This post has been written by Vittorio, a friend of mine very skilled with hand tools. I only translate from Italian (hope not too badly) his great job. Thank you Vittorio and welcome to the blog! For some time I thought to build a metal plane and surfing the net I found a lot of ideas and this very good project:http://user.xmission.com/~jry/ww/tools/a13/a13.htmland my adventure started!
I thank you Jim Yehle from Salt Lake City, the author of the project from which my plane was inspired. I used Fe 430 steel. I think it is strong enough for good plane sturdiness and at same time permits to use hand tools for working it easily; I used 6 mm thick plate for the sole and a 5mm one for sides.
I started by coupling sides together, marking joints and boring for reducing the steel amount to be discarded; with patience I shaped the dovetails. These have 60° angles, as well as files have.
I thank you Jim Yehle from Salt Lake City, the author of the project from which my plane was inspired. I used Fe 430 steel. I think it is strong enough for good plane sturdiness and at same time permits to use hand tools for working it easily; I used 6 mm thick plate for the sole and a 5mm one for sides.
I started by coupling sides together, marking joints and boring for reducing the steel amount to be discarded; with patience I shaped the dovetails. These have 60° angles, as well as files have.
I cut the sole, marked out tails and sawn them as precisely as possible; this job was far more difficult.
Finally, the two sides are ready as well as a wooden support, useful for dovetail peening. 
The iron holder comes from a 10 mm steel plate. It has a 47.5° angle and also is useful as support to the file for cutting the mouth back. 
Side shaping, first lapping with 100 grit abrasive paper and 6mm rivet plugging in for blade holder fastening. 
The dovetail peening is the most important step; although the wooden support helps, it is important to control that the internal part of sides is square, to avoid troubles during plane assembling.
Cleaning up with a file and abrasive paper, until joints disappear and the sole is flat.
For making the lever cap I used template steel, a very strong material. I had to do more work for shaping it.
Handle and knob come from a 3mm thick well seasoned ash board; apparently working wood seems easier than shaping metal, but I spent several hours to obtain the right shapes.
I used 8mm steel rods (bored in a machine shop) as spacers for handle fixing. Rods were threaded inside and inserted into the wood; as said above if the inner side is not square to the sole, the spacer ability of firmly holding the wood in place will be decreased. 
The wood has been finished with 8 coats of shellac, fixed to metal body with screws firmly screwed and then clinched. Unfortunately ordinary screws have the conical section too low, so the countersink has not completely filled. However the final lapping helps to attenuate the gap.
The blade comes from an old industrial cutter. It has been worked with glass paper for obtaining the 25° bevel and with 3M abrasives (40, 30, 15, 5, 1, 0.3 microns) for honing a 30° microbevel.
Finally the road test. I tried the plane with fir, lime and beech. Its a pleasure use it. This is sufficient for satisfying me enough of the job, done only using hand tools.
The mouth opening is 1 mm. The plane weights 2260 gr.
Here is a pic of the polished infill plane. It is already at work.
Final notes.
While I am waiting for a knurled screw for lever cap, I have done a wooden cap.Although the plane lacks of adjusting mechanism, its set up is easy.
The handle tail could appear too accentuate, but the grip results very ergonomic.After all I am very happy beaucause has been a great experience with a good result.Ciao
Vittorio
