Leigh Multiple Mortise and Tenon User manual

Joining Tradition with Today
Multiple Mortise
and Tenon Attachment
Multiple Mortise
and Tenon Attachment
LEIGH USER GUIDE
LEIGH USER GUIDE

ii
Your New Leigh M2 Attachment
Congratulations! You now own the world’s
only jig for routing multiple mortise and tenon
joints; one of the most difficult joints to hand-
cut is made simple with the M2.
The M2 is an optional attachment for the Leigh
Dovetail Jigs: 24" [610mm] models D1258,
D1258R, D3, D4 and D4R. Most illustrations
in this guide show the M2 mounted on the
D4 jig but the instructions are identical for
all the D4R and all earlier D series jigs.
Important: Inches and Millimetres
Leigh makes the M2 attachment in two models;
inch or metric. Text and illustrations in this
Leigh English-language user guide indicate
dimensions in both inches and millimetres.
Dimensions are indicated in text and illustra-
tions with inches first, followed by millimetres
in square brackets.
Example:
3⁄4" x 51⁄2" x 8" [20 x 140 x 200mm]
Do not be concerned if the inch/millimetre
equivalents are not always exact. Just use the
dimensions which apply to your jig.
Where finger assembly or template scales
overlay an illustration, the inches scale 
will be at the top, the millimetres scale will
be at the bottom. Only the right “active” half
of the scales are illustrated. Setting positions
are indicated in this guide with a red line.
On the jig, the lines are black.
General views of the scales will usually
show inch markings.
2
1
3
We recommend that you first mount the M2
on your Leigh Jig, carefully following the
instructions in the first section of this manual.
Then read the rest of the manual, following
along with the basic functions and principles
of operation before you try to do any actual
joinery routing. By all means, cut a few practice
joints in scrap boards before you use the M2
to rout a precious workpiece!
If you have any questions that are not answered
in the manual, please call the Leigh customer
support line.*
*See Appendix III – Customer Support

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Glossary of Symbols........................................................................................................ iv
CHAPTER 1 – Assembly and Mounting....................................................... 1
CHAPTER 2 – Using Your Attachment Safely..............................................7
CHAPTER 3 – Adjusting the Finger Assembly.........................................13
CHAPTER 4 – How Routers with Guidebushes Work............................19
CHAPTER 5 – Basic Jig Functions..................................................................23
CHAPTER 6 – Wood Preparation ....................................................................31
CHAPTER 7 – The Multiple Mortise and Tenon Joint............................35
CHAPTER 8 – Operations Procedures for Mortises.............................. 39
CHAPTER 9 – Operations Procedures for Tenons..................................49
CHAPTER 10 – Beyond the Basics..........................................................................59
Appendix I – Guidebush and Cutter Selection..........................................63
Appendix II – Parts List......................................................................................69
Appendix III – Customer Support....................................................................73
C O N T E N T S

Glossary of Symbols
The Leigh M2 Attachment can be in any one
of three modes, depending on what part of
the joint is being routed. Each finger assembly
scale has its own mode icon, identifying that
joint part. You will also find the mode icon in
the top left hand corner of most illustrations,
indicating which finger assembly mode to use.
Sometimes a mode icon will be used to identify
a board.
Mode and Scale Icons
Mortises
Tenon (first side of tenons)
Tenon (second side of tenons)
iv G L O S S A R Y O F S Y M B O L S
How to Read the Symbols
To help you understand the instructions and
illustrations in this manual, we have used a
number of international symbols, plus a few
special ones of our own.They are all explained
below. You needn’t worry about memorizing
these symbols now, because they are repeated
quite frequently in the manual, and you will
soon get used to them.

The following symbols indicate:
Left side of item (drawer, box,
case, etc.)
Right side of item
Top of item
Bottom of item
This edge against side stop
This edge against side stop
Sawcut allowance
Caution: use special care for this
operation
Reference in text
Which Way Round Should the Board Go?
In nearly all the illustrations we have indicated
which side of the board faces you when it is in
the jig, e.g., this tenon board can face either
inward or outward on the finished piece.
This indicates the side of the board that
will face outward on the finished
project.
This indicates the side of the board that
will face inward on the finished project.
This indicates a side that can face
either inward or outward on the
finished project.
Diameter
Centreline of board or layout
Equals
Does not equal
Approximately
Less than or equal to
Greater than or equal to
v
1

G L O S S A R Y O F S Y M B O L S
vi

Assembly and Mounting
CHAPTER 1

A S S E M B L Y A N D M O U N T I N G
Chapter 1 M2 User Guide
2
Make Sure You Have All The Parts!
Before you start to assemble your Leigh M2,
check to make sure you have received all the
required parts.
The carton contains:
1. 1 finger assembly on two bars
(10 pairs of fingers)
2. 2 scale assemblies for guidefingers
3. 1 fence assembly complete with two end
plugs
4. 2 scale assemblies for fence
5. 2 support brackets*
6. 1 standard cutter, 1⁄2"[12,7mm] spiral
upcut
7. 1 Leigh M2 user guide
8. 2 Side Stop Extensions
If any of these items are missing from your
jig, please notify your supplier or Leigh Industries
immediately.
*D4 and D4R jigs already have these brackets, so
these become spares.

1
3
6
7
4
2
2
5
8
3

1-1
D1258, D1258R, and D3 jig owners:
Replace the short support brackets with
the extended M2 brackets. These are
marked LH to left, RH to right. Raise to
full height and tighten the knobs. Use these
new extended brackets for all dovetailing
or template jointing functions.
D4 and D4R jig owners: your M2 attach-
ment may come with the extended support
brackets. Put these in your “spares” box.
Raise the support brackets to full height
and tighten the knobs.
1-2
Place the finger assembly on a bench with
finger screws upwards and the small
square bar away from you, and the 5⁄16"
[7,9mm] ฀mortise scale-to the right
at both ends. Loosen the scale screws .
1-3
Slide complete finger assembly with loose
scales onto support brackets. Set scales at
say, 3⁄4" [20mm] on the 5⁄16" [7,9mm] 
mortise scale and tighten thumb screws-.
Now tighten scale lock screws firmly with
Leigh screwdriver. Do not over-tighten. To
ensure correct alignment, follow this same
procedure whenever scales are removed from
finger assembly.
Move the outer finger on both ends out to
touch the scales (shown in red).
2
3
4
1
2
1
A S S E M B L Y A N D M O U N T I N G
Chapter 1 M2 User Guide
4
Note: Most illustrations in this guide feature the D4 model jig.

1-4
Place fence extrusion flat down on bench
with fence upright and towards you.
Slide tongue into left hand fence scale as
shown, with brass thumb screw outward
and away from you. Repeat for the right
hand scale but do not tighten fence scale
lock screws yet.
1-5
Slide complete fence assembly with loose
beam scales onto support brackets. Set
scales to the same reading at both ends
and tighten brass thumb screws . Now
tighten scale lock screws firmly with
Leigh screwdriver. Do not over-tighten.
To ensure correct alignment, follow this same
procedure whenever scales are removed from
fence.
1-6
Using the M2 requires a small modification
to your Leigh jig. Multiple tenons are routed
in two separate stages at both ends of the jig
…first on the left-and then, with the fin-
ger assembly and tenon board flipped end
for end …on the right-. In this second
position it is impossible to guarantee perfect
indexingbetweentheguidefingers,sidestops
and partly formed tenons-. This is mainly
caused by the cutter not being concentric to
the guidebush-.(greatly exaggerated in this
illustration).
1
2
3
5
2
3
1 2
2
4
3

1-7
To solve this problem and correctly index
the side stops, we have provided two metal
sidestop extensions-. To complete the
modification, you will also need to cut a
simple 1⁄2"[12mm] square by 5"[125mm]
long wood “mortise block”-. The block
and extensions will allow adjustment to
compensate for any cutter to guidebush
eccentricity. The procedure is explained
later in this guide.
1-8
To install the extensions, lightly clamp a
board in the front clamp centre-. This
will maintain tension on the clamp bolts
and keep them in position while you attach
the extensions. Use a 1⁄2"[13mm] open end
wrench to loosen the two front clamp bolt
nuts-sufficiently to slide the extensions
beneath the washers. Lightly tighten the
nuts for now-.
1-9
When you’re not using the jig with the
M2:
On the D4 and D3 jigs turn the extensions
outward-.
On the D4R jig, the extensions can be
retracted-.
Always tighten the clamp nuts after setting
or retracting the extensions, .
1
11
2
2
2
3
1
2
3
1
1 2
3
A S S E M B L Y A N D M O U N T I N G
Chapter 1 M2 User Guide
6

Using Your
Attachment Safely
CHAPTER 2

U S I N G Y O U R A T T A C H M E N T S A F E L Y
Chapter 2 M2 User Guide
8
Chapter Foreword
Safety is not optional.
Read and follow the recommendations in
this chapter.

2-1
Read the owner’s manual that came with
your router. It is essential to understand
the router manufacturer’s instructions
completely.
2-2
Always wear hearing protection when using
a router.
2-3
Always wear approved safety glasses when
using a router.
9

2-4
Protect yourself from harmful dust by wear-
ing a face mask.
2-5
Never drink alcohol or take medications
that may cause drowsiness when you will
be operating a router.
2-6
Always disconnect the power source from
the router when fitting cutters or guide-
bushes, or making adjustments.
U S I N G Y O U R A T T A C H M E N T S A F E L Y
Chapter 2 M2 User Guide
10

2-7
Before connecting the router to the power
source, make sure the cutter and collet
revolve freely in all the areas you plan to
rout, and the cutter does not touch the
guidebush or jig.
2-8
Do not tilt the router on the jig.
2-9
Keep the router flat on the jig assembly.
11

2-10
If you insist on removing the router from
the jig while it is still revolving, always pull
it straight off the jig horizontally, and do
not raise or lower the router until it is
completely clear of the jig.
An obvious exception is while routing mor-
tises, which requires the plunge mechanism
to be raised before removing the router.
2-11
Do not rout at face level.
2-12
If you have never used your router before,
be sure to follow the router manufacturer’s
instructions for its use. Make plenty of
simple open-face practice cuts without a
guidebush before you try to use the rout-
er on the Leigh Jig. You must, of course,
always use a guidebush when routing on
the Leigh M2.
U S I N G Y O U R A T T A C H M E N T S A F E L Y
Chapter 2 M2 User Guide
12

Adjusting the
Finger Assembly
CHAPTER 3

A D J U S T I N G T H E F I N G E R A S S E M B LY
Chapter 3 M2 User Guide
14
Chapter Foreword
The finger assembly is the heart of the
Leigh-M2. Spend a few minutes now
to familiarize yourself with these simple
adjustments.