As mentioned in my introductory post, I've got a late model Speedex 1631 without a mower deck. I finally got some time to work on making a mount for a 48" Deere deck.
The rear attachment points of the Deere deck are considerably higher than the Speedex deck. This means the lifting arms need to be much shorter. Also the deck is longer front to rear than the Speedex deck so the front links need to mount farther forward on the tractor than the Speedex links. Finally, to have the front links the same length as the lifting arms (so the nose of the deck raises/lowers at the same rate as the rear) the mount for the links needs to be lower on the tractor than the lift arms.
Dropping the front mounts down will also leave me plenty of room to route the drive belt around the frame and to the mower deck without getting into the linkages.
I started by making a subframe similar to what Speedex used except longer to work with the shortened lifting arms and forward mount of the links.
The lifting arms are attached to the subframe with pins. The arms are welded to an angle iron cross piece at the mower end. There is a center hole on the cross piece with a section of chain that goes up to the lifting arm on the tractor. There are two mounting tabs for the deck hung from the cross piece by bolts.
I did some measurements and finger/toe math to figure out how far forward and how far down the front mounts needed to be. Then I came down another 1/2 inch so the front of the deck will run a bit lower than the rear. I built a structure to carry the mounts and attached to the subframe.
I had hopped to use turnbuckles for the front links. Unfortunately their working length needs to be 7 1/4" and the folks at the supply house tell me that to get a turnbuckle that short I'll be into screen door hardware - too light for the job. The guy pointed out that it's not something I'll need to adjust often so I went with some threaded rod and clevises.
Now my deck would raise and lower with the tractor hydraulics.
My geometry worked out pretty well, the nose of the deck seems to be 1/2" below the rear throughout its range of travel.
Two issues remained. The deck didn't hang quite level and adjusting the bolts on the mounting tabs just rocked the lift arms rather than leveling the deck. Also, with the hydraulics lowered the deck was going to mow closer than I like. I solved both problems by attaching pieces of chain near the ends of the lift arm cross pieces and a pair of hooks on the tractor. Now the deck will only lower as far as the chains let it. Since the cross piece is now hanging from both ends instead of the middle the adjusters on the mount tabs work. Each link I take in or let out on the chains changes the deck height about 3/4" and I can fine tune with the nuts on the mounting tabs.
Next step is to get power to the mower. I just ordered an SS/16 mule drive (thanks @TAHOE) to guide the belt around. Thanks @jabelman for the offer of your spare, but I found one for less than pulleys to put on yours.
The pictures were taken before the limiting chains were added to the lift arms. Please do not look too closely at my welds.
