Civil Engineering Reference
In-Depth Information
You will quickly find it is very easy to work accurately and to size using this
method.
Machining accurate widths
Often you will have to machine a component such as a piece of sheet metal
to an accurate width.
Clamp the metal on to the milling machine table (use a piece of scrap ma-
terial or a piece of wood under the metal to protect the table) and put a cutter
of known size in the spindle. Machine one edge to size, winding it towards the
metal in the Y direction until it touches the edge of the work, wind backwards
and forwards in the X direction making sure it is cleaned up.
Set the machine's dial to zero. Assuming we want to mill the piece of sheet
metal to 100mm wide, move the machine table over by 116mm in the Y dir-
ection (100mm metal width + 16mm cutter diameter), lock the machine table,
and clean up the second edge. To eliminate backlash you must turn the hand-
wheel in the same direction as when you machined the original side; if you go
past the 116mm, wind the table back a couple of turns and then wind to the
116mm reading on the handwheel. (We will look at backlash again later when
we discuss pitching out holes.)
Using a depth micrometer
A depth micrometer is very useful when cutting slots or steps to size. The an-
vil on a depth micrometer is usually only 3 or 4mm in diameter so it will fit into
most slots and steps you are likely to cut.
