Setting up on parallels

[Metalmann]

When I set up a workpiece on parallels, and then tighten the vise, the parallels are loose enough to slide out. I can sometimes beat this by getting the jaws snug, but not tight, and tapping the work with a nylon faced hammer, and then finishing the clamping.

Is this normal? Is it a sign of out-of-parallel jaws? It's an old 3" vise that fits nicely on my Rockwell mill. Do the parallels need to remain tight under the workpiece, or am I too concerned about a non-issue?

Something you may want to try is using a lead hammer. In the old days, the shops had copper, brass, lead, and rubber hammers.

Don't be fooled into buying a cheap dead blow hammer,:nono: if you are trying to achieve production run, repeatability.

To be very precise, the workpiece should be touching the parallels at all surface edges.

Something else you may want to check...indicate in the bottom rails of your vise, to check for flatness. If that's out, your parallels won't seat accurately.

 

[Pacer]

FWIW - I am not a machinist, nor have ever worked around machines - (and didnt even sleep at a Holiday Inn) I have been a home hobbyist for some 12-15yrs, and most of the method Frank describes I figured out by trial and error (a lot of error). In the last few years I have become friends with a skilled machinist and his method is, for all practical purposes, the same as Franks (which I have adopted the parts I didnt know) I agree with Frank in that we all will find a variation on a method of accomplishing a task - I have another friend who machines so totally different its --- just strange! yet he does some very nice stuff...

I use a lot of scrap yard finds which can be really crappy with rust, odd cuts, weld slag, etc and I often use a piece of wood to compress into a rough surface and get started with a flat surface.

 

[Tom Griffin]

Frank,

I'm not going to get into a tit for tat argument with you about details. These forums are full of that nonsense and I refuse to be lured into becoming a part of it. As I said before, there are many ways to accomplish a task. If you feel that strongly about the way you do things then by all means feel free to step up and enlighten all of us by making your own video. Picking apart the suggestions of others is both rude and counterproductive.

Tom

 

[Hawkeye]

Some, if not most, knock-off vises have a slot setscrew in the end of the moving jaw facing the screw handle. If you snug it up (not over-tightened), it will take out some, but never all, of the lift.

If you're thinking of using a ball bearing between the moving jaw and the uneven surface of the work, try a lug nut, with the tapered end toward the work. It will bite in and grip quite well. If it works for you, use it. If it doesn't, don't.

While you're at it, find some bolts with the same thread as the lug nut. They make quick and easy machinist's jacks, especially if you face off the marks on the heads of the bolts.

 

[Tom Griffin]

Tom If I upset you I apologize! It was not my intention. I simply thought a discussion of machining methods would benefit all the would read it. I feel that if I continue it would old add to to the problem and do no good!
I did post the location of the Trigger shoes I made and the Pistol I build, I want everyone to feel free to criticize what I've done if they think I didn't do something correct. I welcome it and will learn from it.
Lets simply say we agree to disagree.

Frank

Thank you Frank, I accept your apology.

Tom