PHD ?

Geo-TH,In · Mar 9, 2011

What grade bolt should I use to connect the auger to the gear box of a post hold digger or is there a special shear bolt for this purpose. Same question for the PTO shaft. If there are special shear bolts, where can I purchase them?
Thanks
George

Dean · Mar 9, 2011

Though I suppose there may be some manufacturers who specify otherwise, most manufacturers specify grade two bolts for torque limiting (shear) protection systems.

Dean

BCnT · Mar 9, 2011

shear bolts are usually in front of the gear box like on the pto hub...bottom of the gear box gets extra strain and shock...grade 2 bolts would be breaking all the time.
personally i run 5's on the auger and 2's on the input shaft/pto union.

buickanddeere · Mar 9, 2011

Shear bolts are often a metric size. If somebody subs in an undersized imperial bolt. The shear pin hub holes becomes worn.
Nobody here has ever seen wallowed out shear pin holes have they?

PJH · Mar 9, 2011

I thought they came wallered out. Never owned a brand new PHD.

Fordfarmer · Mar 9, 2011

(quoted from post at 12:17:34 03/09/11) Shear bolts are often a metric size.

Only on imported or fairly late-model machines. Even new machines often have fractional size shear bolts, if they were built for the U.S. market.

Geo-TH,In · Mar 9, 2011

Forgot to mention, the auger has two places for bolts. Do you put a bolt in each hole? Also, the pto shaft is 3 sided, triangler shaped. Why isn't square shaped? Was looking for a new PTO yoke at Rural king and TSC. Neither has the correct size, However Rural king had the exact replacement pto shaft for PHD with the odd size yoke. Is this a clue that my PHD is imported or metric?

Russ from MN · Mar 9, 2011

I think the reason they have gone to asymmetrical triangle is so you can only put it together one way, makes it fool proof, can't get the u-joints out of phase, at least that is the way our KK mower is.

RalphWD45 · Mar 10, 2011

I have a HOWSE PHD and it uses a 1/2" grade 5 bolt, at the pto end of the gearbox, and one 1/2" grade 5 bolt, at the augar end of the gear box. There is a second hole on the augur end , but I choose to leave it open, for extra protection. Grade 5 bolts shear in time to protect my gear box, and I have had quite a few shear in our boulder filled soil.

Tx Jim · Mar 10, 2011

This is the shear bolt for a JD PHD PC #1412 - 31, 31A, 31B and 31C Posthole Diggers - 06Feb02

Part Number: 19H3636
Part Price: 1.10 USD
Description: SCREW, HEX HEAD
Specification
Weight 0.07 LBS 0.03 Kg
Diameter 0.312 IN
Thread UNC2A
Length 2.500 IN
Thread Length 0.875 IN
Width Across Flats 0.500 IN
Head Height 0.211 IN
Material Grade A17F
Finish B

PHD ?

Geo-TH,In

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Dean

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BCnT

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buickanddeere

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PJH

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Fordfarmer

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Geo-TH,In

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Russ from MN

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RalphWD45

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Tx Jim

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