building a small theshing machine

Tue Aug 20, 2013 4:47 pm

I grew some wheat in the garden this year and hope to grow more next year. Harvested with a scythe. We threshed on a tarp with a rubber hose. It took forever. I am thinking about building a little plywood box sort of like a wood chipper with a shoot on the top, then cutting a piece of 6" pipe in half for a concave. Then putting a shaft with bits of chain welded to it as a thresher into the concave with a refrigerator grate just past this “threshing drum”. Then putting a fan on the bottom blowing up through an old refrigerator grate as a screen. With a door on the bottom to catch the grain. So to all you combine experts would that work or instead of chain should I use the drum from an old reel mower I have? By the way everything I know in life about combines is from this picture. Thanks.

Re: building a small theshing machine

Sun Aug 25, 2013 8:50 pm

Not sure if swinging chains would be the way to go or not!--- You really need a solid cylinder with rasp bars on it and the concave adjustable for height so different grain could be set.---If the wheat is tuff,---you need closer clearance than if its paper dry!---that way you wont crack the grain.---also speed of cylinder needs to run around 1,100 rpm for wheat/oats/etc.
At one time the Rhodale institute had a crude design for one to make from plywood and electric motor, plus shafting/pulleys/etc,---I had the copy of their build procedure at one time but not sure if I still have it or not! thanks; sonny

Re: building a small theshing machine

Mon Aug 26, 2013 7:24 am

Threshing cylinders have two basic designs that I know of. Rasp bar which is like the name implies, a bar with diagonal groves in it which rubs against the grain removing it from its husk and dropping it thru the concave. the other is a hammer or flail in which the hammer is hinged and when spun knocks the grain from the hull and thru the concave. Your chain would resemble this type of thresher. The size of the hole in the concave must be sized close enough to allow the grain thru, keep as much straw as possible from going thru but not so small you crack the kernel or worse yet allow grain to go out with the straw. Combines have changeable height adjustable concaves for different grains The lawnmower reel would I believe be too sharp and would damage the grain unless dulled, kind of like my mower blades. :D It would also have a tendency to move the material to one end which might not be too bad of an idea for removing the straw. I have not run a combine in 55 years so I'm sure there are those out there who know a lot more than I. Vern

Edit: What are you growing the wheat for? How clean of a threshing job do you need?

Re: building a small theshing machine

Tue Aug 27, 2013 8:31 am

Internet search for "rice thrasher" or similar wording.

In the military, stationed in Korea, Koreans had small, engine powered, hand feed, thrash machines.

Re: building a small theshing machine

Fri Aug 30, 2013 9:35 pm

I just saw a simple unit on display at our tractor show, (Central states Threshermans Reunion, in Pontiac, IL.) --I took a couple pics of it and had to laugh at the thing, BUT the design is neet!---looks like factory made and may have been so!---pics are still on my hard drive and will have to be uploaded to p bucket before I can post themm thanks; sonny