Small Hydraulic lever info needed for Thumb

[racerboy832]

I'm builiding a thumb for my hoe. I'm going to tap off existing lever block with a line then back, What is the smallest lever setup I can get that is non electric. It should be similar to a log splitter one with just open and close. I'm getting overwelmed on some of these Hydraulic sites.

 

[kennyd]

The max flow (GPM) of your hydraulic system is what will determine the valve size. Do you know what your GPM rating is? What tractor do you have?

 

[J_J]

This valve

https://www.surpluscenter.com/item.asp?item=9-7861&catname=hydraulic.

You could also use a log splitter valve, and remove the detent, or use the thumb with detent, and when the thumb opens fully, the valve will kick back to neutral. They are some of the lowest price valve around at $60. You could look on Ebay, Craigslist, Baileys hyd, or the above link to Surplus Hydraulics.

 

[racerboy832]

I'm getting all my stuff lined up now. I found 2 cylinders someone was junking. They are 26" long and have 16" throw. 1.250 Shaft. I thought it was a good score. I have just about all the stuff I need except the hydraulic line. Do guys think 1/4 line will be good enough just for the thumb?

 

[nybirdman]

A friend of mine put one on his small excavator....mechanical ...not hydraulics
thumb pivots to a fixed position...bucket does the clamping.You may want to check those out.This was a weld on unit..pivots out of the way when not in use.:thumbsup:

 

[kennyd]

I'm getting all my stuff lined up now. I found 2 cylinders someone was junking. They are 26" long and have 16" throw. 1.250 Shaft. I thought it was a good score. I have just about all the stuff I need except the hydraulic line. Do guys think 1/4 line will be good enough just for the thumb?

1/4" hose is perfect. No need for bigger on a thumb or grapple.

 

[racerboy832]

i'm building mine out of 1/2 plate left over from a Job. I want the lower pivot point to go through the bucket pin. I don't like the idea of welding onto the dipper arm. The hydraulic cylinder is going to connect to the thumb and i'm going to cut the triangle that stops dipper are from closing all the way. I'm goin to replace it with 1" Plate in a triangle shape so it does the same job as before but also acts as a top mount for the cylinder. So far my biggest expense is going to be for the lever and finding 1.250 Harden rod for extending the pin. That and a source for the 1/4 hydraulic lines.

 

[dfkrug]

...and finding 1.250 Harden rod for extending the pin.

Since you have decided on using the bkt pivot at a shared pivot with the
thumb, you will need a longer pin, but it does not have to be hardened.
Mild steel is fine. You will have to make both elements (bkt and thumb)
greasable on the same pivot, however. The bkt already is (pin is fixed
to bkt), but your thumb will need to use bushings and a zerk on each one for
lubrication.