# A Question Of Vises...



## wawoodman (Oct 20, 2015)

I have a 5” Kurt that I picked up used, on ebay. It was pretty filthy with what I think was cast iron dust. Anyway, I've cleaned it, and it works pretty well. But...

I  generally set a narrow part on a single parallel, with either paper or a wire on the moveable jaw side. Even when I tap the workpiece down, sometimes one end or the other of the parallel will wiggle when I tighten things up. The same is true with two parallels; I just have trouble getting them both tight.

Does this indicate user error, or a problem with the vise? If it's the vise, is it the jaws, or deep inside?

Replacement jaws from Kurt are pretty pricey, but still, less than a new one.


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## wrmiller (Oct 20, 2015)

I have a 5" Kurt as well. 

When I use parallels I always tap down on the top of the part being held (once the movable jaw is tightened) because the part *always* lifts off the parallels. One of the first things I learned way back when I started this stuff. I use a rubber coated dead blow so the hammer doesn't bounce. I usually just thwack it a few times and check for tension on the parallels. Once they are snug you're good to go.


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## Andre (Oct 20, 2015)

When machining a precision part, I use paper around it to keep the sides from getting chisel marks from the top edge of the vise jaws. Never had an instance where it's affected accuracy to a noticeable degree.


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## wawoodman (Oct 20, 2015)

I'm not concerned about marks. I thought you did it to take up any micro gap in the grip.

Thanks for the info!


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## sanddan (Oct 25, 2015)

I have a older Kurt 6" D60 vise that does the same thing. Very hard to get the part seated on the parallels. I could see the part tilt slightly up when tightening the vise. I had been using a new 5" Glacern vise and not having the same issue but sold it when I upgraded the mill (went from ZX45 style to full size knee mill). I ended up getting a new Kurt D688 vise and no issues now. I will keep the D60 as a backup (only paid $125 for it). You could try to tighten up the adjusting screw for the ball in the moving side of the vise, that is supposed to be the feature that pulls the moving jaw down when tightening the vise.


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## wawoodman (Oct 25, 2015)

Thanks, sanddan.

What did you think of the Glacern? A 6" is too big for my Rockwell mill, and Kurt doesn't make the 5" anymore, AFAICT.


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## coolidge (Oct 25, 2015)

wrmiller19 said:


> I have a 5" Kurt as well.
> 
> When I use parallels I always tap down on the top of the part being held (once the movable jaw is tightened) because the part *always* lifts off the parallels. One of the first things I learned way back when I started this stuff. I use a rubber coated dead blow so the hammer doesn't bounce. I usually just thwack it a few times and check for tension on the parallels. Once they are snug you're good to go.



^^^ Bill nailed it!


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## wawoodman (Oct 25, 2015)

That's the problem! Very often, I get one end tight, and the other loosens up. Or, if I use two parallels, three corners are good, but not the fourth.


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## wrmiller (Oct 25, 2015)

I just thwack it right in the middle, and as near vertical on the downstroke as possible.


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## Terrywerm (Oct 25, 2015)

wawoodman said:


> Thanks, sanddan.
> 
> What did you think of the Glacern? A 6" is too big for my Rockwell mill, and Kurt doesn't make the 5" anymore, AFAICT.



I have a 5" Glacern that I purchased new last year and use it on my Clausing 8520 mill.

LOVE IT.

Nuff said.


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## wawoodman (Oct 26, 2015)

Thanks, Terry. If I can't get the Kurt to behave, it might be the next big purchase...


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## stupoty (Oct 26, 2015)

I like putting a copper sheet strip between the movable jaw and the part, helps a lot with my down market vice 

Stuart


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## chips&more (Oct 26, 2015)

I like my lead hammer for thwacking. And if things get difficult, I’ll add a piece of round stock on the movable jaw side…Dave


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## wawoodman (Oct 26, 2015)

How thick of a sheet? Thinking, if I bent a hook at the top, it would be self-supporting, and more convenient than a wire.


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## derf (Oct 26, 2015)

If the part you are clamping lifts off the parallels, something is out of square. It's either the part you are clamping, or the jaws are not square with the base. You might want to swing an indicator on the jaws to find out. Sometimes it doesn't take much.


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## derf (Oct 28, 2015)

With years of use and abuse, being tightened with a "hammer" and smacked with dead blows, the stationary jaw gets the most of the damage. The footprint of the stationary jaw is less than half of the footprint of the movable jaw, and it's held down with 2 bolts and a key. After numerous "hard" clampings, the bolts tend to stretch and bend, given the fact that most of the time the part that is clamped is usually at the top of the jaws, essentially adding extra leverage to tip the jaw away from the base.


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## JimDawson (Oct 28, 2015)

I had a good quality 6 inch Kurt clone vice and I was having the same problem.  I replaced the 1/2 inch stationary jaw cap screws with 5/8 cap screws and torqued them to about 200 ft/lb.  The new bolts extended almost to the top of the jaw.  Pretty much ended the problem.


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## wawoodman (Oct 28, 2015)

I'll be tearing the whole thing down as soon as the repair kit comes in. I'll look at extending those bolts. Thanks!


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