The parts were created in Part Design WB with the occasional use of Part WB for primitives, sweep and loft etc. where necessary.

Thanks to you all for your helpful input

Thanks wandererfan.

A request for information chaps, Often I get requests to upload the files pertaining to the steam engine models I post. I am not uncooperative the files are very often just to large to post. What is the maximum size file I can upload which could be easily accessed by others, I do not have a drop box...

The file of parts for this model is 6MB and so unable to post here, I used Assembly 2 in FC V0.16 and worked from the base up, after having created subassemblies of the Moving, con-rod and valve beams and also the crankshaft.

This was done on FC V0.16 in November 2017. only took a couple of days.
The plans are by JDW Draughting services NZ and can be found here:- http://www.vapeuretmodelesavapeur.com/telechargements5/

Not sure if this is what you are trying to achieve, as your pattern was not dimensioned or constrained I just guessed at final object. This comprises 3 files. The first is the tube, the second is the shape you wish to remove, the third is an assembly, importing the tube then the pattern shape, then ...

Nice modeling Dirk.

As vocx kindly pointed out I should have noted "assembled with A2plus V0.4.25 WB " NOT "Assembly v0.4.25 WB" sorry for any confusion.

Hi Supdoc, looks like Papybalaise has you covered.