MuellerNick
Well-Known Member
- Joined
- Oct 5, 2012
- Messages
- 398
- Reaction score
- 191
Hi!
Long time no read. I have been distracted by other things.
And as a side-side-side-side-project, I made a bunch of crankshafts for a BWM R 75. This is a sidecar motorcycle from WW II.
I had the idea while working on something else. For me, it was quite obvious to build exactly this crankshaft. First, the motor(cycle) is quite famous. Second, in my little villige, there is a guy making spare parts for them (I do make some grinding jobs for him). He has all the original plans.
So I asked for the drawings and also got a crankshaft.
This is the result:
5 of them, together with the original on a drawing (part of) the crank. If you are clever, you can detect the scale. Right! 1:5
Pictures were taken with a flash, the finish looks much nicer in real.
Jig for the second milling op. The brass pin indexes the second crank pin relative to the first.
With the work in the jig. The jig for the first op looks similar. Just shallower, because in the first op, the center web is machined too.
The outer web is milled with an endmill. The crank pin is milled with a circular saw, like the inner web.
This crankshaft is only intended for look and see. For playing at your desktop, or attached to the keys, or ...
It is made out of stainless (1.4305). Machining almost takes 1 hour. Can't rush the sawblade ops, or the blade will start to climb out of cut.
The original is pressed together, for the conrods. As I don't want to add them, a single piece is good enough for the purpose.
Nick
Long time no read. I have been distracted by other things.
And as a side-side-side-side-project, I made a bunch of crankshafts for a BWM R 75. This is a sidecar motorcycle from WW II.
I had the idea while working on something else. For me, it was quite obvious to build exactly this crankshaft. First, the motor(cycle) is quite famous. Second, in my little villige, there is a guy making spare parts for them (I do make some grinding jobs for him). He has all the original plans.
So I asked for the drawings and also got a crankshaft.
This is the result:
5 of them, together with the original on a drawing (part of) the crank. If you are clever, you can detect the scale. Right! 1:5
Pictures were taken with a flash, the finish looks much nicer in real.
Jig for the second milling op. The brass pin indexes the second crank pin relative to the first.
With the work in the jig. The jig for the first op looks similar. Just shallower, because in the first op, the center web is machined too.
The outer web is milled with an endmill. The crank pin is milled with a circular saw, like the inner web.
This crankshaft is only intended for look and see. For playing at your desktop, or attached to the keys, or ...
It is made out of stainless (1.4305). Machining almost takes 1 hour. Can't rush the sawblade ops, or the blade will start to climb out of cut.
The original is pressed together, for the conrods. As I don't want to add them, a single piece is good enough for the purpose.
Nick