running gear/deck attachment

[jimg]

Got my running gear this w/e, put it together and have a question about adding a flat deck. From the first 3 pics you can see the front axle is fixed and the rear articulates. In fact the range of movement is pretty wide. I was thinking that both front and rear would be fixed but clearly thats not the case here. It seems that some Cory gear I looked at recently wasnt set up like this but I also didnt look that closely. Is it common for one of the axles to articulate?

About the deck...it sure would be great if I could accommodate at least some of the rear axle movement instead of letting the deck twist or having wheels come off the ground. I thought about it for some time but really couldnt come up w/ a simple way of causing the deck to 'float' w/ the rear axle. Im sure though it has to be simple and Im just missing it. My feeling is that most decks are just built to twist. Eventually I think itll wind up pulling itself apart. So, if I can easily avoid that maintenance by building technique that would be better. The last picture shows the std attachment points where the back would be attached at each axle.

ETA: My plan for the deck construction was to run 2 4x8s the length of the gear and then either add 4x4s 2'OC across those and then a 2x deck on that or stick frame a wall sheathed w/ plywood layed flat on the 4x8s. The deck is planned to be 8'x20'. Ill eventually band it w/ heavy angle w/ stake pockets unless I can find a used rack.

 

[jimg]

I suppose some sort of scissor type affair that connects gear to deck would work. Not sure what thats called though.

 

[RobS]

What if you leave the rear supports un-bolted? Gravity will hold it down. On the other hand, that same gravity is going to make it twist with the axle articulation. It would have to be a pretty beefy structure to NOT twist. OK, scratch my original thought and just let it twist.

 

[zzvyb6]

You would need to add a center pivot to the deck front (meaning a beam with a center hinge) to make it completely free. Why not consider using 4 motor mounts at each corner? This gives you some extension and compression flexibility yet still anchors the deck laterally and fore/aft to the support beams.

 

[CATMAN]

I can tell you how older farm wagons/ gravity boxes/ hay racks are attached that I have been around. On the rear bolster(metal upright), you only attach one side with a bolt using a self-locking nut and big flat washers. You leave that nut/bolt assembly loose and the hole in the wood is oversized a little. Say 1/2" bolt in a 3/4" hole in the wood. On the other rear bolster/axle area, you add a chain around your 4x8" wood beam down around the axle with about 2-3" of slack in the chain.(This allows flex for gopher holes, but still keeps the 4x8" beam within the bolster height)

Don't worry about the tires/wheels coming off the ground, this happens all the time in the field with farm wagons even with 25,000 lbs of corn in a gravity box.​

On the front axle, you attach your bolt/washer/locknut assembly catty-corner form the rear bolt/washer/locknut assembly, then add a chain to the other side. I know the chain deal doesn't look too good, but many a farm wagons/ gravity boxes use this system. Another thought, maybe you could use 4 oversized(extra tall) U-bolts at each corner(over the beam), that would allow 3" of flex at each corner, but still keep the 4x8" beam below the top of the bolster. Hope this helps a little.

 

[jimg]

Thanx very much for the help!

I really like the chain idea -- simple, quick, effective and cheap. One question about that though...why use any bolts at all, just chain all 4 corners. The only down side I can think of right off is that the deck will move front to back by 2-3"....which doesnt seem to really be a problem.

Its interesting about bolting only one side b/c the Cory gear I mentioned in my post had one front bolster drilled and the other not. The undrilled side was free to move up/down as it wanted. My gear has all 4 bolsters drilled.

When I think of tires coming off the ground I also think of loads begin put on other components that eventually tears them apart which means time spent fixing them.

 

[Lazy J]

We attach the sills to both stakes on the rear bolster with 3/4" bolts and let the front float by using a chain to keep it from tipping.

Jim

 

[slowzuki]

I'll pass on how its done here, all gears float or you would break the centre tube.

The racks generally are bolted at the rear and a loop of chain holds the front.

I built one with the front and rear bolted and it works fine too.

You can get an amazing amount of flex out of the unbolted ones before they lift. Normally they only hit the chain if you unload one side and take them on a steep side hill.

 

[jimg]

Would the center pole break or just twist/wallow out the bolt holes? Guess that would depend on load and amt it was required to move.

Suppose thats what Ill wind up doing then...bolt 2/chain 2 although it *seems* better to chain 4. Then again that might be one of those learning lessons which only becomes obvious (why not to do it) once you give it a go. Although those times might be the ones I learn the most from.

Another quick question. On the used Cory gear I mentioned above it appears the X pieces were tied to the backs by way of a small piece of angle lagged or thru bolted to the back & X piece. Hows yours done? I was debating on that or running a hole right thru the X piece into the back and lagging.

I think its pretty interesting the chain idea is so widely practiced. Here I dont think its done at all or much. I believe one or perhaps 2 corners are let to float and the remainder is fixed. Ive got to start looking underneath wagons to see how theyre made.

 

[slowzuki]

There are older racks here that simply have 2x4 pieces scabbed onto the main beams on either side of each beam bracket on the rack. This way the rack just sits on there by gravity. Great for swapping racks with boxes etc. Rarely lose the whole rack.

I'm not sure what you're talking about in the above post. I've noticed in some areas of the US, racks use main beams, then stringers then a deck running fore aft.

Locally they are all main beams then deck running east - west nailed into the beams. The best lasting ones have self sealing roof membrane drapped over the beams before nailing the deck on. Slows the rot in the beams from the chaff between the deck boards.