Practical Engineering


After making the cam brake pieces it was clear there was going to be issues in getting them to fit. There is not much room between the wheel and axle box for the pull rod. The clevis pin also fouls no the axel box radius arm. The axle box drawing also shows the bottom cam brake pin a 1/16" back from the bearing face. Luckly I hadn't machined the cast boss off as this is a drawing error as the brake shoe sits against this boss. The 1/16" is to give clearance for the return springs. I used 75mm x 9mm diameter tension springs again not much clearance so had to machine the axle box so the springs just missed.  The operating lever was shortened by 3/4" to miss the radius arm. As the 3/16" cam brake pull rod was going to hit the radius rod casting at full length a set is going to have to be made in both rods anyway. The only issue that may come to light is the travel to operate the brakes may have to move further but there is adjustment on the end of the rod. The following photos show the issues.

One of the operating levers shortened by 3/4" to give the required clearance.

Jig for machining taper sides 

Harden buttons used to file end radius

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