Vice slip debriefing

Hello all,
Owner/operator and machine appear to be fine, but I had an incident this evening, and am curious what (else) I should learn from it.
I must have taken too large of cut, though it didn't seem that way at first; that will take some more thought.
The weak spot was the rotation axis of my vice; the clamps holding the base of the vice to the table held. The unintended new position put the vice in contact with the endmill. Here's where I get blurry: I recognized the problem and started reaching for the power switch, but I cannot recall whether the spindle stopped before I cut the power. There was no damage to the endmill and only a small scratch on the vice. The part was trashed, but that's no loss. Ironic given our posts just hours ago!
With the power off and the spindle definitely not turning, I began looking for gentle ways to get the vice away from the endmill. I finally loosened the vice from the table and tapped it with a mallet.
After some draw filing on the vice, it appears to be fine. No circuit breakers tripped. The mill runs properly.
The vice is aligned again. I had an awful time doing it, which I think was because I didn't have the vice clamps tight enough, so my taps were causing large translations. After fixing that, I did some test taps and then did a pass just watching the ball of the DTI pass over the fixed jaw of the vice, fixed a gross error and then started with the indicator. Rather than try to spin the scale on the DTI, I moved the table to offset the DTI and then finally to "zero" it when it was aligned. Comments and better ideas are welcome.
Bill
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Unless you do a considerable amount of work at an angle, it's usually a good idea to use your vise sans the swivel base. They generally cost you considerable time in setup, and, as you discovered, tend to be troublesome. You almost always have doubt as to whether the vise is properly dialed, or not. The worst part is you lose valuable space unnecessarily.
If, by chance, you happen to have keys for your vise, you can use them to locate the vise almost perfectly, then do a fine adjustment with your indicator. Add the swivel base when necessary. I never use one, preferring to make my setups with a vernier bevel protractor when necessary.
Zeroing the indicator is of no concern, which likely stands to reason to you. All you want to know is if there is movement of the hand, so regardless of where it rests on the face, it makes no difference as long as you know where you got started. Certainly no harm is setting it to zero, but not necessary.
When you dial in a vise, or anything, for that matter, it's usually desirable to have one side quite snug, and the other side just slightly less tight, so when you rap the vise with your soft hammer, it moves only a thou or so, pivoting around the bolt that is the tightest. As it gets near perfect, snug them up and repeat if necessary. Dialing in anything that is too loose is rather difficult because of the unwanted movement.
Setting the indicator by moving the table (or saddle) is perfectly acceptable, assuming it doesn't affect your setup. It's often much easier than moving the indicator a small amount to get the hand where you desire it.
Harold
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Harold,

The vertical space has not been a problem so far, but it certainly could be some day. I haven't removed it yet, but I suspect it will make the vice significantly easier to move.

I have keys but they are too small to be of such use. I plan to make some as soon as I stumble onto some suitable metal.
> Add the swivel base when necessary. I never use one,

Unless I'm crossing up gizmos, that means you use clamps when you work at an angle??
Re angles, it sounds as though measuring and aligning to them is acceptable practice. I was wondering by analogy to construction practices in drafting.

Understood, but the "go halfway back to where you started" maneuvers are simpler (and less error prone) if the reading is a nice number or at a compass point, etc. The real reason to play with the offset is that the DTI has a very limited range, so when in doubt, I unloaded it and put it at a known location in its travel. However, I will admit that once I got the bolt tightnesses about right, it got a lot easier.

I'll give it a try.
> As it gets near

I understand the need to repeat, or at least check after tightening. Am I correct in assuming that one would loosen a bolt instead of simply swinging harder?
> Dialing in anything that

As I learned "the hard way" :) Thanks for confirming my suspicion.
Thanks!
Bill
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good
troublesome.
or
It often is more precise, too. Each time you add a lift to a setup, you have more chances of introducing error. Could be a problem for difficult work. Regards handling, if you had a large vise, your point would be dead on. The large Kurt vises are tough to handle alone---------which I recognized when I bought my 5" model, now obsolete. For small work, it's the best of all worlds.

to
By banking off one edge of the T slot, you can still use them to get the vise close, so even they can save some time.
Where I was trained, all the keys were removed from vises and we were not permitted to use them. They wanted the vise dialed in each time it was set up, so that forced the issue. I rely on the keys now, but I'm not turning out critical work (just hobby stuff), but it's a good policy to dial the fixed jaw each time the vise in installed. Mine will repeat within a thou using the keys, which is one reason I've become somewhat lax in retirement.

necessary.
Yes, even when installing the vise at an angle. The bolt holes don't always work out otherwise. That offers some nice advantages, like placing the vise where it is in a better relationship with the spindle if it was otherwise mounted with the swivel base. Not a big deal normally, but it opens the door to options that otherwise would not be available. It's more a personal choice than anything. I don't see a right or wrong in the issue.

Frankly, it's the only way to make a setup. There's no way in hell I'd trust the marks on a vise and swivel base, no more than I'd trust the index on a mill or lathe compound. At best, they're a reference point, nothing more. By using a vernier protractor, you can usually achieve 15 minutes of angle with little effort. That requires the protractor to be properly supported so the angle isn't influenced by tilting. When the angle is critical, it is measured after a cut, then corrected as necessary. On the other hand, if the angle isn't critical, there's certainly nothing wrong with trusting marks on the vise or machine, assuming you have a clue as to their accuracy.

as
zero,
Agreed. It's particularly important when you sweeping a bore, where you view the indicator backwards when it's too the rear. My policy is to use any method that minimizes the chance for me to screw up. When you use an indicator daily, it becomes routine and you don't give it much thought. Now that I use mine very infrequently, the fine edge I used to enjoy is gone. I have to think harder, and often employ methods you suggest.
The real reason to play with the offset is that the

Oh, yeah! If you work with loose bolts, it's like a dog chasing its tail .

less
thou
Depends. If you need a half thou, and you have a decent soft hammer (Nupla Flex), you can often get the half thou you need with a swift blow. The snap often permits a miniscule movement, but I never swing like I'm trying to break things. It really helps to have a firm understanding of what "tight" means. My years in precision grinding really helped in that regard. I don't over tighten fasteners, and I also don't have problems with things moving. Some guys use way too much force on fasteners, in which case my method wouldn't work.

Welcome!
Harold
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On Sun, 23 Oct 2005 18:13:03 -0700, "Harold and Susan Vordos"

Too much tightening often induces a fair amount of stress, bending and so forth, both on the fixture and on the workpiece. Sigh...nothing worse then doing what you think is a marvelous job..and when you loosen the vise jaws...things come aglay. Been there..done that...looked really stupid.
I use a lot of plain yellow legal pad paper under things, in the shop. mill vises, quick change tool holders (KDK) on the lathe, etc. Put a piece of that paper under something you dont want to move..and it wont, and you dont have to use a cheater pipe to tighten things up anymore.
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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Interesting. What about water/acid/etc. content?
Bill
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wrote:

It doesnt seem to bother it much. Try it for yourself. I rather suspect liquids soak in and swell it up a smidge, making it hold even tighter. Its long been a practice to put a couple bits of cardboard under forklift forks to keep Stuff from sliding on them. Perhaps its the same princible?
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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Mon, 24 Oct 2005 17:23:21 GMT in rec.crafts.metalworking :

    Sounds interesting. I'm wondering about "production" where I have 500 six inch lengths of T extrusion to mill (two little parts each), and I don't want to have them come out of the fixture.
    I think I stick with making sure I get the vise tight. Two drinks ought to do it, no?
tschus pyotr
--
pyotr filipivich.
as an explaination for the decline in the US's tech edge, James
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On Mon, 24 Oct 2005 20:31:10 GMT, pyotr filipivich

Ive used paper in vise jaws, particularly when working with tool steels.

Pour a couple shots of Patron in the coolant, kills the biologicals and removes backlash.

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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Mon, 24 Oct 2005 21:51:13 GMT in rec.crafts.metalworking :

    I'm working with aluminum (arrow space). Last night, the vise had to be set to 70 foot pounds, so as to not damage the finish. This is a "cosmetic" fixture, meaning it will be seen by paying passengers.

    I've discovered that if you replace the small aperture nozzles with larger ones, you can keep coolant on the work, _and_ not splatter coolant everywhere, and wash the chips away, and aerates the coolant to prevent the funky smell. Gives me something to watch, too.
    I'm happy, I'm making stuff, and getting paid too.
tschus pyotr
--
pyotr filipivich.
as an explaination for the decline in the US's tech edge, James
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Bill Schwab wrote:

Bill:
    Here is the meat of a post I made years ago in the CNC group.
Vise and part indicating.
What I do is clean the bottom of the vise and the machine table, put the vise on the table and move it around enough to scrape off any chips into the t-slot grooves that might have gotten under it when lifting it on the machine. I put the hold down bolts on and average out the play forward and back and line it up as good as I can by eye. You're supposed to clamp a large parallel block in the vise jaws simulating a part and indicate off of that. I forego that step since Kurt vises are pretty good about staying indicated whether there is a block in the vise or not. I snug one bolt and start the indicator on the side of the jaw closest to that bolt. I move the table and tap the vise while the table is moving, and by the time the indicator has made one pass across (or the vise has made one pass across the indicator - depending on your point of view) it's pretty close. I then snug the OTHER bolt and loosen the FIRST bolt and run the indicator back across fine tuning the vise as it's moving. At the end of the travel it's usually indicated to a half a thousandth. I tighten both bolts (you should have washers under the nuts or the vise may move when you tighten the nuts. I do a final check pass and that's it. It usually doesn't take more than two passes and a final check pass to indicate a vise. DON'T wait to get to the other end of the vise jaw to tap the vise, that is just a waste of time and you'll end up having to move the table back and forth too many times since the pivot point is not precisely at the end of the vise jaw but beyond it a little. The same thing with indicating parts, you snug one clamp and start the indicator near that clamp, tap your part while moving the table then clamp the second bolt and loosen the first and tap while traveling back the other way. Some shops use key ways or dowel pins under the vises to align them. I personally don't like that idea since the vise can be out a thousandth or two using keys and I hate the sound of a vise when it sometimes falls into the keyway slot and you can never tell if some foreign material has found it's way under the vise. If you have to angle the vise the key ways are in the way. I rarely use those swivel bases that you can buy with the vises, they're not accurate at all. If you need to angle the vise I just use an angle block held in the the vise and clamp the vise to the table as if it was a part you were holding down and indicate the on the angle block. You can also use a sine bar to indicate on, laying flat on the vise ways or in a pinch on top of the vise with the jaws clamped tightly shut.
-- BottleBob http://home.earthlink.net/~bottlbob
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Bob, absolutely beautiful machine work. Bill.
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snipped-for-privacy@aol.com wrote:

Bill:
    I assume you're referring to the stuff on my home page. I appreciate and thank you for those kind words.
-- BottleBob http://home.earthlink.net/~bottlbob
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