Dedicated No. 4 1/2

left: The Dedicated 4 1/2 - probably a type 17 - right: a type 11 No. 4 1/2 fitted with a new cryo blade

The 4 1/2 on the left in the above picture came into my possession several years ago.  My guess is that the main casting is a type 17.  It is noticeably heavier than the type 11 on the right.  It’s hard to understand why a wartime casting would be heavier as the US was looking for metals for armaments.  Some folks have speculated that Stanley was beginning to “feel the heat” as American GI’s came in contact with the classic British infill planes built by makers like Norris and Spiers.  But, the truth is we will probably never know the real reason. 

In any event, I decided to dedicate this baby to the sole purpose of smoothing highly figured wood, as in everyone’s favorite, curly maple.  Anyone who has ever tried to plane a piece of curly maple knows that it is about as tough as it gets.  First and foremost, a cutting angle of 45 degrees simply won’t get the job done.  So in order to raise the cutting angle, I decided to back bevel the iron by 17 degrees (give or take a degree).  This puts the actual cutting angle up to 62 degrees, which is about as high as can be achieved before incredible “chatter” sets in, due to the thin section of the Stanley iron and chip breaker. 

17 degree back bevel

The next step was to ensure that, while taking the thinnest possible shavings, the plane left no “tracks”.  So, the main bevel of the iron was gently crowned.  I’m “guesstimating” that the crown is something like .0015″.  If I were more of a scientific woodworker, I would have measured it.  But with me, most of the time, the right brain wins. 

The iron, "gently" crowned

Then it’s time to put the chip breaker back in place.  But wait!  Throw out the old notion that the chip breaker should be as close to the cutting edge as possible (sorry Gramps).  The back bevel disallows this.  Plus, since we’ve raised the cutting angle, we’ve effectively rendered the chip breaker useless, as far as “breaking” chips.  It does, however, still add mass, helping to minimize vibration. 

chip breaker set well back from cutting edge; 1/16-3/32"

The frog has been moved forward to create a mouth opening that is not more than 1/32″.  This minimum mouth opening is what, in fact, “breaks” the chip. 

Minimum mouth opening - a gnat couldn't crawl through it

It becomes immediately obvious that raising the cutting angle increases the amount of energy required to do the work.  This was one of the facts in my decision to dedicate this one plane to smooth high figure stock.  It won’t be much good for walnut or pine, but it will produce the beautiful, glassy surface that can only be obtained by sheer cutting. 

the objective - a highly reflective, glassy smooth surface on curly stock

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