Make two jump rings - these can be double for extra security and soldering surface. Solder the trapezoids across the rim openings - effectively closing them off. Make sure to solder them in the centre of the thickness - you may need to prop the trapezoid up on a 2p (old copper!).

Rotate the rim by just under ¼ and solder on the jump ring in the centre of the thickness of the rim. The lacing ring should be just above central on the eye - not like modern glasses where the arm is at the top. And the trapezoid should be at an angle to the nose where the nose is the straight side of a right angle triangle and the trapezoid piece is the opposite corner - that way it doesn't scratch your cheek whilst wearing.

Remember! You have a right and left rim!!!

Here's the tricky bit!
Trace your normal specs on a piece of paper. This is going to be the model for your nose piece. Make a cross exactly centre over each lens (see photo). A normal pair of frames is made and fitted to your head so that each rim is centred exactly over your pupils. This is so that the curve of the lens is over your pupil so that you suffer the least distortion and get the best advantage of the lens.

Your eye MUST see through the centre of each lens. When you measure and model the bridge, you must make sure that each rim remains exactly over each cross or your optician will reject the frames. Or worse you will make yourself seasick, vomit or give yourself migraines when wearing the spectacles (whilst this affect may be very period, it may not be ultimately desired…)

I stuck the rims to the tracing with double sided sticky backed plastic (v bp!). Then I used a bit of blue tack to get the arch/top of the nose. It was then simple to draw a simple curve on the tracing from rim to rim just above the highest part of the arch to make the pattern for the bridge.

Solder the bridge to the rims making sure you have the lacing rings are level and the bridge is in the middle of the rim thickness (supporting it on a couple of 2p's or a trivet…)

Check the fit and location of the centres!

Finally, pierce outwards from inside the rim perpendicular to the rim, opening the rim for the lens.

Secure the rim by taking a length of binding wire and wrapping it around the trapezoid. The lenses should have been made by the optician to fit the circumference EXACTLY. You can further secure the lens by gluing the lens in place (if it is a bit thinner than the thickness of the rim - you don't want it to rattle) either with proper putty or with a drop or two of superglue (dries invisibly).

Because silver frames are posh - and we aren't! I oxidised the frames with professional oxidising solution (also from Cookson's) to a dirty black. I also did a calculated job on the finishing of all the edges, cut the bridge unevenly, and put some file and saw cuts in to look worn and crude.