Drawing Errors and Omissions

Disclaimer: Note that the things listed here and my fixes for them are exactly that - my fixes. I recommend - nay - insist that you check on your own model first before imlementing anything. I can accept no liability or responsibility for any cock-ups caused by the contents of this table.

DrawingPartErrorCorrection
901 Boiler Hollow stay positions (on the central "zig-zagged" column) are inconsistent with the hornplate drawing Decide which is correct and build the engine to that...
902 Wheel retaining collar Collar retaining pin hole as drawn leaves no material on the collar Move 1/16" further in, maybe make the collar slightly wider as well
902 Smokebox door locking handle (large) As drawn very little space is left between the handle and the nameplate Either bend the handle slightly or make the boss slightly thicker
902 Smokebox door bracket Rivets for the smokebox door bracket appear to clash with the door ring rivets Make the offending door ring rivets countersunk - still tight so move the brackets slightly to create room
902 Door spear No dimension for the "hook" part ~1/2" from the centreline is adequate
902 Nameplates No instruction on how to mount File the back of the nameplates so that the front faces are vertical when mounted on the smokebox
902 Axle fork and / or retaining collar As drawn there could be a 3/32" gap between the retaining collar and the front axle bearing Probably easiest to move the cottar pin slot down the axle fork. I'm not absolutely sure this is an error, and if it is, that it'll cause any problem...
903 Front hubcaps No dimension for the radii on the outside of the hub Don't scale from the drawing! Try ~70 thou radius
903 Knee irons The dimensions of the end which mates with the spud pan rim are a work of pure fiction Don't know, apart from spending the rest of your natural life filing the bloody things to fit. I ended up using an angle grinder...
903 Front wheel bearings The space between the collars on the front axle is 1/32" bigger than the bearing Increase the 3/32" dimension of the bronze bearing to suit
904 Hornplates The dummy stay positions are inconsistent with the boiler drawing Check against the boiler before drilling!
904 Hornplates Poor dimensions of the ring of dummy rivets Drawing here (right click & choose "Save Link As"). Nearside shown, referenced from the crank centre, simply because that was how it was set up in my milling maching.
904 Crank / 2nd shaft bearing housings Rivet holes are referenced from the casting edge Drawing here (right click & choose "Save Link As")
904 Hornplates Front spectacle plate lower 5 holes - the top hole rivet interferes with the bearing housing Space the holes slightly closer (ie keep the bottom hole where it is and reduce the '4 Equal Pitches 2-1/8"' dimension) and / or reduce the 7/16" dimension from the bottom row of holes to the bottom of the bearing housings (from full size engines it seems that this is how it should be done...)
904 Hornplates The hole for the blowdown cock bush is 1/16" too far towards the rear of the engine compared to the boiler. If you've bought the laser cut hornplates, file the hole to make it fit... (Error found during assembly of the CAD model)



The following errors and omissions come from several sources, and haven't been encountered by me yet...
Part / DrawingError
Boiler Depth of hole for tap in blowdown cock is not stated
Steersman's platform Platform overhangs the edge of teh tender by 1-7/16" whereas the gear guard width from the tender face is 1-1/4"
Water pump As shown on the drawing the water pump makes it impossible to lift the lid of the third shaft lubricating box. By lengthening the pump bracket very slightly it is possible to position the front bearing of the pump shaft just clear of the lubricating box lid.
Pressure gauge If you intendto steam the engine you will find the correct position for the water gauge will make it difficult to read. Possible alternative position is on the left hand side of the rear edge of the third shaft stay.
Cylinder casting Take into account expansion of the boiler when positioning the cylinder casting. Position it slightly closer to the crankshaft.
Valve rod drawing "The drawing for the valve rods will drive you crazy. The centre lines are confusing but after much thought I came to teh conclyusion that the 7/32" dimension for the number 2 forward rod should in fact be 15/64". In any event you may have to bend the rods very slightly to obtain a perfect fit to the expansion link."
Fire door The fire door fouls the lower stay behind the hind axle bearings (the extensino plate of the tender floor). Crank the plate downwards in order to obtain sufficient clearance to open the fire door.
Hornplates Both hornplates should have a "church window", not just the offside as stated
Slots for slide bars in the cylinder rear endcap Drawing states 11/16", slide bars are 5/8"
Top steering bracket Dimensions for shaft centre is shown as 2-17/32" (2-13/32" from the offside hornplate). Bottom bracket centre calculated at 2-3/16" from the offside hornplate therefore the steering jams.
Roller mounting bracket No radius for roller mountingbracket (ie tender corner radius) is given
Tow bracket No overall width for the tow bracket is given
Draw straps No overall length for the draw straps is given
Draw straps No til angle for the draw straps is given
Draw pin Draw pin holes are 7/16", draw pin diameter is 3/8"