New batch of Hunslets - Stage 1

Hi, it is quite a long time since the Wrightscale Workshop had anything to report.  With the first batch of Hunslet locos finished in May the summer was spent catching up with the real tasks of living.

First batch of Wrightscale 16mm Alice class Hunslets - the goal we are aiming for

By the Autumn the etchwork for the Hunslets had been revised in the light of experience, as had the laser cut parts. By October the new components were starting to collect in the workshop - which had benefitted from a clearout and clean.
I took the opportunity to adjust and service all the machine tools and run a new supply to the workshop to power a large rotary converter. This was to supply 3 phase to the Britan Lathe that makes all the steam fitttings and a new large lathe purchased to pursue another project.  This is a big project, building a half size loco to run on 10 1/4" gauge track. Sarah and I both have decided we need a railway to move 100 tons of broken rock to fill gabions beside the burn from which our house gets its name. Any excuse to play trains!
Back to the business.

Assembling the chassis step one, positioning the spacers and checking that everything is level and square for marking out

The first stage of building these locos is to put the chassis together.  The construction is simple. Laser cut frame sides are erected with milled block-spacers front and rear with a rod-frame space at the middle of the frames.  This is done on a surface plate with the holes spotted through the frames into the end spacers.  These are drilled and tapped 10BA.  The frame holes are then countersunk and erected with10BA CS bolts. The bearing holes in the frames are hand reamed and the bearings  pressed in.

Final checks before sweating on the cosmetic frame overlays.

The assembly, consisting of assembled frames, bearings and test bars (long axles), is then placed on parallels on the surface plate and checked to ensure it is absolutely plumb and the axles rotate freely. All the bolts are tightened down and the frames re-checked.  Then the frame sides are cleaned, coated with solder cream and the bushes pushed in to retain the frame etched overlays. This sandwich is held down with loads of light clamps and sweated together.  When both sides are finished a final check is made with the parallels  on the suface plate to check that everything is still plumb.

The set-up for machining the wheels. When you are doing something 44 times, you need a lever operated collet and a tail-stock capstan. These accessories make repetitive jobs tolerable.

As a respite some days are now spent machining the 44 wheels and 44 outside crank castings.  Then there are 22 axles to make, parting off to exact length and drilling centres in them all.  We are getting close to where we are at as I write this.  The last big job although only cosmetic is spending 2 solid days cutting, cleaning and fitting the 44 lost wax cast detailing springs to the chassis.
Now the wheels can be test fitted on the axles. This consists of verifying that they all sit level on the surface plate. The cranks can then be fitted to check the clearance at the front end behind the cross head.
The next job to come is fitting the crankpins. All 44 of them, 10BA tapped crankpins, must be fabricated, loctited and pinned into the cranks.  The motion parts - eccentrics, stop collars, spacers, and laser cut eccentric rods will have to made and fettled before the wheels can be finally fitted and loctited.

Stage One finished! Everything is square, all the wheels touching the surface plate. Now it is assembling the motion and finishing and fitting the cylinder blocks.

The final stage of the chassis is to fettle up the coupling and connecting rods, finish the cylinder blocks by machining the pistons, rods, crossheads, slide bars, covers, valve chests covers, valves, valve rods, and not forgetting the 44 gland nuts........ then hopefully by the end of January there will be a Stage 2 report.  Stage 2 has been reached when the chassis run on air.
There is a lot of work in making these engines and do remember there is just me doing it - no lines of Chinese technician bent over their benches on an assembly line.