"Vulcan" non-condensing beam engine, by  Edgar T. Westbury.

David Allinson tells me,
The big end (split bronze bush) on the connecting rod part number 35, is shown to have an
outside diameter of 3/8 in one view, and 7/16 in another. The 3/8 is in error. Read 7/16

STEAMENGINES.ORG, Beam engine.

Some time ago,  drawings of several engines were made available on the www.steamengines.org website.
They were intended to be simple designs for the newcomer, which is an excellent idea, but unfortunately the drawings do not appear to have been  checked for errors.

The Beam Engine will not work as designed.
There is an eccentric on the crankshaft to operate the valves. The eccentric has a conventional strap, and a rod leads to the valve area, where it is fixed to another eccentric. As everyone should know, you cannot make rotary motion by applying force to an eccentric.

The second eccentric, (the one by the valves) will have to be changed to a crank, which will mean altering the supporting brackets, and extending the rod.
It is an easy alteration for anyone with some experience, but if any novice has problems, and can email me copies of the drawings, I will sketch out a new design for that section.

STUART MODELS 10V, 10H, D10,  REVERSING GEAR.
Stuart Models, and their predecessor, Stuart Turner, have been  making steam engines in kit form for almost 100 years.
Their designs are tried and tested,  work well, and are an ideal introduction for newcomers to this hobby.
However, like all of us, they are not infallible.
Tim Rickard has informed me that there is an error on the drawings of the reversing gear which fits the above engines.
Tim says, "The drawings for the valve rod clevis (item 1 which ST call a rod head) are incomplete having a
single view and one dimension only! I think the end should be tapped 7BA but that will obviously depend on what is on the valve rod. The clevis should be slotted 1/8" full (as LBSC would say) deep enough to allow the expansion link to fit on the die and a 7BA passed through the clevis and die. The
cross hole should be 1/8" from the end of the clevis. It should be 7BA on one side and drilled to clear 7BA on the other. I don't know the total length of the clevis but it should not be critical.

Southworth Corliss Engine.

According to Jo Thoms,

The Governor housing cover, part 238, shows the "stub" being 7/16", it should be 23/32". Arguably it would look better with the shorter stub but then you need to shorten the governor shaft and you would loose
bearing surface.

More importantly all of the castings are undersized due to the patterns being an aluminium casting from the original Arnold Throp wood patterns, consequently there is very little, if any, spare metal.