Re: [CAD_CAM_EDM_DRO] :Compucut ?

Richard

The loco chimney is an interesting subject, but what about the GWR safety
valve bonnet in polished brass on top of a GWR taper boiler where the
bottom of the boiler is horizontal? How would you set about working out the
cutter paths for that? Or is this just "maths and spacial imagination"?

snip

>
> My tip is to practice on shapes whose geometry is fairly
>simple. One job that often comes up in steam loco modelling is
>the smoke stack / boiler transition plate. This is cast brass in
>'real' scale. The base collar is a curved disk which follows the
>top horizontal centre of the boiler radius. Into the centre of
>the disk fits the vertical, cylindrical smoke stack.
> Because the radii of boiler, disk, stack and ball-end cutter
>are constant and known, their inter-relationships are defined by
>trigonometrical equations.
> Assume the job will be held in a CNC dividing head whose
>centreline is the centre line of the stack and this rotary axis
>will be the common X-axis. If your maths and spacial imagination
>are up to it, ( get the wife to help??) the data can be generated
>in a spread sheet. First enter in the first column the X-axis
>data, which is the number of steps for one complete revolution of
>the dividing head and spread over a range that suits your
>resolution. Next, operate on the X data using the parametric
>equation which defines Y in terms of X. Then operate on X by the
>equation which defines Z. Now press 'compute' and the data is in
>a file. Import this file into the text editor to re-format to
>3Rxx,yy,zz;
> I have to admit that spread sheet listings are not nearly
>graphic enough for me and prefer the CAD approach, but the
>Compucutters who use this method as 'obvious first choice' find
>it straight forward. (It probably comes down to the age of ones
>brain.)

snip

>
>Yours,
>Richard
>
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