metalwork

Cleaning A Brazed/Soldered Joint (Making Roubo Squares sidebar)

I use some version of the following techniques for cleaning the interior corners of a soldered/brazed joint such as that created at the shoe-and-beam joint for the Roubo squares.  If my brazing technique is on its game this only takes a couple minutes from start to finish.  If not, more minutes.  Actually, were I a better metalsmith there would be no cleanup at all, but this is the kind of joint I usually have after the torch work.

My first step is to clean the excess solder with a half-round Vixen file, which is the metalworking version of a float.  I lay the flat side of the file down flat on the workpiece and press the edge between the flat and half-round sides into the joint to remove any excess.  Then I repeat it on the other flat face.

Once any excess solder is cleaned off I strike the joint with a diamond shaped burin, or engraver, to establish a nice clean corner.  The spatial circumstance of the task does not allow for me to hold the burin properly, I just hold it sorta like a paring chisel.

Finally I find the halfway angle for a triangle fie and undercut the joint ever so slightly for an elegantly clean look.

After that I’ve got a nice surface ready for polishing with a light abrasive to make it finished.  Once I get the edges finished this one will be ready to go.

“Measuring Is The Enemy,” or, Truing A Triangle

One of the tools emerging from the recent Making Roubo Squares workshop was a diminutive 30-60-90 triangle.  This tool is integral to much of my/our shop life for areas ranging from cubic/pinwheel parquetry to laying out the dovetailed tenons of a Roubo bench leg-and-slab double mortise-and-tenon construction.

With the surplus rectangle of brass plate left over from the making of our nested set of cabinetmaker’s squares during the workshop there was plenty of brass plate left over for making other, smaller layout tools.  Included in these were some small triangles that were roughly laid out with a plastic drafting triangle and rough cut on the bandsaw.

I took the opportunity to demonstrate the truing of the triangle to the workshop students, reminding them of the simple truths they learned decades ago in seventh grade Geometry class.  Instead of using a micrometer or something similar to establish the tringle side lengths, a much easier, simpler, faster, and frankly more accurate method is only a compass or divider away.

After establishing the perfect square corner between the two shorter legs of the triangle it was possible to achieve a perfect set of 30-60 degree angles by using just a scrap piece of plywood, a pencil, and a set of dividers.  For work like this I almost always revert to a pair of dividers from an antique navigational drafting set that I bought for practically nothing many years ago.  These German Silver (alloy of brass plus nickel) tools are simply lovely and a pleasure to the eye and the hand.

First I traced the rough triangle onto a piece of scrap plywood, and set my dividers to the exact length of the shorter side adjacent to the right angle.

Then swinging the dividers to the hypotenuse I stepped off two of those lengths.  If you will recall, for a perfect 30-60-90 triangle the hypotenuse is exactly two time longer than the shorter side of the right angle.

Once I determined that two-times-longer distance along the hypotenuse I re-set my dividers to this exact distance then transferred it to the longer side of the right angle, redrew the hypotenuse on the plywood, then transferred it to the brass.

Five minutes later I had cut and filed the new hypotenuse and had a perfect 30-60-90 triangle ready to braze on the foot and put to use in a multitude of applications.

All with zero measuring, although to be honest I did grab my dial caliper afterwards to check.  I wound up being off by almost 0.002″ which probably amounts to a couple seconds or so of angle degree (or, about 1/1800th of a degree).   I can live with that.

To quote my mentor in the pattern shop, John Kuzma (cleaned up considerably for a family-friendly venue), “Measuring is the enemy.  Layout and transfer are your friends.”

I cannot recall my 7th grade Geometry teacher’s name but I do remember Mr. Fiske, who taught me Trigonometry in 11th grade almost fifty years ago.  Together these men impressed on me the importance of triangles in every-day life.  Thank you, gentlemen.

Less Is More, or Supercharging A Mill File For More Precise Metalworking

Not too long ago I discovered something that perhaps many of you knew already (and if so, why didn’t you tell me?), and my response to the problem and solution imparted great satisfaction.

Being both a metalworker and a tightwad I  am pretty fussy about my files, and in fact have a substantial number of them.  One I could never talk myself into getting was a die-maker’s mill file with one shoulder devoid of cutting function.  All the ones I had seen while shopping were simply more money than I wanted to spend.  Since this is a utility I need on a fairly frequent basis I generally just put a strip of tape along one edge of the file so I could work into one side of an inside corner without boogering up the adjacent shoulder.  Perhaps I had some bad tape but recently I was continually frustrated as it peeled off while I was working the inside corners of the Roubo squares.

I decided to deal with the problem once and for all.

I took my new-ish mill file to the disc grinder and very gently just ground away the teeth/grooves on one edge.  I say “gently” on purpose because I did not want to heat up the tool and have it lose its temper.  So gently it was.

After that I took it to the vise and dressed the sanded edge to a fairly nice polish (1200 grit diamond stone).  In almost no time  (less than ten minutes) and for no money(!) I had a die-maker’s mill file that allowed me to work both more aggressively and more precisely on inside corners.  And if I need to do any edge filing, I simply rotate the file 180 degrees and use the opposite edge.

I hope I don’t hurt my shoulder patting myself on the back…

Workshop Teaser – Make A Set of Roubo Squares

Every participant will begin with a slab of brass which we will cut on the table saw to yield the preferred number of graduated squares.

Once these have been cut and the corners cleaned up, they will be laid out for the graduated nesting sizes.

Ogees are cut and filed into the ends, and all the detailing is finished in preparation for the silver soldering of the shoe on the outside of the beam.

If this workshop interests you, drop me a line via the Comments or Contact functions of the site.  It will be June 20-22, and the tuition + materials is $425.  You will leave with a completed set of squares.

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Other workshops at the Barn this summer are:

Historic Finishing

Make A Roubo Shoulder Knife

Make A Ripple Molding Machine

Summer 2019 Workshops at the Barn

I have settled on the topics and approximate schedule for next summer’s classes here in the hinterlands, with three of the four classes emphasizing toolmaking.  I will post about them in greater detail in the near future.  One minor change I’ll be instituting next year is that three-day workshops will now be Thursday-Friday-Saturday rather than Friday-Saturday-Sunday as before.

June’s class will be a metalworking event, Making A Nested Set of Roubo’s Squares.   The objective will be for each attendee to create a set of four or five solid brass footed squares, the sort illustrated in Roubo’s Plate 308, Figure 2.  The special emphasis will be on silver soldering, a transforming skill for the toolmaker’s shop.  The tentative dates for this are June 6-8 or 20-22, $375 + $25 for materials.

July’s class will be my annual offering of Historic Wood Finishing.  Each participant will complete a series of exercises I have devised for the most efficient learning experience to overcome finishing fears and difficulties.  Of particular importance are the aspects of surface preparation and the use and application of wax and spirit varnish finishes using the techniques of the 1700s.  Probably July 11-13, $375.

In August we will continue the pursuit of Roubo’s tool kit, this time Making and Using Roubo’s Shoulder Knife.  I have no way to know exactly how prevalent was this tool’s use in ancient days, but I suspect more than I can imagine.  Each participant will fabricate a shoulder knife to fit their own torso, so its use can be both the most comfortable and the most effective.  Probably August 15-17, $375.

The final class for the year will be a week-long Build A Ripple Molding Cutter.  As I have been pursuing this topic and blogging about it, fellow ripple-ista John Hurn and I have settled on a compact design we think can be built by every attendee in a five-day session.  Together we will be teaching the process of ripple moldings and fabricating the machines that make them.  September 23-27, $750 plus $200 materials fee.

Save the dates and drop me a line for more information.

New Tool For Making Backsaws (And Much More)

Six years ago when I wrote my article in American Period Furniture on making my own dovetail saw I had the advantage of access to an ultra-sweet 12-inch Houdaille precision shear and a matching 12-inch brake.  I loved those tools and have been looking for the pair ever since I left Mordor, preferably for a modest outlay.  Alas, even used these run about $2k for the pair, with the new showroom price north of  $6k.  If I ever find them for next to nothing I will still pick them up, but that is an unlikely occurrence.  I believe Houdialle is now re-branded as Di-Acro but I cannot be certain.

Many moons ago I got a notice from Micro-Mark that they were discontinuing the very tool I wanted, and it was on sale at a very deep discount.  The tool in question was a mini-shear/brake for sheet metal, precisely the kind of tool I could use when making, or teaching the making of, petite dovetail saws.  The width capacity of the tool is 8 inches, which pretty much defines “petite” when it comes to saws.

I recently unpacked it and gave it a try.  Very, very nice.  I am fairly certain that this unit was manufactured by Baileigh, as theirs seems identical in every way.

The uses of this tool are many, from cleanly cutting spring steel coils to length and width for the saw plates, to bending brass backs for the saw structure.  I make saws with a folded 1/16″ back, which is a bit stout for this little tool, but if I anneal it first there seems to be no problem.

I’ll be using the tool in the near future as I build another saw in practice for the upcoming workshop Making A Petite Dovetail Saw, June 8-10.  I’ve got one opening for that class, so if it interests you drop me a note.