HackSpace – September 2019

(Wang) #1
FORGE

You can make your own soft jaws, or buy them
ready-made for popular brands of vice. You can also
buy ‘universal’ soft jaws that fit onto existing vice jaws
using magnets or tape, although these are less secure
than replacement jaws that bolt onto the vice body.
Clamping tube or hollow stock is tricky, and you
really only have two good options to avoid deforming
the part. You can either use shaped jaws that match
the profile of the object you’re working with (a
dedicated pipe vice is an example of this), or you can
increase the rigidity
of the part before
you clamp it by filling
the hollow part with
something solid. Musical
instrument repairers
sometimes use low-
temperature plastic as a
packing material in brass
instruments. The plastic
is heated, pushed into
the desired section of
the instrument, and then
allowed to cool. When
the repair is finished,
they warm up the plastic
again and remove it.


DOGS AND COOKIES
Holding work flat onto a surface poses a different set
of problems, particularly if you need to work all the
way along the edge of the material. Clamps are an
effective strategy in some cases, but the jaws of a
clamp can get in the way of tools you’re using. If you
have a workbench, it might be worth investing in some
bench dogs. Although the name might not be familiar,
you’ve probably seen a bench dog before on a portable
workbench. Bench dogs are the small stoppers that
fit through regularly positioned holes in a workbench
and butt up against the edge of a piece of wood
to stop it sliding around. You can make these quite
easily with a 3D printer, or by gluing a piece of dowel
into a wooden block. Bench dogs won’t stop your
work from flipping upwards, but they will keep it in
position on the table when you apply a lateral force.

Above
A pipe vice typically
has different-sized
inserts that let you
hold different sizes
of pipe. They’re
relatively cheap and
are very useful if you
work with lots of
hollow stock

Silicone mats or
baking grips are
useful for holding
and moving hot
metal objects.

QUICK TIP


Left
This work area is
drilled with holes that
accept bench dogs
and holdfasts. It can
be removed from
the workbench and
replaced with a blank
piece of wood when
it isn’t needed

Threaded bar, bolts, and machine screws are very
difficult to clamp effectively without damaging the
threads, even if you are using soft jaws. Last month we
looked at how to make a stud clamp for just this
purpose, but another option is to use a split nut. To
make a split nut, you will need an ordinary nut with the
same thread as the workpiece that you need to clamp.
Hold the nut in the vice with one of the high points at
the top, and cut down to the middle with a hacksaw,
parallel to the direction that the bolt fits. Clean up any
rough edges, then screw the nut onto your workpiece.
Tightening one or more of these nuts into the vice with
the cut part between the jaws will deform it slightly,
gripping the threaded bar firmly without damage.

SPLIT NUT

Free download pdf