How many times have you gone through setting up your job in a machine vice, made sure everything is lying level and square, maybe even done a little machining - only to find that one of the holes you are drilling is going to penetrate into your parallels?

The seemingly universal solution to this situation is to scour the earth for thinner and thinner parallels in the quest to eventually find the perfectly thin parallel that will prevent you from ever having this experience

Relax - there's a simpler solution... with a simple trick I learned from my journeyman and a little forethought, you'll never have to worry about damaging your parallels again (at least not with a drill bit)

Step 1: The Trick

Well this is a tooltip so its a relatively short instructable.

Make sure you have parallels that are slightly thinner than the parallels you are going to rest your job on (by 1mm or 2mm)

Place the wider set of parallels right up against the sides of the vice

Then place the thinner parallels on either side of the block you are clamping.

Finally you should use a rubber dead weight hammer to tap the job onto the wider parallels checking that they are held tightly by the job clamped ontop of them

This should ensure that your job is resting only on 1mm or 2mm of each parallel once the job is clamped allowing you to drill away to your heart's content without having to worry about hitting a hardened parallel
I'm not quite seeing what you're doing here. When you say "thinner" parallels, do you mean not as wide or not as thick? (I'm calling the middle dimension--the one that varies in a set of parallels--the thickness.) Are you clamping the workpiece between parallels? Maybe a drawing or some more pictures would make it clear to me. Thank you.
yes I'm clamping the job between parallels while resting it on another set of parallels... I'll make a comment on the intro picture of a parallel to highlight what I mean by thickness ... also if you check out the picture on step one you'll see the parallels (although maybe a bit dark) between the job and the clamping jaws of the vice
OK, if I'm seeing this right, the workpiece is supported by a two-parallel tall stack. Then, a small piece of square stock (the "thin" parallel) is between the vise jaws and the workpiece. I understand that the use of two stacked parallels is governed by the height of the vise jaws and a single set of parallels of the right width would work here as well. Am I interpreting the photograph correctly? The "thin" parallel looks like it might be a piece of 1/8" square stock or key stock. (I had to copy the picture and boost the brightness to see it on my computer.) Thanks again for the tip and for the clarifications.
you're 100% right - I recommended the procedure to a colleague of mine and then took a picture of his setup (should have edited the photo above the first parallel of the two parallel stack so you'd have been none the wiser :P) The square pieces on the sides are actually small square high speed steel tool bits that haven't been shaped yet - they're shiny steel but deeper in the jaws of the vice so thats why they came out so dark. If you don't have the smaller parallels you can clamp the job between parallels of the same thickness and just space the bottom set (the ones you're resting the job on) away from the side of the vice... I prefer to just use thinner parallels if possible. I like the idea of boosting the brightness - let me see what I can do
Ah, great. It looks like you fixed up the photo, too. It's much easier to see. Thanks again for the tip.
wow, I'm surprised how quickly people have viewed my little page... thanks for the feedback - I agree the deadblow is important. I used to tap out the parallels but i'm always uneasy doing it... they're kind of like a Linus blanket for me... can't explain it
My Dad just showed me this today, he was boring some holes close to the edge of a piece of Aluminum. I like how you mention to always make sure you tap the piece down with a dead blow to make sure it is seated, always a good idea.
Smart tool tip. Maybe I could show this to my dad, might come in handy for him. Great job, and good pictures too!
Or you could tap the parallel out from underneath the block. As long as your job is clamped tight and your only drilling its no problem.

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