Ball Drive torque vs standard hex head

[bad daddy]

Guys,

What's the strength loss on hex keys that have the ball drive?

Guessing its about 50% less, but not sure...

 

[TheGrooveking]

Without having all of the physical properties and geometries to calculate from I would go with surface area of a cross section at its thinnest point.

TheGrooveking

 

[bad daddy]

I figured...

Snapped off a brand new Snap-On 7/32, with 32ft-lbs...

Guess I'll be visiting the tool truck, doing the walk of shame...

 

[diesel research]

Its not snap-on, but a rough idea from a reputable competitor:

 

[larry_g]

On the Bondhus site they have a chart giving the strength of a hex key. Plug in your information using the minimal cross sectional area of the necked down portion of the tool.

link to DR's chart here

lg
no neat sig line

 

[bad daddy]

Well, 316 inch-lbs = 26.5 ft-lbs. I was doing 32 ft-lbs.
It's official, I'm an idiot!
if only I had that chart a little while ago...

I just bought the set off the truck, and less than 24 hours later, broke it.

Thanks for posting that chart. I'm gonna keep a copy in the box.

On the Bondhus site they have a chart giving the strength of a hex key. Plug in your information using the minimal cross sectional area of the necked down portion of the tool.

link to DR's chart here

lg
no neat sig line

 

[zkling]

Yep as the chart above states around 50% strength of a standard key.

I keep it a personal rule to never use the ball end to break a fastener loose. That is why it is located on the long end of the hex key usually; to prevent over torquing.