Although using a jointer is mostly safe, careless use of a jointer can lead to injury.
It is the reader's responsibility to ensure that the jointer is solidly
constructed, especially in regards to the cutter head bearing mounts,
cutter guard, and table attachments.
It is assumed that the builder is skilled in woodworking.
This should not be your first woodworking project.
It is also assumed that the builder is already familiar with the safe
operation of jointer planers.
Woodgears.ca cannot be held liable for injuries
that you may incur with your homemade jointer.
Some safety tips
It is recommended that only cutter heads of the style where knives
are inserted into a slots, as opposed to attached to the side of
the cutter head are used. These cutter heads run quieter and
provide greater kickback protection (kickback protection is less
of a priority for thickness planers)
It is important that this machine always be used with a cutter guard
in place. Each homemade machine will be slightly different, and even
starting with a good design does not guarantee that nothing will not go wrong.
The knives should get about as close as 2 mm from the metal edges of the
tables. Too close, and there is risk that the knives may strike the
table (which may have catastrophic consequences). Too large a space, and
the risk of kickback something pulled into the cutter head increases.
The worst failure of the jointer that I can imagine that might happen to a jointer
is that the cutter head knives strike and hook onto the infeed table.
This could potentially rip the cutter head loose from its mount. The fence,
cutter guard, and belt are important components in terms of containing such
a failure inside the jointer. Use good quality birch plywood for
the bearing mounts, and attaching each bearing mount with four 4" (100 mm)
wood screws deep into the frame makes to make this scenario unlikely.
Although the jointer can remove as much a 3 mm (1/8") of material at a
time, the motor from a small planer is not powerful enough to remove
this much material over its full width. Never cut deeper than 1 mm
when planing full width.