A temporary axle was made to check the alignment of the axlebox pairs when fitted in the guides. A bit of careful filing and scraping corrected the fit
A toolmakers clamp on the lathe bed provides a back stop whilst reducing the centre of the axle, The head end of the machine has a saddle stop.
A crank axle set up between centres for final machining. Note the wheel seats are left oversize until the wheels are bored. As these are a taper fit, once the machine is set to cut the tapers the wheel seats and the wheel bores are finally machined to the same taper setting.
A wheel set up for boring. The centre is located by measurement from the inside of the wheel rim. As this may not be truly circular some judgement is required on determination of the best location
Once all the wheels are carefully bored to the same diameter a mandrel is made to fit in in the lathe spindle taper and used to set up the wheels for all further machining operations in the lathe and on the rotary table on the milling machine. A wheel is seen set up for facing
Machining the inside edge of the tyre. Note at this stage there was no intent to fit steel tyres. That came later.
Rough machining of the tyre profile. Final profiling should be done after the wheels are pressed on to the axles to correct any run out that may develop
Back in the milling machine for rounding the back of the spokes. The wheels were reversed and the front of the spokes were also machined with a radius cutter.
The spokes as cast were not perfectly regular in spacing and thickness and had some casting defects. Whilst time consuming the end result is a great improvement on the original cast.
An epoxy metal filler was used to finish the wheels where machining had not completely removed the defects. After curing the filler is easily smoothed by hand with a fil
The wheels were then returned to the lathe, trued using a dial test indicator on the tyre and bored to a taper of 2 thousandths of an inch in the wheel thickness.
Once the wheels were bored the axles were returned to the machine and the wheel seats were machine to the same taper such that the axle would enter the wheel bore by a third of the length of the seat. When the wheel was pressed home this gave an interference fit of 1.5 thousands of an inch, a little over the recommended thou per inch.
A jig was made up to hold the broaching guides for the crank webs and this was modified and reused for the wheels to ensure the axle keyway was exactly in line with the crank pin centre
The driving crank pins were made as a pair and one is seen having the keyways cut using a between centres set up in the milling machine.
The rotary table was used to set the angle for machining the square for the return crank, accuracy being essential for correct operation of the valve gear.
The same between centres set up in the milling machine was used to cut the keyways in the axles. These needed to be accurately machined at 120 degrees so the cranks would be "quartered" as the wheels were pressed on.
The crank axles need setting up carefully in order to get the correct relationship between the centre and outside cranks.
