New Thumb Build

[lcgoatboy]

Hello all,first time posting long time lurking. I built this thumb in the last couple of days. It works very good but the ram has developed a small leak. My question for any of you hydraulic guys is the thumb ram fully extends itself (no mechanical stopper on the thumb) relying on the end of the cylinder to stop the ram.
I'm just wondering if I shouldn't install some sort of limit or will the ram stroking out on full extension be sufficient. Right now I'm thinking this or poor quality ram??
We have only used it for maybe 10min. I can weld and fab but when it comes to hydraulic,clueless. Thankshttp://www.tractorbynet.com/forums/files/build-yourself/408928d1422413901t-new-thumb-build-imag3269-jpg

 

[LD1]

The cylinder should not need a mechanical stop. I am guessing low quality cylinder?

Nice build though.

 

[pmsmechanic]

I wouldn't worry about a stop for the ram. I'd be more worried about the need for a pressure relief for when you curl the bucket against the thumb too tightly. You maybe haven't done that yet but there will come a time when it you will.

 

[lcgoatboy]

I wouldn't worry about a stop for the ram. I'd be more worried about the need for a pressure relief for when you curl the bucket against the thumb too tightly. You maybe haven't done that yet but there will come a time when it you will.

Found out about that today from the dealer. Definitely going to do the relief kit. Thanks

 

[deerseeker001]

Welcome from Wisconsin

 

[lcgoatboy]

Welcome from Wisconsin

Thanks. Used the thumb today to cut up a load of firewood. So nice! A buddy of mine said an excavator is useless without a thumb,well I wouldn't go that far but close.

 

[skyhook]

I'm not the best either when it comes to hydraulics,
but I'm wondering, it looks like the plumbing was already there for you cylinder,
so wouldn't there already be a relief incorporated in that feed.

 

[firemanmike69]

I've installed a ton of thumbs on those mini excavators, if the plumbing is there then so is an adjustable relief valve for both sides of the circuit. It will likely be under the cab of the machine and not too easy to access or adjust, if you give me the model and serial number I can tell you which valve is the one that needs adjusting. I wouldn't worry about having a stop for the cylinder extending but I would install one on the retract side to prevent the cylinder from bottoming out when retracted all the way

 

[Xfaxman]

Thanks. Used the thumb today to cut up a load of firewood. So nice! A buddy of mine said an excavator is useless without a thumb,well I wouldn't go that far but close.

Yep, thumbs are very useful. I have one on each hand!

Need to see a picture like your first, but with the cylinder fully retracted.

 

[woodchipper]

:welcome:from Québec! Good looking thumb! As the pressure from the bucket against your thumb could be more than the rod could take without bending, it would prove wise to make sure you have a releif valve on the extension circuit. The cylinder should not leek...