small wheel and a rubber covered large wheel. The large wheel can be grooved and a large O-ring snapped on for a tire.

Arcane
05-12-2009, 08:25 PM
As an old farm boy, I remember when we had a grain roller that did exactly what you describe. It required a tractor to run it....direct drive from the 540 RPM PTO and the rolls weren't much more than 10-12 inches wide and I am not too sure about the diameter but they were fairly thick. They were spring loaded with a considerable amount of force and had longnitudal grooves to grip the grain kernels. It didn't grind the grain, it crushed it...just enough to break the husk (or hull) open. Both rollers turned at the same speed because of the grooves. As the grooves got worn, the rollers would slip on the grain and after awhile (a considerable number of bushels) it was necessary to have them regrooved. I don't want to get your cornflakes all wet but I don't think what you have in mind is going to work. I think you might be far better off to hunt up an old grain grinder or an old roller and go from there.

Mike Burdick
05-12-2009, 08:28 PM
If one uses spur gears how do the rollers adjust for different grinding gradations desired?

The grinders I've seen power one roller and idle the other. The idler is on a slot for adjustment for crushing oats, corn, etc. Shearing the grain is better if one is making a flour mill but you said you're making a grinder.

I'm sure you have it all planned out but I'll just add a suggestion for thought...

Since this is hand powered how about stepping up the speed of the roller to at least twice the speed of the crank - one-to-one is just too slow. A nice heavy fly-wheel is very handy too!

I wouldn't use spur gears but rather roller chain and sprockets. These can be had at any tractor and implement dealer and they are not that expensive.


.

Paul Alciatore
05-12-2009, 09:59 PM
Why bother with gears? It isn't critical that the two rolls stay synchronized. Use a knurled metal roller for the small wheel and a rubber covered large wheel. The large wheel can be grooved and a large O-ring snapped on for a tire.

Or use pulleys and a Vee belt. All are easily available and relatively cheap.

gmatov
05-12-2009, 10:58 PM
How BIG is a "small" grain grinder? Are you talking about a so many bushels per hour or are you talking about something that will make you some rolled oats for breakfast?

If you want to grind a couple pounds of something, you need a small grist mill, if that is the right word. I have one, never used it, don't know how fine it will grind anything, steel burrs.

If by small you mean so many bushels, yes, I can see the need for gears. 2 gears counter rotate, so you feed the grain as you grind, or mash, I guess you should better say.

Cheers,

George

camdigger
05-13-2009, 10:29 AM
IIRC from my youth on a farm, we had three basic options for seed type feed prep.

Hammer mill - a set of pivotted hammers forced the dindividual kernels through a heavy duty screen. Power intensive, expensive, and slow. Produced a crushed kernel if the kernel hit the edges of the screen. Screens were available from 1/8" to 1" perforation sizes. With different screens a hammer mill can handle other feeds as well like hay or straw....

Roller mill - crushed the kernels between crimped rolls. Less power required, not as dusty. Produced a flattened and opened kernel with the hard to digest outer bran of the kernel opened up and the germ or "meat" of the kernel smashed flat.

Plate Grinder (grist mill concept)- ground the grain kernels between two flat plates like an old flour mill. The plates were ridged in a specific pattern that threw the ground grain out from between the plates into a shaped volute that directed the ground grain into a discharge spray. Less HP than a hammer mill roughly the same throughput, dusty as flour and almost the same size if the plates were set close enough. The grist mill product yielded a product that was easier to digest than the others becuase the bran was completely smashed up and all the "meat" was exposed to the digestive process....

Sounds like the OP is trying to get something between a rooler mill action and the plate grinder concept.