Rear Blade Repair on scrape blade

[NTG]

My friend gave me a scrape blade and I'm using it to define my roads on my land and start getting crowns established. Because it's a lot of raw land that I've cleared trees on, there are a lot of stumps and unseen roots beneath the surface. Sure enough, I caught the blade on a root and snapped the pin that goes down in the holes that set the angle of the blade. It kind of turned it, raised the plate up about a quarter inch and snapped the pin off at an angle jamming it in there. No telling how old this blade is and the pin and chain holding it were pretty rusty, but overall the blade is in real good shape, you know how old farm stuff is. I'm pretty sure I can get my angle grinder in there to cut the pin in half and then the halves will come out, but what do I replace it with? I'm guessing the pin is about 3/4" to 1" and I didn't know if I needed something hard to keep the blade in place, or if this is where I go with a softer bolt to act as a shear pin. I've got room to get up under there and put a nut on it to tighten it down and I think that'll keep it in place as the pin that was there just stuck down in there allowing the blade some wiggle room and I think that's probably what ended up shearing it off because the plate could move and raise up a bit. That gave the pin just enough room it needed to bend to the point of shearing off. Please advise. Thanks!

 

[CincyFlyer]

I'd go with an ordinary hitch-type pin, having it be the weakest (and cheapest) link. Maybe buy a few of them ...

 

[Gary Fowler]

Hitch pins are much harder than normal A36 plate that is used for farm implement fabrication. If you want it to be the weak link, get a Grade 5 bolt that will likely bend a bit before shearing. A grade 8 bolt might just shear and not bend but it wont be cheap for a 1" bolt.

 

[Thomas]

Better to shear pin or bolt than parts/plates $$$'s if you have TSC store they should offer different assortment and chart of strength.

 

[NTG]

I guess smarter to start with something soft and then go upwards if I shear too many to be workable.

 

[WranglerX]

While browsing a site (forgot where) it stated the the pins with the blue paint on top ring were hardened steel (grade 8?) and the pins with the red painted loops were a mild steel (grade 5?)....

After you get through all the gore, page 16 or so is where the specifications on pins starts...

https://www.extension.purdue.edu/extmedia/ppp/ppp-94.pdf

If you want to use a pin as a shear pin I would say grade 2 would be best....Concept of using a shear pin might be a pain to replace them but it might save you big expense and down time in repairs...

Dale

 

[NTG]

I agree. I don't want to be getting off the tractor every 5 minutes to replace the pin, but I understand the concept of a shear pin and agree. I also probably need to do more to try to find stumps and roots and dig them up before dragging through with the scraper in the first place. That was just laziness on my part.

 

[CincyFlyer]

Hitch pins are much harder than normal A36 plate that is used for farm implement fabrication. If you want it to be the weak link, get a Grade 5 bolt that will likely bend a bit before shearing. A grade 8 bolt might just shear and not bend but it wont be cheap for a 1" bolt.

The pins I have are made in a nice Asian country, and are by no means made of good steel, and have certainly skipped the heat treatment. I've use a couple as "fuses". I suppose the better ones I actually tow with are stronger (I would hope!)

 

[NTG]

Ah yeah, there's a time and place for all things Harbor Freight..... LOL Maybe I can try one of their "high quality" hitch pins. 5/8 in. Easy Grip Hitch Pin