Thursday, July 21, 2011

Some manual work for a change

What to do when it's baking out?  I know, weld some parts!  One of the myriad custom small parts for the bottom end of the engine is a double gear for the electric start system.  Yup, when my rider has rare occurrence of hitting the pavement (of course due to some other rider's error) they'll be no yelling at recalcitrant marshals for assistance here.  A press of the magic button and the bike will start right up and be back in the action.

Several of the electric starter components are sourced from various OEMs and this double gear is one of them.  It needs to have an increased separation between the gear faces than the original part.  To accomplish this I'll start with 2 complete gears, machine one face off of each, then weld a spacer in between with the appropriate jigging to keep both gears and bores properly aligned.

Original gear:

Machining large ring from one part:

Gears machined apart and spacer ring prior to welding:

Assembly pressed together:

and welded:

I used a Miller Syncrowave 250 TIG welder using stainless rod to join the gear pieces with a piece of 1018 steel.  This should provide a weld that is not too hard and does not have too much alloying element diffusion.  I took care to keep heat input to a minimum to avoid losing the hardness of the teeth and let the part cool very slowly to prevent cracking.  The part looks good and both gear faces run true so I can take one more part off the to-do list.

I am waiting for some metric 5C collets to arrive then will finish the oil pump shafting and some other various simple round parts like front suspension arm inner races and rear swingarm link and pivot races.