Stone Clamp

Some details of the stone clamp I built, which I freely admit is a copy of the Probst boulder clamp (http://www.probst-handling.co.uk ) . I've used the clamp to build a retaining wall (see it here) and plan to use it to gather stone for other projects.

Here is the materials list to build it.

9' 3"x2"x0.25" tube

9' 1/2"x3" flat bar

1' 1/4"x2-1/2" flat bar

13'-6" 3/8"x2-1/2" flat bar

6' 5/8 round bar

6" 1.25" X 0.250" DOM tube, with 0.75" inner diameter

1 -- 3/4" grade 8 6" bolt, 4 flat washers, 1 lock washer, one nut

2 -- 18" sections of grade 70 chain

2 -- 3/8" slip hooks grade 70

2 -- 3/8" chain connectors grade 70

1 -- 3/4" shackle

Drill a 1-1/4" hole at the pivot point of the 3"x2" tube, weld in 1-1/4" DOM tube to support 3/4" bolt. Weld 3/8" flat bar to 1/2" 'claws' to provide lateral support. Use 5/8" round bar to form pickup points. Download the boulder clamp manual from the Probst web site, it contains good drawings to get an idea of how to assemble it.

Don't use grade 30 hardware.

Use at your own risk.

See other projects here

Overall assembly diagram. If the image does not display properly, click it to view full size.

If the image does not display properly, click it to view full size.

Testing the clamp, at this point I still need to welding on the 3/8" flat stock to the "claws".

Another test, this stone is in the 900-1200 lb range (36"x28"x13" ~ 7.5 cu ft).

The finished clamp used to build the retaining wall.

...develop, race, win!