Need Help!- Vise Help

[Ashish B]

Hi

I was browsing through brochures of vise manufacturers. They specifically state as - "*All sides Parellelism & squareness with in 0.005mm / 150mm.. "

What does this actually mean -
1. Does it says that PARTS upto 150 mm will be square to machine in 0.005mm (when clamped on vice)
2. Does it mean that the Jaw travel accuracy of vice is 0.005 mm upto 150 mm.

Also,

If i have a vise (5 years old) & in continuous use, then what accuracy of alignment/squareness should i expect from this old vise

Thanks

[Algirdas]

repeatability is more important. It can't be stated just after production. Hence, manufacturers declare linear accuracy.
Since you have already the vise, measure it several times the same etalon block clamped

[Geof]

Originally Posted by Ashish B .... "*All sides Parellelism & squareness with in 0.005mm / 150mm.. ".....

All this means is that if you measured the width of the vise base at two point 150mm apart the difference would be less than 0.005mm.

Or if you measured the angle between the face of the jaw and the sides it would be less than .005mm away from a true 90 degrees of the same distance.

These specifications do not tell you very much about how repeatable the vise is because that depends on how tight you clamp it and how much the base of the vise deflects. For best repeatability with a vise you should always clamp it to the same torque on the handle, this means the deflection is repeatable. The specifications also do not tell you how much the moving jaw tends to lift when clamping.

A 5 years old vise, with one exception, should be more or less the same as new regarding oarallelism and squareness. The exception is on a used vise the moving jaw may lift more due to wear but unless you have been using the vise a great deal I doubt you would have detectable wear in only 5 years.

[Ashish B]

Friends,
Thanks for posting your opinions on VISE.

Thanks
Ash

[handlewanker]

Hi, a vice is only as good as the vice jaws.

My old vice is 30 years old, a 160mm Abwood, cost me $100, but the jaws were new only a couple of years ago, and are hardened and ground toolsteel.

The ability to grip the work between the jaws at the TOP, is most important.

If it grips the work at the bottom it will only grip there as the jaw tends to lift and open out as it's tightened.

The fixed jaw MUST, without compromise, be dead square to the vertical.

All vice jaws, except those specifically designed to pull down as they tighten, will lift as they grip the work, that's why the job is tapped down as the jaw is tightened onto the parallels.

There are many other factors in vice parameters that apply equally importantly, but vice jaw factors are at the top of the list and can make or break a vice.

$400 to $600 spent on a vice can get you quite a good vice, not the best, but quite a good one by anyone's standards.
Ian.