Thumb questions ?

thebig450es · Oct 12, 2009

Who makes a good quality thumb? How do you measure proper size? Any ideas on how i can connect it into my hydraulic system since my PC50uu-1 has no aux hydraulic connection? Thanks

coopers · Oct 13, 2009

http://www.cwsindustries.com/
http://www.psmcorp.com/
http://www.hpf.com/home.asp

I don't like HPF's thumbs for 120 plus size excavators but they make decent thumbs for minis. PSM and CWS are my favorites.

thebig450es · Oct 13, 2009

Im starting to think a manual thumb may just work.

Hendrik · Oct 13, 2009

It is unusual for a 5 tonne machine not to have aux hydraulics but I guess the aux hydraulic circuit may be used for the knuckle boom?
Apart from a mechanical thumb the only other option is to add another hydraulic circuit.
If you are going to be only using the thumb occasionally then a mechanical one will do.
From memory USA attachments are good value for money.

nobull1 · Oct 13, 2009

I cannot give you any specifics on how to hook into another hydraulic circuit to power the thumb, but it should be something you can do. The biggest problem is how to activate the thumb. If there is not a switch/foot pedal it could get expensive. Are you sure there is not a switch or pedal that is not being used? Personally I had a manual thumb on my last two machines for a total of about 7 years. It works fine, but was a pain to go out and put the bar on and then have to take it off. I found most of the time I just wouldn't bother and just use the bucket. Just last month I installed hydraulics on mine and now use it all the time, because of convenience.

thebig450es · Oct 13, 2009

i can just use the off set boom hydraulics, i cant see a reason it won't work. just put a valve to lock the off set boom cylinder and divert the fluid to the thumb.

nobull1 · Oct 13, 2009

thebig450es said:
i can just use the off set boom hydraulics, i cant see a reason it won't work. just put a valve to lock the off set boom cylinder and divert the fluid to the thumb.

Makes sense to me. My "guess" is you would need a T in both lines with a divertor in each line to switch between boom and thumb. The easiest way would be to do it between the hoses and control valve IMO. I am sure your local hydraulic shop could tell and supply you with the required parts

kthompson · Oct 15, 2009

For tractors they make an electric control solenoid you can use one hyd circuit to operate two switching between them. You should be able to install such. I know Agri Supply did have these units but you may find at local tractor dealership also.

I have a 5 ton machine and the Aux on it only is one direction. I use a mechanical thumb and for my use it works fine. No doubt if hyd it would have advantage but at same time it would weigh more and when just digging be harder to remove and reduce the amount of weight capacity for dirt.

thebig450es · Oct 15, 2009

Do you have any links on the electric control soleniod? Thats what i wanted to do but couldn't find one yet. Thanks

nedly05 · Oct 16, 2009

www.northsaw.com you wont be dissapointed!

thebig450es · Oct 16, 2009

Well i found the thumb i like, im just in the process of figuring out how to plumb the hydraulics.

kthompson · Oct 19, 2009

thebig450es said:
Do you have any links on the electric control solenoid? Thats what i wanted to do but couldn't find one yet. Thanks

http://www.farmequipment24-7.com/PhotoGallery.asp?ProductCode=SCVMULTPB

Not 100% sure this is the same brand Agri Supply does or did sell but looks like what I remember. I could not find it at their site and no idea on price or this company who the link is for. I have no problem recommending Agri Supply for have dealt with them for years and yes with returns and they stand behind what they sell.

One other link:
http://www.vandminc.com/vmsite/vm/PDF/Add-A-Valve.pdf

philsbs · Oct 20, 2009

I built a thumb for my PC50uu-2 and used a solenoid selector valve in the offset boom curcuit. I use a rocker switch between the two functions and also put a relief valve to protect the thumb cylinder. Got valves from surpluscenter.com.
Link to valve?
https://www.surpluscenter.com/item.asp?UID=2009102008593914&item=9-5117-A&catname=hydraulic

thebig450es · Oct 20, 2009

Thanks philsbs , i sent you a PM do you have any pictures and what thumb did you use HT 1035 or HT 830 or something similar in size? http://www.excavatorthumb.com/

The machine hydraulics are JIC?

kthompson · Oct 20, 2009

The valve philsbs used looks like the one in my first link. I sure would go with surplus center for the quick disconnects probably will be of no value.

thebig450es · Oct 20, 2009

im not planning on going with quick connects , im trying to figure out what size hoses and all the connection and adapters i will need.

kthompson · Oct 20, 2009

thebig450es said:
I'm not planning on going with quick connects , im trying to figure out what size hoses and all the connection and adapters i will need.

I have never dealt with surplus center but if you can verify what size fittings you have on the hoses on your circuit would think they could also supply them. Of course you know to do your best to mount such where it is protected as much as possible. For me that means as far as possible from the bucket.

It would also be good to have specs on cyl you need.

Pay careful attention to the switch you use also. It should be a weather proof one if open cab.

I would like to hear back from you how this valve works for you. I was looking at the set up for my tractor but might also give consideration for my thumb.

willie59 · Oct 20, 2009

thebig450es said:
The machine hydraulics are JIC?

Are you sure about that? I could be wrong, but most Komatsu machines I've work on use JIS fittings. They look similar to JIC, but they're not the same. Just don't want you to purchase the wrong stuff, especially crimped hose fittings as you can't return them if they are wrong.

philsbs · Oct 20, 2009

Like ATCOEQUIP said they look similar but are not the same as JIC. What I did is took the lines off the offset valve (they were in good condition) and had a shop with hydraulic crimper cut them and crimp standard fittings to adapt to solenoid valve, then measured and made up rest of line to relief valve and on to the thumb.
The thumb is similar to the ones posted. I built it a couple years ago and didn't take any close pictures and can't remember measurements and the machine isn't home now. I know I used 5/8" for the 2 fingers (made a pattern and cut them with a plasma cutter).
I will try to get some measurements and pictures but it works very well.
Here's a pic after it was finished.

thebig450es · Oct 20, 2009

Thank you very much, any more info and pictures would be great. You have a very nice machine

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