Breaking shanks... thoughts?

[Dadnatron]

I recently purchased an 80" Gannon 4x2, of CL. It had no shanks at all, but the hydraulics works well.

I looked for quite some time, until finally giving in and purchasing the shanks from eBay. They arrived, along with teeth and new spring clips, 8 sets in all. The shanks appear to be cast iron. The notches in the front turn out to be too narrow (clue #1) for my blade, so initially, I had a machine shop cut notches in the right location. They simply used a cut off wheel and notched it out. They put the teeth on, and $30 later, I was fully shanked and ready to roll.

They work fine, sticking roughly 6-8" below the box when fully extended and locked. However, I've broken 3 shanks so far. I know when I've done it, it was when I was working around some big trees, and I hooked on a root. I got a little resistance, then everything continued on its way. Come to find out, each time I noted this resistance, I was breaking a shank.

My tractor is 100hp at about 9K lbs. The blade is huge and heavy. Nothing has twisted, tweaked, or torn... other than the shank.

Now, I know that this is a cheap 'shear pin' type safety to keep my tractor and blade intact. However, It seems as though these shanks are breaking rather easily. They break at the bottom of the tube through which they pass, right at the bottom of the 'new notch'.

Any ideas about whether I can get any stronger shanks or where I can get some which would fit my Blade in design?

I don't know whether these are just weak shanks or whether notching them for fit is weakening them to the point that they break far too easily. But regardless, I need to see whether I can find an alternative. There really seems to be very little 'stress' put on the machine as it 'catches and breaks'. I don't even have time to hit the clutch to stop it, before its already moving on. Thus, it seems to me the shanks are weak or weakened.

I'll have to remeasure, but my top tube through which they hook and pass is approximately 5 - 5 1/4". The notches inherent in the shanks I have found have notches only approximately 3 1/2 - 4" apart, necessitating my additional notching.

 

[jenkinsph]

I have pulled up 4 inch roots with my box blade (Frontier Gannon industrial) and have often stopped the tractor in its tracks. I have had one shank failure when new, think it was defective to start with. The oem shank was about $75 and was replaced with no failures for the next 9 years. If it were me I would make sure to buy the correct shanks and see how they hold up.

I have not personally seen the 4x2 model box blade you have but mine is a BB1384.

 

[Gary Fowler]

From what I have seen, there are two types of shanks, the ones with a notch in the front AND the better ones with a hole in the middle of the shank for a pin. I think the ones with a hole are twice as strong as the ones with a notch that effectively gives the shank a place to start ripping apart plus the notch takes out about 1/2" or more of the shanks shaft. So instead of having about 3" of shank, you only have 2 3/4".

Every box blade I had seen uses the same size shank so with a little modification to the pinning connection, the ones with a center hole should work on your notched type.

 

[Gary Fowler]

By the way, the shanks aren't cast iron, they might be cast steel but more likely they are forged steel. They are weldable as I have welded back mine more than once using 7018 rods. They then hold as well as a new one, but still break at that notch. I haven't used my box blade since I got this implement The shanks seem to be much stronger on this thing which I use to uproot rocks prior to tilling.
NOTE the pins thru the middle of the shank rather than a notch

 

[rustyshakelford]

I busted or bent every shank on my industrial frontier behind a 5055e with r4s. Dealer told me I shouldn't be able to break anything with my setup but I showed him! I'm trading my current bb3284 in with my tractor and bought a monster frontier bb4296H but it has the same shank design. I guess we will see how long this one holds up! Might need to look into having some laser cut out of a stronger metal without them being to brittle

Brett

 

[Gary Fowler]

I busted or bent every shank on my industrial frontier behind a 5055e with r4s. Dealer told me I shouldn't be able to break anything with my setup but I showed him! I'm trading my current bb3284 in with my tractor and bought a monster frontier bb4296H but it has the same shank design. I guess we will see how long this one holds up! Might need to look into having some laser cut out of a stronger metal without them being to brittle

Brett

Did yours have the notches or the holes in the shank?

 

[rustyshakelford]

Did yours have the notches or the holes in the shank?

The notches. When I saw them I immediately saw that as a fail point. Don't know why they designed them that way. If I get replacements made, they will be the entire size of the cut out and I'll weld a bracket on top of them to pin it. Should make it much stronger but I'll give it the benefit of the doubt for now

Brett

 

[oosik]

My Bush Hog ROBB has shanks set up just like in Gary's pic - adjustment holes. I've never stopped the tractor but have pulled so hard that the top of the shanks came forward and put a "dimple" in the leading edge of the shank slot. The entire ROBB pivoted upward, slightly, on the lower arms and reset the unit. So in that case, I did find the buried edge of the bedrock shelf !!!!. Scared the pee-wadding right out of me.

My shanks are 3/4" x 2 1/2" x 19" and look to be cut from plate steel or forged.

Now if I'm going out - looking for trouble - I use the shank of the moldboard plow, with its carbide tooth, to define the limits of where to cultivate. That unit has a spring loaded release and limits potential damage.

 

[Dadnatron]

I had some better pics, but this is all I can find for now.

In order to change over to 'center hole' shanks, I have to weld brackets to the top to hold the cross pin. While that isn't a HUGE problem, it is a moderate hassle at this point, as I don't currently own a welder. I just haven't gathered the $$$ for one, given everything else begging for $$$ as well. I guess I need to just buck up and get one.

But, I really believe, this is a big blade, and they surely wouldn't have been having as much trouble as I am having, and kept the design. Surely, there is someplace I can buy replacement shanks that aren't as weak as the eBay ones I have found thus far.

And yes, I meant to say cast steel, I guess the 'iron' just follows 'cast' so easily that I didn't even recognize what I was saying. I don't believe it is forged. Neither did the machinist.

 

[topbuilder]

Just a thought. I have a similar blade, I think the purpose of the teeth is to break up the ground for the blade to cut . My teeth do not extend that low. I don't have your HP either.