Ok here we go, next steps!
So we marked the lengths of the long tubes so that they end where the corner of the link starts to curve.
Next step is to cut them.
It's just as you would expect, but make sure not to cut too deep.
Next step is to pick two links, doesn't matter which. We're going to make one "Model" right hand (short) hinge, and one Model left hand (long hinge).
We're going to make these two mate up just right.
Then we're going to make all the others to match these two models - this way all of the links end up being interchangeable, and can be placed in any order.
Not too much science to it - just lay the hinges next to each other and decide about what size you want the middle knuckle and the outside knuckles.
Then mark them. I don't do the marking scientifically - I cut one (this time I did the double knuckle first) and then match the other one up.
It's a good idea to sort of try to center your middle knuckle and outer knuckles around the theoretical centerline of all the links, since all the centerlines of all the links should line up, and everything will thus turn out perfectly symmetrical since all of your links are EXACTLY the same height. Actually, if you can do that, then:
. That requires a lot of measuring, precision, and even math, however, so I just eyeball it. You only have to do it once. Mine are just centered, and the link heights of the various links vary by a few mm, since I didn't cut the stones super exactly. It ends up looking fine though, as long as they're sort of close and centered.
In cutting the short knuckle, it's just like trimming the ends of the long knuckle as above. Mark, cut down through the tubing.
For these cuts I like to position my piece in the vice so that my saw is travelling downward, rather than your normal "travelling forward" position.
Maybe it helps me see it better to keep it straight, I don't know. It's awkward and it hurts my arm but that's the way I do it!
You can tell where your saw is in the tubing because at first it cuts smoothly, as it's cutting through the top of the tubing - no ridges for the teeth to catch on.
Then you'll cut through to the hollow part, where there are now two vertical walls you're cutting, and the saw blade will tend to catch and hang a little.
Finer blades will catch less. I was using 4/0, which still wanted to catch. But that's useful!
Then you'll cut through to the solid part again, on the other side of the tube, and you can feel the teeth stop catching.
That's how you know you've cut through the hollow part, when the blade stops wanting to catch.
Stop here. Don't cut too far!
Then, turn the piece in the vice and cut in from the ends. No wandering sawblades!
Pay attention! It's pretty hard to avoid cutting into the backplate if you're not a master. Ask me how I know!
Just focus and cut slowly, and err on the side of leaving some extra tubing to file off later.
(Sorry I forgot to take a pic of this part).
Easy! Clean up the ends with the white silicone wheel and then the black silicone wheel.
Next is the harder part - cutting out the center part of the double hinge.
Lay your finished Model Left (ML) up against the hinge that will be the "Model Right (MR)".
Mark where you want the hole to be so that it lines up perfectly with the ML.
Focus on centering your links vertically, so that their center lines are even. More or less.
One time I tried to mark the actual centerline of each link by making a nice X across it.
Ended up not in the center at all! Eyeballing it works much better.
The way I do the mark, since I don't like doing precise marks, or precise cutting, is to remember that for this one, I'm cutting out the middle.
So I start drawing the line from the inside, and widen the line until it lines up about exactly with the end of the short knuckle of MR.
Doesn't matter how fat my line is - I know that I need to cut at the outside of the line.
But not exactly the outside, since you can't add material back later. But almost.
Pardon the sharpie marks on the second pic - it would have been easier to see that they line up perfectly if I cleaned those off.
All my acetone is in the storage unit right now though, grr.
Now I have one perfect double knuckle and one perfect single knuckle.
The next step is just making all the rest match.
I started with the short knuckles - take ML (the double knuckle), and hold it up against each uncut short knuckle, and mark.
Remember, you're cutting in from the outside this time, so gauge your sharpie mark so that you can cut at the inside of the mark.
And leave a little extra.
Repeat till you've done them all. Notice you can't do the one on the right side of ML - do that last, using one of your other double knuckles you'll make next.
Since you did them all to match ML, they all have the same size knuckle. More or less centered.
Now go back to MR (not one of your others!) and mark and cut all the double knuckles to match it.
By going from the model, you minimize "creep" in the size of the knuckles.
Thank you to Brad the engineer teacher for this tip.
Cutting out that center section is the trickiest part of this whole project. Which means, not that tricky.
But it's a little fiddly and you have to be careful.
Same method as before - cut down through the tubing till the saw blade starts chattering, and then stops chattering.
Stop, and turn the piece 90 degrees so it's vertical in the vice.
I stuffed them full of papertowel to make them more secure in my vice and so I didn't mangle the bezel - ymmv.
(That's a picture of the other knuckle but you get the idea).
Insert your sawblade back in, then back it out half a mm (or 1/3 of a smidge if you work in english units),
then start turning the corner. If you don't know how to make pretty good square corners with a jeweler's saw, it would probably be a good idea to practice first.
Basically though you just get to the corner, back up a fraction of a smidge, slowly start rotating your blade, while gently sawing back and forth in place with no forward pressure.
Saw saw saw turn saw saw saw turn.
Then CAREFULLY saw down along the solder seam, cutting off the middle section of tubing cleanly, and perfectly mating up with the other cut you made below.
I expect all of you to do it perfectly, even though I didn't.
Here's a bad one - notice I gouged into the backplate, then overcorrected and left lots of extra tubing to file off later.
Here's a better one. I left a bunch of tubing and solder there, that I have to file off, but at least I didn't gouge the backplate.
A couple of them actually came out perfect, but not most of them.
I used a white silicone wheel to take off the extra tubing. Use a nice fresh square one to get into that corner, and be REALLY careful not to grind down into the backplate when you're doing that.
You can shape those wheels with a cheapie diamond file. I.e., make them square again.
Clean up the edges of the tubing again with white wheel then the black wheel.
Then the big test - stick them together with junk wire and see if they fit! I had to file down a whole bunch of corners and various sections that were close but not quite right. Mostly I used the white wheel. You might also want to use a hand file with a safety edge if you're not super comfortable with the silicone wheels.
It worked! They all match up. Because this wire is thin, it allows a lot of play in the mating of the hinges, so the joinings look pretty sloppy.
It will tighten up when we use fatter wire later!
I forgot to take pictures for awhile but the next steps are pretty easy - we're done soldering now, so clean up the links. I used a knife edge silicone blade to clean up between the hinge tubing and the bezel, as well as whatever they call the flat but not knife edge ones - discs? - to clean up the rest. I'm leaving the backs for after the stones are set since they always get banged up when I set the stones.
Links are done! Going to break this into two posts.