First, though, the vice body must be inspected for another possible problem area.
The viewer may not be aware that when a casting's outer surface is removed this relieves
internal stresses that may cause it to bend, most likely almost immediately, but
also gradually over time. This though usually much less than any initial movement.
If then a body that is twisted is fastened to the worktable directly, or using parallels,
it will be pulled into contact with them but will then return to the twisted state
once removed. Any flat surface that was machined during this process will on the
machine be flat but when remove will be twisted. It is essential that this situation
I first tested the surfaces on which the jaw moved to see how near parallel they
were with the base and found relatively small errors in three, acceptable for a budget
drilling vice but not for one intended for milling in the home workshop, Photo 2.
The fourth vice though exhibited something that for a while puzzled me, that is the
reading was nominally equal at the two ends but lower in the middle. I did eventually
spot the reason. The surface had been machined with a fly cutter whose diameter matched
the distance between the fixed jaw and the back of the vice, and the machines spindle
was obviously not upright compared to the worktable and produced a concave surface,
one problem with using large diameter fly cutters.
However, having carried out those tests I realised that the upper surface on which
the jaws moved was the first to be clamped down and was therefore essential that
this was flat. Using a angle plate with an accurate face I was able to place this
on the faces of the larger ones and test to see that it did not rock, Photo 3. Actually,
I decided after I had taken the photograph that it would be more sensitive if I placed
the angle plate in the bench vice and tested the vice, face down on it. The smaller
ones I tested with a smaller angle plate and 321 blocks. Whilst the vice with the
concave surface was not actually flat the four corners were all at the same level
so would suffice with the method I had in mind. The other three were adequately flat'
With the testing complete it will be time to start machining.
I should add that as I am machining all four sizes of vice illustrations could be
of any one, but sometimes two or three photographs showing the same operation but
with differing vice sizes. However, it is likely that the reader will only be working
on one size but I feel the instructions as shown should be understandable.