Thumb for a JD310SG TLB

rScotty · Jul 15, 2014

I want to put a thumb on my JD310SG with extendahoe. Before I go out to the dealer, can anyone give me some idea of what questions to ask and what kind of expense to expect? It already has remote outlets mounted on the BH; they are controlled by a foot pedal and probably work, but I've not yet used them.
thanks, rScotty

brain55 · Jul 15, 2014

I would give Amulet a call. I used one of their thumbs on a Cat 305 excavator. Their number is 1 800-526-8538 they were very helpful in helping me choose the right thumb.

Brian

Barnbuilder · Jul 19, 2014

You might try ShowtimeFabrication.com. I found them on Ebay and contacted them about building a thumb for my JCB 212. There stuff looks well made from the pictures. Someone else purchased one for his JCB and waiting to hear how he likes it.

Greg9504 · Jul 26, 2014

Hi rScotty,
I'm the person Barnbuilder is referring to. To answer your questions:

Hydraulics:
- You need to verify that your auxiliary hydraulics have bidirectional flow. In a lot of cases the aux hydraulics on the hoe are setup to only run one way, as the most used attachment (rock/concrete hammer) only require flow in one direction. So look where the hoses go. If one runs back directly to the tank, you have one way hydraulics. The valve used could still be two way, so then look at the valve and see if it has any plugged ports. Does the foot pedal rock back and forth so it seems like it would operate hydraulics both ways?
- Even if you only have one way hydraulics you can still make it work but you'll need to do a lot more on the hydraulic side.
- If you are not sure post pictures here of what you have.

Thumb:
- You need to decide if you want "weld on" or "pin on" style of thumb. Weld on are the most basic kind are usually generic. They are easy to install and do not interfere with bucket changes but do require welding to a large part of your stick. Pin on has the advantage that they attach to and rotate with the bucket. This gives you better range of clamping than weld on. Pin-on are usually more $$.
- Material - The thumb tines should be made out of abrasion resistant steel, AR400 or similar. And if possible the whole thumb. For your machine minimum 3/4" thick tines.
- All pins should be made from hardened alloy (4142 )as well.

Price:
Anywhere from about $1300 to $3400 plus the cost of wherever you need on the hydraulic side. Showtime Home was the cheapest that I found and what I ultimately went with. Other options are brandt.ca they make attachments specifically for JD machines only. So you know it will fit. I was quoted $2380 (Canadian, about $2000 US) for the series 50. As mentioned above Amulet. There are others too.

I made this video that goes over the install including the hydraulics for my JCB 212S:
http://youtu.be/cEjhr2V3GXA

Here is one I made picking up rocks:
http://youtu.be/pUYcdUwdKjU

Any questions just ask.
Greg.

rScotty · Aug 17, 2014

Greg, thanks for that very complete reply. That's just the kind of info I was needing to think about...but didn't even know where to start.

You say, "- You need to decide if you want "weld on" or "pin on" style of thumb. Weld on are the most basic kind & are usually generic. They are easy to install and do not interfere with bucket changes but do require welding to a large part of your stick. Pin on has the advantage that they attach to and rotate with the bucket. This gives you better range of clamping than weld on. Pin-on are usually more $$."

I'm thinking probably pin-on....The bucket is the size I like, and also I'm not sure about welding to the 310 with extend-boom....for that matter I'm not even sure about how a pin on fits on this type of bucket mount. Here are some pics; anyone have any comments?

The hydraulic foot pedal is an electric foot switch that is always sliding all over the cab floor. Originally for a tamper I think. So the switch itself is one way flow... but I haven't traced it back to the valve yet to see what's happening there. That's a good hint about looking at the valve itself. Thanks.

Whether I do it myself or take it to a shop I still want to get smarter about the different ways to do it. My wife has mentioned several times that it sure would be handy for rock work if the JD had a thumb like the Kubota does.... My preference for the install is towards a good independent shop - though I don't know of one around here. I'll mention that link you posted on the install video you did on yours. Nice work.
Thanks again,
rScotty

Greg9504 · Aug 17, 2014

Hi rScotty,

It looks like you have a quick coupler installed. You can ignore what I said about pin on thumbs interfering with bucket changes since you have the quick coupler. You would probably want to keep this as it makes bucket changes easier. Without a quick coupler the bucket and thumb would both pivot on the same pin (the one circled in blue in the attached photo), but with the coupler your bucket hangs off the coupler not on the dipper/stick. The thumb and the coupler would share the same pin (the one circled in blue). The only thing you need to make sure to do is tell whomever you buy the thumb from that you have a quick coupler installed. They will then make the thumb a bit longer to compensate for the coupler.

I've attached another photo that shows the pin on thumb mounted on my backhoe. As you can see the thumb and bucket both share the same pin, on yours the thumb and coupler would share the same pin. Oh and you still need to weld on the upper mount for the hydraulic cylinder to the stick of the backhoe. It's just that with a pin on thumb there is a lot less welding to the stick.