Author Topic: GWR 517 Class Loco  (Read 632 times)

0 Members and 1 Guest are viewing this topic.

Offline 753

GWR 517 Class Loco
« on: Oct 09 2019 14:55 »
I am building a GWR 517 Class loco using a CNC milling machine to make the various components.

Members may be interested in a description of the process and methods I use in the build. Parts are first drawn full size in a CAD program, CAM then reads the drawing to create a code that in turn instructs the machine to cut the part.

Here are the parts for the basic chassis in 1.5mm steel, the frames where longer than the mill table so have to be made in two parts, and will be silver soldered together, the spacers have fold groves cut with a 90deg centre drill along with hole spots. The other two parts are for the outside frame for the rear bogie wheels.

Mike




Offline 753

Re: GWR 517 Class Loco
« Reply #1 on: Oct 10 2019 15:54 »
The chassis soldered together; I use a resistance soldering technique to join parts.

It is like arc welding where you clamp an earth to the metal and when you touch the probe you get intense heat at that point, and by running the probe along a join you get a neat fillet of solder.

Mike





Offline 753

Re: GWR 517 Class Loco
« Reply #2 on: Oct 11 2019 15:08 »
My method of forming rivets is to spot drill to half the depth of the material, which allows for less material to be formed and locates the punch for accurate spacing.
The press was found in a junk shop many years ago and adapted to take different sizes of anvils for various rivet sizes.

Mike








Offline 753

Re: GWR 517 Class Loco
« Reply #3 on: Oct 15 2019 14:58 »
Chassis finished using Slaters wheels, I made new crank pins and nuts as more GWR practice. The coupling rods were made of steel and the webs reduced as pic.
The front and back axles are fixed with the centre axle floating, and will be held in contact with the rails by the weight of the motor gearbox assembly.

Mike






pic hosting

Offline 753

Re: GWR 517 Class Loco
« Reply #4 on: Oct 26 2019 11:23 »
Due to limited space in the boiler/tank area, it was a problem finding a motor/gearbox to fit. The ever-faithful eBay came up trumps with a motor/gearbox combination that fitted between the frames, and a brass worm spur gear set.
The motor sits in an oversized yoke that allows the motor to rock as the axle moves up and down, the ashpan will mask the motor from the eye.
The basic body is made from brass sheet in modules that follow the colour scheme.

Mike






Offline hornbeam

Re: GWR 517 Class Loco
« Reply #5 on: Oct 26 2019 18:05 »
Very nice!

Offline 753

Re: GWR 517 Class Loco
« Reply #6 on: Nov 17 2019 13:09 »
Progress on the 517, most of the main construction now complete just the back head and a few details to add, then a paint job

Mike



Offline 753

Re: GWR 517 Class Loco
« Reply #7 on: Nov 30 2019 11:43 »
As a life long GWR man I prefer the earlier period of the railway late Victorian to Edwardian, to my eye the engines have an elegance not found in later examples.
The now complete 517 class is a good example, built in Wolverhampton, designed by Armstrong they are one of my favourite engines.
Coincidently I joined the G3 Society a year ago and have had a very pleasant year building locos and stock to 2.5” gauge, meeting fellow members and running a Prairie at Brian Torr’s GTG.

Mike