A while back, the topic of using baltic birch ply for templates and jigs came up. Well, here is one small application for baltic birch templates. I am cloning the Henry TS-1000 loader for a 1959 Allis Chalmers D-17 tractor. This is one massive loader and can lift as much as 3500 pounds to 9 feet. Unfortunately, its also a long term project.
I found a manual for the TS-1000 loader on ebay and this is the starting point. The problem is that the tractor is nothing but curves under its belly and this makes fitting struture very difficult. The TS-1000 loader is also an industrial loader meaning that it has backhoe ears and no three point swing arm ears. So I will need to change that aspect of the design.
So I re-engineered the back support backet based on the orig. Henry photos and now I need to fit the two support uprights. Big problem! First of all, the bracket has to slide under the differential as close as possible but not so close as to prevent changing the oil back there. I also need to add some base support structure to hold the upright structure for the top link. Second, the axle tubes are tapered and are not a perfect circular cross section. This is esp. true around the cord line where the fender ears are located.
So I had to do some trial and error. I cut some circular cutouts into some baltic birch and cleaned them up on the kindt collins spindle sander. Then I located these and checked the fit. Then back to the sander. Then back to the tractor to test the fit. In doing this, I found out that I am not dealing with a perfect circle here! I started out by taking a girth measurement and calculating the diameter from the circumference of a circle. I then dropped the drill press to 460 RPM and setup a trepanning head to cut the intial circular cutout in baltic birch. The first photo shows the result of this fitting process. The two top items are the ones that actually fit. The bottom one is one that was to small.
I then transfered these contours to actual size upright blanks made from baltic birch. Again, back to the bandsaw and the spindle sander to fine tune these shapes. They are identical to the ones intially hand fit. Its nice to have these shapes now as now I know what fits and what does not fit.
The second photo shows an intial fit. The cross member is a 60 pound section of 4x6x1/2 inch steel angle. It is now vital to fit the vertical dimension of the inner upright. The two inner uprights determine how much space there will be between the tractor belly and the angle bracket. Once this dimension is set, then the outer two uprights need to be fit as well. This fitting process is needed to compensate for the tapers involved. Notice that the arcs are different and so are the locations of these items relative to each other. The outer upright sits higher than the inner upright.
The third photo shows the two templates relative to one another.
All this trial and error fitting must first be done with painstaking woodwork in the construction of these templates. The first template was a bust because I did not compensate for some geometry issues with the inner arc. Fitting a template out of baltic birch is easy and quick compared to working 1/2 in steel plate. Once the project is done, I will be able to clone as many of these loaders as needed. The templates are varnished and put away in storage. All the fine tuning and fitting work remains with the templates. Also bear in mind that this type of woodworking allows you to work around the various issues that the tractor has. This is not very possible with modern CAD methods in this application, thus making the woodworking aspect of this project not only reasonable but pragmatic as well.
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