Posthole Digger Old Posthole Digger Questions??

LouieJunior · Sep 3, 2012

You are probably correct. I assumed the smaller diameter bolts would be the ones to shear. The bolt through the gearbox input shaft measures 7/16". If that one shears, what prevents the PTO shaft from spinning wildly out of control?

Do you suppose there something else attaching the two shafts? I didn't notice another bolt -- but I have been, so far, unable to separate the drive shaft, assuming the two are rusted together. Guess I better take a closer look!

bulldog69 · Sep 4, 2012

On most phd the pto shaft will have a small set screw that fits in a groove on the input shaft. This keep the shaft from falling off the input shaft when the shear bolt breaks.

kebo · Sep 4, 2012

bulldog69 said:
On most phd the pto shaft will have a small set screw that fits in a groove on the input shaft. This keep the shaft from falling off the input shaft when the shear bolt breaks.

Yep, the set screw rides in a groove on the input shaft so if the shear bolt does shear, it keeps that end of the PTO shaft from coming off and wreaking havoc.

If you watch the video of PHD assembly on EverythingAttachments.com, Ted will show you the set screw on the PTO shaft.

LouieJunior · Sep 10, 2012

I double checked and find no set screw securing the drive shaft. View the first 10-12 seconds of this clip and let me know what you think. I still can not remove the PTO shaft from the gearbox. I removed the "shear bolt" through the middle.

http://db.tt/kavbZPAc