There's nothing like a full scale mockup of a project that you want to make. That's the approach I took to make this magnetic bucket broom for my small Kubota BX tractor. The basic idea was to have a tractor broom that could be attached and removed from the tractor bucket without getting off the tractor seat. First I installed a number of rare earth magnets to check the idea out. I started with four old brooms that I borrowed from an earlier broom project. I gave the prototype a real test sweeping heavy gravel on my asphalt driveway and it worked just great. That gave me the necessary incentive to go ahead with a finished unit.
I switched from the rare earth magnets to tool holding magnetic bars. Rare earth magnets are fragile, and, more importantly, they rust quickly. The tool holding magnet bars use ceramic magnets. Ceramic magnets are very slow to rust and the sturdy steel channel that holds the magnets is well suited to the kind of heavy use they will get in this project.
The opening video shows the broom in operation and the steps I took to get to the final unit. The still photos indicate the sequence of approaching and attaching the broom to the tractor bucket.
Step 1: Cardboard Mockup and Rough Prototype
As I mentioned the full size cardboard mockup is well worth the effort in a project like this. As shown in the video I even had the bucket pivot on a screw to help me get a good idea of what sizes and angles were needed during the catch, sweeping and release operations.
After I tested the rough prototype (with old brooms and the rear earth magnetics) I got to work to permanently and securely install new brooms and hardware parts.
(I was lucky to find the tool holding magnet bars on special. I paid just $10 for a set of three.)
Step 2: Installing Broom Release Arms, Magnets, New Brooms, Casters, and the Guide Brackets
I used stainless steel wood screws to attach the tool holding magnets to the 2x12x49-1/2 inches pressure treated main board. Stainless steel is non-magnetic and won't rust. Dealing with loose regular steel screws around powerful magnets is a bit hectic so no need for that in this application.
The old brooms were in bad shape but they served the purpose to check out the feasibility of the magnetic broom idea.
Installing the broom release arms with ground contact blocks
The two broom release arms consist of lengths of 1/8 x 1-1/2 x 1-1/2 x 20 inch angle iron. I cut the related plastic blocks from a length of UHMW plastic that I had on hand. I decided on 2 pieces for each block and the blocks end up measuring about 4-3/4 x 3 inches with a finished thickness of about 5/8 inch. The blocks secured with 1/4 inch hex screws and locking nuts.
Installing the tool holding magnetic bars
Two #10 x 1-1/2 inch SS wood screws are required for each bar.
There is no particular arrangement in the layout of the magnets. But the magnets should be placed well clear of the side angle iron (broom release arms) otherwise there could be a clearance problem with the bucket sides and the magnets during and after the broom "catch" action.
The most important thing here is to leave between 1/16 and 1/8 of inch space between the bar and the wood. This allows for some wiggle room to let the magnets conform and securely attach to the tractor bucket even when the bucket bottom is not perfectly flat.
Installing the new brooms
Four regular 24 inch push brooms
Three 1/4 x 2 inch galvanized lag screws per broom.
I drilled a 1/4 inch hole through the broom wood before securing the brooms in place. It helps to clamp the broom down while installing.
Installing the swivel casters and guide brackets
Because the casters can take a fairly high load from the bucket it's best to find heavy duty casters. The main size requirement is that the caster wheel is abut 1 inch above the ground when the broom bristles ends are touching the ground. Install them with 1-1/2 inch galvanized lag screws.
The two front guide brackets are heavy duty galvanized units measuring 8 x 1-1/4 inches. The steel is about 3/16 inch thick. Install them with 1-1/2 inch galvanized screws. These brackets overhang the wood edge about 3-1/4 inches.
The two side guide brackets are heavy duty galvanized units measuring 6 x 1-1/8 inches and are about 3/16 inch thick. Install with 1-1/2 inch galvanized lag screws.
At one point I laid a sheet of construction plastic over the magnets to see what affect it might have on the attraction between the magnets and the bucket. There was no apparent change in the connection so I filed the idea away as a possible weather protection means when I park the broom outside.
Step 3: Broom and Bucket Centering Brackets
There's no real need to have the bucket and broom perfectly centered when they are magnetically locked together. But I experimented with temporarily installing a dock hook bracket on each side of the broom. That worked fine in guiding the bucket and broom in place; so I installed the brackets by hammering them between the side guide brackets and the broom release arms. I might do a more permanent attachment later.
Step 4: Final Notes
The magnetic bucket broom has worked out well. It is surprisingly easy to make and I look forward to putting my broom back to work next spring.
I don't see any reason why the same design would not work on other tractor brands. The main requirement is to have a flat surface at the bottom of the bucket.