Monday, June 30, 2008

Busy Weekend

Saturday and Saturday night we got less than 1/8" of rain, but it was wet and drizzly all day. While Matt and his friend Nate hauled in a couple hundred bales of last years hay (from a neighbor) and stacked them in the hayloft I worked mostly on building a new tongue for the Horse Mower. This time I took my time and used my head and my tools, we'll see how it works out.

The biggest problem with using a Horse Mower behind a tractor is the angle that the machine is working at. The end of the tongue is designed to be harnessed to a team, and that is a bit higher than the hitch of a tractor. I'm a lousy artist, but this is more or less what I'm talking about:

With the shaft as low as it is behind the tractor, it collects hay and jams the mechanism. I suspect it may put extra load on the tongue.

Every couple of years we break the tongue. The first year was because the tongue was rotten, I suppose it had been sitting out in the weather many years before we got it. After that it has been because we just use whatever chunk of wood I can get my hands on at the moment. Since the outside dimensions need to be pretty close to 4x4 (not 3 1/2 x 3 1/2) I can't just run up to the lumber yard and buy a piece of wood. And I believe the originals would have been made from Oak or Ash. Gee, I wonder what a nice chunk of wood like that would cost nowadays?

This time I bought 3 2x6x97 pieces of lumber. I got fairly good quality fir, no large knots and pretty straight.I decided to try to fix the angle problem at the same time I made this tongue if I could figure a way around it.

I laid a large piece of OSB across two sawhorses. Since the current tongue was cracked, not totally broken, I propped the tongue up on a jackstand so that the angles looked like what I thought they should look like, then measured from the ground to the top of the tongue. I also took measurements from the ground to the tractor hitch as well. Then, I drew the tongue on the sheet of OSB and also marked where the tractor hitch is located, as well as getting measurements for the holes that needed to be drilled.

While getting measurements I realized that the far back end of the tongue could only be 3 inches high, since a strut passed under the tongue. With the cutter bar down there was lots of room, but with the cutter bar up I only had 3 inches of clearance. This provided my first opportunity to adjust the angle. Here is what we've always done in the past to allow clearance:

This time, I went at the relief from a totally different direction:

Now, with the angled part up in the mower, the front end of the tongue is lower, raising the front of the mower just a bit.

I was planning on gluing the three 2x6's together side by side, hoping for some additional strength. But then I realized that every time the mower tongue has broken, it has done so at the back end of the tongue, under the mower. It would appear to me that most of the strain must be at that point, so what would happen if I moved the weakest part of the tongue to somewhere else? The worst part of making a new tongue is boring all the 1/2 holes for the bolts (and getting them in the correct locations), how can I change that?

How about if the tongue is made into two parts, a strong back end and a weaker front end? And, if I made some more angle change with that weaker front end? And make the front end really simple, so that when it does break it is easy to replace? Here's what I did:

I cut the 2x6 that I was working on at 48", and took another piece of 2x6 and duplicated the first. I then took my third piece and instead of cutting it off square at 48" like the first two I marked the angle that I still needed to get the tongue at the tractor's hitch height:

I drilled the holes in each individual 2x6 separately on my little bench drill press. A problem in the past has been getting the holes square, by using the drill press I solved that problem.

I lined up the three pieces and glued them together, also used a few carriage bolts to pull them together as well as a handful of deck screws. I let the glue set overnight.

Sunday I took another piece of 2x6x48 and left the ends square (for now)

(angles rather exaggerated).

I then realized (Oops! missed that measurement the first time) that 5 1/2 inches is rather far apart for the hitch, 3 inches would work much better. So, let's gain a little more here while we are at it:

Here is a photo of the finished product:

Matt and his friend Nate took it out for a short test run:

Later, Matt and I took it out and finished the field that we had started the other day. The mower ran the best that is has, the mechanism didn't get plugged up, and the cutter bar adjuster worked the way we expected for the first time. I may have gotten the front of the mower a little too high, not sure, but it does work great this way.

Matt did mention that it is very weird seeing the tongue flex. That short section of 2x6 flexes a LOT as you are mowing. I'm not sure how long it will hold up to the flexing. In any case, it is relatively trivial to replace the front part. It's not glued in, just 2 bolts and some deck screws holding it on.

A picture of the rose bush this morning.

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