That is indeed a wartime plane.  The type study was done on the no4.  The bigger planes didn't get the changes until later.  The frog design with the ogee and kidney bean lever cap started with a type 16.  The bolts that hold the knob and tote being steel is also a t17 hallmark.

Fella 20 miles north of me had one on fb marketplace for $65...maybe I should go snatch it up.  Right now I'm in the middle of restoring a Stanley No.4 smoothing plane I've had for about 10 years that had been gathering dust in my garage.

FYI Put your magnet in a plastic bag. It makes it MUCH easier to get all those tiny shavings off later.

Yan done good, real good!

This is a type 17—the type 15 molding marks weren’t done on the 5-1/2 even through the type 18–my 18 doesn’t have them. The unplated lever plate is another clue. Finer grit applied to the sole and sides will look better, work smoother, and resist rust better. Don’t use vinegar—too acidic. You have a nice plane!

The main parts you want flat it's the very edges of the front and the heel and in front and behind the mouth. If your plane is longer than your abrading surface your never gonna get it true/flat.

Thanks, I like the 5-1/2s.
Your 5-1/2 reminds me of 1 of my No. 4s, it looks like it is 'parts' plane.
BTW, I think I found an easier way to flatten the sole.
I have some concrete/cinder blocks that are clean, smooth, & fairly flat sided.
I 'plane' the flat side (w/ iron withdrawn) of the blocks.
It seems faster & it gives a nice finish, it reminds me of 120 grit sandpaper.
Since I do it outside I just brush off the 'dust' & the block's surface is ready to go again.
I'll prolly finish it w/ 120 or 150 wet/dry sc sandpaper.
I like it because it seems to be faster than sanding the sole for hours.
Have a GREAT day, Neighbor!

Looks like steel knob and tote screws also, I'd say WWII type 17 maybe earlier production got the nicer rosewood...

She's a beaut! About the depth-control knob, the wartime ones were hard-vulcanised rubber. And rather amazingly (to me 😁) after years and years of looking at this stuff I think this is the closest view I've ever had of one! So thanks for that.

It is a well-known thing that some Stanleys from the factory used up older spare parts from the stores, and this is probably much more common for the fractional sizes (as well as maybe the 2s, 7s and especially the 8s). So I'm thinking definitely wartime production on this one. All the other details seem to match – the cheeks look thicker than typical for earlier Stanleys, no nickel plate on the lever cap, no paint in the logo recess, and it has the steel handle screws instead of studs with brass nuts.

Have you had a chance to work on the handles some since the video was posted? I was wondering if they did turn out to be rosewood, because wartime ones were mostly stained hardwood. As these are in such nice condition for their age i was thinking they could be that, without any telltale wear-throughs or scratches that reveal the natural wood colour.

BTW glad to see you have tons of the Johnson's paste wax left in that tin since I just found out they stopped production of it a while back 😢Hope it lasts you for a good long while!

I love Hock blade chipbreaker combinations. But i have never bought one after Ron retired and sold to Lee Valley. But I seriously doubt Lee Valley will mess with it🙏. You cannot lap the sole of a plane using sandpaper that is shorter than the plane. Because the sandpaper contacts the center of the plane all of the time  and the ends only sometimes you have made a hollow in the center of the plane. This is lapping 101. This is not meant as criticism but just information. Also do you know that Johnson paste wax is about $150 a tin now?

Gave up on this when you failed to complete the sole.