JB I did tell you that Helen Verral makes exceedingly good boilers. DJ
I think I'm starting to get the hang of this caper! Who was it who said that revenge was a dish best served cold.....
This is straight out of the pickle, and given just a brass brush off. I'm quite pleased with it! I just put 3mmX1mm section silver solder inside the barrell, shaped to rest on the throatplate, and 'drew' it thru with the 35mm burner. The top of the barrel is where I wanted it! How I did the joint will remain a closely guarded secret between the boiler inspector and me.....
Time for the inner firebox. The firehole is interesting, because the first one I made as specified was tiny, and completely unsuitable for my potentially arthuritic hands. Here is the first one: it fell out of the chuck whilst sizing it so there was a good excuse to make a bigger one!
Here is the second one in the making, much bigger!
Machined and flattened:
Fitted in the doorplate ready for rivetting to the wrapper:
I don't know how I ever found time to go to work....... JB
Post by Shawki Shlemon on Oct 2, 2009 10:24:44 GMT
Now that you have retired and found another job ( making boilers ) , once this prototype is completed and well as I expect , then you can start making them for sale , I bet that DJ will want to buy one from you . You are doing a great job, congratulation .
OK, nearly there. Today's job was the 10g boiler tubeplate, and it involved bashing out the deepest flange (3/4") that I'd ever done. The words & music optimistically said "You may have to anneal it two or three times...."
Most expensive ashtray I ever made!
Turning to correct diameter was a little iffy as the boiler end wasn't quite round.
Tube plate tapped in gently. The AUTOCAD template was very useful as the hole centres are shown as points.
Tube plate drilled and countersunk. All I have to do now is conjure up a 5/8" reamer and I can fit the tubes in the combustion chamber. Then it can be assembled and brazed up, hopefully sometime next week. I'll be taking orders after that......joking!
The holes for the water tubes in the combustion chamber are a bit tricky. I got around it by using a template (drawn in CAD) with the elliptical outline of the tubes stuck to the shell. I drilled smaller holes and then carefully filed them out to slightly less than the correct size. Finally I put a reamer through both top and bottom of the shell to clean them up and make sure they were in line. You can always open them out slightly if the tubes are too tight.
Hi John (baggo), I think I will do something similar. As I'm only a poor old pensioner and too tight to buy a one-off reamer, I''ll exercise those long lost filing skills and fit the tubes manually. That reminds me: one of my apprentice jobs was to create, by hand, a 3" hole in a piece of 1/2" steel plate, using a ratchet and post (I bet only a few people know about that!) and half-round files. They gave us a 3" plug gauge, and the test was it had to fall through the hole by its own weight..... So this is quite easy then? Ha Ha! I think not! JB
Good question Chris. Both ends are 10g, so plenty thick enough for my purposes. However, my friendly boiler inspector just sent me an email asking me if my drawings had been updated to show the new bushing requirements! JB EDIT. I don't wish to restart the debate, but I just re-read the examination and testing book (2008) and it says " Ensure that screw threads of fittings and their mounts are of adequate depth to maintain sufficient strength". so perhaps I'll just leave things as they are....
JB. This is just my line of thought! For what little extra effort it involves, I like a bush. More depth of clean thread. Nice flat machined face to seal down onto. Added strength. Leaves a margin for error repair. Go on - Bush It.
Oh, all right then, you persuaded me far more easily than any regulation ever did! The dome bush appears to go in flat instead of being shaped to the boiler curve. This will look terrible unless there is some sort of cosmetic cover for it that I haven't found yet! JB
A vernier caliper JB? This is boiler making...... Andy
I know it's a bit of bullshine Andy, but I have to get the centreline right, hence this little cardboard setup. As it happened the wrapper was slightly longer on one side, thus making the boiler lop-sided. I can imagine myself driving it round the track and being distracted by an out-of-position dome bush!