Help me figure out my new milling vise

[ehatcher]

A freind gave me a five inch milling vise. He doesn't know anything about the vise, in came a lot of other tools he bid on.






I Googled Gressell, but their website does not show this particular vise (I suspect the vise is too old.) I did see that they make vises with torque multipliers and load limiters. From what I can determine, this unit has a multiplier on it. However, I don't think the vise is working right because the jaws will only close down to about an inch. I don't want to take it apart and risk screwing something up, this thing looks COMPLEX inside. I am hoping someone here has direct experince with this tool and can tell me about it. I sent an inquiry to Gressel but I have not heard back, I am guessing they only deal with proffesional shops.


Thanks!
Eric

 

[Hawkeye]

Eric, I don't know anything about your vise, but I'm thinking this is the load limiting type. Try turning the setting up to 40 kN and see if it will advance any further. It may be dirty inside and the crud is hitting the 20 kN limit. I don't know how big a kiloNewton is, but it sounds like a lot.

 

[Rbeckett]

Have you tried putting something init and seeing if the little tick mark moves when you apply pressure. It may be a uniform tightening indicator so that each piece is held at the same tension. Just a guess, but I would stick something in it and see if I could make the needle move anyway. Have fun and let us all know what you find out.
Bob

 

[63VDub]

20kN yeild approx 4500lbs force. that a good squeeze. a little google-fu and it looks like you indeed have a pressure limiting clamp:
http://www.freepatentsonline.com/5192062.html

 

[Tom Griffin]

Eric,

There may be a quick release somewhere on the vise that will allow the moveable jaw to slide up to the work piece. That might explain why you are running out of travel. The dial looks to be a torque limiter. Forty kilo-newtons is about 9000 pounds of force which is comparable to putting about 90 pounds of force on the handle of a Kurt.

Tom

 

[ehatcher]

I believe this vise may also have a torque multiplier because when the jaws close on something, the crank seems to engage a second set of threads located under the knurled collar. Once the second set of threads are encountered, I seem to recall that the jaw moves much slower.

You guys have given me some ideas, I will experiment with the vise some more tomorrow and report back what I find.

The little kn indicator does not move when the jaws are tightened. It does turn freely with an allen key. There does not appear to be a quick release of any sort.

Part of the problem is that I don't even know if this tool is working correctly. For all I know this thing is a boat anchor (though I suspect not since it is in remarkably good condition.)

Thanks all, the mystery continues!

Eric

 

[Charley Davidson]

Do a search on You Tube, they don't show your vice but they make some bad ass vices

 

[ehatcher]

I agree. I think your best bet is to post it to me and forget all about it Should I PM you my address?

I was all set to pack this in a box and send it to you, but I was also concerned that you might hurt your back moving this thing around (it's really heavy.) There was no way I wanted to feel guilty about hurting someone I hardly know, so I figured it would be best if I stuck with it and figured it out.

I very carefully disassembled some of the vise to clean it and see if I could figure out how it works.

First discovery: the vise is constructed in such a way that it cannot close any tighter than a 1/2 inch. I will have to use a spacer block for anything smaller than 1/2 inch.

Next I discovered that the movable jaw is on a base that can also be moved to increase the opening of the jaw. Remove this pin:


Slide the whole jaw back and reinsert the pin in the other hole:


and now the vise opens enough to hold something 7 3/4 inches long:


Next, there are two sets of threads that the crank handle engages, the first set it a coarse thread that allows the jaw to move quickly as the handle is turned. Once the jaws begin to clamp on something, the second, finer thread is engaged, giving a much higher clamping pressure.

In this pic a space between the crank handle and collar is narrow, the second set of threads have been engaged:


Here the jaw pressure has been released and the the space is wider:


I also discovered that the crank handle is spring loaded and it can be engaged into the knurled collar to give a better fell for the clamping pressure



The dial on top does seem to limit the clamping pressure

At least I think thats how it all works. I hope to some day meet some one who is familiar with this tool and can tell the finer points of using it. In any case, I now have a working vise for my milling machine!



Eric