Low Profile Clamps
Reference to an industrial supplier catalogue will show that there are a number of
specialist clamps intended for the purpose of clamping relatively thin items to the
machine table whilst still leaving the workpiece top surface free for machining,
Photograph 16 shows a typical example.
The T nut itself is fixed firmly in place by the grub screw seen at the right hand
end being tightened onto the base of the T slot to fix the nuts position. The head
of the main screw is off centre from the thread and rotating it will, as a result
of the head's cam action, advance the hexagon clamp piece to provide the clamping
pressure. One advantage of these is that if a number of clamps are employed, irregular
shapes can easily be held, as the clamping action does not need to be axially in
line with the T slot holding the nut. However, for rectangular parts just two clamps
will suffice when used in conjunction with a fixed jaw as seen in Photograph 17.
Where batch work is being undertaken the clamps have the advantage of being able
to cope with a fair range of variation to the size of the parts being machined.
Their main benefit is that they make some tasks easy that would otherwise be very
difficult to perform without them, perhaps impossible. Photograph 18 show 5 types
for construction in the workshop, see my pages relating to these for details. Of
course, not all five types are necessary and the viewer can choose which one that
suits his or her needs best. I would though suggest a minimum of four, all the same
type or two and two.
The requirements for mounting workpieces onto the machine table are very varied and
the suggestions in this article can only cover a small number of them. However, the
basic principles will be the same for almost all situations so hopefully will help
to give the workshop owner some confidence about even the most complex set-up.
For more examples of workpiece clamping see my pages on the
Alternative to the Four Jaw chuck. And Machining Cast iron