Anatomy of a Threshing
by Lynn R. Miller of Singing Horse Ranch
photos by Eric Grutzmacher & Lynn R. Miller
On the list I have for writing and editing projects, right after completing ‘The Harness Book,’ I have already begun the work to compile a volume on ‘Threshing Machines’ to be followed by ‘Grain Binders and Reapers.’ I have amassed lots and lots of materials on these two subjects – stuff in books, manuals, parts lists, and catalogs – the compilation is a work in continuous progress as I will never stop searching for additional artifacts. As part of our mission to get these materials gathered in a form that might have a long and useful shelf life, I have identified that I need to dig a little deeper into the contemporaneous aspects; how these implements, some well over a hundred years old, might be used today and tomorrow. To that end, I requested of my great good friends, the McIntoshs, that they allow me and Eric Grutzmacher to chronicle this year’s threshing bee process with a keen eye directed towards what they do to get the thresher setup. They consented and the result is 350 photos over two days. I’ve selected a few to go along with a progression of captions I call ‘Anatomy of a Threshing.’ Here ’tis the result, likely to be included in the coming volume ‘Threshing Machines.’ LRM
The McIntosh Threshing Bee of 2021 was, for the sake of the times, scaled down to a much smaller, safer group of participants. As for implements, they employed their Case threshing machine, an old Oliver tractor for belt drive and a John Deere grain binder. All of the equipment has been well maintained and is fully operational.
Two days before the scheduled threshing, the Case separator was taken from barn storage along with the required hand tools; these included pitchforks and old wrenches, but also a shop vacuum cleaner, a grease gun, grease, oil and a compressor.
This vintage machine has grease cups which need to be checked and filled. Mike McIntosh likes to use a battery operated grease gun which adds some umph to the grease filling.
Mike blows out debris from in, through and around the concaves at the lower front of the machine.
A view of the backside and underneath of the wooden straw walker. Below this there are screens appropriate to the crop being separated, in this case oats. To the left in this picture is the maw of the fan drum where straw, conveyed by the straw walkers, falls and collects to be blown up and out of the straw chute.
All round the Case thresher there are many handy inspection ports and access doors. Jacob and Jamesy McIntosh use both compressed air and vacuum to disturb and remove any nests, dirt and settled chaff and seed. They work methodically walking around the big machine and cleaning through inspection holes then turning the corresponding pulleys a little to clean some more. They spend pretty much all of a half day with this process.
In the upper cutaway diagram, the straw walkers, those jagged wooden sections sitting on angle, are moved back and forth rapidly and horizontally when the thresher is operating. This shakes the grain loose allowing it to fall down to the rightward descending tray directed at the grain conveyor. The separated grain is then blown and/or augered up the grain stacks where it then runs through metering systems before falling to fill waiting sacks. Top right in the diagram, with the feed tray folded down for transport, you see the side of the mouth of the machine into which grain bundles are fed.
After the thresher is thoroughly cleaned and lubed, we go to the field where Mike has mown a strip between the Oliver belt-power tractor’s parking spot and the thresher’s working spot. Years of threshing on the Lazy M Ranch has determined about where the tractor needs to be. This takes some time and doing when you are setting up for the first time. You want level ground. And you need to layout your drive belt to determine distance between machines.
At the thresher end of the belt lane, two planks are put down to drive the Case’s front wheels up on.
Jamesy pulls the thresher to the site and up on the planks with his John Deere A tractor. The planks help to keep the front wheels from settling as the thresher is shaken and pulled upon.
Thresher is parked and set to the level desired. The two vertical tubes auger and further clean the grain. On the left the straw blower inspection door is open.
For it to operate properly the unit must be level sideways with a slight elevation towards the front to assure that the crop is moving back.
Mike unrolls the main drive belt, looping it around the inner concave pulley and making sure his white arrows are pointing back towards the Oliver tractor.
At the Oliver end, for our purposes, Mike demonstrates what happens with this wide front end tractor when the drive belt is simply taken over the axle and looped on the pulley. Jamesy is using a shovel handle to hold the belt up from the axle to avoid grease and damage.
As you can see (bottom right) once the tractor has been backed up and the proper tension is on the belt, unwanted contact is made with the axle.
So another approach is tried with the belt coming over the axle and returning under. Mike’s hands show that, with this, the return path belting slaps up against the axle. No good.
The final and usual solution was to dig a depression in the ground at exactly the right place (to maximise the belt tension) thereby lowering the tractor on the right side and providing stability as the belt runs.
Then came the threading of all remaining belts. The long belt running from the ‘concave’ pulley back to the straw blower needs to be tight and requires rolling the pulleys to get it mounted. (above)
Belt at straw blower, note tensioner pulley beneath.
There’s a lot to understand and know when it comes to properly setting up belts. When the right belts are on hand they tend to answer questions silently as they will only fit certain places.
The long view back to the Oliver tractor, belts at proper tension.
The large crank pulley belt circumnavigates the two concave pulleys and the cleaning fan pulley. It sure helps to have two knowledgeable people like Mike and Jacob to loop the belt. Note spring-loaded tensioner pulley above.
Once the belts are on, Mike ties a livestock panel to the loading side. This isn’t required to run the machine. He does it to protect any volunteers, especially children, when belts are whizzing around and it is hard to watch everything.
The bagger pipe is mounted to the auger tower and Mike hangs the first two burlap sacks.
The Y shape of this bagger pipe allows that grain can be directed from one bag to the other. This way a full bag can be taken from the thresher while it is running and without any spillage. You just need to have someone paying attention.
There are two measuring counters on the Case. One at the bagging manifold, and the other at the top of the auger tower. These are mechanical. To reset them you need to pull the cover and carefully remove the two gears, realigning them to zero and replacing.
Jamesy is doing the same thing with the counter at the top of the tower.
There is so much to marvel at with these old machines. Any time spent with them and you can literally ‘feel’ the experience-driven engineering that went into their design. Couple that with the nature of the materials used in the later galvanized makes and models, and you have machines which, with a modicum of care, can last lifetimes.
Morning of the threshing, the machine units are ready.
That includes the McIntosh John Deere grain binder, drapers on and waiting patiently for the three black Percherons to draw her through the oat field.
Last but certainly not least, the horses are ready as well. Jacob’s three blacks and Jamesy’s sorrel Belgians.
Jacob McIntosh guides his hitch and binder into position while Clay Penhollow watches for any fine tuning and adjustments to match the crop. The goal is to cut the oats just long enough to receive a twine and make a bundle. Too low and weeds needlessly add to the thresher’s work.
Jacob deposits his first cradle load of bundles and everything clicks along perfectly. That morning haze is from forest fires burning across most of western and central Oregon.
Nellie and Jamesy, brother and sister, drive and load the bundle wagon as volunteers pitch in.
Wagon in place for unloading, team is unhitched for volunteer safety.
When the machine is up and running smooth, Mike will double check the rpms with a hand-held velocimeter touching the center of the concave pulley. Raising or lowering the throttle of the Oliver will attain the perfect 980 rpms to assure separation is working properly and the machine is neither lugging nor working too fast.
Svelte, dapper and semi-retired auctioneer extraordinaire, Dennis Turmon, wields a deft bundle fork as he pitches into the waiting maw of the operating thresher.
The working end of the Case threshing machine. (right)
Bundles go in, strings are cut, the grain crop is conveyed across an oscillating bed of four jagged and tilted wooden straw ‘walkers.’ These shake the crop to have the grain fall through where it is agitated, blown, shaken and further separated from the chaff. The grain then finds its way on the angles to the belly of the beast where it is blown and augered to its destination; in this case (Case), the bagger.
And the culmination: grain begins to flow to the sacks.
A very big thank you to Mike, Joanna, Nellie, Jamesy, Jacob, Rachel, the Mac McIntosh family and the Lazy M ranch, for permitting Eric and I to get in the way at this year’s threshing. They have provided us with hundreds of excellent photos to incorporate into our future project, a book on ‘Threshing Machines.’