Part six by Jason Ballamy

The bottom of the A-frame which supports one end of the crankshaft started out as a length of 1" x 3/8" hot rolled which was cleaned up to the required 7/8" x 5/16" and a recess machined in the bottom face. This was why I chose hot rolled as it is less likely to bend if an unbalanced cut is made.

The top face was then counterbored for some bosses around the mounting holes and 1/8" wide x 1/16" deep slots cut to locate the side flanges and a central web.
I've had some 1" x 1" brass T-section hanging about for years so thought that would be suitable to make the legs with. These were faced off at the required angle and the leg of the tee reduced in length part way, here they are stood in the slots.
It does not show too well in the photo but this bit of 1/2" steel also had the ends machined to the correct angle and then a slot cut with an 1/8" saw for the wide part of the tee section leg to locate into.
I then milled away some of the waste either side and put a hole in where the bearing brass will go to reduce the mass so it was easier to get up to soldering temps without overheating the brass and risking it melting or distorting.
A strip of 1/8" steel was shaped up for the bottom web using a 5/8" cutter to get the internal radius required.
Finally a couple of screws were added to help hold things together while soldering.
After a quick clean up the ‘casting’ was then packed up at an angle on the mill table and the sides tapered, along with the shaped parts either side of the main housing, which also got rid of the assembly screw heads/ends.
When both sides had been done it was set horizontal and the pocket for the bearing milled out, I also added a couple of small holes in the corners to make it easier to file them out square.
Following a good cleanup, easing external corners and adding fillets to the internal corners it looks like this.
To stop the bearings dropping out the bottom requires a keep plate. The original smaller drawings just show a flat bit of bar but looking at photos of pumps in preservation they have a stiffening web on them. So a piece of bar was duly drilled and slotted and some bits shaped to fit in these holes and slots.
And after soldering etc they look a bit more like cast items