With the outer diameter parallel, now very lightly face the outer ring of the end.
This is essential as only by turning the outer diameter and the end in succession
can the accuracy of the base relative to the sides be assured. Finish by parting
off as close to the chuck as is possible. Now make a second square making it the
same diameter and length as the first. Neither is critical but getting the diameter
within say 0.01mm may be of help subsequently. If you do not achieve this do not
be overly concerned as it is of little importance.
The next task is to face the parted off end. Place the square in the three of four
jaw protecting the machined surface using a strip of thin copper wound round it,
check that the end is running reasonably true, visually should be a sufficient check.
Now, using a small centre drill, centre drill to a diameter of no more than 4mm and
support with tailstock centre. Face the end as close to the centre as is possible
and make substantial chamfer on the end, say 3mm wide. The chamfer indicating which
is the non working end.
Next, drill though to make contact with the hole drilled from the other end. However,
as the drill may have wandered over that length use a drill one or two sizes larger
than originally used. Repeat for the second square. Drilling the hole should remove
the small portion that did not get faced.
You will not want this precision item going rusty so wipe them an oily rag but then
wiping with a dry rag to remove the surplus.
Why then have you made these items. Probably the most likely use is an alternative
to an angle plate, especially useful if an angle plate is being machined from a raw
casting for use in the workshop and another is not available to support it, Photograph
2. Mounting the angle plate diagonally , as shown in Photograph 3, will result in
the end being perfectly square to both faces.
Photograph 4 shows one being used to set a piece of angle upright, for machining
its end, whilst being held on the workshops angle plate. Such a set up is particularly
useful if a number of identical parts are to be made as it is much quicker than
using an engineers square to set each one upright. Where heavy machining is involved
then a square can give added support.
Finally, Photograph. 5 shows a shorter one being used to set up a piece of steel
in the vice. This can be easier than using a small square which may slip between
the vice jaws.
See the page on making an Angle Plate using cylindrical squares.