Built a quick and dirty thumb.

Gordon Gould · Feb 24, 2017

Very nice professional looking job. You will learn to love it !!

gg

nybirdman · Feb 24, 2017

Just curious why you didn't make it a bolt on.I have a Green's Machine Thumb,great tool for sure but it doesn't open as wide as yours.

BukitCase · Feb 24, 2017

"Understanding the flow rate between .040 and .050 for example is significant!!! "

Yeah, Richard - I just did the math and that small change would make a difference of 1.5625 TIMES as much flow at any given pressure - unless the #60 hole is 'WAY too slow, I'd probably only go up in size maybe 2-3 numbers at a time... Steve

Actually, I'm usually too impatient for a lot of "cut and try", which is why I ordered a needle valve for my (yet to be installed) grapple :laughing: ...Steve

aarolar · Feb 24, 2017

Well thanks for all the compliments but I'm afraid I have some bad news, I've already broken it. I was trying to grab a pile of brush and had the thumb half open and pinned it against a tree and rolled the bucket down at the same time and bent the rod and tore the mount off. I was a little worried about the welds on the mount tearing out being I used AR plate and I know how to fix that issue but there ain't no fixing a bent rod. Now I gotta decide if I'll cut my losses and buy a dedicated grapple or invest in a new cylinder to fix this.

ovrszd · Feb 24, 2017

The bend might be fixable. Can't tell from the pic.

There are operational lessons to be learned about using a Grapple. First and foremost is never apply more pressure to the cylinder and it's mounts than the hydraulics can apply. But you know that now.

aarolar · Feb 24, 2017

ovrszd said:
The bend might be fixable. Can't tell from the pic.

There are operational lessons to be learned about using a Grapple. First and foremost is never apply more pressure to the cylinder and it's mounts than the hydraulics can apply. But you know that now.

I knew that before I just couldn't tell what the heck I was doing up there just raking around blindly. Plus I didn't know what the mounts could stand but I do now

Next attempt will have a nice fat repad between the AR and my mount, the cylinder is another issue however.

aarolar · Feb 24, 2017

Fix or toss? Ovrszd

RNeumann · Feb 25, 2017

I'd run it bent till I got all the kinks with the grapple worked out. It can't get worse. Fix the weld and drive on. I wouldn't mind the weld being the weak point. Easy to fix a weld. More costly to replace a ram or other more serious damage.
When I was Jeeping we saw guys with expensive and strong hubs. They would break u-joints, axles or gears. I carried an extra couple cheap hubs-easy to change (don't even have to remove the tire) and cost very little. Same concept with sheer pins in some attachments.
Another option would be a relief valve on the hydraulics.

olPete · Feb 25, 2017

aarolar said:
Fix or toss? Ovrszd

View attachment 499802

Reckon that tweak would press right out

have seen crowd rods bent a lot more than that

aarolar · Feb 25, 2017

RNeumann said:
I'd run it bent till I got all the kinks with the grapple worked out. It can't get worse. Fix the weld and drive on. I wouldn't mind the weld being the weak point. Easy to fix a weld. More costly to replace a ram or other more serious damage.
When I was Jeeping we saw guys with expensive and strong hubs. They would break u-joints, axles or gears. I carried an extra couple cheap hubs-easy to change (don't even have to remove the tire) and cost very little. Same concept with sheer pins in some attachments.
Another option would be a relief valve on the hydraulics.

Had the same thought about the welding last night as I was settling down I think I'll just reweld it as is but maybe add a little preheat to the AR before I do. Here's the pics of the pin you wanted I took them then got sidetracked with broken stuff.