Today's update: completing the Eccentric Rod.
I drilled and reamed the hole for the Eccentric Rod on one side of the ring, and on the other side, I drilled and tapped the set screw hole. The set screw will ride in the groove on the eccentric to keep the ring aligned.
With that done, it’s time to solder the pieces together. I decided to try silver soldering. I probably could have gotten by with soft solder, but I need to overcome my fear of silver soldering. So, that’s what I did. Here I’m all setup for the operation – flux and a short length of solder in place:
I was trying to be careful not to get things too hot, but I think I just wasn’t aggressive enough. It took too long to bring things up to temp and my flux melted away. I added a little more, and eventually, the solder went zap and melted. So, I finally got there.
A pickle bath and cleanup, and finally ready for the other side. And here’s that operation complete. Went much better!
After cleanup, I bent the rod, as directed, and discovered that even with all my careful planning the rod was too long. I was trying to figure out exactly how to deal with this – do I re-solder? Or just bend the rod WAY more that shown in the plans? No, bad idea. A sharp bend in the rod looked stupid. OK, re-solder. But how do I get the thing apart now?
About this time, the rod just came right out of the ring. Apparently, there was no real solder connection. It just came apart. Guess that solved THAT problem.
So I adjusted the length of the rod – THIS time I checked it more carefully to make sure it would be about the right length:
Then I went back and silver soldered it again. This time I tried to be more careful to make sure I got an actual connection.
But alas, as I was cleaning the part – snap – it came apart again. Clearly the solder was not wicking down into the hole.
Then I started thinking – I had a 3/32” rod, in a 3/32” reamed hole. It was a nice snug fit that I was proud of. But there was no room for solder to wick down there. Kozo talks about this in his silver soldering technique description in his “Building the Shay” book (the original one – I don’t have the “New Shay” book (yet)).
So, I opened up the hole a bit. I used a 3/32” drill instead of the 3/32” reamer. That loosened the fit just a bit, hopefully enough. So, I get it all setup and try a third time. This time I added a little extra solder just to be sure. And I was pretty sure I got a good solder fillet. And I could see that it came out the other side of the hole too (on the inside of the ring). Success!
After cleanup, it still looks good. And it didn’t break off. Nice solder fillet all the way around! And a nice ring of solder on the inside of the hole too.
And here’s a close-up of the other side of the rod. That joint looks pretty good too (though it could stand a bit more cleanup – it’s amazing what you can see in these close-ups that you can’t in real life!)
And here’s the completed Eccentric Rod:
Well, I guess this is what I wanted! Some education to help me on my way to gaining confidence in silver soldering.
Clearly the solder was not wicking down into the hole. And in fact, looking back at a zoomed in version of the first two attempts, you can see that is the case.
Here’s a zoom-in on the first attempt. You can see that the solder has melted onto the larger part (the ring) but doesn’t touch the rod. There’s a bunch of crystalized flux that is holding them together. And if you don’t look closely, it almost looks like a shiny solder fillet. But its clearly not. The flux is very brittle and will just break away.
The second attempt has a similar problem. The picture doesn’t show it as clearly but you can see the same problem. Solder all around on the big part, but the shiny fillet between the ring and the rod is just a bunch of crystalized flux.
A zoom-in on the third (and final) attempt shows that you can actually see the solder fillet here. There’s still crystalized flux around but you can also see an actual solder fillet. And even more telling, was the solder that came through the back side. Sorry, no pics of this.
Remember – in each case these pictures were taken to show the excellent solder fillet I thought I had. But the first two cases there was no actual solder contact on the smaller part. Just a shiny looking fillet that turned out to be nothing but flux.
The real give away, I think, is the fact that a little solder came out the back side through the hole in the third attempt, and it didn’t in the first two.
Anyway, I’m a bit smarter now than I was this morning! So it’s a good day. And I’ve got a completed Eccentric Rod that will fit where its supposed to go!
Thanks for checking in on me,
Kim