Build Diary entries for April 2021

Here are the diary entries for this month. You can use the forward and backward links to see the next or previous months. Most photos taken before 2018 are small size. From 2018 onwards, most photos you see below will have a link to a full size image by clicking on the photo.

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Bogie Suspension System
12/04/2021
	We are now starting to procure parts for the bogie suspension system. The bogie differs from the the other wheels on the locomotive in that the springs do not bear directly on the axleboxes. The main spring is an inverted leaf spring, 1 fitted on each side of the bogie frame in a spring cradle running alongside the frames of the bogie. The spring cradle is in effect a compensation beam in that the movement of one axle is partly transmitted to the other axle as well as to the spring. The central buckle of the leaf spring is attached to the central bogie stretcher whereas the ends of the leaf are attached to vertical spring links, the upper end of which is secured by a cotter sitting in these Spring Cradle Brackets - fitted to the Spring Cradle - made for us by Alpenbury Precision Engineering Ltd in Rotherham. They've also made the pins that will be used to secure the brackets into the cradle - these will be welded into the cradle.
Bogie Centre Slide
19/04/2021
	The bogie centre slide was released from the machine shop today. Geoff, Alan and Keith ran a check to see if the pivot bush will fit in the slide. The pivot bush is made from cast iron and is an interference fit in the centre slide. We will fit it by freezing the bush in liquid nitrogen and giving it time to shrink. Hopefully the bush will then just drop into its place and expand as it warms up. The bush is secured by 2 set screws which hold the bush in position. Today's check was to make sure that it was just over size and that when frozen, it should fit in place.
Bogie Lubrication Parts Completed
26/04/2021
	A big thank you to Ian C who has completed all of the components for the bogie lubrication pipework. Most of the pipework is 1/4" diameter and is for grease lubrication. The 2 angled connectors at the top are for the oil lubrication feed to the centre slide. They will be bolted to the bogie pivot stretcher on the frames and flexible pipes will be connected to the angled ends. The flexible pipes then drop down to the centre slide on the bogie. At the bottom are the brass cones which will silver soldered to the 1/4" pipes. The steel connectors are bulkhead connectors and grease nipples will be fitted in them.