3

FORGE

After
cut and
assembly,
finger joints are
typically glued together
with an appropriate adhesive
for your material type, such as
wood glue for wood, or acrylic cement
for acrylic.
Note, you can place the tabs wherever you like
on the edges, so long as you match them to the
gaps of the joining face. It’s not uncommon to see
finger joints run across the entire length of each
edge, which is what the parametric online software
usually does, but that’s not usually necessary — you
can get away with many fewer tabs, which makes
for a quicker cut on the laser.

MORTISE & TENON JOINTS
Another popular technique is the mortise and
tenon, which is the woodworking name for a
fitted slot and peg joint These are great when you
want overhanging faces for some parts, such as a

rounded lid that sits on

top of the side walls.

This face will have no

tabs, only mortises

that fit over tenons

protruding from the

side walls. By limiting

your tenon height to the

material depth, you’ll

create joints flush to

the surface.

CAPTIVE NUT AND SCREW

T-SLOT JOINTS

Finger joints and mortise and tenon joints

are usually glued together. If you need to

open and close your case, consider using screws

and nuts with the clever t-slot design. You’ll be able

to join panels at right angles as before, but this time

by holding a square nut (a hex will do, just not quite

as neatly) in one panel, and sending a screw through

from the face of the second. No glue required!

Don’t forget, you can mix these methods as

needed, such as creating an enclosure with five box

jointed/glued sides, plus a t-slotted back panel for

easy removal using screws and nuts.

By designing your enclosure to fit your parts,

you can make the exact fit and spacing you need.

Use data sheets, dimensional drawing, and a set

of digital callipers to fit things such as cut-outs for

buttons and jacks, mounting holes for parts, and

windows and bezels for displays.

There are, as you may imagine, many other

ways to join together laser cut parts, but these

fundamental methods will serve you well, and get

you building great enclosures quickly.

Left

The finger joint is

usually designed

by automatic

software, but can

be customised for

your needs

Left

Mortise refers to the

hole (from the old

Arabic word meaning

to ‘cut a recess’) and

tenon is the finger

(from the Latin word

meaning ‘to hold’)

Right

You can combine

techniques, as we’ve

done here with

a t-slot to give a

removable panel to a

finger-joint box