vises ?

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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spro
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Re: vises ?

Post by spro » Sat Apr 16, 2016 1:10 am

Would it be OT to mention that old iron can be improved? I understand that the Kurt system is superior but does that mean all old vises are junk? When the flyin' did that happen? ( the minute you started typing- someone thought) I'm not the engineer as another, yet fine grained American iron as a platform. Could not an earlier vise be modified and trued?
Okay, look. I have a few mill vises and one is a Bridgeport and a super knucklehead and others. It is enlightening to know that these vises were good enough for industry yet lacking in home machining. There is something else besides searching and buying another bangle to a questionable machine . Perhaps it is a way of finding the problem isn't the vise, can't say.
If an old vise isn't trashed, it could be improved in a similar way. The play in the screw allows different ways of the moveable jaw to be guided perpendicular by the pressure it receives. There was milling and an angle but don't remember.

Harold_V
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Re: vises ?

Post by Harold_V » Sat Apr 16, 2016 3:32 am

spro wrote:Would it be OT to mention that old iron can be improved? I understand that the Kurt system is superior but does that mean all old vises are junk?
Junk might be a bit harsh. It all depends on what one expects from a vise.
When the flyin' did that happen? ( the minute you started typing- someone thought)
The moment a better design was introduced to the market. That was a long time ago---more than 40 years.
Could not an earlier vise be modified and trued?
Sure, and you most likely can improve its operation, but unless there's a major change in how the screw addresses the moveable jaw, it won't come close to the performance of a Kurt. Most vises with a moveable jaw cause that jaw to ride up when the vise is tightened. Hammering a piece down in the vise was common practice. It's not necessary with a Kurt, and generally yields no improvement.
Okay, look. I have a few mill vises and one is a Bridgeport and a super knucklehead and others. It is enlightening to know that these vises were good enough for industry yet lacking in home machining.
The problem is, they "aren't" good enough for industry, depending on the industry. In fact, it was a virtually new Bridgeport vise that was the reason I purchased my first Kurt---which worked properly, when the BP did not. They simply aren't made to perform at an elevated level of precision, very unlike a Kurt. In my case (which I've mentioned before), I was machining hundreds of 5/8" blocks of brass, which, eventually, became read and write heads for IBM computers. I had to hold squareness to .0005", and the BP vise wasn't capable of doing so. I had to offset the milling machine head to achieve that end, yet when I started using a Kurt (purchased for that job), the problem went away.
There is no doubt Kurt vises are superior, although many functions can be addressed perfectly well with lesser vises. To suggest that they are not adequate for the home shop may not be a reasonable assumption, depending on the level of precision expected.

Only the operator of a machine can dictate if a Kurt is a requirement. Some folks do work that doesn't demand a high level of precision, while others may do nothing but that kind of work. A Kurt is chosen to eliminate one of the possible issues that impede getting a job done properly, or well. The choice is yours.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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NP317
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Re: vises ?

Post by NP317 » Sat Apr 16, 2016 10:16 am

From Harold's reply, I get the message that only Kurt vises perform the desired clamping action.
This begs the question:
Are there other brands that similarly clamp the moveable jaw like a Kurt?
~RN

TomB
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Re: vises ?

Post by TomB » Sat Apr 16, 2016 10:31 am

NP317 wrote:From Harold's reply, I get the message that only Kurt vises perform the desired clamping action.
This begs the question:
Are there other brands that similarly clamp the moveable jaw like a Kurt?
~RN
It also begs a second question: Is there alternate mechanisms that could produce the same clamping effect but depend upon parts that could be retrofit in old iron?

Tom

Harold_V
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Re: vises ?

Post by Harold_V » Sat Apr 16, 2016 3:36 pm

In regards to altering similar designed vises to the level of performance of a Kurt---
I can't respond from personal experience, only from what I've read from others who have experienced working on similar vises. From what I've read, they have achieved mixed results. The mechanism that provides a downward thrust on the moveable jaw (on various copies) is apparently a cast feature, which doesn't always work as designed. The comments I've read are that it is rough, and doesn't necessarily work as hoped.

A lot of this is really how an individual perceives things. The guy who must hold tight tolerances will struggle with things that are a non-issue to the guy who doesn't care, or doesn't even understand the problem at hand. One will be unhappy with the results achieved, while the other may not even recognize there's a problem. That's why I suggest it's up to each individual. Trying to impose my thoughts, as one who specialized in small precision work, gives me a totally different view on things. What's true for me may not be true for another.

Plain and simple--so long as the force applied to the moveable jaw does not create a downward motion, the jaw will rise when pressure is applied, especially when thin objects are held with the top of the jaws. Kurt understands that problem, even with their design, but they address the issue (on some of their vises, if not all) by inserting a pair of small O rings under the slide, forcing the moveable jaw upwards, so it is restrained by the keeper. That way it has no where to go when the vise is tightened. That feature, alone, could be added to any vise, assuming one is capable of cutting the glands for the O rings (assuming that the moveable jaw has a keeper).

It's not for me to say that there may not be a better design out there, but if there is one, it has escaped some brilliant minds for many years.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

J.Ramsey
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Re: vises ?

Post by J.Ramsey » Sat Apr 16, 2016 4:21 pm

Harold_V wrote: Kurt understands that problem, even with their design, but they address the issue (on some of their vises, if not all) by inserting a pair of small O rings under the slide, forcing the moveable jaw upwards, so it is restrained by the keeper. That way it has no where to go when the vise is tightened.
Harold
As the material is being clamped tight the jaws compress the o-rings helping to pull the material down against the parallels.

When I bought my 688 about a dozen years ago it came with instructions on the o-rings and how they work.

https://www.kurtworkholding.com/downloa ... ll_Use.pdf


I called Kurt and asked why the o-rings were supplied loose and the customer had to install them because I didn't feel that I should have to take apart a brand new vise and they replied "the o-rings have a limited life and pre installing them would make it shorter".

I can tell when they need replaced when the part needs tapped with a dead blow.

pete
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Re: vises ?

Post by pete » Sat Apr 16, 2016 4:47 pm

TomB wrote:
NP317 wrote:From Harold's reply, I get the message that only Kurt vises perform the desired clamping action.
This begs the question:
Are there other brands that similarly clamp the moveable jaw like a Kurt?
~RN
It also begs a second question: Is there alternate mechanisms that could produce the same clamping effect but depend upon parts that could be retrofit in old iron?

Tom
Kurt is pretty much the standard in North America that all others are judged against. But there's multiple clones that use the same anti lift design on the movable jaw that Kurt uses. But if money were no object I think I'd rather have an Orange vise instead. There starting to make a very good name for themselves and I think Sol put a great deal of thought into his design. I've got some friends in the U.K. and the Kurt name is known there as well, but there are some extremely well made European mill vises (Gressel for one) that carry a much higher price tag than the Kurts do.

Depending on just how much wear a used Kurt has they do offer rebuild kits for there vises. But given enough abuse and wear a surface grinder might be of help to rebuild one as well. And Kurt has a few rebuild and repair locations that your not going to find with most of the others. But one thing I don't think I've seen mentioned in this thread yet. There's a great many vise accessories made from machinable jaws, quick change jaws, torque sensing handles, vise stops etc etc that are all designed around and meant to fit the Kurt D-688 6" size Anglock vises. Most of the important dimensions are shown on there web site. I don't know about the others, but my Glacerns have most of the exact same dimensions and thread sizes on them so they can use pretty much anything the Kurt can. If that's important it might be worth checking on any vise a person is interested in buying.

As far as retro fitting new and better anti lift parts into an older vise that didn't come with that? Maybe, but each different vise would have to be redesigned around the original parts obviously, and I can't recall seeing any threads on any forum showing that done yet. Doesn't mean that it hasn't been done by someone somewhere tho. http://www.docsmachine.com in the projects section shows an extensive rebuild of a 4" offshore vise and all its faults that I wish I'd seen before buying 2 of them.

spro
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Re: vises ?

Post by spro » Sat Apr 16, 2016 11:26 pm

Thanks for the more detailed explanation, Harold. I appreciate not being taken to the "wood" shed. There is much to gained by a question as this and perhaps a reasonable improvement will be more widely known. I will investigate the links provided by our Members as well. I think this particular nut can be cracked a different way and many heavy vises are not to be scrap.

spro
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Re: vises ?

Post by spro » Sun Apr 24, 2016 11:15 pm

I do own a D 60 but its right heavy with the swivel base. I must admit that it would have done better.

pete
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Re: vises ?

Post by pete » Mon Apr 25, 2016 12:34 am

I can sure relate Spro. There's no swivel bases on my Glacerns but a pair of them tip the scales at around 170 lbs. Lifting just one of them off the floor and onto the mill's table is about more than I want to do now.

earlgo
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Re: vises ?

Post by earlgo » Mon Apr 25, 2016 8:58 am

If you wish to see what constitutes the locking mechanism in an Acu-Lok vise feast your eyes on the guts of the one that came straight from one of the eastern supply houses.
The sliding clamp surface on the left was rough machined and dimpled. The hemi-spherical ball that applied the pressure looked like it had been filed on the end of a rod and parted off leaving the teat. The ball socket was just cast into the lower part of the frame. UGH!
starting with.JPG
Works better now that a few 'adjustments' were made.
--earlgo
Deja Poo - The feeling you have seen all this crap before.

spro
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Re: vises ?

Post by spro » Mon Apr 25, 2016 1:27 pm

Thank you Earlgo. I don't know why this example was made so poorly but I'll bet it looks and works MUCH better now.

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