Craftsman Chair Reproduction
June 20, 2006
- The above chair is the subject of this reproduction process, which will be
described as it happens in these pages.
Inspiration
often pops up when you least expect it. Subject chair was purchased at a
garage sale for ten bucks a few years ago and has been a mystery as to
its origins and why there was only one.
An inspection of the chair reveals
that it was made by the hand of a master craftsman (with an obvious love for
what he wrought that shows right through the clumsy attempt of some misguided
re-finisher), and, judging from the joinery and hand tool marks, more than likely around the turn
of the last century (circa 1900).
The chair is white oak, with pegged mortise
and tenons, all the parts are from 1" to 1 5/8" thick stock (no 3/4" stuff in this
baby!) and it is as solid as the day it was built.
It is definitely
not a beautiful chair to look at, but comfortable despite its plain looks, and
its beauty is in the details of its construction, and the knowledgeable skill
of the maker, which shines through like a beacon to those who know and
appreciate such things.
Upshot is that the only thing I
would like better in a chair to go around my own Mission Trestle Table on
Page 5, and
the "Arts and Crafts Bench on Page 6
of this journal, is six more exactly like the one above, in
quarter-sawn white oak.
... and
perhaps, at the same time, pay tribute to a woodworker from another era whose
skill has stood the "test of time".
So,
here we go:
The
Planning of the Prototype.
Because of the
many angles, some compound,
the plan is to first do a prototype using a cheaper wood (poplar) to work out all the
joinery details.
For this project
a decision was made to use "loose tenon" joinery, a variation of traditional
mortise and tenon joinery, whereby a mortise is cut into both pieces to be
joined and a "loose tenon", milled separately from the same material and cut
to length, is glued into the opposing mortises to join the two parts.
Research and
previous experience indicate this variation of traditional M&T joinery to be
sufficiently strong for the task. It also has an added benefit of allowing the
various parts to be batch cut to final dimension, making for increased
accuracy and more efficient use of shop time in a small production run that
has the ultimate goal of producing identical parts for six chairs.
The first step is to take
measurements of the original chair and do a full scale drawing on 1/4" MDF of one side of the chair
frame. Since each chair will have two identical side frames, each with a front and back leg,
a side seat rail, and a stretcher, this is as good a place as any to start.
We'll worry about the parts that go between later.
The next step is
to do a template for the back leg out of 1/2" MDF, which can be seen at the
right side of the first picture above.
This template
will be used with a pattern bit to identically route all the back legs of the
chairs. I spent the better part of an afternoon dimensioning, cutting out, and
fairing the curves and angles of this back leg template. Since each leg will be an exact copy, it pays to take
the time and get it right.
While we're at
it, and with the complete back leg template in hand, now is a prudent time to
"dummy up" one front leg, one seat rail, and one side stretcher out of MDF in
order to work out the angles and dimensions for the joinery. You can see this
process in picture two above. This step will also provide dimensions for a
good start on a cut list, which will be necessary to order the wood
when we're ready to build for real.
With the back leg template complete and joinery locations marked, it is not a
bad idea to make extra copies for safe keeping. Using the original to trace
out two copies on MDF, rough cutting them on the band saw, and using a pattern
bit on the router table, produced two additional copies of this all important
template for when Murphy strikes.
At the same time, some 8/4 poplar was milled, then routed using the same
process to produce the two back legs for the prototype.
Clamping them to the master back leg template at the same time makes it easy
to precisely transfer the joinery locations onto a matched pair of legs ...
and now the parts are starting to resemble one side of a familiar chair frame.
As anticipated,
working out methods to cut the project mortises is turning out to be time
consuming in the early stages, and it's easy to see why so many small shops
are going to the
JDS Multi-Router to simplify the task.
Besides the fact
that routing angled mortises into the faces of legs with this particular
homemade jig has a great deal
more imprecision built-in than anticipated, it also takes four
separate, carefully crafted, "shims" just to cut the four joints, with three
different angles, shown above.
Finding router
bits long enough to do the job with this jig has also been a problem, solved
with the use of extra long, carbide, "end mills". The 3/8" joints above were
cut with multiple passes of a 1/4" carbide end mill, and, as a result, sizing
the loose tenons is problematic because the shoulders can't be easily rounded
over using a standard round over bit.
I am not really
satisfied with the fussy nature of the setup, so it's time to rethink the
basic jig, and re-build it for a 3/8" end mill that can do the proposed 3/8"
mortise width in one pass, which will hopefully solve the imprecision noted
thus far, as well as the problems fitting the loose tenons. Back to the
drawing board.
The solution to the jig problems on the
project thus far can be seen in the background ... the
JDS Multi-Router. In the short span of a few hours, including
coming up to speed on a new piece of equipment, we now have a prototype chair frame,
made up of numerous compound angles, all done with floating tenon joinery and
using the Multi-router to cut the mortises.
While there is still some evidence
of imprecision due to two separate methods of cutting the mortises, the light at
the end of the hoped for, small "production run" tunnel is apparent.
With the introduction of this one tool, batch cutting, and the subsequent
routing of parts should improve the overall precision and make this project move
forward with much greater speed
Jigs
for jigs ...
The next
challenge to be met is to come up with a "production" method for doing the 12
mortises needed for the six backrest slats in each chair's curved crest and
intermediate rails.
A total of 12 of
these curved rails will be needed (two for each chair), not counting extras,
so the ability to do these 72 mortises quickly and accurately is
important. (Note: the intermediate back rail pictured above is just a spacer)
To the left is an mdf
prototype of the "crest rail", looking at it from the bottom side and showing
the desired location of the backrest slat mortises. The second, "intermediate" rail's
mortises will be in a mirror image location on its top side.
In a sort of
"belt and suspenders" approach, two jigs/methods were simultaneously
developed. The first centering around the Multi-router, and the second using a
plunge router to perform the same task.
Method 1
uses the Multi-Router with an additional jig:
Since the curve is an arc of known radius, and the centerline of the mortises
must be perpendicular to the "chord" of the arc at each mortise location, it
was a logical jump to use these elements in designing a jig to be used in
conjunction with the Multi-router (just think of Samuel Colt and the
development of the "revolver", which works on a variation of the same
principle):
The jig is
first referenced, then clamped to the centerline of the x/y table. The rail to be
routed is then
clamped along the curve of the jig body, which corresponds to the same arc
radius as the rails.
In operation, each desired mortise location is
subsequently revolved along the arc to the top reference line of
the jig, where it is re-clamped, then routed precisely perpendicular to its chord in the manner in which the Multi-router excels.
The slot in the
jig front also aids in referencing the bits travel, and, used in conjunction
with the Multi-router's built-in stops, makes it easy to set the mortise
length. The "depth of cut" line can also be seen in the last photograph above
Method 2
uses a plunge router with a "collar guide" equipped base.
The idea for this jig
is based on an article by Terry Moore in the March 1990 issue of Fine WoodWorking magazine, entitled "Production Chairmaking".
These two pictures should be
self-explanatory. The workpiece is simply inserted under the top between a
curved plate and a cauls and the whole enchilada slipped into a bench vise.
Both
jigs/methods are simple
solutions to the problem of locating, and quickly and accurately routing
mortises in these curved chair parts.
Method 2 has
the advantage of being within easy reach of those without access to a
Multi-router or slot Mortiser (although in this case I did use the
Multi-Router's capabilities to great advantage in locating and routing the
initial collar guide slots for the jigs top).
Method 1,
besides taking advantage of the unique capabilities of the Multi-Router, has
the ability to easily change the locations of the mortises by simply marking
the parts appropriately, without having to "re-invent the wheel" for different
chair back designs. Once made, this jig is immediately ready for future chair projects
and it greatly enhances a tool already superior at tasks of this nature.
Although there
are undoubtedly many alternate methods, either of the above jigs handily solve
the last big challenge in finding methods to do this small shop "production
run" of chair parts.
I still have to
finish the jig(s) for actually making the curved crest and intermediate rails,
but this is the same, time honored methodology (using a router and pattern
bit) that was used to do the back legs, so it is familiar territory.
Above, the chair
frame, dry fitted, with the joinery details worked out and complete.
All
that's left to fabricate is the seat, It is almost
identical to the one made for the "Arts and Crafts Bench
on Page 6, but we first need a
stable, frame to work out those details, so it's time to think about
assembling and gluing up the prototype's frame.
First step in a multi-step glue-up process, and an excellent opportunity to
rehearse and get the sequence down for the real thing.
In most
complicated, multi-part glue-ups, a little thought will suggest a sequence
that will allow for ample time, and one of the first things is to decide
whether there are any sub-assemblies which can be glued up first.
In this case the
backrest, with the crest and intermediate rails (above left), and the slats;
and the three leg stretchers (above right), are two logical candidates for
sub-assembly glue-up.
A caveat:
when gluing up sub-assemblies, and after the glue and clamps are applied to
same, it is not a bad idea to go ahead and dry fit and clamp the rest of the
components to the sub-assemblies to insure that everything fits as it should
... although not pictured above, I usually leave the whole enchilada dry
fitted and clamped together while the glued up sub-assemblies dry.
The prototype's frame, fully glued, standing on its own legs, and next to it's ancestor as a likeness
check.
Wood,
or upholstered seat?
I'm not a fan of solid wood seats in a dining side chair and after spending
this much time on the project, and even though the original intent was to
faithfully reproduce the original chair first shown above, I hate to miss an
opportunity to try a method that may possibly work better for the overall
design. After all, it is a prototype
and experimentation is allowed.
So, for now, at least on
the prototype, we're going to experiment with a traditional upholstered seat
over webbing stretched across the seat frame, shown above, which is more
comfortable than foam on plywood:
This
method is also traditional and typical of many
Harvey Ellis and
Gustav Stickley chairs of this period, although they used horse hair as
the padding.
The next step is to
put some type of finish on the prototype and put it into service, both to see
how it stands up to actual use, as well as to give the upholstered seat a
trial run while we build the frames for the production run of six chairs.
... And here is the finished prototype, with one coat of General Finishes'
"Java" Gel Stain, and four coats of sprayed shellac.
Now, enough of
this prototype business ... onward to
the real thing.
NOTE: After much
angst/discussion it was decided
to forego the upholstered seat for the final six chairs and maintain the
spirit of the original wooden seat with the following:
10/20/06 - The end result of
the "reproduction" process, with one of the six chairs fabricated
from lessons learned during the prototyping, shown next to its parent:
10/22/06 - And here are those
six chairs, the purpose of this entire exercise, completed and shown with the
Kitchen Dining set.
Page
1 (Bedside
Table; Kitchen Cabinets)
Page 2
(Trivet; Writing
Desk; Trad. End Table; Lamp)
Page 3 (A&C Coffee
Table; TV Cabinet; Walnut Coffee Table; A&C End Table)
Page 4 (Walnut Hall
Table; Granite Top Mission Table; Mission Hall Table)
Page 5 (708 Style Writing Table)
(Mission Trestle Table)
Page 6 (Arts and
Crafts Bench)
Page 7 (New
Construction 2005-Kitchen)
Page 8 (Tool
Drawers; Stacked Tansu)
Page 9 (Plan
Rack; Door Restoration; Spice Rack; A&C House# Frame)
Page 10 (Craftsman
Chair Reproduction)
Page 11 (A&C
Kitchen Dining Set)
Page 12
(Cherry/Walnut Hope Chest)
Page 13 (Mission
Sideboard)
Page 14 (Kitchen
Drawers; Calendar Frames)
Page 15 (Corner
Cabinet)
Page 16 (2008
Kitchen Project/Trash Pullout)
Page 17 (2009 Straw
Bale House
Kitchen Project/Kitchen Hutch)
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