Hey welders, I've got a question

[dbeardslee]

So after TC's recent thread about lengthening the u-joint yoke for the 750/850 FD mod, I decided to go ahead and lengthen mine. I've got a couple u-joint assemblies on the way, and I intend to cut the end off one and have it welded onto the other one.

I've got another drive shaft to keep the splines aligned during the process, but my question is this - What affect is the welding going to have on the strength of the surrounding metal? Will it be as strong and tough as it was before, or is the heat generated from welding going to booger up the temper of the steel? Is there a best type of weld to use or is one as good another, assuming they're all done correctly. MIG, TIG, stick, or something else? Pros and cons?

I know basically butkus about welding, so I'll have a local shop do the deed. But I hate walking in cold, so any info experienced welders have to share would be appreciated.

[DiverRay]

My understanding is the yoke is the "soft" steel, and the drive shaft is hardened. If this is the case, and I'm 99% sure it is, welding the yoke will have no adverse effect on the properties of the yoke.
As a disclaimer, I do weld, but not for a living. I've had a few classes, the last one a TIG at the community college, so I know just enough to be dangerous.

[CaptonZap]

You might ask the shop to cool off the shaft between spot welds on the yoke, not just shove it in and weld all the way around. Some spot welds at 4 to 6 places around the periphery would be a good start, then fill in between two spots, cool the shaft, go to the opposite side and do the same, continue that procedure until it is done.
Personally, I would use a stainless rod with Tig, since it tends to weld cleanly on oily old metals.

CZ

[dbeardslee]

You might ask the shop to cool off the shaft between spot welds on the yoke, not just shove it in and weld all the way around. Some spot welds at 4 to 6 places around the periphery would be a good start, then fill in between two spots, cool the shaft, go to the opposite side and do the same, continue that procedure until it is done.
Personally, I would use a stainless rod with Tig, since it tends to weld cleanly on oily old metals.

CZ

That sounds prudent. I'll see if they can TIG weld it. And I like the idea of letting it cool between welds.

And here's another question regarding the yoke. I saw one thread that said the yoke was made out of cast iron, but I read yet another that said the yoke could bend while changing out u-joints. If that's correct then I have to assume it's made out of steel since cast iron doesn't bend. Any thoughts?

[crazy steve]

Yes, all those driveline parts are steel, and mostly forged. As to welding the driveshaft, don't do it. Welding will make the metal brittle, and while re-heat-treating after welding will help, you'll never get it back to where it needs to be and chances are fair-to-good that it will break. Virtually all racing organizations outlawed welded axles years ago for just this reason.

There's a thread on here somewhere about modified driveshafts, and somebody found a company that built/sold custom-length shafts for the V-Max. IIRC, the first-generation V-max used the same front/rear splines as the XS11, it was just a different length. This company would build a shaft to any length you wanted.

[dbeardslee]

Yes, all those driveline parts are steel, and mostly forged. As to welding the driveshaft, don't do it. Welding will make the metal brittle, and while re-heat-treating after welding will help, you'll never get it back to where it needs to be and chances are fair-to-good that it will break. Virtually all racing organizations outlawed welded axles years ago for just this reason.

There's a thread on here somewhere about modified driveshafts, and somebody found a company that built/sold custom-length shafts for the V-Max. IIRC, the first-generation V-max used the same front/rear splines as the XS11, it was just a different length. This company would build a shaft to any length you wanted.

I don't plan to touch the driveshaft - just the yoke on the u-joint assembly.

[crazy steve]

OK, I misunderstood your post.... but the same thing still applies. This is a better method as your weld will be larger and much less prone to twisting, but you'll still want to have the piece tested for hardness before welding and then heat treated after to bring back the 'correct' hardness for wear. Each piece is hardened to a specific number, if the 'match' gets too far off the harder part will 'eat' the softer part.

[dbeardslee]

OK, I misunderstood your post.... but the same thing still applies. This is a better method as your weld will be larger and much less prone to twisting, but you'll still want to have the piece tested for hardness before welding and then heat treated after to bring back the 'correct' hardness for wear. Each piece is hardened to a specific number, if the 'match' gets too far off the harder part will 'eat' the softer part.

You brought up a REAL interesting point. The idea of this whole thing is to get more spline engagement, which could be accomplished with a longer yoke, or a longer driveshaft.

So I went digging around. Since the XS11 search function is often an exercise in futility, I just did some googling. I assume this is the thread you were referring to - Shaft Question, which referenced this website - Blue Ridge Mtn. Sportmax.

Is that the thread and custom driveshaft maker you were thinking of?

[crazy steve]

Yep, that's it! I knew it was in here somewhere....

The major problem with their shaft is it's OD; twice the size of the XS. This will not fit inside the stock swingarm, but maybe a phone call to see if they can turn one down for you would solve the problem.

[dbeardslee]

Yep, that's it! I knew it was in here somewhere....

The major problem with their shaft is it's OD; twice the size of the XS. This will not fit inside the stock swingarm, but maybe a phone call to see if they can turn one down for you would solve the problem.

So, you're talking about their Sportshaft, right?

[crazy steve]

That's the piece.... Keep in mind I don't know if it was ever verified that they share the same driveshaft splines, but that info shouldn't be too hard to get. Given what custom welding costs these days, I suspect this will be the cheaper option or at worst about the same. For a better part....

[motoman]

So after TC's recent thread about lengthening the u-joint yoke for the 750/850 FD mod, I decided to go ahead and lengthen mine. I've got a couple u-joint assemblies on the way, and I intend to cut the end off one and have it welded onto the other one.

I've got another drive shaft to keep the splines aligned during the process, but my question is this - What affect is the welding going to have on the strength of the surrounding metal? Will it be as strong and tough as it was before, or is the heat generated from welding going to booger up the temper of the steel? Is there a best type of weld to use or is one as good another, assuming they're all done correctly. MIG, TIG, stick, or something else? Pros and cons?

I know basically butkus about welding, so I'll have a local shop do the deed. But I hate walking in cold, so any info experienced welders have to share would be appreciated.

Didm't botjer to read any of imput, but as a certified welder, lay-out and fabricator, metal urgest I suggest welding if using arc welder LH-70 rod. Eight inch rod followed by 5/32nds rod. You als realize it willhave to be machined afterwars for splines to align correctly. Eight inch rod first for max penetration with no weaving allowed. To better the fill weld initially grind each end first, then get spline alignment correct, Initially you want to tack weld around it in 6locarions. Each tac-we;d opposite from each other. Check srtaightness after EACH tac-weld. After that is finished, weld all around in one COMPLETE pass with a new rod. Chip slag off getting shiney-clean and one more complete pass using 5/32 LH-70 rod. Now chuck it up and have wels machined, leaving an ever so slight rise in weld for strength..........hope that helped. BTW, that first complete pass IS the root bead.....and most important!

[motoman]

I HAVE RO ADD, ANY LOAD FROM A CLUTCH 'SNAP' or speed shift........kiss that type od connection goodbye........seen it too many times in a lot larger applications. Unless both drilled 90degrees apart and FIRST pinned with steel rods.........never gonna work my friend. Maybe I didn't read closely, but what heck you building?......are you considering a different 'breed' of final drive or what?

[dbeardslee]

I HAVE RO ADD, ANY LOAD FROM A CLUTCH 'SNAP' or speed shift........kiss that type od connection goodbye........seen it too many times in a lot larger applications. Unless both drilled 90degrees apart and FIRST pinned with steel rods.........never gonna work my friend. Maybe I didn't read closely, but what heck you building?......are you considering a different 'breed' of final drive or what?

Just want to replicate what 3Phase has already done - lengthening the yoke on the u-joint assembly. This explains it - but you gotta read down a ways. Variation of the 750/850 final drive

[MPittma100]

Weld It

Tig weld for this application is the best choice. Any welding to driveline parts is going to affect the original strength of the metal, but tig will be the least intrusive. The driveline is not likely to fail with this mod as it is not the weak link as compared to other components. Just not enough torque output to break the driveline.