Source for shear bolts?

kiotibill · Sep 15, 2009

I picked up a post-hole digger at the local Tractor Supply (Country Line, I believe). Seems to be working just fine after a number of holes. I wanted to get some extra shear bolts for the connection to the gearbox (just in case!) and stopped back in to the Tractore Supply store. They all looked at me like I was nuts and had no idea where to get them. Any chance someone can point me in the right direction - I don't wan't to out digging and snap one without any backups.

ToadHill · Sep 15, 2009

I use grade 5 bolts, some recommend something softer but 5's have worked well for me.

EddieWalker · Sep 15, 2009

I also use Grade 5 bolts. They snap real good when you hit something and are cheap enough that you can buy quite a few of them to keep in supply. Get either the crown nuts with the plastic in them, or extra nuts so you can put two nuts at the end of the threads. Just tightenign the nut on the bolt wont hold. Even with a lock washer, the nut will come off. Double nuts are cheap, easy and re-usable.

Eddie

jinman · Sep 15, 2009

My rotary cutter uses 1/2" shear bolts, but my PHD uses 3/8" I believe. Take one with you and go to TSC's hardware bins. They have grade 2 and grade 5 bolts for about $1.99 per lb. I buy grade 2 mostly, but keep a few grade 5 as backups for shear bolts. I don't buy locking nuts, just the regular nuts. When I put the nut on, I grip the threads sticking out of the nut with my channel-lock pliers and stake the threads a bit so the nut won't back off. If I can find the end with the nut when the shear bolt breaks, I can hold the bolt and remove the nut, but at the low price of nuts, it's rarely worth my time unless I can't find a nut to put onto the new shear bolt.

If your TSC has a display with PTO shaft parts and such, they normally also have a pack of 3 or 4 shear bolts, but they will have a huge inflated price and not be anything different than the ones you can find in the open bin stock in the hardware section of the store.

boughtaJD · Sep 22, 2009

TSC - after breaking 5 grade 2 bolts in one day I went up to grade 5 and they work a lot better. The model of Bush Hog PHD I'm using specifies grade 5, I just had some grade 2's on hand. Grade 2 is just too soft unless you know your soil is rock/root free.

foggy1111 · Sep 22, 2009

I bought some extra grade 2 and grade 5 bolts for my new 5' KK rotary cutter last winter. I had read posts that many have replaced grade 2's with the 5's and thought I would be prepared if needed.

After operating all spring and summer (I imagine 40 hours with RC?) ....I have yet to break a shear bolt.....and I have a grade 2 bolt (original furnished bolt) in the cutter. I have hit many stumps, humongous rocks, big logs, stalled the engine, and hit lots of wire and such. Had to tighten the bolts on the gearbox.....still original shear bolt.

This has me a bit nervous.....as I have stalled the tractor quite a bit. I considered adding a slip clutch...but still have not done so. I removed the shear bolt (when I had to tightnen up my gear box) and I noticed the shear bolt had a slight bend.....but I installed it again and I'm back in biz.

Either I got the best shear bolt in the world or not enough power (25pto HP) to break it.

What am I doing right / wrong here?

Scotty370 · Sep 23, 2009

I think torquing has a lot to do with it! If installed the slightest bit loose, I think the parts 'thrash' back and forth and 'fail' the bolt. If too tight, the bolt is already stressed in tension and will prematurely fail. (I know, I know, Goldlock-Syndrome!) If I get one tightened just right, it will last the season, and beyond! I'm speaking of a JD 48" Snow-Thrower. If I break one,........I'll break 3 in succession, until I get one in there.."just right"! I use grade 2's (1/4"-20) with Ny-Lock nuts. ~Scotty