Two Steps Forward One Back

 It's taken a little while but eventually after scouring the junk box and filling a few holes I managed to transform some scap material into three rollers to use in the bender to form the rake on the fork blade tubing.

Ready to roll

Manual crank

 Thinking that I might save my good material I searched aroung for some scap 1"dia tube and found an ax Halford's bike I had been given for spares that had 1" frame tubing. So another digression while I stripped it down and extracted the tubing only to find that it was best quality gas pipe with amazingly thick walls - so scrub that idea.
 
 Anyway I found somewhere to mount the bender and using my good 18swg tubing set about trying to set a bend. First problem the rollers could have done with being a bit bigger as there was not much travel on the

Oops no teeth

adjusters and it was apparent that to set a bend a good allowance for spring back would be needed.  Undaunted I forged ahead and cranked up the adjusment towards its limit and then disaster struck - the load on one of the gearwheels was exceeded  and teeth were shed.  The trouble seems to be that the gear wheels are cast iron which is not good under high tensile or shear loads.  The question I now have to ponder is can I salvage this basic design or do I need to try something completely different.


The trouble with posting bloggs as you go is that when you realise that you have made a big gaff you have already told the world. Well so be it.

 I have been doing what I should have done all along and got out the paper and calculator and rapidly realised that the forces required to bend a 1" dia tube in my design of rollers are absolutely enormous - no wonder it broke.  So I am now doing more research (and calculations) to work out the best way forward.  With my background I should have known better - thats why we had designers and stress men etc to make sure our concepts stood a chance of working before they were built.  My trouble is being a thermodynamasist / fluids mechanic engineer (fancy names for rocket scientist) I tend to gloss over the mechanical stuff.