I just bought a pc-50uu2 that came with a manual thumb(it can be swung out and pinned in place with a piece of 2x2 tubing so it can be leveraged against with the bucket) I would like to make it a hydraulic thumb by adding a cylinder in place of this metal stationary piece. I am working out the hydraulic plumbing for accessories (see my other post). What hydraulic cylinder should I use for this? I have heard you dont want to over power the bucket or get over powered by the bucket? Anything else I should know about this job? Thanks very much
I used a Bobcat boom swing cylinder for mine. It is overkill but I have two adjustable relieve valves installed in the valve body. I have mine adjusted pretty tight so you don't drop what you picked up once it is in the air with more pressure on the thumb. I can crush concrete with mine so I have to be careful, but it doesn't appear to be doing any damage to the components.
If you could post a picture or two of the current set up, along with some measurements we may be able to help a bit better. However you probably want a cylinder the same diameter as the bucket tilt cylinder, if you cheap out and get a smaller diameter cylinder you may bend the cylinder piston ram. I did this once with a tractor mounted front end loader, guess that tree I was picking up was just a bit too big. However I dropped the tree before the ram snapped and it was an easy fix in a big press. The length depends on how far you want the thumb to travel. Measure from the fully stowed/retracted position to where you want the fully extended thumb to be. Just remember the longer the cylinder piston ram is the more likely it is to bend, so if you want to go long you may have to go for a bigger diameter.