urgent - sheer bolts on post digger

[beenthere]

If I'm following you right, I wouldn't shut off the PTO but instead raise the 3 ph just before the going gets tough.
Engaging the PTO with a full or partially full auger puts a big load on the shear bolts. As well, if the PTO has a brake, there is a reverse load on the shear bolts when turning off the PTO drive.

I'd engage the PTO, then leave it run until the hole is dug.

But be safe.

 

[jasonp]

beenthere:
oh! never thought to try that. so keep the pto drive run, just lower/raise the 3pt. hmm.....

another question - the rpm of the pto... the rpm of the actual tractor is what runs the pto drive. so if i have the tractor idling at it's lowest, is there any other way to slow down the auger?

 

[hawkeye08]

some good advice already... reminds me of when we were putting in RR ties for corner posts and several were in some marginally wet areas in grass pasture. We had to be really careful to not let the auger just "screw" through the sod or it would bury the 3pt hitch before we could stop it... then we had to go get the other tractor with a loader and chain and pull it up. The old tractor we put the digger on did not have the lifting power in the hitch we needed at times, but it was easier to use most of the time than the bigger tractor with loader...

Good memories, some of those fences are still there after 35 years. Some will need to be moved this fall when some boundary lines are adjusted.

 

[JohninCT]

I replaced the grade 2 shear bolts with grade 5. When digging post holes in the rocky New England soil I find that when I lift the auger up to pull the dirt out of the hole rocks will often fall to the bottom. When the auger goes back down this make it difficult to dig any deeper. I pull the auger out, stop the PTO and clear the rocks out with a manual clamshell post hole digger. Sometimes a few whacks with digging bar is also needed to knock rocks out of the sides of the hole that interfere with the auger flights. This might have to be done several times in each hole. Digging in rocky soil is no party

 

[wedge40]

If possible add water to the hole. This will mean pulling the auger out of the hole, but if you seem to be able to get 3' before any problems, then I'd go down about 2 1/2' pull the auger and fill the hole with water. While you're waiting go to the next hole. I've read that it only take a few minutes of soaking to help loosen things up.

Wedge

 

[flusher]

hi all,
it's saturday night at 11pm... i'm on a job with my new tractor digging post holes. needs to be finished tomorrow. i did a bit of research, but wanted to get something specific before everyone went to bed!

my digger has been going through grade 2 bolts like crazy today (pto digger on a 50 hp tractor). ground is clay with random big rocks. usually happens getting close to 3ft in the ground. hits something, then snaps the pin. auger manual says to use grade 2... i searched everywhere in town and only was able to find 5 bolts and went through them all!! lowes/home depot has grade 5 bolts.... stupid question... can i use em???
if so, i was going to run out in the morning to get some! if not, i'm screwed!
thanks for any insight.

In a pinch I'd try using the grade 5 shear bolts only maybe 3/32 to 1/8" diameter smaller than the grade 2's that you're using now. That way you'll lessen the risk of damaging the PHD gear box when using the grade 5s.

 

[TGF]

dig slower, slower RPM and slower feed. You are binding up on something. Clear the hole often. The sheer bolt is basically to protect your equipment so I wouldn't switch to a harder grade.

 

[jasonp]

i found some grade 2 carriage bolts at tsc. they're a different type of bolt (rounded head) but the guy there said it was as soft as a regular grade 2 bolt. i'm off to dig some holes... i'll take all the advice from above with my new bolts and hopefully things work out.
thanks all for the info. i know why i've narrowed all the different forums down to this one!!

 

[sixdogs]

... i'll take all the advice from above with my new bolts and hopefully things work out.
thanks all for the info. i know why i've narrowed all the different forums down to this one!!

.....

Yeah, same for me. Guys here are pretty clever and couple a good blend of practical experience with solid book knowlege. This is the best site.
I see you're a newbie so maybe check out the "build it yourself" or "projects" tabs sometime.
Any photos you may take are greatly appreciated so don't be bashful about sending them in.
Any updates on your project appreciated.

By the way, for fencing info find the "Kecove Fence" site or get their catalog --it's packed with great info.

 

[jasonp]

well time for supper.... never thought to upload some pics... will do that when i get a few free moments.
update... the grd 2 carriage bolts work well! although i think next time i'll get a bit longer (the rounded head is big and there is just enough room to screw on the nut).
i shattered a couple, so i guess they work well! did a good dozen holes (using some of my new found tips!) and only shattered a couple. good stuff.
back after supper for more holes. only 10 left to finish the one field.
just an fyi... the parts guy at my kubota dealer said i shouldn't have a problem moving up to grade 5... he didn't seem 100% sure of himself... just glad i found some grade 2's on a sunday!!