Herman
Hjorth, "The Router" Home Craftsman 18, no 6 November-December 1949 pages 18+; reprinted as chapter 12,
under pen of Milton Gunerman, How to Operate Your Power Tools New
York: Home Craftsman Publishing Corp., 1950, pages 124-136
Herman Hjorth's article, "The Router", could be a sort of break-through document in the history of the use of routers by amateur woodworkers. It's appearance in the last issue of the Home Craftsman published in 1949 ? the November-December issue ? puts it just inside that historic decade when America fought in World War II, and just two years before Hjorth?s death in 1951.
(It is a mystery why, in 1950, as a book, How to Operate Your Power Tools, these same articles appeared under the pen of Milton Gunerman, at the time listed as a Senior Editor for Home Craftsman)
In the years 1949-1950, under the umbrella title, How to Operate Your Power Tools, Hjorth published a series of articles for Home Craftsman on a wide variety of poer woodworking tools of potential use by woodworkers in their homeshops. Among power tools he covers are the radial arm saw -- domesticated versions of the industrial level units manufactured by Delta and Dewalt -- the drill press, the circular table saw, the bandsaw, the jig saw, the lathe, and the power planer. (Not covered is the combination tool that made a big splash with amateur woodworkers at this time -- the Shopsmith Model 10ER Hans
Goldschmidt and his Shopsmith-- a fact that is mentioned by Gunerman in the Preface to the 1950 book.)
Rightly, Hjorth characterizes the router as descending from a long line of commercial routers, which themselves sprung out of heavy production routers. (See Glossary_R_ Router_annex. ) Here's Hjorth's opening sentence
"The router machine in its heavy-duty production form is a type of machine that mostly resembles a drill press."
To demonstrate, Hjorth includes an image of the production router, reprinted below.
But I don't think the router's lineage is what excited the wannabe woodworkers of that day; instead, what they found exciting is the idea of the router's versatility in perfoming at least 13 distinctive operations: cutting rabbets, cutting dadoes, cutting grooves, cutting "gains" for door hinges, for cutting shallow mortises; with the aid of a dovetail jig, a dovetail router bit and a template guide, for cutting dovetails; for cutting grooves and recesses for inlaying; and for flat carving, -- "for flat carving the hand router cannot be surpassed" --; as a shaper, the hand router can be used to cut moldings along the edge or end of tables, bureaus, and other types of furniture; with the use of a special stand to hold the motor, the router be used for fluting or beading, a spindle shaper; fluting, chamfering and V-rabbeting; and many molding cuts can be made easily with the hand router and pilot tip bits.
In other words, the hand router, consisting of the motor, router base and guide, can be used for making almost any cuts required in joinery.
Hjorth's entire article on the router is in the box below:
The Carter-Stanley Hand Router
The router machine in its heavy-duty production form is a type of machine that mostly resembles a drill press. The hand router, which is more familiar to the home craftsman or the shop owner doing light production work, is primarily a motor held in a base provided with two knobs as shown in Fig. 1. It is a very versatile machine and can not only bore holes, but also make mortises, cut grooves for inlay lines and insets, cut rabbets, cut gains for hinges, make dadoes, groove curved work, bead and round small moldings, and do veining and routing after templates. With the aid of a jig and fixtures which can be readily obtained, the hand router can be used to cut dove-tail joints, bead and flute turned legs. A fixture can also be obtained for the con-version of a hand router into a shaper. With the aid of a router stand, the hand router becomes a bench router similar to the heavy-duty production router.
The Production Router
Production routers, Fig. 2, are large machines equipped with a table that can be raised or lowered by means of a screw. The router arm extends to the center of the table. In most machines the revolving part is connected to the driving mechanism with a belt, which gives the router a speed from 10,000 to 20,000 R.P.M. The table can also be raised or lowered with a treadle and the length of the stroke can be set beforehand. Some routers also have a chuck for holding a shaper spindle. In this case the shaper cuts are necessarily made from the top while a regular shaper cutter projects through the table and cuts from below.
The hand router motor can be raised or lowered in the base, thereby
controlling the depth of the cut. The base also has a reversible guide fastened to two steel bars. One side is flat and used along straight surfaces; the other has a depression in it and is used for cutting along curved surfaces.
Typical HSS Router Bits of the Post-WW II Era
Router cutters for the hand router can be obtained with straight cutting ends as shown in Fig. 2 for routing out rabbets, grooves, dadoes, gains or mortises.
These routers come in sizes from to 3/32" in 32nds of an inch and from 1/4" to 3/8" in 16ths of an inch. Bits for veining shown in Fig. 4 come in sizes from 3/32 to 7/32".
1. Rabbets. The hand router, consisting of the motor, router base and guide, can be used for making almost any cuts required in joinery. Figure 8 shows the router being used for cutting a rabbet. This can be done across the end as well as along the edge. A straight-end router hit is set in the chuck, then the motor raised or lowered in the base to permit the hit to project below the under surface of the base equivalent to the depth of the rabbet. The guide is set to control the width of the rabbet.
Since a rabbet must extend to the end of the stock, a strip of wood should be secured to the gauge with short wood screws. Holes to take these screws are already provided on the straight edge of the guide. If a rabbet is to be made wider than the diameter of the router bit being used, it can be done by setting the guide for the ultimate width, then making two or more cuts in the wood. The cutting of a rabbet on a circular piece is done in the same manner except that the opposite end of the gauge is used as shown in Fig. 9.
2. Dadoes. The cutting of dadoes, particularly on wide pieces of stock, can be done much easier and with more accuracy when a router is used. Figure 10 shows the guide being used for the dadoing operation. The choice of the router hit is dependent on the width of the dado. The depth of the dado is controlled by raising or lowering the motor in the base. The location of the dado is controlled by the gauge.
With the use of the gauge, the position of any dado is limited to the distance from the base that the
gauge can be set. This may be no more than 6" from any surface. Should it be desired to cut a dado beyond this limit of the gauge, it can be done with the aid of a template and a template tip. The template tip shown in Fig. 11 can
be attached to the router base with two screws and used for the cutting of all dadoes. The template, which can be made from a piece of 1/4" plywood or Masonite, will require the cutting of a slot to take the template tip.
Since a 3/8" straight router bit is the largest size available to a machine such as this, the widest dado that can be made in one pass is 3/8". The outside diameter of the template tip that rides in the template is 3/4". If a 3/8" router bit is to be used to cut a 3/8" wide dado, the slot in the template should be cut to a width of 3/4". For wider dadoes, using the 3/8" bit, the width of the template slot should be increased accordingly. A 1/2" dado when made with a 3/8" bit will require a template slot of 7/8". Figure 12 shows the router being used to cut the template slot.
The template, when completed, is held in position on the stock that is to be dadoed by the means of small clamps or several brads. With the template tip secured in the router base, and the router bit set for the required depth, the cutting of the dado as shown in Fig. 13 is a simple matter.
3. Grooves. The cutting of grooves, that is, slots that extend with the grain of the wood, is done in the same manner as was outlined for the cutting of dadoes. The guide provided with
the hand router is designed for use against straight and circular surfaces, but there are occasions when neither end of the guide can be used satisfactorily.
This is so in the case of routing a groove in a curved surface such as shown in Fig. 14. When such a setup is required, a template or guide having the exact reverse shape of the piece that is to be grooved should be fastened to the
straight edge of the gauge with wood screws.
4. Gains. Gains are slots cut
into the wood similar to dadoes or grooves except that one end is closed. Such cuts are frequently made to take hinges or shelf members. The cutting of a gain in a wide piece of stock is done in the same manner as was outlined for the
cutting of a dado. If the gain is within 6" of a parallel surface, the gauge can be used to guide the router. If the gain is beyond this measurement, it will be necessary to use the template and template tip to cut it. Since
router bits leave a curved surface where the gain ends, it will he necessary either to cut the corner square with a chisel or round off the corner of the stock that is to set in the gain.
The cutting of a gain for a hinge may be (lone with nothing more than the gauge, or gauge may be used in conjunction with a guide to limit the length of the cut as shown in Fig. 15. A strip of wood 1/2" square should be fastened to the straight edge of the gauge so that the router bit will not come in contact with the metal. Where several hinge gains are to he cut, it is advisable to make up the guide. The guide is made of three pieces of 3/4" square stock as shown in Fig. 16. The guide is secured to the stock with clamps, and the stop blocks set to control the limit of travel.
5. Mortising. For the cutting of shallow mortises, the hand router is the most satisfactory tool available.
When cutting a mortise within 6" of a straight surface, as shown in Fig. 17, the limits can he con-trolled by a guide similar to the one shown in Fig. 16. When cutting out a mortise more than 6" from a parallel surface, the
template tip and template as shown in Fig. IS can be used to advantage. The method of preparing the template for the cutting of a mortise is the same as was previously outlined for the cutting of a dado. Since the router bit leaves
the corners of the mortise round, it will be necessary either to clean out the corners with a chisel or round the edges of the tenon that is to fit in the mortise.
6. Dovetailing. One of the best joints for assembling drawer members or small boxes is the dovetail. With the aid of a dove-tail fixture, a dovetail router bit and a template guide tip?
the hand router can be used for the cutting of dovetail joints as shown in Fig. 19: The dovetail sockets cut into one member and the dovetail pins cut in the other are done at the same time, assuring accuracy of the joint. Stock from ;" to 1" in thickness can be dovetailed. Setting up of a router to do dovetailing with the aid of a dovetail
jig will require accurate preparation of the machine and jig according to the
manufacturer's recommendation. The dovetail jig shown in Fig. 19 has a template
designed for the cutting of dovetails on stock from 7/16" to 1" in
thickness. This template requires a 1/2" dovetail bit. By replacing the
large template with a smaller one and using a 3/8" router bit it is
possible to cut smaller dove-tails on stock ranging from 5/16" to
5/8" in thickness.
To set up the router for
cutting large dovetails with the 1/2" bit, attach a template guide tip to
the base of the router. The motor unit is now placed in the base with the chuck
well down to the template guide. Do not have the chuck in contact with the
template guide. The 1/2" dovetail is inserted through the
template guide tip and into the chuck. The chuck is now tightened to hold the
bit securely. The motor unit in the base is adjusted so that the bottom or
lower end of the dovetail bit is exactly 19/32" below the underside of the
base as shown in Fig. 20.
To set up the router for cutting small dovetails with the 3/8" dovetail bit the same procedure as outlined above must be followed with the exception of adjusting the motor base for the depth of cut. In this case, the bottom or lower end of the bit must be set exactly 7/16" below the underside of the base.
The dovetail fixture should be secured to the bench top with two flathead wood screws. The forward edge of the fixture should project slightly beyond the front of the bench. With the fixture secured, the work to be dovetailed can now be set in the fixture. It is advisable to make trial cuts in two pieces of scrap wood so that you can check and adjust the fixture should it be necessary. Mark these pieces "A" and "B".
The piece which is to be the side member and should be marked "B" is clamped against the front of the fixture base with the inside surface out, so that it protrudes
or more above the top surface of the base. This is simply a temporary setting to locate piece "A" in the fixture. The front or back piece of the box or drawer marked "A" is placed under the clamp bar and on top of the base with the inner side up as in Fig. 19. The stock is moved forward until its end is in complete contact with piece "B". The edge of piece "A" must he in contact with the guide piece. Piece "B" can now be relocated. The end of this. piece must be flush with the upper face of piece "A" while the edge of piece "B" must touch the guide pin in the front of the fixture base.
With the pieces secured in the fixture, the template can now be set in place. The slotted brackets of the template are placed over the template studs between the adjusting nut and the clamping nut. The template must rest evenly on the surface of piece "A" before the clamping nuts are tightened.
Figure 19 shows stock being cut on the left-hand end of the fixture. The right front and left rear corners of a box or drawer have the members at this end for the cutting of dovetails. For the dovetailing of left front and right rear corners, the stock should be placed at the other end of the fixture.
7. Routing. For the cutting
of grooves and recesses for inlaying and for flat carving, the hand router
cannot be surpassed. Commercially, routers are used for pierced work which
previously was done on the jig saw. Almost any pierced work can be done by the
home craftsman with the hand router in considerably less time than it would
take him to do the same work on the jig saw.
8. Inlaying. Inlaying requires
the cutting of a recess or groove slightly less than 1/20" or
1/28" to take the thin inlay strips
or marquetry design. When cutting the recess for a marquetry design such as
shown in Fig. 22, the first step is to place the design on the surface of the wood
where it is to be recessed, then outline the design with a sharp thin-bladed
knife. This out-line should be made with care, as it establishes the ultimate
limits of the recess. A straight router bit of suitable size is secured in the
chuck and the motor adjusted in the base so that the bit projects .below the
base slightly less than the thickness of the inlay. Due to the high speed of
the machine and the fact that the cut to be made is extremely shallow, the
router can be used to cut the recess to approximate size without the need of a
guide. Work almost to the knife lines with the router. The final step is to
clean out the corners of the recess with a sharp chisel and knife.
Strips of inlay such as
are used for borders parallel to straight surfaces can be cut in the same
manner as grooves. The router bit to be used should be of a diameter equal or
less than the width of the inlay that is to be applied. The router bit is set
in the chuck and the motor adjusted in the base so that the bit projects below
it slightly less than the thickness of the strip that is to be set in. The
location of the grooves that are to be cut can be laid out with a sharp pencil,
but this must be done with care. The gauge is attached to the router base and
set so that when the gauge rides along the edge of the stock, the router bit
will be within the limits of the recess as it
was laid out. Figure 23 shows the router being used to cut a recess for an
inlay border.
Frequently, inlay borders
have the corner sections set in to follow a curve. The cutting of the recesses
for inlays of this type can best be done with a pattern made of 1/4"
plywood or Masonite and the use of the template tips. This operation is shown
in Fig. 24. When using templates, it is important that the surfaces against
which the template tip is to travel be finished smooth and without any
irregularities as these would show up in the groove.
9. Carving. Flat carvings
either in relief or incised can he made readily with the hand router. Figure 25
shows the router being used to work out a rustic wood sign in relief. A sign of
this type can be produced by the freehand use
of the router. The design is laid out on the stock, then a straight router bit
of suitable size is set in the chuck. In work of this kind the depth of the
recess need not exceed 1/8". At this depth no difficulty will be
encountered in guiding the router freehand along the outline.
Incised carving is usually
done with a veining bit. Figure 26 shows a rustic sign being carved with such a
bit. As the letter is in a freehand script, no template or other guide is
needed.
When a number of carvings,
either relief or incised, are required or where the carving must follow a
definite geometric pat-tern, another method must be used. Such carvings will
require the use of rigid sup-port for the router and a table provided with a
guide pin such as shown in Fig. 27. While the pin may be of any diameter, it is
best to have it the same as that of the bit being used as this simplifies the
preparation of the pattern. A pattern out-line of the design to be used is cut
from thin stock then fastened to a piece of plywood, preferably 3/4"
thick, with brads as shown in Fig. 28.
The minimum spacing of the
slots in the pattern must be controlled by the diameter of the guide pin
inserted in the table. Two thin brads are driven through the pattern and back
and allowed to project at least 1/8" above the surface of the backing. The
placement of these brads should be within the area of the stock to be carved.
The stock is forced on the projecting brads in the backing; then the entire
assembly is placed on the table with the guide pin engaging a slot in the
pattern. The router is started and racked down to start the carving. The router
is secured at this point and the stock being carved is worked under the bit.
Because of the fact that the pattern can only follow the guide pin, the carving
will be an exact duplicate of the pattern. This operation is shown in Fig. 29.
10. Piercing. The craftsman
who makes a business selling jigsawed projects will find the router a better
piece of equipment for mass production of this type of work. Figure 30 shows an
upright of a shelf member being shaped on the router. Work of this type will
require the use of a pat-tern similar to that described for the carving of
duplicate pieces. Since router bits are round, thereby producing round corners
as they cut, the design used for piercing should be one that does not have
sharp corners.
A veining hit or straight
bit may be used for piercing and since all that is required is the cutting
through the stock with a fine slot to remove the sections, the smaller diameter
router bits can be used. The first step in doing pierced work is to prepare a
pattern the exact duplicate of the pieces that are to be made. This can be done
on 1/8" stock. The jig saw can be used for this master pattern. It the
craftsman has developed sufficient skill with the router, this may be used
freehand to work out the master.
The pattern is fastened to
a backing of %" plywood and several thin brads are driven through the
pattern and backing and allowed to project about 1/8" above the backing. A
guide pin of the same diameter as the bit that is to be used should be inserted
in the table directly under the bit. The piece
to be pierced is secured to the backing by forcing it on the projecting nail points.
The assembled unit is placed on the table with the pin in one of the pattern
openings. The router is started, then racked down to begin to cut. On thin
stock, the piercing of an section can be done by one cut. Thicker material will
require two or three cuts to complete the piercing.
If desired, the sides of
each pierced section can be molded as shown in Fig. 31 with one of the molding
router bits. These bits are provided with a pilot tip which rides against the
edge of the stock, making it unnecessary to use any other type or guide or
pattern.
11. Shaping. With the use of
the router molding bit shown in Fig. 7, the hand router can be used to cut
moldings along the edge or end of stock as shown in Fig. 32. With the use of a
special stand to hold the motor, the machine - be used for fluting or beading a
turning as shown in Fig. 33. By installing the motor in a unit called a shaper
plate, the router can he converted into a spindle shaper as shown in Fig. 34.
Shaper cutters to make
straight, con-cave or convex cuts are available in a variety of sizes. Corner,
spindle and surface head cutters are also available. Fluting, chamfering and
V-rabbeting cutters can also be obtained. These cutters can be used
individually or in combination as shown in Fig. 35.
12. Fluting and Beading. The
attachment for beading and fluting consists of a gray iron motor holder that is
mounted on a wooden sub-base. It is adjustable for up and down position.
For most beading and
fluting work, the attachment with the motor is used on the lathe. A board may
be clamped to the bed or the ways of the lathe to provide a flat working
surface for the attachment. For large lathes, extra blocking on top of the ways
will bring the hoard surface up to the correct working level.
Two methods are
recommended for beading and fluting work. A guide collar, furnished with
attachment, fits around the spindle and is held directly against the work so it
follows the contour accurately.
The guide collar is
adjustable for depth of cut. Where many similar pieces of wood are to be beaded
or fluted the same, a plywood template may be fastened to the board on the
lathe bed at the proper location. The rounded end of the plywood sub-base
guides against this template to assure uniform outline and accurate depth of
cut.
Beading and fluting work
does add an extra finishing touch on all your turnings. The spacings of the
cuts or the number all around the turning can be arranged accurately with the
index head on your lathe or with an improvised disk as shown in Fig. 36.
13. Molding. Many molding cuts
can be made easily with the hand router and pilot tip bits. The pilot is round
and smooth and does no cutting, but acts as a guide along the edge of the work.
The pilot is small in diameter and will follow straight or irregular shapes (Fig.
37).
When using a pilot tip
bit, do not hold the bit in one place, but keep it moving or remove it from the
work. Do not press the pilot too tightlyagainst the edge of the work or it will heat and discolor both the bit and the
work.
With the shaper table you
can produce an infinite variety of cuts without purchasing a special cutter for
each cut. The table is equipped with a tilting motor holder that can be tipped
from vertical position to any angle up to 45°. With four cutters, a great many
cuts can be made simply by rearranging the cutters on the spindle and by
changing the angle of the motor unit.
For the molding of straight surfaces, the fence or straight guide is used. For the shaping of
curved or irregular patterns, the circular guide is secured to the table in
place of the fence.
Source: Herman
Hjorth Home Craftsman
18, no 6 November-December 1949 pages 18+;reprinted as chapter 12,
under pen of Milton Gunerman, How to Operate Your Power ToolsNew
York: Home Craftsman Publishing Corp., 1950, pages 124-136