I have to confess that the subject of this project is not an idea of mine but is
one that, to my recollection, I have seen only once.
When requiring to use parallels in the drilling vice most workshop owners will, myself
included, make use of the same ones as used for milling, even though the requirements
are very different. When used in the milling vice the parallels will most often be
used to raise the workpiece to permit the top surface to be machined in some way,
that is quite different to their use in the drilling vice where the purpose is to
raise the workpiece so that through holes do not damage the vice below.
In the drilling vice therefore the height of the parallels is rarely critical but
have to be positioned so that the drill does not make contact with them as it breaks
As holes in a workpiece are rarely very close to the edge then relatively thin parallels
placed against the vice jaws will most often eliminate the problem, that is if you
can keep them there. During setting up they will be prone to fall over making them
difficult to work with and often move due to vibration whilst drilling is taking
Various methods of keeping parallels against the jaws can be used but almost all
have only a limited closing range. In my case, I use strips of soft rubber but this
becomes inconvenient when more than a few strips are required to make up the distance,
and I am still using 6mm wide parallels which is often too wide when holes are close
to the edge. Compression springs are another method but these are prone to buckle
when the length is many times its diameter and so large diameter springs are necessary
and even then a number of different lengths would be required.
The subject of this project, Photograph 1, surprisingly re-surfaced when my wife
threw out some spring loaded skirt hangers and I decided to salvage the springs from
them. Having to suit a range of sizes the compression springs in these are long and
the turns well spaced making the range between free and fully compressed relatively
large, being 65mm. These hangers are commonly supplied with the clothing purchased
and the reader may be able to locate some of the same springs. Incidentally, each
hanger contains the two springs required. However, any small diameter compression
spring could be stretched to extend its range.