Undercarriage Data

OM--any info on the yield strength of the track bolts?

Dan, all the Cat hardware specifications are listed in the chart below, along with dimensions and P/No's.

https://parts.cat.com/wcs-static/pdfs/09_OSS_Hardware_low_res.pdf


OM, thanks for the hardness update, I was relying on memory for the previous shoe hardness quote, I should have referred to the books for preciseness.

I might add, I have seen specs for some aftermarket shoes where they were rated at 58RC hardness.

The hardness will vary according to age of the item, there have been substantial and major improvements in steel qualities, steel hardness, and hardening and tempering techniques, over the last 50 yrs.
I have been amazed at the lifespan of some of the newer, latest quality Cat undercarriage, I have seen D9T undercarriage that has done 7000 hrs and the wear was minimal.
In the bad old days we were lucky to see 5000 hrs before the undercarriage was totally scrap.

No specific data other than track bolts exceed Grade 8 standards of minimum 150,000 psi tensile and 130,000 psi minimum yield.

Hi OzDozer

Was that system one undercarriage on the D9T ?

shovel man.

Shovel man - No, it wasn't, it was just the older, standard-design Cat SALT undercarriage.
It was one of my middle nephews D9T's, he owns a big fleet of Cats (about 60), and he always has the latest Cats in his fleet.
His tractors do a lot of mining work (he dry hires to many mining companies) and they get all kinds of abuse, but they stand up to it well.
Of course, if there's anything needing repair when they come back off hire, he just gets it fixed and sends them the bill - and they pay up! Way to go! 😊
I'm not sure if he actually has any System One undercarriage in his fleet, I can't keep up with his purchases!
Here's some pics of his machines ...

http://www.nashbros.com.au/dozers.html

Regards, Ron.

No specific data other than track bolts exceed Grade 8 standards of minimum 150,000 psi tensile and 130,000 psi minimum yield.

OM--thats about a 15% increase in tensile over yield strength--i would surmise that they do not stretch very much.
Ron---thats quite a comprehensive chart on the hardware!!

That's correct. Probably why torque procedure on 3/4" and up track bolts are tightened to an initial torque plus 1/3 turn rather than just a final torque. (with anti-seize)

Thats interesting---that 1/3 turn is the alternate procedure for A325 HS Bolts for bridge beam connections one other method was to calibrate a toque wrench each morning on a 15/16 bolt in a load cell to get a 30,000# tensile load-=-another procedure was load indicating washers but we didn't allow them as the gap at the washer would allow moisture and rust in the severe salty environment---most of our bridges are in close proximity to the Atlantic