In the near future I'll be needing cribbing to replace rails on my Cat 941B loader (~12 tons) so was wondering the best method for making my own cribbing. Was thinking of cutting up 2x6's into 18" or 24" long pieces and stacking them jenga style. I figured the 2x6's would be more stable and somewhat cheaper than using 6x6's but looking for input from the experts.
I used tree trunks upright when I did my hoe. A couple of 12" logs 18" long worked well.
I'd recommend no less than 4x4s. The more smaller pieces you put together the more compression affects each piece. You can try that out by jacking up something heavy like a truck axle with a 2X6 on the jack face and see how much damage happens to it.
I don't like 2x6 pine because it can so easily split under weight. I prefer oak in 4x6- it tends to sit flatter than a 4x4, but 4x4 or 3x6 all are okay. Bigger timbers is fine, but in oak it gets too heavy to move around. My bigger cribbing is 6 or 8"x12" and I prefer fir for that. Its light enough to move around, but doesn't splinter up very quick. If you need a source of oak for cribbing, find someone by you that gets in crated materials and gets rid of the crates. A lot of those have rough cut oak under them, and you can disassemble the crates to get the wood. Even the bigger crossboard/ uprights from pallets in 2x6 oak, would be better than pine 2".
You'll be fine if you mean solid, like 4 2x6's wide so 22" with no gaps, but that makes a ton of wood. You'd want to use a hardwood 4x6 at least for the top where it bears against the steel. Unless the steel you're supporting is relatively flat? Round trunks on end is somewhat risky as the steel could push into the end and cause splitting. Use Elm to avoid that. Don't put the whole thing up that way, one side at a time with the other track on the ground would remain stable. Do you have any sawmills locally? they cut tons of boxed hearts into 4x4 blocks they'd probably rent you for a case of beer. Railroad ties cut up make decent blocks too, use a circular saw to cut four sides, then a sawzall to cut the center, a chainsaw will be dull and not cut in no time.
x2 on the 4x4's. The best are the oak rough sawn 4x4's used as dunnage on pipe deliveries. If you have a commercial pipe yard near you might stop in and see if they have any extras laying around. The dry oak is very hard compared to pine and once they get doused in hydraulic and motor oil a few times weather pretty well too.
Actually, I used walnut.
Some years ago I needed some wood, I lived at a place that had some nice fir trees, just cut one down and used a chainsaw to make huge blocks bigger than rail road ties. And not too many years now I just bought some I think 4x6 (didn't measure them before writing this) boards and cut them about 2 feet or so. And one place you can get some good size wood is to talk to the folks building new houses in your area, ask if you can have the scrap. In the day when using any kind of wood to support a very heavy machine I always padded it with a large plate of steel to distribute the load as to not concentrate in a small area and split or crush the wood.
HeavyEquipmentForums This thread had some good words on the subject. I use 4x6 pine with some 4x5 oak to top off. 18" long. Sometimes too short, but better than the crap mix I was using before.
Company I worked for used railroad ties.. cut to length w a chainsaw..
I am pretty fortunate and have a saw mill that makes crane mats near me. I go down and get a truck load of their "trimmings" from time to time. 12"x12" oak blocks that are 2' long work great for cribbing and if you are half decent with a chainsaw can trim them down to any size you need. I know there aren't many saw mills near you but I know there are several crane companies that may have some old mats you could cut up.
I've got a stack of old utility poles that I custom cut to length when needed. All of these run 12" diameter and larger as they were transmission poles. They are creosoted so they are very heavy and cumbersome to move about. They work well and rarely split. Final height adjustments are made with oak boards stacked above the pole sections. Oak boards are a must have. The lightest, easiest crib pieces that I have are from a customer's cabin kit. He had a bunch of cut off ends that are roughly 12"x 8" x various lengths. Easy to move about but the sides have to be trimmed of the tongue and grooves.
I don't like to top the cribbing with steed, as steel on steel is quite slick. A rough cut piece of oak will resist crushing without the sliding risk of steel.
I use 4x6 and 6x6 pressure treated, cut offs from fence posts. I could never justify spending money on wood for cribbing, there is so many free options. If you have big enough tree trunk i'd be fine with that but have something on top to prevent the metal from possibly digging into and splitting it. There is sometimes 12x12 4' lengths at auction here that goes for virtually nothing. Heavy to move but they would work great.
I saw mention of pine. I think that is a pretty soft wood, not a good idea to use a soft wood. Fir, Hemlock, Maple, Oak, Walnut etc. are okay. About steel plate being slick, true it can be, but with 20 tons of force on a nice 1 foot by 1 foot 1 inch steel plate sitting on flat and level wood cribbing, you have zero to worry about it slipping if all is done correctly. In this area no one can find or afford large pieces of Oak, or Walnut to use as a cribbing block. IMOP Iron wood would be the best, I can imagine what that costs. I have used Oak for padding for lifting cars on pinch welds, by slotting the piece, yeah good strong wood.
Use a piece of 3/8" plate. The weight setting on it will deform it some making a dent through an onto the wood. It won't slip. Lots of rust helps also.