When I was ordering the grate from Blackgates I saw they also stocked the Southworth vertical steam pumps. One of these has been on my project bucket list for a while. I went for the 3" because the 6" would be too large for a loco this size. If it was too small it could always go on the Rob Roy. Anyway for 28quid it wasn't going to break the bank.
Ordered on the 8 July, delivered to me in NZ in about a week later and finished a week ago. As Stew had done a good write up over here
http://madmodder.net/index.php/topic,4763.0.html there wasn't much point in doing another one. But I have added a few points to Stews thread to help others.
and running, 20psi in and 60-70 psi out (and with leaks). The 1/2" steam piston and 1/4" water pump ram gives a theoretical gain of 4
I had identified some drawing errors and found Bob Potter, who is now the proprietor of Southworth, is a member of this forum so I've been in touch with him. The 3" pump does seem a tad small for a 5" gauge loco so I was toying with the idea of making a scaled down version of the 6" pump.
To cut a long story short; my intention to take the Simplex out to the track this weekend to try out the new grate was thwarted by heavy rain. So what else do you do on a wet Sunday? Install the pump....
I had it running on air this evening with water in the tanks it was capably filling the sight glass. With the boiler full and the regulator shut and the pump ticking over I got it to a hydraulic pressure of 30psi. It would have done more if I'd let it.
With a single acting pump and about a 2cc displacement it not going to get me out of trouble. But with the hand pump, axle pump and injector it's only there for show topping up when stationary for long periods.
If you want to try your hand a clock making this pump has enough little parts to make it an interesting build. I thoroughly enjoyed doing it.
(BTW all that 'rust' on the saddle and smokebox is copperease grease from when I had the boiler out)Pete