Thursday, 21 November 2024

The Quarry Hunslet 'Alice' class from PDF Models - The Making Of.

Part 1 - The chassis


Purchased in 2021 from PDF Models, this kit would make a brilliant addition to my fleet of engines. The only difference this time is that there will be no need to charge it up or raise steam before it can be operated.

Although a relatively easy kit to build, I would say it is more for the medium experienced modeller. The instructions lack punctuation, so a good read through and familiarisation with the components before starting is a must. PDF Models also provide contruction videos via their website.

Starting off with the chassis, identfy the two sides and frame spacers. Glue into the spacers 2mm nuts, using the bolts to hold them in place whilst the glue dries. Once set, remove the bolts and paint the chassis parts.


I used Halfords spray cans throughout the making of this model. Here the chassis was given two coats of grey primer and finished with two coats of satin black.

During this process I prepared the two cylinder covers for painting. This involved removing the 3D printing ridges using various grades of sandpaper, starting with 80, 180, 1200 and 2000. It takes some time, but well worth it.


After 24 hours once the paint had hardened, the chassis was bolted together using 8mm bolts.

At this point, the centre cylinder holes were lightly opened up using a 3.2mm drill bit. This enabled the brass cylinder tube to be inserted and glued leaving a protrusion of approximately 7mm at the rear of each cylinder.


In preparation of fitting the cylinders to the chassis, the two holes on the rear of each cylinder were opened up slightly with a 2.5mm drill bit and tapped with the 3mm cap head bolts.

Now to make the cylinder slide bars and mechanism. Take each cross head and glue in the 2mm steel rod. I then temporarily fitted the cylinders to the chassis with cap head bolts. Slide the cross head and rod into the cylinder tube and fit the slide bar holder. Once checked for free movement a spot of glue was applied to the holder and rear cylinder and the slide bars were fitted. Once set, I remove the cylinder from the frame and fitted each connecting rod* using a 2mm x 6mm bolt (but not too tightly as it has to slide freely.) 
*I thought it a good idea to paint the connecting rods before fitting using Red Primer with a top coat of Fiat Red Orange.


Taking the gearbox housing, the bearing holes were opened up to 4mm (drilled) and the bearings fitted. The axle was then slid through the bearings and the gear added. Once happy with its free movement, a spot of glue was daubed onto the outside of the bearings to hold them in place. Once all okay, I tested the movement with a 3v battery before adding a spot of gear oil.


The chassis was now un-screwed and the wheel bearings fitted. Do not attempt to fit these with the chassis screwed together! Fit with a wooden or nylon head modellers hammer making sure that the 'top hat' is on the outside of the frame.


The wheels were next fitted to the axles by pressing them on until a distance of 41mm for 45mm gauge (28mm for 32mm gauge) was achieved. Either use a vice back to back or in my case my nylon headed hammer.


Fit the the chassis back together, slotting in the axles and wheels to complete the frame.


Refit the cylinders with the 3mm cap head bolts.


Part 2