Here are some photos of an Advance thresher steam tractor that my good friend Mike Shanley and I have restored.
It is owned and kept at our local museum in Vista, Calif. This is a 16 HP tractor no. 6744; it was built in Battle Creek, Michigan, in 1902.
We started this project in December of 1989, and with a good deal of help from other club members and a little over 1,000 hours of work, we were able to steam the tractor again in December of 1991, almost exactly two years later.
Assessing the tractor
The boiler and cylinder were in good shape from the start. The flues had been replaced a few years ago by the man we bought the tractor from. Our work was all in the repairing of cracked gears and re-babbitting all of the larger bearings. We knew the bearings were bad, but wow! There was a gap between the cross shaft and its bearing large enough to slide a Bic pen into! The main shaft bearings weren’t as bad, but had to be done as well.
Then there were broken and cracked gears and a crack in the casting for the flywheel support bracket. The intermediate gear and stub axle had to be bored and sleeved to get a good fit again, and then we found a crack on the inside bevel gear that went from the keyway all the way out to the rim! Add to this the usual complement of broken or missing small parts, some piping that needed to be replaced, the paint job, and that’s about what we had to do.
Beginning with the boiler
We started by removing most everything from the boiler we could, including the stub-axle casting and the flywheel support bracket casting. These two needed work that could not be done while on the tractor. These parts together had 15 bolts going through their castings and into the boiler shell.
The bolts proved to be quite a job to get out, and we broke a good make of a 1” open-end wrench in the process, so when we were done the bolts were not in real good shape. Luckily, a club member machinist volunteered to make us up some new ones with square heads and all, to replace the now bad ones. The threads in the boiler shell took a beating too, and later getting these all to seal up under pressure was a job in itself.
Pouring babbitt bearings
The stub axle and intermediate gear were then repaired and replaced, along with the flywheel support bracket, so we could get started setting up to pour the main shaft bearings. Now neither Mike nor I had any experience pouring babbitt bearings, and while we were offered ideas and tips on how to do this, we were pretty much on our own.
In the end, the results were quite good. We only had to repour two of the eight halves that needed to be done. I must say that here is a job that takes two days of set up and five minutes to do! We did a bit of research and decided that pouring to the shaft itself was the best way for us to go. Then, despite our best efforts, we were unable to remove the flywheel from the shaft. This made balancing the shaft in the chains a job all by itself.
It also added a lot of weight that we had to deal with in hanging the shaft above the tractor and in aligning it just right in the bearing boxes. Basically, we hung the shaft and flywheel so that it “floated” in place, passing through the bearing boxes just right. We made small adjustments as needed with turn buckles placed in the lines that held up the shaft, and added new lines where needed to pull this way or that until the shaft was in place.
The alignment of the main shaft is quite important on a steam tractor if it is to run smoothly. It must be exactly 90 degrees to the cylinder’s bore. It must also line up with both the top and bottom cross-head guides and still mesh with the gears on the other side. Except for a leaky dam built up around one of the bearing boxes, all went well until the very end when we ran out of fuel on the torch keeping the babbitt hot. This happened just as we went to pour, and the top half of the bearing didn’t come out very well. We did that bearing over again and all was well.
The broken bevel gear had bearing surfaces on both its inner and outer races that were included in the crack. It was turned down and a sleeve was shrunk on to hold the gear together. It was then turned back to a size on both the inner and outer races to fit again. The remaining part of the crack was welded up and ground flush. To re-babbitt the cross shaft bearings we reassembled the differential and aligned its shaft much like we did the main shaft. Pouring the bearings went smoother this time but the reach into the bearing on the differential side of the engine was very awkward.
Being under the boiler on my knees, lifting a heavy pot of molten babbitt above the level of my shoulders and into a very tight spot just didn’t work. Again we lost the top of the bearing. The pot held just enough babbitt to fill the box, but I couldn’t empty the pot because the boiler got in the way! We later rigged some pipe and two funnels out the side of the gearing (this then had to be kept hot), and repoured the top half.
Speaking of keeping things hot, there is a lot of iron on a steam tractor, and everything around a bearing box has to be hot if the bearing is to come out right. During all the babbitt work we had five or six good, large torches heating the iron for better than an hour before doing the job, and you bet everything gets real hot!
And for the rest of the tractor ...
There is quite a bit more that goes into restoring something like this. One thing is a tremendous amount of cleaning, scraping and painting. For us, since we needed to keep the tractor mobile, whenever we had work around the rear wheels we would have to take them off and then put them back on when we were finished for the day.
We had to pattern and cast a part for the steam powered feed pump, and there are a few things we still want to do. I suppose that part will never end, but we will replumb the engine to make it more like the original, and we will need to make a new grate for the fire box. We haven’t yet decided if it should have a canopy. Not many of the small size tractors from Advance did.
The paint scheme was our “best guess.” There is little information on how a 1902 Advance steam tractor should look. After sending many letters and going through what old catalogs I could find (nothing from 1902), it was found that even in the same year some things could vary, so we did what seemed best. All I can say is we like it.
On March 21, 1992, we received our state certification on the boiler. It took a lot of work and research, but we have satisfied the inspectors and ourselves as well. My thanks go out to everyone I have talked to across the country! IMA