From the Workshop

Spiers Style Shoulder plane -4

Apologies for the 4 week gap in postings for those of you who have been following my blog.  I have been a bit busy with visitors (though always welcome it does tend to put me behind a bit), and the new project (transitional plane) keeps on snapping at me;  it is coming along quite well if a bit piecemeal.

 As I mentioned in the last posting that I had mislaid some pictures so here I am going to replace them with some from an A7 Norris type shoulder plane as they are very close in construction.

The front infill of an adjustable shoulder plane is probably the most complex infill of all my planes; especially as they are part of the adjuster design.  This infill is integral with the bridge and the clamping screw bush.  The clamping screw bush (which is illustrated in a previous posting) is screwed through the bridge. It also has a shoulder which secures the front part of the infill by clamping down on to a counterbore recess in the wood. This arrangement eliminates the need for a rivet here.  

All the boring, counterboring and tapping is done in a set sequence whilst everything is in situ.  After this process the whole plane is disassembled for further work.  This includes the fixing of the infill to the bridge with the brass bush.  With the fixing secure and complete the brass bush on the underside of the bridge can then be flushed off.  By offering the filling back into position in the plane I can scribe the contour lines from the plane sides for reference for the shaping of the horn detail around the brass bush.  

Here the rear end of the shoulder plane is polished before the blade bed is fitted, otherwise it would be inaccessible.  This is typical of the importance of getting the sequence right throughout the whole project.

Just showing the whole rear end without me in the way.

The front end of the plane can be flushed and polished after the infill has been fitted and secured for the last time.

The front end after polishing.

The throat of the shoulder plane is another tedious task.  Of course most of this work is machined so I know that it is right but there is always fitting allowances that need flushing.  This includes part of the plane sides and the infill.  When this is complete it will determine the line of the bed.  In this picture I have used a piece of brass shim to avoid any damage from the filing work that is to follow.

The dovetails as seen here, are only partly flushed.  The irregular shapes are only from peining.  The final flushing of the plane sides is done near the finish of the plane.

Filing work on the frog area of the throat.  With the shim in place it provides a bit of protection to the areas that I do not want to file.

Another useful tool is this file which I have ground flush on the two sides making them safe so that I can use the edges of the file for cutting into corners etc.

The roof of the throat also requires flushing and polishing.

Now that I am almost complete, with a piece of ground plate I can check that the frog surface is true.  I use a bluing ink or light to check for the high spots.

This picture shows one small process in the grinding of the blade.  On this blade there are seven surfaces that are precisionally ground.  The contoured edges are polished.

All my blades are made in house from a pre-ground stock, mostly in A2 steel, then drilling and shaping is all done on the mill whilst in its annealed state.  The only part which is out sourced is the heat treatment as this is very specialised and critical.  This heat treatment includes the over used term of cryogenics.  I was the first person to introduce this alloy for plane blades on a commercial basis, which since then seems to have become a standard with other makers.  You need to bear in mind that the analysis of this alloy is variable and the recipe of the process I use is a secret that I now guard.  You can be sure that not all A2 blades are of the same standard.

The wedge.  As you can see here there is a little bit more to the hand shaping than just filing.  The camber illustrated is consistent.

The finished item.
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