My Threshing Machine

Some of you who know me, probably also know that my Father is a wheat farmer, and thus know that I spent the majority of my childhood working on the farm during the summers.   Those memories are cherished, and will always be.   From Grandpa napping under the wheat truck, to pushing my combine to absolute max, it was a blast.

One other thing that I’ve always done, is think about building my own from scratch. I’ve always tried my hand at… well… hand threshing wheat. I used various methods as a young teen, and took most of my 20’s and 30’s off, but last spring I finally got around to it.

This is the first revision. It worked out ok, but didn’t have its own air for blowing away the chaff. I used a 3’ shop fan to generate the necessary wind.   I have updated it this year to have an actual belt drive blower, but we’ll get to that in a second.   I built this machine over a 2 week marathon dose of inspiration. Everything seemed to just fall into place. Most of the components came in a just under $300 in total, but I already had the electric motor which saved a ton.

I started with the threshing cylinder and the concaves. Followed directly by the separating tray and cam bouncer mechanism.   Mind you, I had much more grand plans for the cleaning mechanism, but time, money, and effort limited me to a more simple design.

The frame is basically made out of 2×4 studs. I had wanted to use 1”x1” square tubing, but instead opted for wood for a first go. It’s easier to fix design flaws with wood. The frame is enclosed by 1/8” wall board, which is smooth / shiny on one side, and rough / textured on the other. The separator is made of some “fancy” clover styled screening that I used for the lid on my turtle tank.

I decided on the proper cylinder speed by increasing the belt ratio until I started throwing wood slats. Then I reduced it by about 1/3 and settled on that speed.   The cam system for bouncing the separator was pretty easy overall, but it was originally supposed to shake instead of bounce. It works ok, but does tend to get plugged up.

The original concave system was open, much like modern combines. But after the first round of threshing, I decided that a closed concave would work better for tougher smaller heads of grain, which kept falling through the open concaves.

It works by feeding the wheat head first into the cylinder, then pulling the stalks back out. You “could” feed the whole plant in, and it will thresh it, but the separator plugs up with straw too easy.   It’s much more efficient to just thresh the heads, then pull out the threshed stalks and pile them up. Some heads get removed, but most thresh out just leaving an empty head.

Very little grain gets thrown over.   Which is good. But it also means that most of the chaff doesn’t get blown out either.   This year will be interesting given I have a new high volume blower. More grain will get thrown over, but I should get virtually no chaff in the clean grain that falls through.   I can’t wait to test it out.

In total I threshed & cleaned about 4.5 gallons of wheat in 2014. This year I’m expecting a bit less, because I planted a bit less. However, what has grown so far, is healthier than last year’s so only time will tell.   I also purchased a grain mill this winter, so we’ll be making some truly homemade bread this year. Again, I cannot wait! Should be loads of fun.


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