I need to fit a hydraulic thumb and have noticed that there are 2 ways of mounting it. Some have linkages the same as the bucket while others have the ram going directly onto the thumb. Question; which is best and why? Tones
A linked thumb or progressive thumb, will travel farther with the bucket and tuck away a little better than a non linked thumb/ cylinder mounted straight to it. From the ones I have operated I prefer the linked style.
The progressive link thumb will also contact the bucket in the same place regardless if bucket position at the expense of extra weight,bushings and install time. Also makes switching buckets a real bear
The two posters above already explained it but I'll add my $.02. If you are going to run a hyd. thumb and switch buckets often, plan on a quick hitch as well. A progressive link thumb and quick coupler adds a lot of weight to the end of the stick on a 321CLR. I've had both and I prefer the progressive link. Currently running a manual one (321DLR) and I'm happy with it, does what we need it to do.
The reason for asking is that I own a small landclearing operation so the excavator will be used for clearing trees. I have used mechanical grabs in the past and they are a PIA and time consuming to change over. I use a ripper to loosen the tree before pushing them over. My thoughts are that using a hyd thumb combined with the ripper I can clear and stack the trees all in one operation. At times the excavator will be working to absolute max and beyond. Can you put as much pressure against a progressive link thumb as against a non linked thumb?
Just my 2 bits we have a Deere 350D with CF linked thumb and bucket and operators love it and we also have a Deere 270d with a Tag bucket and a boom mount amulet thumb and the plate where the teeth shanks weld to has cracked and been replaced twice and has cracked again and the only thing we can figure out is because of the thumb so we are looking for new linked thumb but they want $10,000 at least!!
Check out ACS in Ohio. I bought a stick mount non-link for my 210 last spring cost $5100 delivered with five tines. What I liked about ACS was they send the thumb body and tines separate so you can build the thumb to fit your bucket perfectly. I can post some pics of my thumb tomorrow if anyone wants to see it. I did a little more than just weld each tine to the body. I cut a hole in each tine halfway between end of tine and thumb body and ran a length of 3½" diameter, ½" wall thickness pipe through all 5 tines plus a little more reinforcement in the body. My reason for the added steel is I run a coupler, and I wanted the tines to mesh with bucket teeth so they are a little longer than normal. I would have preferred a progressive link thumb as well but I also do a lot of ditch cleaning and I had to be able to drop thumb easily. I can remove or install the thumb by myself in about a half hour. If I remember correctly the progressive was only another $500. And that was for either a pin or stick mount.
Figured I'd show it off anyway.
The biggest difference I've run into is that the progressive link unit can move from tight to the stick to a straight line with the stick when extended all the way out. If you are running a short stick there isn't enough cylinder length to extend the thumb from all the way tucked in to out to a straight line with the stick. In this area we use a lot of tub grinders as in most places we can't burn anymore. The operators like to clear as much dirt out of the stumps before loading into the grinder so they usually work with the stick out just past vertical and the thumb and bucket working with the thumb extended almost all the way out. They shake as much dirt out as possible before grinding. Nice work on that thumb!
We've got a WBM hydraulic thumb on our 06 270 hitachi. There's times I do wish I had a progressive link thumb but I've always wondered if they would take the same abuse as one like ours will. They definatley look a little more complicated and possibly a little lighter made so I've haven't jumped on ship. Like I said though there are times where it would be nice to be able to grab something with the bucket curled out a little further.
I would never purchase a non-progressive thumb on anything bigger than a mini.