PMR Feed Pump kit - build

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Jun 29, 2011
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While I'm waiting for the new boiler tube and end plates, I started on the feed pump. If you've missed the saga of "The Bass Ackwards Boiler Build", search for PMR Horizontal Boiler.

The feed pump is also a PM Research kit and is up to their usual quality level and completeness of parts. The only change I'm going to make is to the pump handle's clevis pins. The plans show them retained with cotter pins. I'm not wild about the look of those, so they will be replaced with .125 E-clips. Wait. There is one more change. Im going to try Viton balls instead of the stainless ones in the kit. Thanks for that suggestion goes to fcheslop on the MEM Forum.

As with every build I've done, I try to start with a trammed mill whether it needs it or not.

And that's close enough. The BP has to be the easiest mill to tram.

First step; flatten the bottom so I have some sort of reference surface. I'm using a Glacern 2" 45 degree face mill.

With the bottom flat, I mounted the casting on an angle plate and used a square to get it straight. I did try to indicate it with a DTI but the rough surface of the casting had the Interapid doing some sort of Swiss fertility dance. I'm calling this close enough.

After milling the piston housing flat, I flipped the casting over, straightened it again and milled the inlet and outlet port housings.

The Foredom flex shaft tool with sanding drums and various brass brush wheels, files and sandpaper got me to this point. I'll do the final cleanup when it's all done and ready for primer and paint.

There are very few parts to make for the feed pump; drilling and tapping of the main casting, handle, piston, ball valves, and gland nuts. Should be a fairly quick build and then back to the boiler.

More pump parts tomorrow. Stay tuned.
Now that the feed pump has been milled and a cleanup of the casting has begun, the drilling and threading commences.
With the casting in the vise, I checked for level.

The inlet and outlets were drilled and tapped. I'm using ¼" copper tubing from the big box store. I also picked up some ¼" to ⅛" compression fittings that I will modify to thread into the inlet and outlet.

The drilling sequence

I used an end mill here to get the flat bottomed hole.

Just following the sequence

Then the casting is turned, checked for level and plumb and another sequence is done.

Tomorrow, the gland nuts and the rest of the parts. Should be pumping water by the end of the day.

And, yesterday, as promised, the replacement boiler parts were at the front door.

Quick build so far. a nice pump kit. When this is done, we'll go back to the boiler.

Gland nuts and the rest of the bits

The gland nut is turned from supplied hex brass. Just following the drawing.

The drawing said 0.560.

Then the BA die (not British Association), more like Big A**.
The only one I could find was a 1-½" diameter. Just what I needed, a break to turn a die holder.

Then drilled, reamed to .375 and done. When I test fit the piston after reaming it was tight. I remember reading a build thread on this pump by Simon and he had some tightness here also. I was about to go his route with TimeSaver compound, but decided to run the reamer one more time as a "spring pass." The piston slid in perfectly this time.

A test fit to check the threading.

Then the plug.

Both nuts in place.

The pump handle was cut to length, drilled and finished with a trip to Oliver.

Spotting the gudgeons. Not being a birdwatcher, I've never spotted a gudgeon in the wild.

Centering the piston for slotting.

The slot is to be 60 thou larger than my .125 end mill. First the center passes (I'm really feeding slowly with a .125 bit and 303 stainless. Plenty of hand dripped coolant) and then the two 30 thou offset passes to the finished width.

Drill the mounting holes in the feet.

I had thought of using .125 E-clips in the gudgeon pins instead of the supplied clevis pins. I'm sure the 5C collet has about 1/32" in its grasp. I did manage to cut the groove, but I'd need a longer pin to make this work and I wasn't thrilled with the look of the whole rivet-as-gudgeon-pin assembly.

Like Simon, I replaced the gudgeon pins with screws (6-32 SS)

So, done. It does pump water. Take my word on that until I get it properly mounted as I was holding the pump to the kitchen counter with one hand while using the pump handle with the other, and propping up the inlet test hose with my shoulder.

Thanks for following along

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