gold star rear sprocket

[zeppelin builder]

today i machined the worn 42 tooth sprocket off one of the rare alloy finned drums initialy i was going to braze the new ring on but i was worried that i might melt the alloy fins with the heat for silicon bronze
i came up with a safer idea
i machined away the alloy at 6 points to bare the cast steel drum
i preheated to 200 c then laid a bead of 2mm inconel 625 wire so i could now get a fllet weld at 6 points at the back of the sprocket front face was prepped with a long taper at 6 points between the rear welds more pre heat and tack back and front , rear fillets were not easy acess but the old bent tungsten with a long stickout allowed me to get the required wash up the sprocket , front weld were done in 2 passes to flush then the groove for the brake drum was re cut and when cool distortion was minimal and no cracking

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[tom2207]

looks factory ... couldnt ask for more than that.

 

[Seadog]

I've never heard of that type of sprocket, and I've come across all sorts over the years I worked in the British motorcycle trade. Nicely done.

 

[zeppelin builder]

I've never heard of that type of sprocket, and I've come across all sorts over the years I worked in the British motorcycle trade. Nicely done.

only common to goldstars and rocket gold stars "proper ones"

 

[Seadog]

I can see, but we had some strange types come through the door and I don't once recall hearing of this type. You can still buy remanufactured ones for £240.

 

[zeppelin builder]

the were made by hepworth and grandage by the" Alfin process" also used for alloy barrels and heads with the seats cast in , with the fins cast over the drums it was suppoed to give a perfect bond and therefore perfect heat transfer i can tell you that when preheating there was oil and vapour spewing out the egde where i had cut the alloy back

there are new ones available but the rings are shrunk on and not the coveted "Alfin" one