2" hex or 2 5/16" round PHD/auger?

[Fallon]

Which is stronger, more common or cheaper for a Post Hole Digger interface, 2" hex or 2 5/16" round?

I know most PTO PHDs are 2" round. But most hydraulic ones are 2" hex or 2 5/16" round.

My old PTO PHD ran off with my old tractor, but I've still got a couple beefy 2" round attachment augers, 9" & 12" Pengos. I'm likely to get a hydraulic unit to replace my former PTO unit & if so trying to figure out what interface to get. Either way I'll need an adapter for my current augers, so I'm not particularly attached to either style.

 

[jenkinsph]

I don't have an answer for you but was in the same position a few years ago. I had an assortment of the 2" round augers with my 3ph Deere 31B phd and switched to a hydraulic auger with the hex style. I wound up selling the 3 pt auger and bits which were much lighter duty. The hex auger bits were much stronger with thicker flightings (spelling?) than the older bits.

I would suggest you check out the bits for the hydraulic auger of your choice before making the decision.

 

[GreatWhitehunter]

As Steve commented the hydraulic auger are night and day compared to the 3pt. When I was shopping for hydraulic augers it was told to me that the hex was better due to strength. This because the hex stock is what engages the bit rather than the pin that engages on the round stock. So basically the pin on the hex only keeps the auger from falling off rather than taking the shearing force like the round stock does.

Matt

 

[Fallon]

My Pengos are nice & beefy with a selection of replaceable teeth, including carbide frost teeth. The cheap farm store ones are half the weight & price with generic teeth. My cheap 12" augers ran off with the PHD. Have a cheap 6" still, but rarely use it.

 

[RickB]

As Steve commented the hydraulic auger are night and day compared to the 3pt. When I was shopping for hydraulic augers it was told to me that the hex was better due to strength. This because the hex stock is what engages the bit rather than the pin that engages on the round stock. So basically the pin on the hex only keeps the auger from falling off rather than taking the shearing force like the round stock does.

Matt

What he said.

 

[LD1]

From a engineering standpoint, the difference in torsional strength between 2-5/16 round vs 2" hex is almost nil.

AS others have mentioned, there are other factors that make one better than the other.

 

[Rustyiron]

I happen to have the hex drive. I also have a round to hex adapter so both hex & round augers. I have not seen a difference or advantage to one over the other.