Thanks Jeff, I was only thinking of using the plumbing going up the boom its maybe 1/2 or 3/4 not sure. I was thinking looping the Hammer circuit to its self and disconnect the switch. I didn't even think to use the hammer hydraulic supply to a new valve. I'm wondering if that would be cheaper than the diverter valve I bought to use the extra dig circuit as you suggested. The valve was 1k not counting lines and hoses.
Gday Steve,
I played with these a fair bit back when I was doing my apprenticeship, few years ago now but. We used to do a lot of mods on the 3CXs tilt hitches, extra circuits, grabs etc. We did do a thumb, from memory we went the way jeff suggested and bolted a 6 port diverter to the top of the dipper and used the e-dig circuit. Only thing with doing this is to double check that circuit has adjustable circuits reliefs, you'll need to set the piston side relief at a lower setting to prevent damaging the thumb cylinder when your're crowding the bucket. You'll also need to fit the e-dig lock pin each time you plan on using the thumb to prevent it creeping or accidentally moving.
The other option is ctop and use the hammer supply but ctop can be a bit jerky as it's on off unless you spend big and go for a proportional setup. Make sure you fit reliefs as well, the hammer circuit won't protect the cylinder from damage by the bucket as mentioned above
I can't really see any dramas with using the hoses as you suggest, does your machine have powered sideshift? Not sure what model you have (gear or piston pump) but the valving underneath is pretty self explanatory, especially if it's gear pump. Cap it off, pull out the hammer switch and then supply your oil to the hammer hoses. Either by another slice in you control valve (exxy) or putting a 6 port diverter under the back of the machine and diverting one of the other rear end functions eg. powered sideshift. I did once get a bit sneaky and used one of the loader valve spools to supply a grab. Ctop with shuttle valves to work the pilot circuit and a 6 port diverter to divert from the loader lift spool (that was an expensive one though)
A 6 port diverter on the e-dig circuit mounted on the top of the dipper would be by far the cheapest option though