Project: Plywood Forklift Part 4

Some Assembly Included

We left this project partially assembled while we were figuring out casters and how to attach them to the structure.

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After learning more about wheels than we’ll ever need, we found some from the RWM Caster Company who we’d met at the Fastenal 2015 Expo earlier this year. We are looking for casters that work on concrete, corrosion resistant (our shop isn’t conditioned so humidity accelerates rust), handle heavy loads, and the plywood forklift has six legs. The plan is to load a bunk of 3/4” plywood and need to hold ~2520lbs (42 x 60lbs) or 420lbs per caster. To over-engineer and stay far away from any physical limits, we double to capacity needed to 850lbs per caster.

We chose the RWM Series 46. To make it easy to roll, we select a large diameter wheel, 6” tall x 2” wide, in urethane. The steel is galvanized and swivel caster is rated for 900lbs.

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Get on Your Feet

The next problem is mounting the casters to the legs. Using the top plate diagram provided by RWM, we designed some prototype feet in OSB.

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A quick test fit looks good.

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A Better Way - Testing Your Mettle

How can we mount the casters to the feet that will be strong enough? Is wood even strong enough? Luckily, we didn’t have to find out.

About this time we had sent our first project, a Proto-Form, to a fabricator who works with metal. When he visited the shop and we showed him what we were doing, he immediately had a much better solution. He’d built some workbenches for his shop and originally bolted casters on but they kept loosening up. He decided to weld them on. Except, our feet are currently looking like wood.

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We haven’t done very much metal work, only recently learning to remove a set of stairs welded to the dock with a angle grinder and not catching anything on fire. We are planning to build a handrail for the roof hatch so a tool for cutting metal would be a good addition to the shop. We’d like a cold saw but a bandsaw is more in our budget, especially one from Grizzly. The new foot design is using 2.5in steel tubing so the Grizzly G0622 - 4” x 6” Metal-Cutting Bandsaw will work fine.

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It takes about 10 minutes per cut to slice through the tubing. Working in metal is dirty, dangerous, expensive, and…SLOW too so not a great way to prototype.

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This is a test fit of the metal tubing in the early test section of the leg. Sometimes we get lucky. The tubing is a perfect fit.

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We don’t weld. We took a class and learned how it worked but didn’t pick it up. It would take years for us to learn what our fabricator does.

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Hold It Together

To finish up the assembly, we use Liquid Nails and sink 1-5/8” stainless deck screws to hold everything together.

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The casters slide into the leg.

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All six casters are installed and assembly is complete.

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We take the forklift out for a test drive. It rolls very easily and a side effect of six wheels, besides added stability, is that the turn radius drops to zero when you spin the forklift on its central axis. To operate, we roll the forklift out the door and turn it onto the dock next to the stack of plywood. We load ply onto the forklift a sheet at a time (for this test we did seven sheets ~400lbs). Then we turn it back through the dock door and into the shop area.

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What’s Next

A final issue we’re watching is that the floors of the factory are not level and even everywhere. The torsion box design will keep the material flat but we had the idea of adding some suspension to the legs so the casters remain in contact with the floor as we place the material in different spots. We’ll see if that is really needed.