Welds, will they hold up? (or maybe bolts)

So my friend welded up the planet pairs in my Sears 6 planet diff, and since they have been sitting on my desk for so long, ive begun to question their strength.  My friend, after a few inquiries, always said "it will be fine for what you are doing".  Im not 100% confident, so im here with pics to either get a confidence booster (IMO unlikely) or get told that there definitely needs to be more heat and penetration into the tooth contact areas, and not just a "bridge" across the backs.

Man, the pictures really make the light surface rust really stand out.  After welding and cooling, i accidentally left them in my truck when i got home, and they surface rusted a little before i had a chance to oil them.  They arent as bad as they look in some of the pics, the flash really made some of it look bad.  But it all wipes off with a wet fingertip, so i know its nothing serious.

Pair 1








Pair 2






Pair 3






This i noticed first on pair 3, but i noticed it on other pairs when i looked for it.  The weld is not present where the gear teeth make contact with eachother.  But only a weld "bridge" across the backs of the pairs to bind them together.  You can see light through where the teeth almost make contact.  Im assuming this is the bottom level of the penetration.




So either tell me they will be fine with 27x11 Kenda Bearclaws and i shouldnt worry, or tell me to take them to a more experienced welder and have them welded together into 3 blobs that barely resemble gears.  This is new to me, ive seen welded diffs in real trucks, and for those, the people i know that welded them wanted everything welded to everything.

i see very little penetration there. if it was me, i would grind it off the best of my abilities, and re do them. what kind of welder are you using?

i don't think they will. Do you know if they still fit in the case? Does everything still rotate freely?

motorizedeverything wrote:

i don't think they will. Do you know if they still fit in the case? Does everything still rotate freely?

Yeah, everything bolts up back into the case just fine.  They were tacked, and then removed for the weld they got.  Its basically the same diff FearlessFront has in the Suburban, just with 6 planets, instead of 4.  Theres room everywhere.


Willis:
I didnt weld them, im a very green beginner.  They were welded with a Miller 110 FCAW. Im building this tractor in my appt. livingroom, no welding for me. Im making everything bolt on.


I have an idea for a locker idea, bolt on only. Il draw up a little mockup and see what you guys think. If i do my bolt locker, I would use it in conjunction with these mildly welded gears, as i dont think the gears would even see any of the load with my idea.

either way, i would start over, crank that thing up all the way and bubblegum the piss out of it. tripple pass if you have to

Since i have to have welding done by someone else, (i dont own one anymore, and have no garage or place to weld in or on), id like to be able to do everything myself.  Ibe veen building all bolt on stuff so far, so why not a bolt on locker.

Im glad i posted about the welds, they are not strong enough, i was right, unfortunately.

So i came up with this, before my friend offered to weld the gears for me.  Totally bolt on and removeable, i just dont know how strong it would be.  I think strong enough, but i dont know.

Heres an overview with no internals installed


So, being as either main side case of the diff is a machined piece, the side gears that drive the axles are machined, and the weak link ive seen from pulling vids, is the sintered planets splitting in half.  This locker method would bypass all the planet gears and make them useless.  I know the side gears are strong because they broke an axle shaft without breaking a sweat.  My thoughts are to bolt the side gears directly to their corresponding side plates, using probably 6, grade 10.9 metric shoulder bolts, or 6 gr8 thoulder bolts, sized correctly so all the shear loads would be on the shoulders.  Il do some research and see what the best shoulder bolts would be for high shear stress.

I sharpied a quick 6 and 8 bolt pattern on the side gears.  I think i like the 6, it leaves more material, and 6 is easier to center than 8 with the tooth count.


Where it would come out the back of the carrier side


And gear side.



So now my choices are gamble with the bolt on locker i made up, and spend cash on 12 bolts and assorted hardwares, or take the gears to a pro welder and get them welded proper for probably alot more than the hardware.

What do you guys think of the bolt on locker?

I wouldn't trust those welds either if you want it welded take it to a local community college and have the Instructor weld it up for you.

Weld everything on those gears that wont interfere with you putting them in.

Fearlessfront did it in one of his videos. Should look it up and see how he did his.

Doug Fackler wrote:

Weld everything on those gears that wont interfere with you putting them in.

Fearlessfront did it in one of his videos. Should look it up and see how he did his.

I showed my friend that vid, which is why i went with this method.  That and finding noone else locking up one of these transaxles, doesnt lend much to alot of variation.

My only problem with welding is money, since my friend is convinced that these are fine.  I dont know anyone else to weld them, so money is a concern.  Which is why im thinking 12 nice shoulder bolts will be WAY cheaper than paying a welder.  But if someone says they tried to bolt these gears to the sides like i thought of and it blew the side gear to pieces because of the holes in it, id be gung ho cashing out on a good weld job.  But the cheap side of me that loves bolts and nuts wants to try the bolt on.  

I always come up with ideas after ive already executed a previous idea.  Damn hindsight.
Also, what about a weld bead all the way around the perimeter of the side gears. bypassing the planets in the same way my bolts would, but with welds so the strength would be greater?

The community college instructor is not a bad idea.  I live fairly close to a PCC campus.

A VOC center should do it for free or very cheap. I remember welding all sorts of odd stuff when I was in Auto.

I'd try to cut a piece of large diameter pipe to go around the shoulder bolts... it will enclose the bolts and spread the clamping force evenly around the gear...

I'll echo what others have said... I wouldn't trust those welds. I don't think your friend has an idea of how much pressure these gears can be under.

We used to weld up our difs before we started going with solid axles and have had multiple welds fail... when a weld fails in a transaxle it typically jams in between some gears and blows the case apart - which is never a good ending for a romp.

Have someone weld the bejeezus out of them, or try your bolt on option. Or both! Why not?

Lawren Wimberly wrote:

I'd try to cut a piece of large diameter pipe to go around the shoulder bolts... it will enclose the bolts and spread the clamping force evenly around the gear...

What do you mean?  Like the ID of the tube would contact the OD of the bolt heads?  Or like a large washer to cover the entire gear surface?


The way im imagining things, the bolts would essentially just be dowel pins, and the head / nut would just hold it in, all the force would be on the bolts and it should only need minimal clamping force to the face, as friction on the face is negligible.


Hmm, the more research i do, im kind of liking the bolt on locker idea. If i use some fancy hardwares, so far the metric 10.9 in 8mm OD is looking the most promising, though 8 is the largest OD i feel comfortable drilling. Id kind of like 6mm, but im unsure of their strengths. Still researching.

I like that the bolt on locker has a 0% chance to release slag into the trans, and if i lockwire the bolts and nuts to the diff carrier, even if they break, they cant wreak havok.

I think maybe if you do individual sleeves on each one that were the same length and clamped it on that it would work even better. Would give it even more of a surface to rest on and give you less wobble (should there be any).

Im factoring cost of a real nice drill bit perfectly sized to give the shoulders a slight tap in interference fit.  Im going for 0 wobble.  My reservations on a sleeve, is it further reduces the shear pin size / creates 2 different metals to shear instead of a solid homogeneous bolt / pin.

I like the ideas of pins though.

Maybe a hybrid, 3 bolts and 3 peened in hardened dowel pins?

Grind off the weld as best you can as stated above find a local shop have them preheat to 400 degrees and then tag that ship up!

I would talk your buddy into welding a little on the opposite side of the current weld and run it, to me drilling holes in the gears is asking for trouble

Is there room around the smaller gears? then I would get made a watercut or laser cut Locker gear, disc from your local supplier. If not i would make it by hand.

Like a big disc, with the gear pattern all around to lock it solid.

Thunderdivine wrote:

Is there room around the smaller gears? then I would get made a watercut or laser cut Locker gear, disc from your local supplier. If not i would make it by hand.

Like a big disc, with the gear pattern all around to lock it solid.

man i wish i had a water jet