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Thread: OT: Standard forklift dimensions
11-27-2009, 10:50 AM #1
OT: Need help - Standard forklift dimensions
I am building a little pallet to put my 253lb Advance Products Rotary Slide Table on. I'd like to make the thing wide enough for a standard forklift to get under. I'm thinking the little hand-truck type forklifts (pallet jack). Don't currently have one. I see that many are offered in 21 or 27 inch widths. Will the pallet be usable in most shop environments, and possibly in shipping, if I use a 21" spacing?
My design is (roughly) to use 4"x4" material, (about 2 feet long), and use carriage bolts to connect two 2x6" pieces of wood, about 30 inches long, on top of the 4x4s. How much space should I leave between the 4x4s?
Thanks in advance.
11-27-2009, 12:43 PM #2
11-27-2009, 01:45 PM #3
Your sizes are about right for standard size pallet trucks.
Note that actual forklifts generally have adjustable spread for their forks, and so can get under and into slots that pallet jacks cannot.
These folks make a variety of special sizes, a couple of which I've found very handy:
These folks make standard size stuff:
And these folks sell pre made pallets:
11-27-2009, 02:52 PM #4
I'd leave 28" between the 4X4s. My 2 pallet jacks are 27" outside 13" inside, and 95% of the pallet jacks I encounter and all the ones I see in freight trucks are the same. About half the pallets I get are smaller and don't fit my pallet jacks, which forces me to try to balance it on one fork as best I can. If you leave it open between the 4X4s either type pallet jack will work under it.
11-27-2009, 03:17 PM #5
The vast majority of pallet jacks are 27" wide. 28" will give plenty of clearance.
Also, for a 263 lb load, 3" gold deck screws are more than adequate to hold everything together.
Glacern Machine Tools
11-27-2009, 09:08 PM #6
I've made a number of pallets from 4x4s with 2x6 tops for machine tools. It is quicker and cheaper than welding up a cradle with casters.
I make most of them 35" wide, which works well for the 27" wide pallets. I usually put a 3rd 4x4 down the middle.
I drill all of the deck boards and I made a simple drill template for the hole patterns:
I use 3" #6 square head drive deck screws and drill the deck boards 1/8" or 9/64" to make it easy to drive the deck screws.
I space the 2x6 top boards 1/4" apart.
I also bought a pair of Jet pallet jacks that are 20"-21" wide. I've made narrower pallets (~29") for them.
Either size works fine with a forklift since the forks or tines on them are normally adjustable.
11-28-2009, 08:59 AM #7
Peter Miles, nice looking cradle there, although I must say it looks like those welded-on angle sections that the casters mount to are showing a lot of flex under the load of that piddling little c-clamp. I don't think I would ever put a body part under the edge of that load...
11-28-2009, 11:58 AM #8
Thanks, all. The bolt holes on the hold-down flanges are on 19" centers, so leaving 21" would allow access to tie-down bolts, and would be one option. The 28" would take up more space, but would be more flexible in transport. If I use the 28" spacing, I'd have space to put handles on the top of the pallet on either side of the unit, and this would make it easier to move.
Man, Peter, if you put that level of quality into a pallet, I want to see your machine work!
My final plan will have two 4x4s (seen in the pic), plus three cross-members. The middle cross-member will not be permanently fixed in place. This will allow access under the center of the unit, to allow me to reinstall the main taper bearing with proper preload. Once everything is buttoned up and reinstalled, I can lift the unit up, put the center member in, and fasten all down.
This unit is really incredible. Massive castings and bosses, tapered roller bearings on the manual hand-cranks for the XY table, anti-friction inserts under the table. Wow.
The only problem is a little backlash in the worm gear, possibly in the bearings for the worm, too. I plan to remove the eccentric assembly and clean all the bearings, then reinstall everything with proper bearing preload.
BTW, how does one set the pre-load for Timken bearings in this service? A friend was telling me that a precision (e.g. near-micron-level) mill spindle bearing is set by spinning the cone and letting inertia set the preload. Not needed here, but I‘d like to set this thing to last another fifty years. Advice?