Thanks again Guys
Well got this off the back shelf, and made a start on the piston,con rod, and big end assy.
I'm making the piston and big end out of ally bronze which has good wear properties.
First Job skim three lengths of bar down to 10mm the same size will do for the big ends. Ally bronze is not that easy to machine its very sticky and generates a lot of frictional heat, but John advised be to use a slower RPM, and it worked a treat.
The pistons were then drilled a tapped and parted off from one of these lengths.
I'm not making the big ends to the drawing I'm going to make them square more big end shape if you know what I mean
So over to the mill and with the spin indexer mill the 10mm bars to 7mm square.
At this point thing went wrong with the first bar I was planning to drill 4mm holes along the bar for the bearings but I had too much flex in the set up even with a centre and a jack under the bar the holes were coming out all shapes,
Plan B scrap the bar off turn and mill another one up, and drill them in the vice.
With a self centering four jaw in the lathe and using a bit of 4mm rod through one of the cross holes as a stop, face, turn step, drill and tap M3, not forgetting to drill a 1.5mm 3mm dia register hole, this will help pull the con rod concentric when its screwed home.
Remove the cross bar first before turning.
Check that I'd got the correct hole centre.
Whilst I'd got the spin indexer set up I fluted a couple of bars to make knobs out of for the displacement lubricator.
Her are the con rod ends finished and a couple of lose assemblies.
Last job of the day clean the pistons a rods and glue with thread lock, I'll leave them over night so I can make a start on turning the pistons to size in the morning.
Stew
