making a solid stronger.

[Ted Brown]

I can;t find where I was reading about someone saying that because a U joint had grease holes in it, that it was weaker, I would say to the opposite... If you have a stock axle and are having breakage problems, you can gain a lot-O-strength by having that axle center drilled, to a 22 Cal. hole... as this is now a TUBE axle, and has gained another wall to break, making it mucho stronger, same goes for any solid parts, say you can only use or have room for a bracket that needs to be stronger than the 1/4" you have room for?? make it from two pieces of 1/8" welded together, now it is stronger than a one piece of 1/4" material, as to bend it now, one piece has the stretch and the other has to compress, so to speak, I think you get the point, SWC 40 Willys used to run stock Olds axles for many years, center drilling will prolong axle life... just remember to drill and tap the outer end of the hole and install a pipe plug in the hole. hehe keeps the oil in rear end Just a thought for new guys starting their builds...

 

[Youngster]

i did some pit work on a BG/S years ago and they had the axles on the ols rear drilled ... works like a charm. the problem with the u-joints isn't with the grease holes to the bearings, it's with the hole in the center of the body going to the cross drilled holes. had that problem with the willys too. went to greaseless joints and the problem was gone. just had to replace u-joints more often.

Ron

 

[fluidfloyd]

Ted,

You are correct in a tube usually being stronger then a soild shaft. When you twist a tube torsionally you only twist the outer fibers of the material. The closer you get to the center or nuetral axis the less the twist will be. The cente of an axle sees very little if any torsional stresses and that is why they work so well in drag cars. it is also a cheap way to reduce vehicle weight with minimal effort.

But as Youngster pointed out, a grease fitting does weaken the trunion. Actually, it is the threaded hole that is the problem as it is a stress riser and that's where cracks can start. Cracks usually come from shock loads such as hard starting line launches or snatching a hard gear. No one in the drag racing business uses joints with grease fittings. I think that most of the rock crawler crowd has also changed to permanent greased type joints. Also, my 1 ton truck has the permanent style joints.

George

 

[Youngster]

yeah the trunion ... that's what i meant to say ...thanks floyd ....

LOL

Ron

 

[Ted Brown]

Sounds good to me How about having caps with greese fittings in each of them? You just remineded me of something I was going to look into, what do you think about those big rubber donut in place of a rear U joint on the drive shaft of one of the new super ride-quiet cars?? (kinda like a steering dampner onlt much bigger) can't remember which one I saw it on, but thought that would be great for Hot Rods, and would stop a lot of breakage to boot..??? anyone else? have you seen this??

 

[fluidfloyd]

Ted,

The main problem I see with fittings in the end of the bearing cup would be drilling and tapping them. They are basically a bearing race for the needle bearings and are fairly hard. Also I don't think they would be thick enough to take pipe threads for the zerks. Then you would have to cross drill the trunion or put zerks in all four cap ends. The new style u-joints that are greased for life are really pretty much maintance free forever under normal use. If you're going to put some serious power through them then you would be wise to step up yoke and joint sizes accordingly. For the majority of these type cars I don't think u-joints are really a problem.

Now about that rubber donut coupled shaft...interesting idea for a hot rod. Probably worth researching for future use. I'll check around and see what I can find out about them. I would guess that they are using them on aluminum driveshafts and would be trying to reduce shock loads on the shaft. Probably helps in the balancing and with harmonics also. Just a guess and I will check into it.

But Ted, like you have said in the past "sometimes old is better". I too do like simple when applicable.

George

 

[Ted Brown]

George, Simple is ME, hehe well I like things that way, usually less to break I find, BUT the thought of using that rubber coupler sounds like a GREAT idea for light weight hot rods, would save a lot of radius rods and broken axles and such... I saw that critter on a late model car, CRS it hooked up at the third member, I thought at the time, that is perfect, if it holds up.. Only time will tell...