Hello again folks!! I have gotten it in my head that I need to build a automatic boiler feed pump for my new boiler. This is mostly because my new boiler uses a lot of water which is a considerable amount of work to pump in by hand :0P I am going to try and modify a manual boiler feed pump (Cat #BFP-1M) to work with an eccentric crank that will be driven by the engine. The eccentric I plan to use is the very same one made for the 6CI kit I built earlier.
I have assembled a few parts along with my new casting to create the engine driven water pump that will automatically replenish my boilers water supply. I ordered a manual boiler feed pump, 6 - 1/16 NPT (5/16 x 27) close nipples (Cat #PN5M), 3 - 1/16 NPT elbows (Cat #PL5M), 2 - 1/16 NPT tee fittings (Cat #PT5M), 4 - 5/32 x 1/16 NPT tube unions (Cat #TUM5) 1 - 1/16 NPT angled globe valve (Cat #GAV5) and two 5-40 grease cups (Cat #GC-5-40). Along with a few assorted screws and nuts I will put together these items to make the new pump system....
The BFP-1M boiler feed pump will be the basis of my engine driven pump (seen below).
The eccentric casting below is the same one I machined for my 6CI kit last year. I will be using the same machining method as before so I wont go into quite the detail I would normally on the procedure. You will notice that this casting includes the engines crosshead piece (upper right). I will not be using this piece for the build however it will be nice to have it as a spare for my engine...
I decided to start out with the eccentric because I am already familiar with machining this part. I marked up the horizontal plane of the cap and yoke joint and used it to level the casting in my mill vise. I then faced the push rod boss as seen below...
I will be using a 5/16 brass push rod to actuate the feed pump so I will need to drill and tap the boss for the new push rod.
I drilled out the boss with a 17/64 drill bit and then tapped out the hole with a 5/16 x 18 tap....
Using the same methods as in my 6CI build I machined out the screw holes and spot faced them....
After parting the yoke and strap I was able to tap the yoke for the 10-24 strap screws. I then put the eccentric together and mounted it for boring......
Once the bore and facing job was compete I was able to drill and tap the 5-40 threads for the grease cup as seen below....
And now the finished part!!! :0)
Now that the eccentric is finished I can machine the hub the same way I had before. I first sized the hub to fit the yoke and strap and then bored the shaft hole at 1/2 from center (same as on the 6CI engine)....
After a little polishing the eccentric crank is complete!!!
The BFP-1M boiler pump comes with a 3/8 stainless steel piston that is machined to be used with a handle type drive. This will not work for my engine driven system so I will have to make a new piston.....
I will be making a new piston out of a 2.25 long piece of 3/8 precision ground 17-4 PH stainless steel rod as seen below. This rod has been annealed which will make it easier to machine....
The first step in machining the piston is to face the sides of the piston to accommodate a connecting rod yoke. I used my mill to shave off .030 off of each side of the piston for a total thickness of .315. The face of the sides was cut at about .440 in length.....
The next step was to drill out the 3/16 wrist pin hole as seen below...
To keep the wrist pin and piston lubricated I will be using a grease cup oiler at the wrist pin bore. A light oil will be used in the grease cup which will leak out of the wrist pin bore and flow along the piston to keep it moving freely. I drilled a #38 hole to accommodate the 5-40 hand tap that will prepare the way for the grease cup...
I tapped the hole and installed the new grease cup as well as test fit the 3/16 x 3/4 long 18-8 stainless wrist pin (McMaster-Carr Cat #91829A207)...
I now had to machine a connecting rod yoke to mate to the new piston. I decided to make this yoke out of the 1018 alloy carbon steel I bought for the rivet dolly earlier. I cut off a 1-1/2 x 3/4 x 1/2 piece for my new yoke....
I used my mill to machine out a slot .315 wide to accommodate the piston. The slot was made about 3/4 long into the yoke...
I then drilled a 17/64 hole for the 5/16 x 18 tap I will use for the connecting rod shaft....
And now to tap the hole........
I decided to use my rotary table to machine the rounded end of the yoke. I started off by centering the wrist pin hole on the table......
I drilled the 3/16 hole for the wrist pin......
Using the rotary table I was able to round off the end of the yoke as well as taper the sides as seen below....
After looking at the part a bit I decided to streamline it a little by cutting a round taper into the back end of the yoke for a finished look. I used a 15° taper for this cut. You will notice that I used a 5/16 - 18 barrel nut (rod coupling) with a 5/16 cap screw (not shown) as a machining arbor for the yoke....
And now for a little emery cloth and polishing compound.......Voila!!!
And now for the final fit!!!
Not too much longer and I should have a pretty cool boiler feed pump to add to my engine. Please join me again for the next episode of the vertical boiler project. Till then be good to each other my friends!!!
