machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

Tag: steam chest


Apart from contending with fauna in my workshop (a tiger snake) , I did actually make some progress today.


All three steam chests are now attached to the cylinder block. This photo shows the high pressure cylinder steam chest. All of the screw holes are threaded and ready for the screws. More BA7 screws on order.


The time which I have had spare in the past few days has been spent tidying up the workshop,  sorting tools and putting them away.  Today I spent a few hours making a start on the intermediate and low pressure steam chests.

Roughed them out and CNC’d a boss on the bottom of each chest.  Then roughed out the steam chest covers.

This is the progress to date.


So far I have drilled, tapped and inserted ~180 BA7 screws and studs. And there are a lot more to go. The steam chests and covers are sitting on the base.

Attaching the cylinder block bases to the cylinder blocks was tricky.  I drilled the holes with the bases glued to the blocks using Loctite, and then tapped the holes and inserted the screws.  I will apply some heat to break down the Loctite.

It is quite difficult to insert the screws to the underside of the block.  Many are quite inaccessible.  There have been multiple tear downs of the model, with many more to go, so only a small number of screws are currently inserted.  I will have to work out an order of assembly, to make the assembly process as logical and easy as possible.

I am starting to consider which method I will use to make the crankshaft.  It has 6 main bearings, 3 big end bearings, and locations for 3 valve eccentrics and an oil pump.  It is quite complex.  Fabricate or turn from the solid.  I am tending to the latter, but we will see.

Steam Chest Uncovered

I removed the steam chest cover in order to attach the steam supply pipe.
The photo shows the sliding valve (gunmetal) and the valve rod which is moved by the silver coloured rods at the sides.
One of the steam ports is visible underneath the sliding valve.
The photo also shows the 6 steam chest studs which hold the whole thing together.