Stuart Plans, I dislike under constrained dimentions

[HSM01]

I though I was beginning to understand Stuart D10's plans. I was incorrect.
Bare minimum dimensions are given. One would have thought paper was expensive!
I also work in thousands and the conversions from fractions is a PITA. I guess conventions were different back when.

Sometimes I failed to inspect the related sketches on the plans.
I am at the beginning and working on the sole plate.

I was tempted to lay out the centerlines for the standard (V-shaped cylinder support) using the distance between the bearing centerlines.
It didn't look right.
Then I noticed the centerlines between the bore given in the steam pipe layout as 1-13-32 or 1.565".
If I calculate the distance between centerlines on the throws of the crankshaft, it's 1.406".
One is .159 off or the crankshaft throw is not on the centerline of the bore.
I am not getting this. Does anyone care to help me out on this issue?
Thanks
Rick

 

[rleete]

Cranks are not symmetrical?

 

[ninefinger]

I think its just your conversion math that is a bit off, 1+13/32" is 1.406"

 

[HSM01]

I must have typed it into Excel incorrectly. I am going to see how it works out on my layout.

 

[HSM01]

That was it. I consider it a success if I hadn't messed up the part.
The sign of a good mechanic, is they stop right before they mess something up.
I got lucky on this one. Appreciated the help.

 

[Mark_1984]

There’s a great app for the iPhone called Fraction Calculator Plus. Calculates in fractions and gives the answer in both fractions and decimal. A real time and dock up saver!

 

[Richard Hed]

I though I was beginning to understand Stuart D10's plans. I was incorrect.
Bare minimum dimensions are given. One would have thought paper was expensive!
I also work in thousands and the conversions from fractions is a PITA. I guess conventions were different back when.

Sometimes I failed to inspect the related sketches on the plans.
I am at the beginning and working on the sole plate.

I was tempted to lay out the centerlines for the standard (V-shaped cylinder support) using the distance between the bearing centerlines.
It didn't look right.
Then I noticed the centerlines between the bore given in the steam pipe layout as 1-13-32 or 1.565".
If I calculate the distance between centerlines on the throws of the crankshaft, it's 1.406".
One is .159 off or the crankshaft throw is not on the centerline of the bore.
I am not getting this. Does anyone care to help me out on this issue?
Thanks
Rick

I'm with you on the complaints about not enough info on the dims. There may be a lot of dims that are not necessary to put on the plans but there are also a lot that really need to be added. I too like to make p;arts to correct and complete plans. The first Stuart I did, I was astounded when I was looking for certain dims. Had to find them on another part--not the way I do things.

And also, I always do up any new plans in Alibre, AutoCAD or SolidWorks so that I can become more familiar with the parts, put them together in assemblys, print out all the pages I need on clean paper with ALL the correct dims. I've complained other places, far too much before, -- soon I should get my boy scouts complainer badge.

 

[djc]

Old Chinese proverb: man with one watch always knows the time. Man with two watches never sure.

It has been a tenet of engineering drawing since forever that dimensioning is necessary and sufficient. That has been arrived at through long experience and has proved itself least costly in terms of actual and potential errors.

People reading the drawings are expected to develop the skills necessary to work within those parameters.

Consider the alternative: you would complain more (and the complaint would be justified) if a dimension was shown in two places and the two places contradicted.