C2 Project News
May and Early June 2016
May and early June working parties
There have been three working parties since our last update at Easter, as we try to maintain momentum on the project. A number of different jobs have been carried out.
Painting the engine wheels at Easter showed up the casting imperfections on them. Whilst these imperfections have no influence on the functionality of the wheelsets, we want the locomotive to look neat and tidy. Therefore Dave 2 used some filler to fill any low points, and sanded them back flat. Using a die grinder, he removed all the casting flash from the holes in the wheels. It is remarkable how this has transformed their appearance. Another application of primer then undercoat, and we are now much happier with the way the wheels look.
Quite a while ago, we planned how to flatten the existing front buffer beam to make it suitable for bolting a new buffer beam onto. The involved grinding the high points and milling some tapered steel strips to compensate the low points. Andrew has now welded the strips to the existing buffer beam, and Paul and Dave 2 have carried out the necessary grinding. Paul has also designed a fixing arrangement for the new front buffer beam, so we will soon be ready to order the metalwork for it.
Paul has carried out a flatness survey of the existing rear buffer beam, as we will carry out a similar exercise on that too.
The key steel which was ordered at Easter arrived, and Andrew was given a lesson on making keys by Paul Holland, an expert machinist from Red Bull Racing. With such top quality tuition, it didn't take long before Andrew was churning out the keys for the horn faceplates and wedges. There are a lot to do, and because many of the keyways are worn, each key has to be stepped and made to bespoke dimensions. But good progress is being made.
When grinding the fixed horn faceplates, it was possible to clamp them onto a parallel sided block on the surface grinder bed. However, the horn wedges do not have parallel faces, so a different block is required. Dave 1 found a suitable block of steel, and spent a few days machining and grinding it perfectly square before milling a 1:12 taper onto it. This now enables us to clamp the horn wedges (and eventually the wedges faceplates too) onto it such that the correct 1:12 wedge angle can be ground.
Using the new jig, Paul made a first pass at grinding the horn wedges. This gives us flat surfaces to measure, which improves the accuracy of measurements considerably.
Paul and Dave 1 refitted the fixed horn faceplates and the newly ground horn wedges to take another set of measurements. These measurements will enable us to develop a grinding plan for the horn wedges, just as we did for the fixed horns.
During May several sheets of brass were ordered for the sides of the axleboxes. Due to variations in the machining of the axleboxes in China, different thicknesses (between 10mm and 20mm) of brass plate are required.
In early June the brass sheet arrived. First job was to mark out how we wanted to cut up each sheet to get the required number of axlebox sized plates from it. Since most of the sheets were too big to fit in the band saw, Dave 1 used a plasma cutter to make the first cuts. Dave 2 could then fit the smaller sheets into the band saw, and we now have a full set of brass plates ready to be machined to fit onto the axlebox sides.
Andrew has ordered the necessary countersunk screws and countersinking tool for fitting the brass plates to the axleboxes, so we intend to get on with that task at the next working party.