Bob La Londe wrote:

When you set something in your vise with parallels do you slide them out
before beginning work, or do you press down firmly enough on your work
pieces that they won't move easily as the machine accelerates and
decelerates?

I seem to get more accurate work piece positioning if I press down gently
while tightening the vise, but at that light downward force the parallels
can slide out after I have the work piece clamped in.

Seems if you leave them in they could shift on their own or worse slide out
and fall between the table and the column, but if you slide them out
eventually you will wear them out of tolerance from the friction of removing
them.

Not really an issue for a 2 minute job, but I rarely do a 2 minute job.
Heck, I rarely do 2 hour job.



Leave them in place normally. You can use a spring loaded parallel
keeper if you aren't getting a tight enough fit to prevent them from
sliding around.