Leigh FMT PRO, User Manual

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Chapter 4 Frame Mortise & Tenon Jig User Guide
MORTISE & TENON ROUTING PROCEDURES
4-32
The FMT Pro is designed so that both mortise and tenon of
a particular-sized joint may be routed with the same sized bit. So
if you are making say, a single frame with a
1
⁄
4
"[6mm] guide and
bit, this works very effectively. However, it is much more efficient
to rout small tenons with a
larger bit, and particularly useful for
production routing. This involves using two bits instead of one.
4-33 Two Bit Combination
If you want to rout many
1
⁄
4
"[6mm] mortises and tenons, the tenons can be routed much
more quickly with a
1
⁄
2
"[12mm] bit*. The Guide and Bit Selection
charts in Appendix I show how different bit combinations can
crank out such extraordinary joints just as quickly and precisely
as larger ones, and with adjustable joint tightness.
*Note: The maximum bit diameter used on the FMT Pro is 1/2"(12mm).
4-34
Example: 1/4" (6mm) Mortise & Tenon Joints with a
3/8" (9mm) Guide Using the two bits and guide shown above,
you can rout a 1/4" (6mm) mortise and tenon. The resulting joint
is 1/8" (3mm) smaller than the 3/8" (9mm) guide size. Note:
Any two bit diameters that add up to twice the guide size will
produce a joint size of the smaller bit.
4-35
For example:
3/8" guide x 2 = 3/4"
1/4" mortise bit + 1/2" tenon bit = 3/4"
(9mm guide x 2 = 18mm)
(6mm mortise bit + 12mm tenon bit = 18mm)
Mortise
1/4" (6mm) Mortise & Tenon Joints
Using a Two Bit Combination
3/8" Guide
(9mm)
3
/8
x
1
3
/8
x
1
Guide Pin
Guide Pin
1/4" Mortise Bit
(6mm)
1/2" Tenon Bit
(12mm)
Tenon
4-36 Example: 1/8" (3mm) Mortise & Tenon Joints with a
1/4" (6mm) Guide
Using the two bits and guide shown above,
you can rout a 1/8" (3mm) mortise and tenon. The resulting joint
is 1/8" (3mm) smaller than the 1/4" guide size. Note: Any two
bit diameters that add up to twice the guide size will produce
a joint size of the smaller bit.
4-37
For example:
1/4" guide x 2 = 1/2"
1/8" mortise bit + 3/8" tenon bit = 1/2"
(6mm guide x 2 = 12mm)
(3mm mortise bit + 9mm tenon bit = 12mm)
1/8" (3mm) Mortise & Tenon Joints
Using Two Bit Combination
1/4" Guide
(6mm)
Guide Pin
Guide Pin
1/8" Mortise Bit
(3mm)
3/8" Tenon Bit
(9mm)
Mortise
Tenon
1
/4
x
1
/2
1
/4
x
1
/2
1/4" (6mm) mortise bit
1/2"(12mm) tenon bit
3/8" (9mm) guide
1/8" (3mm) mortise bit
3/8" (9mm) tenon bit
1/4" (6mm) guide
Routing Joints Smaller than 1/4"
Production Procedures for Small Joints