There are a large number of drawings, 26 in all, and some are full size so for the frames for example the drawing is over 45″ long. I purchased mine from Blackgates and they came rolled in a tube so no nasty fold lines to deal with.
The drawings cover a number of locomotive variants so there is a lot of identifying to be done to select just the A1 parts. Also I found locating parts not a straight forward task as one would imagine it to be as items can be slotted in places where presumeably there was a space to be filled.
Examination of the general arrangement and frame drawings will show up variations on springing that have to be decided upon. An early decision is needed here as it will affect what holes will be required in the frames. Likewise the axlebox can be plain or split so a decision is required befor ordering castings.
Also it is well to cross check everything between detail and general arrangement as examples arise where the detail omits important information. An example of this is the main horn blocks which have an oil hole for the axle box in the top. The detail shows the hole but does not indicate that the block is handed (left and right frame) because of the hole which is off centre.
Another aspect that affects the drawings is the frame thickness. The original drawings are for a 1/8″ thick frame which was fine in the 80’s when the drawings were done but nowadays metric material is more common and 3mm frames (or even 4mm) may be adopted instead. This will mean adjustment to dimensions of many parts fitting between and on the frames for example.
The drawings have had an update as hole dimensions have been converted to metric. That’s fine if you are solidly based in metric as your first language as it were, but for those of us still in the imperial age they all have to be converted back again to either fractions or number drills to suite the purpose of the hole which in my case will mostly be BA sizes.
Little more to say about the drawings so without further ado lets get started on the frames………….
Building a 5" gauge A1 Peppercorn locomotive 