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Ring Gear RIvets

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Why rivet when you can bolt using high tension strength hardware? I'm in the process of putting my ring gear together using Cap screws and thin jam nuts. Hardware available from Mcmaster-Carr. Make sure the shoulder goes through the ring and the carrier leaving room for the threads without bottoming out. Cut off excess threads.  The bolts are longer than needed to get the right should length (critical). Don't forget the appropriate Loctite thread locker (with primer). Use good judgement. Your situation may need special clearances. 

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Edited by Friartuck (see edit history)
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Like Friartuck said don't rely on bolts with just threads.   I've been into Brass era transmissions where non shouldered bolts were used the gear shucked back and forth and wore the threads.   This loosened up the gear on the hub and it would shuck.  They all had red locktite on all the them and they were all loose. 

 

I remachined the stuff and used shouldered bolts from Mcmaster carr.  That way it's impossible to shuck.  

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Occasionally I mention the 1939 Cadillac owned by the father (who also had a '49 Cadillac), of a friend of mine. My friend's older brother was also like an older brother to me. He taught me to shift a manual transmission on that Cad, which being the older family car, began to serve increasing duty as the boy's conveyance. Now my "older brother " (his name also was Carl - R.I.P. my esteemed brother), had very little restraint, and no mercy whatsoever on that well maintained '39. It often attempted the triple digit barrier, and might have actually kissed 100 under favorable conditions. Clutch and driveline were not spared either, and Carl's jackass starts eventually sheared the ring gear rivets. Towed into Sparling Cadillac, the rivets were replaced with bolts. Those guys really knew what they were doing. A number of them had many decades of experience, the oldest of them at that time (ca. 1959 or '60), had matured with the automobile, and conceivably could have worked on new Model 30 Cadillacs ! A dozen or so years later, I was amused to learn that they still had a couple of mechanics who had professionally serviced the V16s. Oh, them there good old days.    Born on one of 'em   -  CC 

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Twer it me I would use high strength shoulder screws. Much tighter tolerance on the un threaded shoulder portion for less axial slippage. See McMaster-Carr......Bob

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I like the rivets, if properly installed they are sure to be a tight fit. Not hard to do, you can peen the rivets with a hammer. I don't know how you could get bolts to fit as tight unless they were tapered bolts in a carefully reamed, tapered hole.

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Hot riveting is easy and if done right is absolutely tight.  Easiest if you have the proper stake.  Red hot, insert, put stake over rivet and one strike with a heavy hammer and it's all done.

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Thanks! It looks as though I will be bolting this now. I took it to a riveter, and he decided after having a close look that he could not do it with his current setup, as there is not enough room around the rivet heads.

 

The thing that concerns me is that the holes are not necessarily perfectly round, nor the same exact size, as they were intended for rivets. The holes in the case were ever so slightly larger than the ring gear. I read in a Buick shop manual that this occurs because the case is softer steel than the ring. 5/16" bolts fit, but with a bit of clearance.

 

 

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Rivets are used in a lot of places where bolts will loosen over time.  Bolted joints subjected to alternating shear loads, as in starts, shifts, and stops on a ring gear, will turn the bolt heads or nuts and loosen the grip.  We never see bolts get tighter over time, only looser.  Additionally, if the old rivets were drilled out, the holes may be oversized and not round.  When a rivet head is peened over, the shank of the rivet grows in diameter to completely fill the hole, something a bolt can never do.  The two pieces can never shift if the rivet is put in correctly.  Car manufacturers used rivets for good reasons.

 

These guys know all about rivets for cars:  http://www.bigflatsrivet.com/

 

If you must use bolts, omit lock washers, use red Loctite on the threads, and torque to full recommended value.  The socket head cap screws recommended bu Friartuck are good.  Pick an unthreaded body length that allows no more than 1-2 threads inside the holes in the rear gear or plate, cut off the excess threads leaving 1 or 2 threads exposed.  If part of the unthreaded body goes all the way through, use a hardened washer under the nut, but only one washer.   

 

Edited by Gary_Ash (see edit history)
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The ring gears on Auburns came bolted and wired from Columbia Gear.  Never had a problem.

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For what my opinion is worth,  you should ideally set steel rivets with a press jig in an hydraulic press of sufficient energy.   When pressed with suitable heading dies, the shank of the rivet swells in the hole in crown wheel and carrier.    I only use bolts in intermediate holes to ensure alignment, and total tight contact between the surfaces.   Once round, I pull out the bolts and set the rest of the ring of rivets.   I originally had probably 10 new Servex   crown-wheel riveting jig sets in the mass of War surplus stuff.  Apart from one for my workshop, I gave the others to friends in the antique car hobby here.     The same riveting is also essential for clutch discs for heavy duty.     Alan Moffatt has been an Aussie for many decades now,  but I don't think he ever lost his Nth American accent.   He drove Ford in racing for years at Bathurst and similar.  Because he needed a special plate, and the rivets were just hammered, he had a string of retirements.  Someone directed him to Clive Beattie, who was a Lancia specialist, and pressed his clutch rivets from then ,  He never had another clutch failure.

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3 hours ago, Curti said:

The ring gears on Auburns came bolted and wired from Columbia Gear.  Never had a problem.

 

On Franklin's, too.  

The bolts are specially made - shouldered the depth of the hole and almost a press-fit so that there is no chance of movement of the ring on the differential.  Then the nuts are safety wired to the bolts with annealed iron wire, in even lengths to stay balanced.

 

Paul

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Edited by PFitz (see edit history)
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I agree that the grade 8 bolts are sufficient. If you are worried about the gears "shucking" (new to me also), after you get it bolted, I would drill the gear and carrier and press in three or four 3/8" dowel pins.

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About 20 years ago my Dodge 8 broke a crown wheel bolt head off. Luckily it went down the back and not through the pinion. I found ALL the bolts were loose (hand tight or looser) and all the locking tabs were bent up in their correct place! They were the original Dodge Brothers bolts. A few teeth were damaged on the crown wheel and it punched the bolt through the back cover.

 

I put the replacement crown wheel on with Unbrako cap screws, torqued as much as I dared into the carrier and wired in pairs with isocyanate thread locker . I put them in the lathe to drill the caps for the wires.

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On 11/13/2018 at 8:27 PM, 46 woodie said:

I agree that the grade 8 bolts are sufficient. If you are worried about the gears "shucking" (new to me also), after you get it bolted, I would drill the gear and carrier and press in three or four 3/8" dowel pins.

 

You guys a bunch of city slickers?   I've heard that term throughout my childhood from my dad's farming buddies.  

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Well, the holidays are over and it's time for me to get back on this project. I could bolt it, but the holes are not perfect machined holes, and are also slightly oversize when compared to available bolts. Next week I will take it back to the machine shop to get the holes bored out to fit shoulder bolts, and then there will be no turning back.

 

I'm just bumping the thread one more time to see if anyone knows of a shop who can rivet this in the traditional way. Thanks in advance.

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17 minutes ago, Bloo said:

Well, the holidays are over and it's time for me to get back on this project. I could bolt it, but the holes are not perfect machined holes, and are also slightly oversize when compared to available bolts. Next week I will take it back to the machine shop to get the holes bored out to fit shoulder bolts, and then there will be no turning back.

 

I'm just bumping the thread one more time to see if anyone knows of a shop who can rivet this in the traditional way. Thanks in advance.

Your shop should know this, but: ....Center the ring as close as possible and bolt securely. Bore the first hole and set your shoulder bolt tight. Bore the second hole 180 deg across the ring then shoulder bolt that one. Two more at 90 deg apart and you should be able to proceed without losing your hole alignment. If they are truly "boring" the holes the size and alignment should be good. If they are just running a drill through to open the holes I would request they be drilled and then reamed to final size .............Bob

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Well, now it seems I can't get the holes reamed after all. The gear is even harder than expected. I am back to the idea of using 5/16" shoulder bolts and Loctitie and hoping for the best. The temporary 5/16" bolts seem to fit fairly tightly despite the imperfect holes. The flange is already set in high strength Loctite.

 

I'm looking at McMaster Carr's shoulder bolts now, as well as aircraft (NAS) shear bolts. I can probably hit the desired grip length closer with aircraft bolts, and they are cheaper too.

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Can you ream it by grinding?

 

I used Unbrako cap screws with the right length unthreaded shoulder. It is 20+ years ago, but I think they were available in various length shoulder for the length I needed.

Edited by Spinneyhill (see edit history)
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If you are bolting the ring gear, make sure for your safety that you drill the heads and install locking wire. I had a BMW glas 1800, some years ago, it came from the factory with torqued bolts, no lock washers or lock wire. The bolts worked loose and eventually the diff gears locked up solid, destroying the gears. The first time it happened at about 20 miles an hour and the car went sideways up against the curb, the second diff came apart at close on a 100 miles an hour, the diff locked up spinning the car 4 times before we luckily came to a halt. After that I got another new axle, stripped it before installation and drilled and lock wired the bolts. No more problems.

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Yes. I did that with the Unbrako bolts. They are high strength bolts so the tightening torque was limited by the cast carrier they were screwing into rather than the bolt strength.

 

Originally, the crown wheel was held on with bolts with locking tabs to keep them "tight". The tabs were in pairs, with a flat under two bolts with an ear folded up against a flat on each bolt head. I replaced them after one bolt broke its head off, luckily at <5 mph in 1st or 2nd gear going over a speed bump at the Cook Strait ferry terminal. All the lock tabs were hard up against their bolt and every single bolt was loose, not even finger tight.

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