Muncaster Drg Query

[Brian HParticipant @brianh50089]

I've been following the thread started by Ron Laden about the Muncaster Horizontal engine and have downloaded the drawings by JDW for this engine and printed them off at full sized on A3 paper

I'm at a bit of a loss about the scale of the drawings,which often state that they are 1:1 but when I drop my rule on them they seem to be nearer 1:2.

Has anyone else had a look at these drawings?

Brian

[Brian HParticipant @brianh50089]

[Neil AParticipant @neila]

I don't think I would worry too much about what your rule shows the printed paper drawing scales. It's probable that he has forgotten to alter the scale on the drawing.

When I worked in a drawing office all the drawing sheets had "DO NOT SCALE" pre-printed at the bottom of the sheet. In the days when drawings were hand drawn there was always the possibility that a dimension had been altered, but not the actual component feature. Took too much time to rub out and redraw.

Now, with most drawings produced by CAD this is probably less of a risk, but it is always best practice to only go by the dimensions. If the dimension is not there then you have every right to complain very loudly. If I had missed a dimension I would not expect someone to have a guess at what it might be.

The drawing sheets still had "IF IN DOUBT, ASK" printed at the bottom and we hoped everyone would follow the advice. Sometimes it was in vain!

Neil

Edited By Neil A on 25/01/2020 23:09:34

[geoff walker 1Participant @geoffwalker1]

Hi BrIan,

Regarding the scale of the drawings there is, as far I can see, no real logic in what Julius has done.

The stroke of the engine from Muncasters original drawings is I believe 7/8" {22mm]. Julius has the stroke at 36mm giving a scale up of 1.63 : 1.

The original bore is 7/16" (11mm) and Julius has 16mm which is 1.45 : 1.

There are numerous other anomalies.

I have done PDF drawings of this engine to muncasters original sizes. If you are interested in this engine and would like an email copy let me know.

Geoff

[Brian HParticipant @brianh50089]

Geoff, many thanks for your kind offer, I have sent you a PM.

Brian

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