Chapter 6.2 – ManholeThe manhole itself is made out of the same 0.040” sheet brass. If you recall, I cut the piece for this a while back. Before bending it, I squared up the edges and cut it to the exact length I’d calculated that was required to get the desired diameter. (I used the diameter at the center of the wall. Not sure if that was the right place or if I should have used the inside diameter. Regardless, it was close enough that it worked!)
Then I broke out my new slip rolls that I got for Christmas (thank you Santa) and put them to their first use:
After annealing the brass and running it through the rollers again, it came out very nice and round! Just right!
You can see the little attacher piece that holds the cylinder together and aligned.
Next, I needed to make the manhole flange. This was also cut at the same time. I took that piece and laid out the location for the manhole. I made the inner circle just a little small for the outer diameter of the manhole.
After cutting out the circle with the scroll saw, I used a file to carefully and slowly open up the circle till the manhole fit. The thing to remember here is that the manhole is straight up and down, but the flange will be at about a 15
o angle to match the top of the tank. That means the hole for the manhole will be more of an ellipse. Not a big one, but just a tad! So I did more file work to open up the hole and get an angle on the edges.
And here’s out it fits!
Then I added a couple of brass screws – one on the top side (underneath the flange plate) and one at the bottom (above the flange plate) to help hold it in place during soldering. (Not my idea, this was Kozo’s, and it was a brilliant idea I can tell you!)
Here’s the flange and manhole all prepped and fluxed for silver soldering! (Note that I also knocked the corners off the flange to make the flange easier to round up later).
And here’s after the soldering job. Not too bad! I really like how this part came out! Silver soldering isn’t quite as scary to me as it used to be. I’d even say it was almost enjoyable!
Here’s the post-pickle shot. (I just wanted to admire my silver soldering job again
)
Next, I mounted it in the Taig 4 jaw and centered it as good as I could, to make the flange round. With the flange being at an angle, it made for a really bizarre interrupted cut. The first time I centered it up in the chuck, I didn’t tighten the jaws too tight - I didn't want the brass deforming out of round. This was a mistake. As soon as the tool contacted the metal it just popped right off the jaws and went bouncing around in a rather frightening way! Luckily, the damage was minimal (none to myself or the machine, and one divot in the flange where it hit the tool and a few smaller marks in other areas. I was able to gently pound out the flange ding, and everything else is fine. So for my second attempt, I tightened things up a quite a bit tighter and was WAY more careful to sneak up on the cut. I ended up deforming the bottom of the manhole a bit with how tight I got it, but in the end, it won’t matter because that part is being removed anyway. And all the important parts stayed round!
And here we are, the manhole with a round flange.
That’s as far as I got this weekend.
Thanks for stopping by to take a look!
Kim