When you said expensive hand made, I was bracing myself for bad axe saw prices.
€50 does not seem expensive.
So is it basically a rough file? Isn't it going to tear out along the edges? Something you avoid by paring into the middle?
The price is subjective....... you'd pay that for a football match ticket these days. One of those floats will last a lifetime.
No, It's not a rough file. If you want a rough file, they are much, much cheaper; also, it isn't a shaping or cutting tool - rasps will do a better job.
So, what is a float?
It is a finishing cut....gentle forward motion each time. The last few strokes are done with a float and it is capable of good precision. Cut with the grain it will leave a perfectly smooth surface. Cut across the grain and it will leave a flat surface, but with an element of tear - just like a sharp router. So, you don't do that. The sideways approach is best, done from an angle, just like slicing with a chisel blade.
Never force it - it will dig in. The secret is in the name - when it is sharp and you are gentle with it the tool will float across a surface, producing very fine shavings, almost like a good scraper.
The technique is to either use it to shape end grain - plane makers used floats to get the throat faces and iron beds exact - or to take an oblique cut on cross-grain, very lightly, as you would with a paring cut. Cut directly across the grain will result in the dreaded, predictable tear-out. It needs to be an oblique angle against supported grain all the time.
Looking at it, the edge-profile is the same as a rip saw. I've just measured my Liogier float and it comes in at 9 teeth per inch.
So, in a well set and sharpened float, what you have is a flat set of rip-type teeth, about an inch wide that are all exactly aligned in height so that each one strikes the work at the same level and the same angle. Each tooth is about 1/8 inch apart and should be razor-sharp from a file-swipe, presented at about 60 degrees forward angle.
If you had a plane iron mounted and cutting at this angle, it would be the equivalent of 'half-pitch', which is perfect for wavy grained timber.
A float has the equivalent of several dozen half-pitch blades, cutting in sequence, one after the other.
As each tooth transits the work, its cut overlaps its neighbour. It follows that if your stroke is exact or regulated by a block you'll end up with a perfectly flat surface.
I hope that I've explained what is an unusual tool these days......
Going back to the OP's question about the final
leveling the faces of his bridle joint, if it's done with a float, it should, in my opinion, be the very final tool, used after all the fine paring down to the line leaves a slightly proud level that you have mentioned. At this point, hang up the chisel and reach for the float..
If the bridle part is clamped to a very flat board and two blocks about a couple of inches square that are exactly as thick as the bridle's sides are set loose and free to move against each edge, the float can be rested face down on these and the last few strokes taken with sucessive, small nibbles advancing to the middle until there is nothing removed.Turn it round and repeat. At this point you should have a level bridle cheek and if the cutting is gradual and gentle as I described, very flat.
Now, turn it over and repeat on the other side, small, light, oblique skims until it is all flat and nothing is removed.
A combination of a sharp float, and gentle, oblique motion will give a very good and exact finish that can be repeated if you have a batch to do.
Once all this is done, you can cut and fashion your tenon part to fit tightly into the middle gap which should be parallel and flat-sided.
I hope that I've explained how a float is intended to work.... more importantly what it's
not supposed to do!
Good luck
