Flartybarty, I was looking elsewhere & didn't see your thread 'til now. I would've offered the same solution for your 'keeper' (I've always known it as a 'bridge') that you ended up using, so I wouldn't have been much help anyway.
I've been fabricating metal panes for over a decade, but still on the steep part of the learning curve - there's a lot to get right to make a great, as opposed to a usable or merely 'good-enough' plane! :?
A couple of tips that might help others a bit.
The first is to do with peening - I simply cannot get the more malleable brass here at any price, so I'm stuck with the harder, machinable type for everything. What I buy is called 380, which is probably equivalent to your harder alloy. It's supposedly rated as 'good' for cold working, but it won't take a lot of beating without splitting & flaking - I wish I could get the stuff with tin as well as zinc in it, in plate form ('naval brass'). On the other hand, both mild steel & gauge-plate (in annealed form) are quite good for peening, so just make sure you do most of your filling from the steel side rather than the brass. This is pretty easy to do in a typical plane, because of the way the dovetails are cut. If you get a nice initial fit of the sides to sole, most of the metal movement required is to fill the chamfers over the brass tails, the tails themselves should take only a little peening to close any small voids on the sole side.
Second tip - it takes very little metal to lock things together, be it a D/T or a rivet head. Early on, I made the mistake of putting overly large chamfers on my tails, or making the countersinks to peen rivets into, too deep & too wide. If you use a typical countersink bit, it makes a recess that is wider than necessary by the time you get a bit of depth. I now use a very simple hand tool - an old saw file file ground to a triangular point, which is more acute than a typical rose bit. It takes about 6 twists in brass to make a very adequate recess for a 3.2mm rivet:
Keep the amount of rivet protruding to the minimum required to safely fill the hole - I find about 1.5mm just right to fill the recesses shown. If you have too much protrusion, it takes a lot of bashing to fill the recess, and what tends to happen (if the metal doesn't split & flake badly!) is that you think you've got it nicely filled, but when you file off the excess, there are pits & voids. Not at all what you want!
Here is the plane above after the rivets were set & the sides cleaned-up:
I've built a fair number of shoulder & rebate planes, and gravitated to a method that I think is pretty simple & perhaps a good way to launch into metal plane making. Instead of dovetailing sides to sole, I rivet the sides to brass core-pieces. These are the components ready to assemble:
There are a couple of advantages in doing it this way. For starters, it simplifies construction and fairly importantly for a shoulder plane, it gives the tool plenty of heft. Second, the entire blade bed is pre-prepared, and all you have to do at the clean-up stage is carefully level the side pieces - far less mucking about than fitting infill over a thin sole & trying to get it mating perfectly. If done properly, the rivets will give you a very sturdy construction & should disappear when filed & sanded flush. There is one part that needs a bit more attention; those little projections of the sides along the bottom of the blade wedge are too narrow to rivet, so I run some solder in there after the body is assembled.
It's also an easier option for those with few metal-working tools & minimal experience because brass comes in various thicknesses that can be added together to make widths that will fit off-the-shelf blades - e.g. 3.2mm sides plus a 13mm core makes a plane that takes a 19mm or 3/4" blade. I've made them this way for 1/2", 3/4" and 1" blades:
Hope that's a little bit helpful to anyone thinking of giving it a go...
Cheers,
