Sprockets and Sprocket Carriers

Herman-Handlebars

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HH,
You can get 70756061 etc, in billet from Smith's Non Ferrous metals based in Biggleswade, Bedfordshire.
they will cut to size for a nominal charge. Get a slightly oversize billet and machine from there.

Neil

Hi Neil,
That's good, thank you. On googling Smiths, there is a depot in Nottingham so may be able get some there, or Bedfordshire either way.
Cheers
 

Herman-Handlebars

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Yes, I have a drawing. There are a few things you should know. First, Bob Lamour in Canada can supply these to anyone who is interested. I am using one of his on the racer I am currently building. These are done to print, so if the print doesn't meet what your needs are, make your own.

Second, this adaptor was designed for Lightnings and Flashes, so it must use a 1/4" chain, which is generally stronger than the 5/8" chain. If you wish to make one for a different chain you would have to check the dimensions.

Third, you may want to use a different material, like 7075. The ones I have are made from 6061. These have worked well for high hp Comets but based on Greg Brillus having problems with his twin sprocket adaptors cracking I would take some care in choosing the material and the design. My adaptors are solid, which I think is a key to prevent cracking, so I would not machine any additional holes.

Finally, the adaptor can be machined to match the thread on the new sprocket bolts if you choose to. I have done this on mine.

I use AN bolts for the hub to adaptor and I have found for the Comet that 5 bolts are sufficient.

View attachment 38504

I have one or two done to print if someone has a need. Otherwise, the drawing is the best starting place.

Bob Larmour does a nice job. This is one that he anodized. The holes were threaded also for the Suzuki RM sprocket.

View attachment 38505

The part no. is at the top. It is 452 with the number of teeth (48) added.

View attachment 38506


The sprockets are 7075 and are available in tooth sizes from 30T to 74T. The part number is 452, which can be seen in the photo.

David

Hi David,
On measuring my piece of alloy, I don't think I have enough material to hold in the lathe chuck and turn without making a fixture etc..unfortunately.
I tried to contact Bob with his email address detailed on a different thread (pblarmour@sympatico.ca) but it didn't recognize it. Would you have another address to try please?
Thanks
 

vibrac

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Its just a small alloy round fixture (see below) As I remember I think made a fixture like this I marked and drilled the carrier with 5 holes and a center hole used that to mark the fixture and made five holes to match the holes in the carrier and a center hole with a recess for a bolt mounted the fixture on the center hole bolt turned the fixture face and a mounting diameter. took it off the bolt and mounted the fixture on that diameter in the chuck mounted the carrier on the 5 bolts then bored and turned the diameters of the carrier doing the sprocket face and outside first then turning it round to do the tapered inside reduction to the mating face of the hub Some of that faddle was necessary because of the small throat of my Lathe
I thnk the blank I ordered for the carrier was only about an 1/8" longer than the finished length
1605198920349.png
 

Herman-Handlebars

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Non-VOC Member
Its just a small alloy round fixture (see below) As I remember I think made a fixture like this I marked and drilled the carrier with 5 holes and a center hole used that to mark the fixture and made five holes to match the holes in the carrier and a center hole with a recess for a bolt mounted the fixture on the center hole bolt turned the fixture face and a mounting diameter. took it off the bolt and mounted the fixture on that diameter in the chuck mounted the carrier on the 5 bolts then bored and turned the diameters of the carrier doing the sprocket face and outside first then turning it round to do the tapered inside reduction to the mating face of the hub Some of that faddle was necessary because of the small throat of my Lathe
I thnk the blank I ordered for the carrier was only about an 1/8" longer than the finished length
View attachment 38577
Hi Tim,
Thanks for that, its the kind of fixture I was thinking about. My little ml7 myford only has around a 4" swing, and only a small gap in the bed for mounting to a faceplate (with the alloy) size.
I thought I would have had enough room until I was looking through the sizes on the drawing and its right at the limit of turning the edges of the piece.
I think I'll admit defeat on this one , and purchase one from Bob Lamour. There is lots of studs and spindles to be done on the ml7 atm.
As David kindly detailed they certainly look very nicely made.
Cheers
 

Bill Thomas

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A useful cost and weight saving can be achieved by omitting 10 of the unnecessary 20 hub to brake drum bolts on Black Shadows, unless drum flange or hub are of five bolt type. Blank off the five unused holes to avoid ingress of the elements.
Ted Davis Ex factory racer , Talking about Black Shadows !!
 

vibrac

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A useful cost and weight saving can be achieved by omitting 10 of the unnecessary 20 hub to brake drum bolts on Black Shadows, unless drum flange or hub are of five bolt type. Blank off the five unused holes to avoid ingress of the elements.
Ted Davis Ex factory racer , Talking about Black Shadows !!
Glad I have done something right I do wonder sometimes...
 

Herman-Handlebars

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Non-VOC Member
Hi Bill / Tim,
After reading all the options on the 5 vs 10 hole/bolt hubs, I've stalled with building my rear wheel the argument for or against seems equally right to me... so I purchased both hubs!
I might just go for the middle ground and have 7 and a half holes and bolts to get the best of both maybe!
I suppose the importance is to assemble the hub and carrier correctly as Tim and David have explained.
Cheers
 

Bill Thomas

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Hello Herman, The trouble is we have seen some Hubs break with the 5 holes,
So I wouldn't want to make them weaker,
We have been told to clean our Bikes a lot and check for Hub Cracks.
Never really found out why, Old age ?, Maybe a crash at some time before ?,
The hubs and drums can be hard to fit, ie Tight, So maybe the owners being a bit rough ?,
We have had a bit of spoke trouble, Where the head of the spoke touched the drums,
I think Peter B, Came up with the idea of a spacer ?,
We can now buy a thin spacer to go behind the drum to hub, If that is a problem,
But some owners don't know about it ?.
Lots to think about ??, As with everything Vincent !!.
Good Luck, Bill.
 

Robert Watson

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The times I have seen broken rear hubs has been when the drive chain is too tight and the whole piece that holds the bearing cracks around the circumference. I am guessing that a constant load from hard racing could do the same.

Apart from more frequency of loading on a rear hub, I think that with a good set of front brakes one could load the front hub as much as the rear. Think about say 0-60 on the rear hub and then about 60 - 0 on the front hub.
 
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