Type of Wood for Bottle Jacks?

Proper shop practice is hardwood blocks that are free of cracks. I have used softwood blocks when it comes to big stuff (like 24"×24") just due to weight. One of those 3 feet long is heavy enough in softwood. You'd need a forklift to move a hardwood block that size lol.

 

Flatbed typically uses hardwood 4x4s for real heavy stuff, but it's unweildy and sometimes pine works just as well. Not quite what you'd want I imagine.

 

What are you putting the wood on. How high is the wood going to be.

I've used hardwood and softwood as a base. Also used steel and aluminum.

Important is make jack plumb and level.

 

Don't bother with a 4x4, if that jack has a 4inch sq base you need something bigger, I would think that a 10x10x8 oak timber would be your best bet. It isn't as heavy as it sounds and seems to hold up the best. I have a few from the 1930's that I still use to lift cars off the ground to save the tires. By the way, you can find them all over the place, any large city will have a place and it should be about $30.

 

Ditto on the Oak or hardwood.

6x4 or 8x4 are good manageable sizes. Plus you can angle cut and use them as small ramps. Jack up and place under tires and drive off when completed.

 

Oak. What are you lifting with the bottle jack and what kind of ground are you lifting it from? dirt, sand, gravel?

I would use at least a pair of 2x4 oak directly under the jack and then fir or maybe pine under that to spread out the weight. Only hardwood directly under the jack as it will cut through softwood too easy.