Charlie,

        I think you'll be fine on street tires. It's 5 grand, dump the clutch, or speed shifts that will stress the stuff.

                    

Frank/Rebop

Bristol, In ( by Elkhart) 

It is aluminum. It does not say on the packaging what type. It's gotta be 6061 or 7075. It is hard. There is some crush in it. There was just enough clearance so that it would not sit exactly flush with the yoke when loose. When the bolts were tightened it became flush. I think this does fall into the "racing parts" category which I know usually means no good for the street. I'll keep an eye on it. So far, so good, though.


Lawrenceville, GA

Steve,

        Awesome.....probably cost them $2-300 !!

     The caps most likely are 6061 (T-6) but the cross section over the cap is 4 or 5 times the U bolts. I think what would concern me more is the yield strength is low enough to allow the cap to deform and the joint loosen in the bore. I think I'd rather have the steel and maybe have the bore for the bearing done bolted to the Yoke and incorporte a little crush.

      I'm starting to pay a little more attention to this since Columbus, no fun to sit and watch because you broke.

Frank/Rebop

Bristol, In ( by Elkhart) 

Charlie - keep some dimensions of the girdle - if you don't have good luck with that design, I'll bet we can find a piece of 4340 that will work (and have wrench clearance too). That cap looks like aluminum? 6061-T6 is about the strength of mild steel ...........

The gear for the repair job pictures (my own "revised" design by the way) was cut by an outfit in Tempe, Arizona. It is 206" diameter x 15-1/2" face and has 54 x 10 inch diameter tapered rollers in the turntable bearing. The gear teeth were "roughed" (you can imagine the chips really fly - with a heavy duty hob) and then finished on a Maag gearcutter - the tooth profile is "generated" by a rack shaper tool. The finished gear (without the bearing) is about 25,000 pounds of heat treated AISI 4340. My outfit has designed and built huge replacement parts for these machines, drilling rigs, draglines and many other "big diggers". 

The power shovel was built by Harnischfeger (P&H) in Milwaukee, Wis and is operating in a coal mine at Kemmerer, Wyoming.

 
 Steve Metzger       Tucson, Arizona

What are they mining there? I'd love to watch them Hobb or mill the teeth on that thing. Bet it wasn't done on a Bridgeport!

Frank/Rebop

Bristol, In ( by Elkhart) 

That thing's huge! Do you all give tours? I would like to see that up close. The people walking around give it scale but I'm sure the true scope of it's size cannot be had until one is right next to it.



If the girdles give me any trouble I'll come up with something else. I'm sure they are overkill for my power level, anyway.


Lawrenceville, GA

Charlie -

I was looking at the U-bolt "girdle" design, it depends on the thickness at the center of the span and the length of the capscrew "grip" to do what it needs to do. The counterbore rim material around the screw heads is just along for the ride in this application. It could be redesigned to give you some more room - and you could dress/radius the edge of the driveshaft forging if you needed to. 

My guys carry around a hydraulic wrench made by "HiTorque" that runs off a 7,500 psi powerpack. I forget what the stall torque is - but its up there - uses a 1-1/2 inch drive socket for the biggies. The new power heads are aluminum which cuts down on the size of people we have to hire......I don't have a picture of the wrench either - but I do have a couple of pictures of where we use it.

  

We just stripped this dude apart and put a new rotating gear and thrust bearing in it in August. Its a 58 yard power shovel that weighs 2.5 million pounds.

 
 Steve Metzger       Tucson, Arizona

I've not had much luck with socket head screws either. The problem is that I only have about 1/2" to work with and there aren't many tools that will fit that space. A box end wrench will but the girdles have a counter-bore so that the head of the bolt will be recessed and I will not get a good bite on the bolt. There's not much material to spare; I don't think I could grind the clearance necessary to properly engage the bolt with a box end wrench without weakening the girdle severely. These socket head screws are 5/16 with thin nuts so we're not talking a lot of torque. Plus they have lock washers.



Thanks for the link to the catalog. There are some interesting fasteners. Say, where does one acquire a torque wrench that does 1350 ft/lbs? I think I saw that in "cutting edge bolts"


Lawrenceville, GA

Charlie - I've had some troubles with socket head capscrews in the past, due to the inability of the tiny hex drive to deliver sufficent torque to preload the fasteners. When you weld on the hex tool - the temper "goes south" too. This is a personal experience of mine anyway.......

Take a look at this Caterpillar hardware catalog - pages 339 and 355 if you would. The twelvepoint head screws (usually) have the same cap OD as the socket heads but the available tools will deliver much more torque to the fastener. These capscrews are also made of 170,000 psi tensile material - stronger than SAE Grade 8. You will end up with both more preload (clamping force) ....and more reserve strength (fatigue resistance). Perhaps one of the listed parts will fit your application.

www.cat.com/cda/files/87031/7/hardwre.pdf 

Virtually every part in the Cat Hardware catalog is available overnight - but maybe not "inexpensive".

 
 Steve Metzger       Tucson, Arizona

The girdles seem to fit right.

The bolt are allen head.  They cannot be properly engaged with an allen wrench.  A 1/4" hex is required.  I just picked up a cheap 1/4" wrench and a cheap 1/4" allen wrench.  I cut a 1/2" length of the allen wrench and welded it to the wrench, making sure to leave enough to fully engage the bolts.  I had to grind a little of the back of it to fine tune the fit between the drive shaft ad the bolt head.

Lawrenceville, GA