PMR Horizontal Boiler - A Riveting Build

Now I get it. Building a boiler consists of drilling an infinite number of holes, which are then filled with an infinite number of rivets, which then results in the boilermaker running to the the nearest bar and ordering an infinite number of boilermakers.

I've never riveted before and, after the last two days, I don't think I want to repeat the exercise. Not that it's difficult and the instructions from PM Research are excellent. It's really, really boring and I'm hoping that after I get LOTS of paint on it, my crappy Riveting 101 exercise won't look too bad.

The horizontal boiler kit from PM Research is excellent. Quality castings. Everything you need, including stock to make the tools, is included.



Here are the riveting tools. Simple lathe work. Since they look identical on the bench, I "numbered" them with 1,2 and 3 grooves. The riveting dolly is in the anvil, a piece of 3/4"x 2" x 12" CRS (just about the only thing not included.)



Drilling and riveting pictures will now commence.

The drilling and milling template from the plans is taped around the shell. This saved much layout.



Fitting the tube sheets to a slip fit. Yesterday I didn't even know what a tube sheet was, now I'm fitting them.



Drilling the outlet hole for the steam dome.



Deburring the rivet holes for the tube sheets.



Milling the shell





Drilled and milled



The steam dome. One hole is drilled and riveted to hold position. then a second hole is also drilled and riveted. With the parts now fixed in place, the remainder of the holes are drilled.





More holes for more rivets.





It's like building a ship in a bottle.



Next installment - End sheet riveting if you can stand the suspense.

Very nice work Stan, and another thing I have never done. That steam dome looks an awful lot like the hat that the mad hatter wore in "Alice in Wonderland".----Brian

Looks great Stan, I have never made a boiler before, are the rivets the only thing holding it together and sealing the joints, or does it get soldered as well?

Paul.

It does, Brian. I may have a lot in common with him before I finish riveting.

Paul
It's also soldered. They even included flux and solder.

Another day, another rivet

I had decided to drill the hole in the dome after riveting to insure that I had it aligned with the hole previously drilled in the shell for the water level sight glass. There is also a hole 180 degrees from this one on the dome for the pressure gauge. I found the center of the hole in the shell and then carried that across to the dome.



To insure that things were square when drilling, I used the milled out portion against a square.



Clamped, supported, center drilled and then drilled.



Thinking that it might be a good idea to fit the tubes prior to my next bout of riveting, I mounted the 3 jaw, took very light cuts, moved to a file and then wet/dry paper until I had a nice fit. Repeat for both ends of five tubes.





Test fit. All seems well.



To set the plates at the depth indicated on the drawings, I cut a piece of tubing from the plumbing parts box and kept fiddling with the length until I arrived at the correct depth. The tubing also provided a flat surface so that the sheet was level for marking.



As before, drill a hole, rivet to hold position, repeat at 180 degrees. Then all holes can be drilled.



Centered the Y axis to insure that the holes were drilled straight, then unlock vise, locate hole, drill, repeat for 20 holes.



And one end done. One to go tomorrow.



Hanging it up for the evening.



Best
Stan

Stan--What a really great thread!!! I have always kind of wondered exactly how these model boilers were built, and your pictures make it very clear. Thank you for posting this.---Brian

Stan, i would really like to see the steps involved for setting the rivits.

I'll do more detailed riveting picks on the next end plate

Brian
Glad you like it. I'm just trying to give back a small percentage of what I've learned here. When I began this model engineering stuff about 2 years ago, this was my primary learning source. John Moore's (Bogstandard) excellent instructional posts along with Arnold B and many others taught me so much.

Best
Stan

More banging

On to the end plates.
The drawings give the dimension for the recess of the end plates. After juggling a plate and the depth mike, I decided to mill a proper spacer to get the correct depth for prick punching the plate.
A square 6061 bar that will rest on the previously riveted plate.





Now, with the plate resting squarely on the spacer, marking it was not a problem.



Then center drill and ⅛" drill for the first hole.



Deburring



With the spacer bar in place, rivet is placed in the hole and the opposite hole is marked





Then remove the rivets and spacer bar and replace the rivets.



Then I can check the depth of the plate and mark and drill for rivet #3.



Now, Riveting 101.

Disclaimer: I had never done a rivet (other than a pop rivet) until a few days ago. The following is what I know from the PMR instructions and setting 70+ rivets. I'm quite sure that there may be a better, more efficient way to do this and comments are encouraged.

Important: If you don't have one of these hearing protectors and you are going to rivet; get a pair. Not expensive and will keep your ears from ringing and from a (hopefully temporary) high frequency hearing loss. Also, I don't need to say this here but, banging on the end of steel rods over and over and over could cause a metal fragment to chip off. Safety glasses please.



This is the anvil and rivet dolly. The preformed head of the rivet rests here while you mercilessly beat the other end. Clamped in a bench vise and then a c-clamp to clamp down the other end to prevent tipping.





First is Tool #1. The hole is deeper than the rivet length. Its function is to bang the sheets together and tighten everything against the rivet head in the dolly.



Tool #2 is the "swaging" tool. The hole is about ½ the length of the rivet stem. Banging on this causes the exposed portion of the rivet to belly out, locking it in position and filling the hole.



Then forming the head with a small ball pein hammer.





Final step is Tool #3 which smoothes and shapes the rivet head.





Riveting completed.



Next is making the flaring tool for the 5 tubes.There are two of these on a threaded rod. The end with the 45 degree chamfer flares the tube and the other end presses the flare down flat onto the end sheet.

The kit came with a short piece of hex bar which is to be cut in half and each machined to make the tools. Short pieces and the bandsaw don't do well. I've mounted a small drill press vise on a ½" plate to put in the bandsaw vise but that was not quite making it. I've now found another use for 5C collets.





Some turning, drilling and tapping and we have a tool. Another followed.





Hopefully, tomorrow will see the tubes flared, the boiler cleaned up and, if all goes well, soldering.

Best
Stan

On to setting and flaring the boiler tubes.
The drawing shows the tubes at 8" long (assuming you have set the end sheets at the correct depth) with 1/16" stickup at each end for flaring. I measured and, astoundingly, the 8" length will be correct.

After milling one tube to length, I set up a table stop and made quick work of the other four.



The high helix end mill did a nice job on the copper tubing.



A brief detour to make the stays and the stay nuts







Another brief detour to drill a hole in the steam dome top. Note the precise leveling setup.



Now, on to the tubes. All cleaned and ready.



Both ends stick out about this much.



The flaring tool is mounted with the taper in each end of the tube.



A wrench at one end and a 3/4" socket in a ratchet at the other and both ends are flared.



Now both ends of the tool are turned to the spigot side and more turning and ratcheting.







So the boiler is now ready for soldering.

Stan, Thank You for such an informative thread. You are taking some of the mystery out of boiler making. I am still no where ready to try one, but at least I know it is possible.

Thanks

Tom

Tom
My first boiler. It was all a mystery to me also. The PMR kit and excellent instructions were the key. Keep trying new things. You'll be surprised. I know I am.

A very informative build! Makes me want to order up one of the kits and have at it. Nice work Stan.

Very nice build, great photos. But I am confused as to the five flue tubes, I would have thought they should be at the bottom of the boiler, and the stay bolts at the top under the steam dome.
John

Correct. I'm working that out now.

Stan--You didn't did you? I have seen the way you referred to this build in your latest post about the PMR pump.---Brian

Brian
I absolutely did.
There is a lengthy series of posts about it (and the solution) at MEM

Nice work Stan. Very informative and your photography is up to your usual standards. Thanks for documenting this build

Cheers,
Phil

Interesting build so far Stan, would love to see how you worked through the solution.

What is MEM, and where do I find these posts ?

Cheers Neil