Author Topic: PMR Feed Pump build  (Read 10568 times)

Offline sshire

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PMR Feed Pump build
« on: August 29, 2013, 06:47:11 PM »
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.

Best
Stan




Best,
Stan

Offline NickG

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Re: PMR Feed Pump build
« Reply #1 on: August 29, 2013, 08:02:09 PM »
Nice start Stan. Does the BP pivot front to
Back too? Or is it necessary in that plane because you can swing the whole turett?

Offline sshire

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Re: PMR Feed Pump build
« Reply #2 on: August 29, 2013, 08:29:07 PM »
Nick
The tramming (or tilting if you need to angle mill or drill) is done with worm gears. A 3/4" hex protrudes from the top of the ram for front to back tilt and  one on the side for left-right tilt. Just loosening the locking bolts for a particular axis, gives a bit  of drag to the wrench. I can easily move less than a thou.
Damn brilliant.
Best,
Stan

Online b.lindsey

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Re: PMR Feed Pump build
« Reply #3 on: August 29, 2013, 09:32:48 PM »
Yipee!!!  Looking forward to this one too Stan!!

Bill

Offline NickG

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Re: PMR Feed Pump build
« Reply #4 on: August 29, 2013, 10:01:57 PM »
That is great, on mine i would need to shim the whole column for front to back. Think i checked that when bought it and it was ok. Not checked the side to side fir a while though!

Offline Don1966

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Re: PMR Feed Pump build
« Reply #5 on: August 29, 2013, 11:52:05 PM »
Stan I am also glad your doing the feed pump. Mind is waiting under the bench to be done also. Nice start on it thought. By the way do you have the angle grinder attachment for your Foredom, I love mine?

Don
« Last Edit: August 29, 2013, 11:55:52 PM by Don1966 »

Online b.lindsey

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Re: PMR Feed Pump build
« Reply #6 on: August 30, 2013, 12:48:51 AM »
Don, do you mean the head that looks more like a dental tool oor something else?

Bill

Offline Don1966

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Re: PMR Feed Pump build
« Reply #7 on: August 30, 2013, 02:14:56 AM »
Don, do you mean the head that looks more like a dental tool oor something else?

Bill
No Bill that is a collet holder this is the angle grinder great for cleaning casting up with.
http://www.foredom.net/ak69109.aspx
This is the one that looks like a dental tool http://www.foredom.net/a69224.aspx

Don

Offline Steamer5

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Re: PMR Feed Pump build
« Reply #8 on: August 30, 2013, 10:45:50 AM »
Hi Stan,
 Nice start, following your boiler build too......you are doing a great job on that as well. Only comment would be that watch ya balls.....sorry Jo. I used nitrile ones for the non returns on my loco, they work great.......for quite awhile. I started having some not non return issues, so new seats were made & fitted, ok for a bit then trouble again. By a bit of a chance I found that they had changed shape! So depending on how the dropped depended on how they sealed! Easy fixed give them to the workshop elf........he loves them, haven't see them since I put them othe floor, put in new ones. So now I change them as required!

Cheers Kerrin
Get excited and make something!

Online Jo

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Re: PMR Feed Pump build
« Reply #9 on: August 30, 2013, 11:04:36 AM »
Yes nitrile balls have their little challenges. If you can fit bobbins:



In my experience the bobbin (a sort of T valve) is best made from stainless steel, with the three flutes cut at 120 degrees into the stem of the "T", which goes into the feed pipe. You also need to cut a seat in the underside of the head of the T for the "o" ring.

The bobbin should be a loose fit in both the valve body and the feed pipe diameters. The stem length should be the bore of the valve plus the "o" ring. The head length, including the "o" ring, should be the distance above the seat minus the original ball clearance. (I must draw this out  :hammerbash:)

They also have the advantage that if you drop them they, normally, do not roll so far.

An alternative design which uses the nut above as the guide is this commercial one:





Jo
Usus est optimum magister

Offline sshire

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Re: PMR Feed Pump build
« Reply #10 on: August 30, 2013, 01:20:52 PM »
I'm confused. Are the bobbins fitted inside the feed pump? I can't picture how this would work.

Also, what is a non-return? So much to learn.
Best,
Stan

Offline sshire

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Re: PMR Feed Pump build
« Reply #11 on: August 30, 2013, 01:27:59 PM »
Just looked it up. The non-return prevents boiler water from returning to the feed pump.
Is there a separate "non- return" valve or some such?
Why is this the first time I'm hearing this? Is this a steam conspiracy where only partial information is given to non-initiates?
Best,
Stan

Online Jo

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Re: PMR Feed Pump build
« Reply #12 on: August 30, 2013, 02:53:30 PM »
Your balls (in the pump) are operating as the non return valve so that when you move the handle the water is sucked into the pump and then on the next movement of the handle it continues out in the right direction. Think of a pipe with water in it and in the middle is a ball against a shoulder, if it is sucked away from the shoulder then water can flow around it but if you try to push the other way the ball will seal the hole and the water will have to find another way out, which should be past another valve and into your boiler.

Instead of using a ball you can use a bobbin. Bobbins have a larger sealing area  ;) But balls have worked very nicely for years and years...

Jo
Usus est optimum magister

Offline sshire

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Re: PMR Feed Pump build
« Reply #13 on: August 30, 2013, 03:47:55 PM »
Thanks, Jo.
I'll try the Viton balls and, if I'm not happy with them, I've got the stainless steel ones that came with the kit.

Much less confused
Stan
Best,
Stan

Offline Steamer5

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Re: PMR Feed Pump build
« Reply #14 on: August 30, 2013, 07:30:08 PM »
Hi Stan,
 Sorry to cause you some confusion, that wasn't my intention. Just forgot that we all use terms that others may not of heard off. Just wanted to pass on my experience with soft instead of stainless balls. Thanks Jo for a great explanation, & the photos of your bobbins, I'll look into seeing if I can get them to fit.

Cheers Kerrin
Get excited and make something!

Offline sshire

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Re: PMR Feed Pump build
« Reply #15 on: August 30, 2013, 11:59:12 PM »
Kerrin
Not a problem. I'm learning UK English, Oz English and New Zealand English. A total learning experience.

Best,
Stan

Offline sshire

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Re: PMR Feed Pump build
« Reply #16 on: August 31, 2013, 12:00:02 AM »
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 " copper tubing from the big box store. I also picked up some " 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.

Best
Stan
Best,
Stan

Offline Don1966

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Re: PMR Feed Pump build
« Reply #17 on: August 31, 2013, 12:09:29 AM »
Stan, your really moving along here bud. Looking great and I am taking notes here man.

Don

Online b.lindsey

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Re: PMR Feed Pump build
« Reply #18 on: August 31, 2013, 12:47:06 AM »
Some more nice progress today Stan. At this rate you may well be the poster craftsman for CF 2014 :)

Bill
« Last Edit: August 31, 2013, 01:12:37 AM by b.lindsey »

Offline sshire

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Re: PMR Feed Pump build
« Reply #19 on: August 31, 2013, 01:04:00 AM »
Maybe in quantity only
Best,
Stan

Offline sshire

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Re: PMR Feed Pump build
« Reply #20 on: September 01, 2013, 04:19:56 PM »
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-" 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
Stan

Best,
Stan

Online Jo

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Re: PMR Feed Pump build
« Reply #21 on: September 01, 2013, 04:49:00 PM »
Nice  :ThumbsUp:

You are brave with that little slot cutter  :o.. I would have turned it 90 degrees and used a slitting saw  ;).

Boiler time again  :???:?

Jo
Usus est optimum magister

Offline smfr

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Re: PMR Feed Pump build
« Reply #22 on: September 01, 2013, 05:18:46 PM »
Looks great, Stan! I hope my build log was useful. To be honest I still haven't finished off the fasterners for the linkage on mine; I suspect that a single nut will work loose in action, so lock nuts are probably required.

One thing I noticed; the insert you're using to cut the bevels on the nuts looks like it has a corner angle of a bit over 90deg, making your nut bevels just a hit steep. Nut bevels are normally at 30deg, so a 60deg threading tool gives the right bevel angle.

Simon

Offline Don1966

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Re: PMR Feed Pump build
« Reply #23 on: September 01, 2013, 05:42:42 PM »
Looks good Stan and that was quick.

Don

Offline sshire

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Re: PMR Feed Pump build
« Reply #24 on: September 01, 2013, 05:46:35 PM »
Jo
I was concerned that since my widest slitting saw is .06, the .187 slot would be many cuts, most with one side of the saw unsupported. I suppose it's my minimal experience with them plus probably not knowing the correct procedure that pointed me to the end mill. Any suggestions for using the saw would be appreciated.

Simon
Your log was very useful. Thanks! I just found thin, 6-32 lock nuts at McMaster

http://www.mcmaster.com/#hex-locknuts/=obiozs

Best,
Stan

Offline sshire

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Re: PMR Feed Pump build
« Reply #25 on: September 01, 2013, 05:50:35 PM »
Don
A kit with 5 parts to be made is right up my alley. Plus, PMR supplies everything so no running around or waiting for Richie, my UPS guy.
Best,
Stan

Online b.lindsey

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Re: PMR Feed Pump build
« Reply #26 on: September 01, 2013, 08:52:20 PM »
Great log Stan. Now with your log and Simon's, maybe i can attack my casting kit :)

Bill

Offline sshire

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Re: PMR Feed Pump build
« Reply #27 on: September 01, 2013, 08:53:51 PM »
Easy, Bill. I did have a bowl of soup so I could use the empty can for a test water tank.
Best,
Stan

Online b.lindsey

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Re: PMR Feed Pump build
« Reply #28 on: September 01, 2013, 08:55:42 PM »
Lol....i can manage the soup part :)

Bill

Offline NickG

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Re: PMR Feed Pump build
« Reply #29 on: September 01, 2013, 09:51:27 PM »
Nice work Stan, looks like a good pump. The non return valves you were talking about are commonly known as clack valves or check valves too. It is normal to have them screwed into the boiler at any feed in point and not rely on the one in the pump, otherwise the pipe will be full of steam.

Offline sshire

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Re: PMR Feed Pump build
« Reply #30 on: September 01, 2013, 10:07:00 PM »
Nick
When I was testing the pump,  it actually occurred to me that once the boiler got some pressure up, the pump feed line was a likely place for it to go.
Thanks. That was very helpful. I'm learning a lot about steam from folks here since I started this whole boiler/pump saga.

Best,
Stan
Best,
Stan