Vise Clamps

[Susquatch]

I just adjusted my GS jaws per the manual and tried to clamp a block of steel on top of parallels. There is no way in H*** that you are moving those parallels after the Jaws are tightened.

Just for S***s and Giggles, I tried the same block with the same parallels on my 3 other vises (A big Grizzly and two high quality machinists vises). The parallels on all three were easily removed after clamping.

The GS system definitely works. While it is difficult to move the blocks against the springs, it is possible and the movement is just barely detectable.

I ordered new jaws for the GS ($100 each!!!) earlier this morning. I'll see if I can grind the old ones or get them ground by someone else so I can use them as spares - or perhaps make them my working jaws and use the new ones when I need the precision.

I'll also have to see if I can make some triangular jaws for it for working on round parts.

Btw, the Jaws on the GS have threaded holes all over the place for attaching fixtures, stops, and whatnot.

 

[PeterT]

Ya kinda. I don have a clear picture but that's more a limitation on my part. I suspect there is more to the prismatic system from design standpoint like where the clamp & reaction loads are applied, what deflects, what slides slightly & how forces are translated for optimal clamping so that our job is easy - screw this thing until that thing is tight LoL. Its the only system I've seen that has springs. Not that its bad, its probably good, maybe even design protected. It just caught my curiosity is all.

 

[PeterT]

I'm hoping to out live my Bison because they don't make that vise anymore. That's why the price was so good back when I got it, blowout reduction. I haven't checked yet but I'd be surprised if other similar jaws like Sowa match the jaw mount geometry. I guess I could get them made but doubt that would be cheap... tool steel, machining, hardening, grinding, high degree of precision. Its in nice shape & I hope to keep it that way. But seeing all those other kinds of jaws makes me envious. Unfortunately vises are spendy but they are also important. If you cant properly hold work with reliable accuracy, makes it harder to hit dimensions. This style was also used on surface grinders. But what I like is the shorter vertical thickness. Kurt style relies on the massive CI bed for rigidity. Nothing wrong with that but it chews up valuable headroom even on BP style mills.

 

[Susquatch]

I'm hoping to out live my Bison because they don't make that vise anymore. That's why the price was so good back when I got it, blowout reduction. I haven't checked yet but I'd be surprised if other similar jaws like Sowa match the jaw mount geometry. I guess I could get them made but doubt that would be cheap... tool steel, machining, hardening, grinding, high degree of precision. Its in nice shape & I hope to keep it that way. But seeing all those other kinds of jaws makes me envious. Unfortunately vises are spendy but they are also important. If you cant properly hold work with reliable accuracy, makes it harder to hit dimensions. This style was also used on surface grinders. But what I like is the shorter vertical thickness. Kurt style relies on the massive CI bed for rigidity. Nothing wrong with that but it chews up valuable headroom even on BP style mills.

I hear you. Coming in as a milling newbie, I'm sure I don't appreciate all the nuances of what you are saying, but I sure as heck get the drift and the main points.

Calling them prismatic seems to depend on who is talking. GS and Soya both sells jaws for holding round stock that they call prismatic. Those jaws actually do look like multi-faceted prisms. So it makes sense.

Yes, others on here said that the GS ramped jaws are patented. I saw that on their website too. But it's probably an old patent that has already expired years ago.

The collet chuck that I got for my lathe is a 5c Bison. I LOVE it. Anytime I have checked it, the runout is always less than a thou. I hardly ever check it anymore when I use it. Bison makes good, stuff.

 

[RobinHood]

Having glanced at the manual only superficially, I believe they talk about two modes of operation: one, conventional, and two, pull-down mode.

In the conventional way, the springs are fully compressed and the jaws seat against the bottom - in other words, it will not slide down the angled face when tightened - just like on any other fixed jaw vise.

In pull-down mode, the jaws “float up” a little above their bottom stops (due to spring pressure). As the part is clamped, they slide down along their angled faces, in turn pulling down the part hard onto parallels or the vise bed.

I can see that the jaws could marr the surface finish in pull-down mode - especially if there is a substantial vertical component of movement while the jaws bite into the part under pressure.

 

[John Conroy]

Ca Lem built a very nice Gerardi clone. Amazing work, fantastic looking vise.

 

[Tom O]

Apparently Calem might be done making videos he’s looking to move maybe That’s too bad I like his vids.

 

[Susquatch]

Got my new jaws yesterday. They are not a perfect fit replacement. I had to loosen the fixed jaw block and slide it sideways a bit. I didnt think that should be possible, but it did work. It makes me wonder how the vise holds its right angle.

Anyway, they are nice jaws - and ought to be for the money. And 1/4 turn on the jaw screws does seem to be a good compromise between marring and pull down. Overall, I'm happy.

 

[Susquatch]

The other thing I did today was to finish making my vise clamps. Although the mill has a definite drift problem, it is still very rigid compared to my old mill/drill, and the new Clamps work great!

I considered recessing the screw heads, but then they become a chip trap and I thought the bigger hole might weaken the clamp being that I put the screw as close to the vise as practical.

In any event, the top of the screws are below the top of the base so they don't interfere with parallels.

I may polish and blue them when I get some free time.

This thread was a very worthwhile discussion for me and I really appreciate all the help and advice that members have given me.

Again, I'm happy.

 

[RobinHood]

Nicely done!

That is one good quality vise. As good as if not better than any Kurt (dare I say that? I guess I just did…).

 

[PeterT]

That's pretty similar to what made. I'll have to snag a picture next time. I also have a few graduated thickness spacers donuts I can put between the vise body to move the arm out
(red) sometimes an extending parallel will conflict with the arm even though the part is inside the jaws
(orange) its also useful to have slimmed down rods (or in your case threaded rod) when working on thinner parts, but that might be more a function of my projects
I actually prefer my little vise jaw clamp, much quicker & generally more reliable but involves a bit of rethink to work around the non-rectangular jaw like a Kurt

 

[Susquatch]

That's pretty similar to what made. I'll have to snag a picture next time. I also have a few graduated thickness spacers donuts I can put between the vise body to move the arm out
(red) sometimes an extending parallel will conflict with the arm even though the part is inside the jaws
(orange) its also useful to have slimmed down rods (or in your case threaded rod) when working on thinner parts, but that might be more a function of my projects
I actually prefer my little vise jaw clamp, much quicker & generally more reliable but involves a bit of rethink to work around the non-rectangular jaw like a Kurt

My post was focussed on the vise clamps. But you noticed the stop.

I didn't bother with graduated donuts. I just used one big fender washer fat enough to space the stop bar out far enough to clear the Jaws totally. The washer is also big enough to keep the stop bar totally rigid. Once I tighten the machine screw, that thing don't move!!!

I thought about the size of the stop screw for a bit and then decided it wasn't important for my work. The bar slides on a groove so I can always get the screw where I want it even with parallels.

If I ever need a smaller stop pin, I'll bore out a shorter screw and glue in a hardened pin.