This seemed like a major milestone – starting work on the Cylinders….

Decided to do the LP one first – the game plan is to rough skim the top (to provide a footing to rest it on when turned over) then machine the base and bore in one go thereby ensuring that the piston rod in the bottom cover and the piston in the bore are truly in line…

A first skim over the top of the LP cylinder casting

So, as planned we mount the casting square on 1-2-3 blocks to provide clearance to bore thru, and use 80mm facemill (a freebie from somewhere with new tips and arbours from Greenway Tools (a very good firm))…

quelle dommage – cracks!

two scary cracks in the LP cylinder casting!

The first cut over the casting throws up a major worry – not one, but two cracks in the casting, one of which clearly runs from top to bottom 😦

Given that I purchased them second-hand, there is no chance

boring the LP cylinder

 of a replacement, so I figure they might just machine out.. and set off boring the casting – having first made a bush with a carefully miss-aligned hole so I could use a straight HSS tool bit in the boring head.

While the first couple of cuts just panicked me even more  – the crack looked huge, I just kept going and it all came out beautifully – with a LOT of swarf!

quite a lot of swarf!

 A very nice result – and I breathed a sigh of relief as there were a set of Leak castings on show at the exhibition, and the builder had clearly had some problems with the bore, as the finish looked very iffy….

Followed this up with machining the LP valve chest (a bit tricky to get into the corners of the inner valveface, but all came out OK…