Easier fabrication of simple pump valve parts

Having finished my first very basic hand pump (in my album here http://www.model-engineer.co.uk/albums/member_album.asp?a=42953) I'm planning a hand-powered boiler feed pump like the Stuart or the PMR ones made from castings, before getting on to a 'proper' engine powered pump.

I've seen a plan for those having the right-angle type inlet that screws into the valve chamber body but they seem unnecessarily complicated and fiddly. Having spent 24 hours thinking about this (including a couple in the middle of the night!) I think I've come up with a plan based on this layout:

I haven't seen inside one of the aforementioned pumps but I guess they must be similar. Anyway, the salient points are:

The bottom, threaded, inlet 'plug' is a reel type arrangement with the middle section thinner than the bore of the chamber. It will have a cross-drilled hole and a central hole to admit water.

The top plug has a similar thinner part below the threaded bit. It limits ball travel but allows water around the thinned bit.

The middle bit has a central hole, a cross drilled hole from the ram cylinder and a diametrical slot in the bottom half (these last two bits aren't shown in my crappy model as I don't know how to form them in the modelling software :P ).

The thing that makes this 'easier' is that the centre section can be turned/drilled/slotted and then shoved up the tube, held and silver-soldered in place (via the hole from the ram side and top and bottom if necessary). It obviates the need for creating a truly flat-bottomed hole for the valve seat and drilling the small off-centre holes to allow water to flow past the lower ball when in the up/suction position.

Note: there should be holes in the chamber where the supply, delivery and ram tubes enter (I don't know how to do this in the software I'm using) but you get the idea.

Might be useful for someone - I've just started making one for myself...