I just returned from one of my favorite antique machinery shows—— The Oregon Steam up, held on the last weekend in July and the first weekend in August in Brooks, Oregon, north of Salem and South of Portland at Antique Powerland just off U.S. highway 5. There are a very large number of such shows in the world each year, but this one is outstanding for the breadth of old machinery there and in operation, the well-done museums on the land (which are open during the year), and the swell and knowledgeable people who put it on, and who show and demonstrate their stuff. For me, it is also of a nice scale and convenient because it is on the West Coast of the U.S. in one of my favorite states. If you are interested in antique machinery you will especially enjoy this gathering, because of its emphasis on both steam and gas equipment and the in-place large engines, sawmill, etc. If you are not interested in antique machinery you should be. Don't you wish you had the vehicle in the photo above to go shopping in?
But I had another reason for my visit. Some years ago I began restoring a McCormick Daisy reaper, a machine that is in the American history books, and is fascinating to watch, as after it cuts the hay, it has arms that sweep it off of a deck onto the ground in piles, which can then be tied together and taken to the next stage of the harvesting process. The six arms can be controlled so that every arm sweeps the deck each pass, every other sweeps, every third arm, etc. My problem is that the very critical part that controls all of this is missing from my machine. So I need to make one.
There is one of the few complete Daisy reapers like mine that I know of at the Brooks show. A photograph is below. The part I need is sort of contained in the red outline in the photo below (apologies for the photo— the white blur at the bottom is my hand), although many weird curves and shapes are not visible. The part includes the pivot. A complex curve hidden in the photo, the hook at the top, a curved rack of gear teeth that must engage the worm gear inside the main casting as the part turns upon its pivot, and a contact pad at the top of the rack.
I have several problems in re-creating it. First of all, it is difficult to make, since it is a casting with no symmetry, no “parting lines” which would allow a mold to be separated, and critical and strange alignments between the parts which interact with the surrounding parts.
And, don’t say 3d printing —been there. Three dimensional printing is not as easy as the media makes it seem, especially if scanning is involved, and I want a steel part. Sure I could make a mold from the part and cast it, but not surprisingly, the owner and museum were not eager to let me take the machine apart (also difficult) and take the part 400 miles away to use as a master while I copied it in my shop and Stanford’s foundry. Had I been them, I would have felt the same.
So I went to Brooks to take many photographs and make measurements (which I did) to work from. Even with them, it will be a challenging job, as there were no base points on the part or machine to measure from, so I will have to cut and try and weld and curse until I get a prototype that will do the job, and then make a finished version from the prototype. But strangely enough, I love to do that sort of thing.
I will write a post on the process and the finished part, but don’t hold your breath. I am guessing several weeks, since my life is beautifully endowed with many other things to do, many higher on Marian's priority list than my making this part.