I have not done the Larry Jackson conversion however I did work in heavy truck parts and the reason none of the shops have the riveting tools is most likely due to the fact that most all gear sets are now bolted in rather than riveted. This includes new production and replacement gear sets that were previously riveted.

I have the Larry Jackson gear set and have put them on my car.  When I did mine I simply bolted them in.  I did this at least 15 years ago and if I remember correctly the gear set came with bolts so that it could be bolted onto the differential.  If you look you should see that the ring gear holes are threaded.  When I purchased my set I got it directly from Larry.

@1931-roadster Thanks for the reply. Larry made several runs of these gears. The very first were supplied with rivets and were intended to be installed like the original ring gear. He also had a few rivet bucking dies made to properly set the odd sized rivets. The dies were intended to be out there as loners.The later gear sets were updated with threads for bolts. I have the earlier type. You fortunately have the updated type.

Never having see what you're referring to I'm kind of shooting in the dark. Possibly a machine shop could cut threads for you?

@tiny 

Hi Tiny

That would depend on the extent of the hardening process applied to the ring gear after machining.

If the area that bolts to the differential has been hardened, neither drill bits nor taps are going to like going there.

Been somewhere similar... tried something similar.  🙂

That makes perfect sense Ole.

Seeing that the process of riveting ring gears has been discontinued almost universally, unless there is an interference issue, I see no reason not to bolt the  gear.

Many years ago, when I first had these gears made, we were a very "puriest" club.  Not as much so anymore, IMO.  I wanted them to be just like the original 4:10's except 3:50's, as an option Chevrolet overlooked.  Of the riveted type, I will say this, a couple guys told me they drilled their differential carrier out and tapped the ring gear to accept 3/8"-24 bolts.  I was surprised you could do this, but they bought the gears and were theirs to do with as they pleased.  I discouraged it because I made them for rivets and everything was available to do so.  So apparently the heat treating is mainly concentrated at the tooth surface (where it shoud be) and at least 2 guys I know got back to me telling me they had tapped the ring gear.  The carrier is very easy to drill, 13/32" (.4062) or a "Y"size (.404) was the recommended carrier hole size when I went to bolt-ons.  I got "tremendous support" from the club when I did these and am still humbled by the trust they placed in me that make this whole project such a resounding success. TY

@steve-d When you tap the ring gear, the head of the bolt is on the back side of the carrier and clearance is a non-issue.

@lawrence-jackson I am surprised at the size of the bolt used and not familiar with the ring gear being threaded, If it were mine I would thru bolt it if possible and use a larger bolt of fine thread-possibly 7/16 which has almost double the torque capacity . The heavy duty truck gear sets that I am familiar with are bolt thru and fine thread and use a lock nut and hardened washer under the nut. Just my opinion and I am in no way an engineer .

Posted by: @lawrence-jackson

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Many years ago, when I first had these gears made, we were a very "puriest" club.  Not as much so anymore, IMO.

We've only been club members for 20 years so I can't speak to the early club days but I agree many of the club's members have moved away from being "purists" and more toward "traditionalists". I consider myself to be in the second group. In my opinion the change has been driven mostly by the lack of original parts and the cost of original parts. If it costs $XXX dollars to buy an NOS part or have the original part rebuilt but only $x to use a modern, readily available substitute, many will make the change. Of course you also have those who only want it to "look" old but have all the modern conveniences.

@lawrence-jackson , and others. I consider myself to be somewhat of a purist. That being said, I am not going to park my old car while I wait for the exact original part, if I can use a substitute and get going today. I can continue to look for the original part.

Likewise if the modification is hidden and not detectable from the outside, I think that is my business and no one else's. I have LED head and tail lamps on my '35 and '36 Coupe and Truck. They could save my life and/or the vehicle if they prevent an accident. I make no apology for this change. I am working on a stealth electric wiper for my truck.

Hide it from the judges, if you show your car, and smile even bigger if you win. Lets face it, most judges don't know squat about your car anyway.

Mike

@lawrence-jackson Thank you for posting this. As Tiny wrote I assumed the ring gear would be completely hardened and therefore too tough to tap. Never having cold set rivets with my press before I am concerned that I would not have a feel for if I pressed them enough or too much. Also I dont have the dies. Now I know there is an alternative if I am not comfortable with the riveting process.   

@carl-twardy Also, at least one person (maybe more) got back to me saying they had used bolts (can't remember what size) that they ran through the gear and and differential carrier, then secured with nuts on the carrier side.  I remember being told he ground the heads of the bolts on the ring gear side so they wouldn't hit the pinion gear.  So, some people got creative in how they installed the sets.