Giles
Western Thunderer
Out of sheer self discipline I've picked up the three 7mm Decauvilles again, which for a variety of reasons are not easy. The axles will need to be permanent fixtures in the chassis. Which is conventionally anathema (for good reason) - but these locos have a bevel gear for final drive, so the gearmotor can pop out if required, and the valve gear is really going to be quite minute, so one doesn't want any disturbance to it either. Added to which, they will be radio controlled, so no pickups etc ......
This is where I left them....
And this is what I've been up to today. Making 12 outside cranks from 0.9mm nickel silver. A couple of test ones cut to make sure I was getting it right found that the small offcuts of sheet I was using out of the scrap was distorting and moving the job a fraction towards the end of the cut, so th only way of getting reliable accuracy was to cut on the edge of a larger sheet.
I was undecided as to crankpins, as I will be short of space, but I have decided to go with 0.8mm O.D. hypodermic needles silver soldered. I hope it doesn't come back to bite me!
Each crank takes 1 minute 5 seconds to laser, but a lot longer to clean both faces and pop out both holes! (And find it again on the floor when I've dropped it....)
This is where I left them....
And this is what I've been up to today. Making 12 outside cranks from 0.9mm nickel silver. A couple of test ones cut to make sure I was getting it right found that the small offcuts of sheet I was using out of the scrap was distorting and moving the job a fraction towards the end of the cut, so th only way of getting reliable accuracy was to cut on the edge of a larger sheet.
I was undecided as to crankpins, as I will be short of space, but I have decided to go with 0.8mm O.D. hypodermic needles silver soldered. I hope it doesn't come back to bite me!
Each crank takes 1 minute 5 seconds to laser, but a lot longer to clean both faces and pop out both holes! (And find it again on the floor when I've dropped it....)
