Question about riveting replacement sprocket on rear drum

[eddiepanhead]

Working on the rear drum/sprocket of a 47FL. Welded up extra holes and egg shaped holes, re drilled the necessary holes and I'm getting ready to rivet the sprocket and dust ring back on to the drum. Referencing the attached photo of the museum 47, it looks as though the rivet heads are installed on the dust shield side with the tail of the rivet on the drum side to of the bike.
Im confused by the number of rivets in the photo vs. my drum and the rivets that came with the sprocket and kit. (20)
Do all 20 rivets get installed in the same direction? I have 4- 3/16 rivets and 16 smaller ones. Doesn't seem to be 20 rivets in the example photo.
Any thoughts and advice appreciated. I do have the proper rivet set from colony to support the heads while bucking them.
MERRY CHRISTMAS!!!!

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[Rubone]

The 16 rivets are equally spaced. The 4 dowel pin rivets for centering are in between the others at 4 equidistant points.

[eddiepanhead]

Thanks!!
Mine are laid out exactly as you describe. do all the preformed heads face the outside or left hand side of the bike. Are the tails upset like a normal aircraft rivet ? or do they have a rounded shape on the back side as well? I just dont see 20 heads on the above photo with the spacing you described. and I curious about what I'm missing

[Rubone]

Rivets go in from the drum side to the dust ring side. They are finished in a rounded shape on all 20.

[DEEBS47Chief1991]

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[T. Cotten]

The search function works, Eddie,..

And this has been covered extensively: https://forum.antiquemotorcycle.org/...ual#post218785

Cast iron drums don't like hammers, and the results are usually obvious.

...Cotten

[eddiepanhead]

Thanks for all the help. I’m guessing that the tool shown is home made? Will read what Palmer has to say, should have started there. Will need to re think my approach

[Rubone]

Thanks for all the help. I’m guessing that the tool shown is home made? Will read what Palmer has to say, should have started there. Will need to re think my approach

The tool shown is a modern repop of a factory tool. Here are factory riveting jigs for 45 (bottom) and Big Twins/K and Sportster. DCP_3915.JPG

[DEEBS47Chief1991]

https://www.wwag.com/en/riveting-tool-for-rear-sprockets

Rivet tool.jpg

[vph-d]

The fixture is real nice to have, but the job can be done by two people with a good vise and two of the rivet tools.
vph-d

[jim d]

The tool is nice but certainly not a necessity. It’s more about the tools to support the factory made head, a tool to draw the pieces together and one to set the newly formed head. And the ability of the person wielding the hammer to hit only the rivet and form it uniformly. The jig is a device for holding it but you can just get a friend for that. You can reference some of my advice in the earlier posts recommended by Cotton.

[eddiepanhead]

Thanks for all the advice!!

[knucklehead 61]

anyone have a used drum holder available? i riveted a sprocket on today & it would have been much easier with the holder kit.