Leigh FMT PRO User manual

Frame Mortise & Tenon Jig
LEIGH FMT PRO
Joining Tradition with Today
Leigh Router Joinery Jigs
User Guide
1-800-663-8932

ii
Frame Mortise & Tenon Jig User Guide
Your New Leigh Frame Mortise & Tenon Jig (FMT Pro)
Congratulations for selecting the unique Leigh FMT Pro, the best
mortising and tenoning jig available. The FMT Pro will allow you
to rout a large range of sizes of mortise and tenon joints with total
control over joint fit.
To gain the most advantage from this unique tool, please read all of
this User Guide; carefully set up the jig following the simple set-up
directions, and thoroughly familiarize yourself with the basic functions
and principles of operation. Use scrap wood before attempting any
actual projects with valuable hardwood.
Customer Support
If you have any questions that are not answered in this user guide, please
call Leigh Customer Support: 1-800-663-8932 in North America or
email: [email protected]. For support contacts in your country of
purchase, see Customer Support on page 69.
Reminder: If at first you don’t succeed, read the instructions!
Important! Inches and Millimeters
The Leigh FMT Pro is available in two models; Inch or Metric. The
only difference is in the guides and bits used, otherwise the jig itself is
identical. Text and illustrations in this English language User Guide
indicate dimensions in both inches and millimeters, with “inches” first,
followed by “millimeters” in square brackets, i.e. 1⁄2"x 2"[12x50mm].
Do not be concerned that the inch/millimeter equivalents are not
mathematically “correct”. Just use the dimensions that apply to your
guides and bits.
Technical Bulletins
Downloadable pdfs are available at leighjigs.com on the Support page
for these How To’s and more for your Leigh FMT Pro jig:
• Rout Tenons on Extra Wide Boards
• Mortise & Tenon Joints on Shaped Pieces
• FMT Pro/Super FMT – Specialty Guides
1-800-663-8932

iii
Frame Mortise & Tenon Jig User Guide
Contents
CHAPTER 1 Mounting the FMT Pro................................................................. 1
CHAPTER 2 Mounting the Router................................................................... 3
Fence Rod Mounting.................................................................... 3
Screw Mounting ........................................................................... 8
CHAPTER 3 The FMT Pro Jig........................................................................... 11
The Clamp Plate and Clamping ................................................11
The Table......................................................................................14
Jig Operation Concept...............................................................16
Safety and Router Operation ................................................... 17
Wood Preparation......................................................................19
CHAPTER 4 Mortise & Tenon Procedures.....................................................21
Single Mortise & Tenon, Test..................................................... 21
Production Procedures ..............................................................27
Small Joints..................................................................................28
CHAPTER 5 Multiple Joints ............................................................................31
Double In Line Joints.................................................................. 31
Twin Joints...................................................................................33
Quadruple Joints ........................................................................35
Triple Joints ................................................................................. 37
CHAPTER 6 Workpiece and Joint Options...................................................41
Different Workpiece Thicknesses.............................................41
Longer and Shorter Joints ......................................................... 42
Thicker and Wider Boards ......................................................... 44
CHAPTER 7 Special Joints...............................................................................47
Angled Joints ..............................................................................47
Through Tenons..........................................................................48
Bridle Joints.................................................................................50
Asymmetric Tenons ....................................................................51
Haunched Joints .........................................................................51
Doweling .....................................................................................54
Appendix I Joint Specifications, Guide and Bit Selection.........................55
Joint Specifications.....................................................................55
Guide and Bit Selection .............................................................57
Appendix II Jig Adjustments..........................................................................61
Appendix III Parts List......................................................................................63
Appendix IV Customer Support ......................................................................69

iv
Frame Mortise & Tenon Jig User Guide
Square Tenons
Square tenons are often used
for replicating period furniture.
Item 670900
Visit www.leighjigs.com for more details
SPECIALTY GUIDES
Y-Axis Mortise
In instances when mortises
need to be routed at 90º to the
clamp plate, this guide does
the trick.
Item 6701YAM
Extra Clamps Save Time
Leigh Surface clamps are identical to FMT Pro clamps. Save time when
switching between mortise and tenon boards. Bonus! This tough,
versatile cam-action clamp can also be mounted on any flat surface, on
any angle or on a table saw. You can never have too many clamps.
Item SHDC1 Surface mount (one clamp)
Add Leigh Accessories to make your jig even more versatile.
Louver Doors
Make beautiful
louver doors with
these guides and bit.
Joint Guides
Three optional guide sets
are available increasing the
number of joint sizes you
can make to 68! 16 op-
tional guides in 1/4", 3/8"
Accessory Kit for Savings Combine an optional
guide set and boxed inch bit set for the best savings.
Includes an 8-piece boxed inch bit set and 16 optional
guides in 1/4", 3/8" and 1/2" (6, 10 and 12mm) sizes for
a complete set.
Item ACMT or ACMTC
Router Bits
8-piece set in HSS or Solid
Carbide opens up your
possibilities for joint sizes.
Item 162-180 or 162-180C
Optional Guides, Bits and Accessory Kit
for Great Savings
and 1/2" (6, 10 and 12mm) sizes, make a complete set.
Each guide can be purchased individually or as a set for
better value. Buy all three or as part of the accessory kit
below for even greater savings.
Item 6720 or 6820
Use on jigs and fixtures
Routing tenons with mortise board clamps in place
Routing mortises with tenon board clamps in place Use vertically on bench
1/8" to 3" capacity
1/4" HSS Louver
Guide Bit, 1/2" shank
Item 168-500
L/R matching pair
Item 6701LGP

MOUNTING THE FMT PRO
FMT PRO CHAPTER 1
1
Mounting the FMT Pro
1. 1The main Jig Body, complete with:
1 Table
➀
2. 1Router Sub-Base ➁
3. 1User Guide
1 DVD Video
4. 1 Box Containing:
A 2 Vacuum Hose Adaptors
B 4 Jig Hold-Down Nuts and Bolts 1⁄4"-20
B 4 U-Posts with 4 Set-Screws and
Four
3⁄4"Countersink Screws
B 4 1" Countersink Screws
B 3 Hex Socket Button Head Screws 10x24 x 3⁄8"
B 2 Hex Socket Button Head Screws M6
C 4 High Shim Spacers
C 4 Low Shim Spacers
C 1 1⁄4"and 1⁄2" Centering Mandrel
C 1 8 and 12mm Centering Mandrel
D 1 5⁄16" HSS Spiral Upcut 1⁄2" Shank
E 2 Outrigger Bars with 4 Screws and Nuts
F 1 Leigh Square Drive Screwdriver
F 1 Leigh
1⁄8" Hex Ball Screwdriver
F 1 5⁄64" Hex Key
F 2 Router Hold-down Rods
G 5 5⁄16" guides (or 6x8mm with FMT Pro-M)
& 1 Guide Stand
H** 1 Side Stop Fence with Lever**
I 2 Cam-Action Speed Clamp Assemblies
3
A B C D E
F G H** I
4
2
4
1
1
2
Jig Assembly and Mounting
The Leigh FMT Pro comes almost fully assembled with all adjustments factory set — however, before you start to
set up your Leigh FMT Pro Jig, make sure you have received all the required parts.
**SIDE STOP UPDATE: Some illustrations show
the side stop fence with a “knob”. All FMT Pro jigs are
shipped with a side stop fence with a “lever”, (see H in
drawing above).
VACUUM BOX UPDATE: Most drawings throughout this
user guide show an older version of the vacuum box, clamp
plate and top extrusion. All FMT Pro jigs are shipped with
the newest parts. These changes are reflected in Appendix III.
Note: Any optional accessories that you ordered may also be inside the parts box, or packaged inside the main carton.
If any of these items are missing from your order, please notify your supplier or Leigh Industries immediately.

2
Chapter 1 Frame Mortise & Tenon Jig User Guide MOUNTING THE FMT PRO
1-1 Mounting the FMT Pro: Prepare a flat board at least
3⁄4"[20mm] thick, a minimum of 24"x5"[600x125mm]. Drill four
9⁄32"[7mm] holes on 153⁄4"x35⁄16"[400x84mm] centers, 1⁄2"[13mm] in
from the front edge of the board ➀. Countersink ➁, or counter-bore
➂if board is thicker, the underside so that the four 1⁄4–20 x 1" long
machine screws will project above the top surface by 3⁄8"[9,5mm] ➃.
35/16"[84mm]
5"[125+mm]
153/4"[400mm]
24"[600mm]
1/2"[13mm]
1
2
4
3
1-2 Turn the jig upside down on two wooden blocks ➀(to
protect the table and sight knob). Using the four nuts and four
flathead countersunk machine screws, bolt the base board to the jig
using the two nut recesses in each end housings. The 1⁄2"[13mm]
front edge ➁to the front of the jig (of course). Now you can
clamp your FMT Pro to any bench.
2
1
1-3 For routing long vertical rails it may be necessary to build
a jig stand to mount securely on your bench. Make the stand and
bench height combination sufficient to accept the board length
you have in mind. The jig stand should be bolted securely to the bench.
Make up a stable platform as shown here to stand on. Do not use
a collapsible step stool, these are unstable and unsafe. ■

MOUNTING THE ROUTER
FMT PRO CHAPTER 2
2-1 The Leigh FMT Pro Sub-Base Place your router, the
FMT Pro Sub-Base and all the mounting parts on a clear bench.
From the Sub-Base diagram and chart on this page, find the make
and model of your router.
Mounting the Router
3
ROUTER MAKE HOLES NOTES
LR RR LF RF
AEG OFS 50 2
BOSCH 1450, 2
1611EVS,1613EVS,1617EVS
BOSCH 1619EVS
BOSCH MRP23EVS
1 *1 1 *File notch in U-Post if req’d to avoid Turret
CRAFTSMAN 2
DEWALT 616/618
1 3 1 3
DEWALT 621
2
DEWALT 625
3
ELU 97 1 3 1 3
ELU MOF 131 2
ELU MOF 177/02 2
ELU 3304 3
ELU 3338 2
FESTOOL 900E, 1010 7
FESTOOL OF1400 11
Requires 1/16" packing shim. See 2-9
Use 2 #5130 screws provided. See 2-30
Use 2 #5130 screws provided. See 2-30
FESTOOL OF2000 2
FESTOOL OF2200 12
FREUD FT2000E 2
HITACHI M12V
HITACHI M12VC
2
4
HITACHI TR12 2 **8 2 **To avoid Turret
MAKITA 3600B 1
1
MAKITA 3612BR 3 **6 **To avoid Turret
MAKITA 3612C 3
METABO OFE728 3
METABO OFE1028 3
MET
MILWAUKEE 5616
ABO OFE1229 3
4
RYOBI R-150 3
RIDGID 10
RYOBI RE180PL 2
2
RYOBI R-500 2
RYOBI R-E600 2
4
PORTER CABLE 7539 *2 *Reverse U-Post to put screws outside rods
PORTER CABLE 7529, 8529 5
FLEX OFT2926VV 5
MAKIT
MAKITA RP2301FC
A RP 1100 Series
Use 3 #6410 screws provided. See 2-30
Use 3 #6410 screws provided. See 2-30
Use 3 screws from router base. See 2-30
Use 3 screws from router base. See 2-30
Use 3 screws from router base. See 2-30
Use 3 screws from router base. See 2-30
Use 3 #6410 screws provided. See 2-30
Use 3 #6410 screws provided. See 2-30
MAKITA RP 0910 4
4
PORTER CABLE 693
PORTER CABLE 890, 893
PORTER CABLE 893 Type 2
10
4
TRITON, TRC001 31/4hp
TRITON, MOF 001 21/4hp
9
9
Use 4 No.6677 1/4-20 x 3/8" button
head socket screws
44
7
9
9
10
10
11 11
12
10
9
9
7
7
6
8
6
6
6
7
4
5
5
5
Left
Rear
Left
Front
Right
Rear
Right
Front
12
2
13
123
123
2
13
mThe FMT Pro must only be
used with a plunge router. Never,
ever use a fixed base router!
2-2 Mark the appropriate mounting holes on the Sub-Base. Use a
non permanent medium e.g. chalk, sticky tape (ink will permanently
stain the anodized surface).
Note: If the chart at left indicates your router is a “Screw
mount” (routers in shaded rows) go directly to 2-30. If your
router is not listed here, proceed to 2-3. For the most up-to-
date list of routers, go to www.leighjigs.com.
Fence Rod Mounting
Screw Mounting
Foreword The threaded sub-base mounting holes on many routers are not strong enough for the stresses
produced when routing joints with the FMT Pro, so Leigh developed the Universal Fence Rod Mounting System.
The Leigh FMT Pro Sub-Base provides great attachment strength and lateral anchoring. Depending on your router
model, fitting the Sub-Base to your router may take up to an hour…the first time only. Once fitted, the router
can be removed and reattached in about a minute. Mounting the Sub-Base correctly is critical to the accuracy of
the jig, so take your time and get it right the first time. Here’s how...
Fence Rod Mounting

4
Chapter 2 Frame Mortise & Tenon Jig User Guide MOUNTING THE ROUTER
2-3 If you have a plunge router that is not listed in the Sub-Base list,
it is essential that your router have two parallel fence rod holes through
the router base. These must be at least 5⁄16"[8mm] in diameter ➀. Fit
the correct shank sized centering mandrel to your router, place it on the
Sub-Base and plunge the mandrel into the base hole. Place the fence rods
through the rod holes with an equal amount protruding at each end.
1
2-4 Take the four U-Posts and by trial, establish which four
Sub-Base slots or holes will serve to attach the U-Posts. Mark these
with chalk or sticky tape and follow instructions 2-5 through 2-29.
2-5 Most plunge routers will be mounted to the Sub-Base like this,
with rods through the fence rod holes
➀
and clamped down with the
U-Posts
➁
, but it is essential that the correct shim spacers
➂
are
selected.
1
3
1
2
3
2
2-6 Depending on the make and model of your router, the height
between the underside of your router and the bottom of the rod
hole ➀will vary. This dimension will determine if you need to
use low ➀or high ➁shim spacers, or possibly both together ➂.
1
2
3
2-7 To measure the “rod height”, place the router on a bench.
Either use a calliper ➀, or insert a rod (flat side up) and use a good
rule to measure between the bench top and the bottom of the
rod ➁.
0
10
20
30
40
50
1 2
2-8 If rod height is between 3⁄16"[4,5mm] and 3⁄8"[9,5mm],
use low shim spacers ➀. If rod height is between 3⁄8"[9,5mm] and
17⁄32"[13,5mm], use high shim spacers ➁. If rod height is between
17⁄32"[13,5mm] and 3⁄4"[19,5mm], use both shim spacers ➂, with
the high one on the bottom. Note: If the rod height is less than
3⁄16"[4,5mm], see 2-9.
1 2 3

5
Chapter 2Frame Mortise & Tenon Jig User Guide
MOUNTING THE ROUTER
2-9 Note: Use of the shim stops is essential, not only to provide the
correct rod height but to also act as side-to-side stops for the router ➀.
If the rod height of your router is less than 3⁄16"[4,5mm] you must
provide a shop-made packing shim between the router and Sub-Base.
We suggest one or more sheets of sandpaper ➁, rough side up. Don’t
forget the center hole.
11
2
2-10 Adjust the four U-Post set-screws with the set-screw end
flush inside the arch of the posts ➀.
1
2-11 There are two lengths of U-Post screws; 3⁄4"[19mm] and
1"[25mm]. The 3⁄4"[19mm] are factory fitted as a quality control
measure. Use these for either the low or high shim spacers ➀.
Change them for the 1"[25mm] screws if both shim spacers are
used ➁.
1 2
2-12 Using the four selected screws, lightly attach the four U-Posts
and correct shim-stop combination through the previously marked
slots or holes in the Sub-Base. The screws must enter from below
➀. Only very lightly tighten; you will need to move the U-Posts
and the shim-stops during setup.
1
2-13 In most cases, position the U-Post screw leg to the inside
of the rod ➀or depending on the size and shape of the router
base, to the outside ➁. Slide the shim-stops away from the router
position ➂. These will be repositioned against the router later.
1 2
3
3
2-14 Place the Sub-Base flat down on the corner of a smooth
bench, the handle to your near left ➀and the guide pins touch-
ing the adjacent edges of the bench ➁.
1
22

6
Chapter 2 Frame Mortise & Tenon Jig User Guide MOUNTING THE ROUTER
2-15 Unplug the router.
Note the collet size of the router. Choose the matching size center-
ing mandrel and fit it into the router collet.
1/4"
1/2"
8mm
12mm
2-16 Holding the router as you would in normal use, place it base
down onto the Sub-Base; the rear of the router toward the rear of
the Sub-Base and large notch ➀. Plunge and move the router so
that the large diameter of the centering mandrel fits through the
Sub-Base center hole…
1
2-17 …and touches flush to the bench. Lock the plunge.
mConcentricity of bit to Sub-Base bit hole is essential to FMT
Pro accuracy, so never mount the router without using the center-
ing mandrel.
2-18 Align the router so that the fence rod holes are parallel to the
front edge of the Sub-Base (except Festool 900 and 1000 Series,
see 2-19).
2-19 Festool 900 and 1000 Series:
Align the fence rod holes to the previously positioned U-Posts.
2-20 Loosen and raise any router fence rod knobs ➀. Move the U-Posts
and adjust as necessary to slide the two hold-down rods through the
U-Posts and router fence rod holes, flat side of rods on top ➁. Leave
an equal amount of rod projecting through each U-Post ➂.
mNever use the router’s fence rod knobs ➀to “help” secure the router.
This places uneven pressure and could damage the router base.
22
1
3 3

7
Chapter 2Frame Mortise & Tenon Jig User Guide
MOUNTING THE ROUTER
2-21 Using the hex screwdriver, turn down the four U-Post set-
screws until there is only very slight and even pressure on each
end of both rods. Leave the shim stops in the outer position.
2-22 Check that the rods are still centered in the rod holes ➀and
check that the router collet can rotate without excessive binding in
the Sub-Base hole. Mandrel touching side of hole is OK; mandrel
binding tight is not! Move the router if required to allow mandrel
to rotate.
1
2-23 Tighten the top U-Post set-screws a little more securely to
hold the bars and router.
2-24 Slide the router/Sub-Base assembly on the corner of the
bench so that one U-Post bottom screw is overhanging the edge.
Loosen this screw just slightly (if necessary) to take any pressure
off the shim spacer above. Push the Shim spacer in to touch the
router base and, holding it in position against the router base,
firmly tighten this bottom screw.
2-25 Repeat this procedure at the other end of the same rod to
position the shim stop against the router base. Re-check the collet/
mandrel for relatively free rotation. Turn the router around on the
corner of the bench and repeat this procedure on the two U-Post
assemblies on the second rod.
2-26 Tighten the four U-Post set-screws to the rods. The hex driver has
high leverage so use common sense when tightening.The rods will bow
slightly. Objective: have the collet concentric to the bit hole; the four shim
stops providing secure side thrust security, and the U-Posts clamping the rods
which hold the router against the Leigh Sub-Base. Router /Sub-Base are now
a unit. Release the plunge; remove and store the mandrel. You’re set to go.

8
Chapter 2 Frame Mortise & Tenon Jig User Guide MOUNTING THE ROUTER
2-27 Here’s how to remove the router for use elsewhere:
Loosen the four top U-Post set-screws ➀Slide out the two rods ➁.
Do not remove the U-Posts. In about a minute, the router is free
to be used for other tasks.
2
2
1
1
2-28 To re-mount the router: place the Sub-Base over the corner
of the bench. Make sure surfaces are clean. Place the router on the
Sub-Base with the centering mandrel in the center hole. Insert
the fence rods. Evenly tighten the four U-Post set-screws. Check
that the mandrel rotates freely. In about two minutes the router/
Sub-Base assembly is ready for making mortises and tenons.
2-30 These routers do not have suitable through fence rod holes:
Porter Cable 693, 890, 890 Type 2, 893, 7529, 8529; Flex OFT
2926VV; Festool 1400, 2200; Makita RP0910, Makita RP1100
series; Triton TRC001, MOF001. We’ve provided Sub-Base holes
and screws to mount these directly to the Sub-Base. Using Porter
Cable 7529 and 8529 as examples, here’s how.
2-31 Note: Porter Cable 7529 & 8529 (Flex OFT2926VV) have
two sets of 3 threaded holes. Use the inner circle of FMT Pro Sub-Base
holes. The outer circle holes align with threaded holes, but are not deep
enough for the screws. For Porter Cable (Flex) 693 & Makita RP1100
seriesrouters use the outer circle of Sub-Base holes. Firmly attach
the Sub-Base using the three 6410 hex socket button head screws
provided ➀. Do not use the router’s Sub-Base screws. See 2-32.
PORTER CABLE
7529 and 8529
(FLEX OFT2926VV)
PORTER CABLE
693
890
890 Type 2
893
MAKITA
RP1100 SERIES
FESTOOL
1400 and 2200
1
2-29 Hint: If you plan to fit a different make/model router and
later use the current one again, you can greatly speed up the re-
installation of the first router by marking around the original four
U-Post/shim-stop positions. ■
Screw Mounting

9
Chapter 2Frame Mortise & Tenon Jig User Guide
MOUNTING THE ROUTER
2-32 Unplug the router. Remove the router’s plastic Sub-Base (except
Festool 1400) and template guidebush adaptor from 7529 or 8529.
Remove the clear plastic dust cover from 8529 router base top (screw
holes are used to attach Leigh FMT Pro Sub Base). Store removed parts
for future use. Fit the correct shank sized centering mandrel to collet.
With the Leigh Sub-Base on a flat bench corner, place router on top
and plunge mandrel through to bench and lock the plunge.
2-33 Remove the router and stand it upside down on the bench.
Depending on the router design, you may need to support it in
a soft-padded vise. Place the Sub-Base upside down onto the
router’s metal base with the mandrel centering the router to the
base through the bit hole. Rotate the Sub-Base until the correct
threaded screw holes in the router base align with the counter-
bored holes in the Sub-Base.
2-34 Festool 1400 series routers attach using the two No. 5130 screws
provided, through base holes No. 11. Festool 2200 series routers attach
using the two No. 5130 screws in the No. 12 holes.
5130
2-35 mIn addition to the base screws it is vital to attach the four
U-Posts and four of the shim stops (either size) and position and
tighten these against the edge of the router base to prevent lateral
router movement. Note: You do not use the fence rods. For correct
positioning, see 2-16 through 2-18, 2-24 and 2-25. Note: Porter
Cable 7529 and 8529 handles will be slightly angled (not parallel)
to the FMT Pro Sub-Base. ■

10
Chapter 2 Frame Mortise & Tenon Jig User Guide MOUNTING THE ROUTER

THE FMT PRO JIG
FMT PRO CHAPTER 3
The Clamp Plate and Clamping
11
The FMT Pro Jig
The Clamp Plate and Clamping
The Table
Jig Operation Concept
Safety and Router Operation
Wood Preparation
3-1 The clamp plate ➀is adjustable up to 30˚ from vertical and
is held securely by two quadrant knobs ➁. A set-screw ➂allows for
positive return to 90˚. To ensure flush and in-plane joints, it may
be necessary to adjust the clamp-plate angle. See Appendix II, Jig
Adjustments. An angle scale is provided, with an indicator adjustable
to zero ➃.
mThe clamp plate and cam-clamps are a self contained clamping
area. Under no circumstances should any other jig component be
used for clamping and no auxiliary clamping method used, other
than as illustrated in this guide.
10
20
30
0
1
3
2
4
3-2 The two clamps are powerful cam-action rocking-arm
clamps with capacity from zero to 3"[76mm]. TheT-bolt is inserted
directly into the T-slot opening ➀, moved to desired position and
brass thumb nut lightly tightened. Normally tenon workpieces
will be clamped vertically ➁, and mortise workpieces horizontally
like this ➂, or...
2
3
1
1
3-3 …like this ➂. For clamping very small workpieces see
Chapter 4, Small Joints.
3
3-4 Never force a cam-action clamp. It has great leverage, and
using excessive force may damage the workpiece. The powerful
clamp, combined with a non-slip clamping surface, requires only
moderate clamping pressure to hold the workpiece securely in
place.

12
Chapter 3 Frame Mortise & Tenon Jig User Guide THE FMT PRO JIG
3-5 A smooth, firm action is enough to engage the clamp.
Rule of thumb: if you can’t throw the lever comfortably by strong
thumb pressure, reduce the tension. A few minutes of trial and error
testing will soon give you the feel for the correct clamp tension.
3-6 Do not use the lever as a torque arm!
Adjust the clamp pressure only with the clamp disengaged.
3-7 The clamping pressure is the same whichever of the two
directions the lever is thrown. But if the lever is uncomfortably
positioned at the correct clamping pressure...
3-8 ...release the clamp, remove the workpiece and turn the
step-washer a quarter turn. The step height in the step-washer is
one quarter of the thread pitch.
3-9 Then adjust the clamp until the lever is in the correct posi-
tion at the required pressure.
3-10 The clamp T-Bolt Slots and “keyholes” allow for full clamp-
ing coverage.The two lower keyholes ➀are for the rare requirement
to clamp mortise boards between 43⁄4"[120mm] and 51⁄2"[140mm]
wide ➁. Always clamp with the heel and toe of the clamp over
the surface area of the clamp plate ➂.
mNever allow the clamp arm heel pad in these red shaded areas ➃,
even if (particularly if) the mounting board or bench is there.
2
4
4 4
1
3

13
Chapter 3Frame Mortise & Tenon Jig User Guide
THE FMT PRO JIG
3-11 The clamp T-bolts nuts need only be lightly finger tightened
to prevent accidental clamp movement. The nuts are knurled to
provide a good finger grip.
Never use a tool to tighten these nuts!
3-12 The clamp plate is provided with twelve through-holes.
If for any reason a facing board is required to be attached to the
clamp plate, No.8 or M4 wood screws (not supplied) may be used
from the rear. See chapter 4, Small Joints.
3-13 The FMT Pro’s sidestop fence is attached in all modes by a
single knob and T-bolt inserted to the center clamp plate slot ➀.
Most tenon pieces are routed vertically, and for that purpose the
short part of the fence ➁acts as a T-square against the edge of the
clamp plate ➂. In this mode the Leigh logo faces toward you.
1
3
2
3-14 The sidestop fence is squared at the factory, but check your first
test joints. If your router/bit is not perfectly perpendicular to the table
adjust the sidestop fence: slightly loosen the 'pivot' screw ➀and the 'lock'
screw ➁. Adjust the angle ➂to match the bit and retighten. Rout test
joints to confirm correct setting. Once locked in this position it should
never need adjusting when used with that same router.
1
2
3
3
3-15 Angled Joints: Remove the knob andT-bolt. Reverse the fence so
the short end faces toward you ➀.The fence may now be set at any angle
along the center clamp plate slot ➁by tightening the knob.
mNOTE: Never rout tenons with the short part of the fence to the top, in
the bit opening.
2
1
3-16 'Mortise steady': When routing mortises in small stock the piece
may 'flutter' causing poor joint fit. Invert the fence with the short end
up in the bit opening ➀. Clamp the mortise piece against the face of the
short fence ➁which is perfectly flush with the clamp plate face ➀. When
routing mortises at the end of a board, always move the table as far as
possible left or right to minimize the length of unsupported workpiece.
2
1

14
Chapter 3 Frame Mortise & Tenon Jig User Guide THE FMT PRO JIG
3-19 The outrigger bars allow for attachment of shop-made outrig-
ger beams on which to mount sidestops or add pencil marks. This
makes for efficient routing of multiple mortises. See Chapter 4,
Production Procedures.
3-20 The outrigger beams should be 3⁄8"[10mm] plywood, shaped
as suggested to minimize weight. Drill as shown and attach with
the small nuts and bolts provided. The top edge should just clear
the underside of the locked table. Store the outriggers on a wall
hanger when not in use. The deep shoulder ➀provides canti-
lever support against the end of the clamp plate assembly. ■
1
3"[75mm]
6"[150mm]
3/8"[10mm]
3-21 The table is clamped in any desired position by the Table
Clamp ➀. Turning the clamp lever up 90˚ releases the table,
which can then be moved in any direction to any position within
its range. Clamp tension is factory preset. See Appendix II, Jig
Adjustments.
1
3-22 Adjustable Limit Stops ➀are used to limit or prevent table
movement left to right (X-axis) and front to back (Y-axis), and
to precisely align double and quadruple mortises and tenons (see
Chapter 4). Use Limit stops when you see these icons:
LR
for left-to-right table movement
FB
for front-to-back table movement.
1
1
LR
FB
3-17 mWARNING: Never rout tenons with the sidestop
fence in the inverted position (with the short end up in the bit
opening). The inverted fence mode is only used to support small
mortise stock.
3-18 The jig clamp plate has an opening on each outer edge in
which to fit the included “outrigger bars” ➀. The bars are retained
by set-screws ➁tightened with the hex driver.
1
2
The Table

15
Chapter 3Frame Mortise & Tenon Jig User Guide
THE FMT PRO JIG
3-23 The table has a bit opening ➀and Joint Aligning Sight ➁. Pulling
the sight fully forward to its detent provides precise table positioning over
joint cross-marks ➂. Because the human eye excels at comparisons, we can
perceive differences as small as 0.004" in the space between the edges of the
line and the triangles ➂.That’s 0.002" off center! You can readily center the
sight using slight table movements until the spaces appear the same ➃.
4
3
12
3-24 To the right front is the right-hand “PinTrack” ➀. The right-
hand router sub-base Guide Pin runs in this track in all routing
operations. To the left front is the Guide Recess ➁, in which all
Joint Guides ➂are placed. The left hand router sub-base Guide
Pin runs in the guide slot ➃for cutting mortises or around the
outside of the Guides ➄, for cutting tenons.
1
2
3
5
4
3-25 The Guide Pin cannot move horizontally outside the
recess ➀, and prevents the bit from touching the sides of the bit
opening ➁.
1
2
3-26 Two small projections on the Guide fit into undercuts on
the right side of the guide recess ➀. The left end of the Guide is
pushed down and retained by the spring-loaded Guide Latch ➁.
mNote: the guide end shapes are not identical. Guides can
only be installed one way as shown here.
1
2
3-27 Snap the Guides in like this.
Use firm pressure just next to the guide latch.
Note: The guides are injection molded acetal and the guide bases
may vary slightly in tolerance. Some may require more pressure
to insert. The tighter guides will become easier after a few inser-
tions.
1
2
3-28 To remove a Guide, pull back the latch ➀and push through
the finger-hole from below with your fingertip ➁.
1
2

16
Chapter 3 Frame Mortise & Tenon Jig User Guide THE FMT PRO JIG
3-29 If the finger-hole is not accessible from below, use your fin-
gernail or a small non-metallic pry to lift the Guide up ➂. ■
3
3-30 The selected guide is placed into the guide recess and the
matching bit fitted to the router.
1
2
3-31 The centers of a mortise and tenon are marked with a cross.
90˚
3-32 Tenon workpieces are usually clamped vertically ➀. Mortise
workpieces are always clamped horizontally ➁.
1
2
3-33 The jig table is centered over the marked workpiece with
the extended sight ➀.
1
1
Jig Operation Concept