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Overly complicated vise stop

PeterT

Ultra Member
Premium Member
#1
One advantage you guys with Kurts & their clones mill vises is they have rectangular jaws. They lend themselves to jaw replacement, sacrificial jaws and those clamp-on stops. I'm a big fan of stops. They help a lot with accuracy as the part can go in & out as often as you like & preserve the same position. Unfortunately my mill vise has prismatic jaws. I shouldn't complain because its super accurate. But you cant use the typical rectangular clamp on stop due to the taper on the back face & also there is very little lip. I have a stop that comes in from the side but it takes a little longer to set up. When you have little parts around the middle of the jaw, these kind of stops are easier.

So I came up with this arrangement. Its basically a steel bar with a bolt on front lip stop. It saved me milling away a bunch of material from solid & gives me flexibility to attach different thicknesses or custom shapes if I choose. I had to relieve a notch in the top bar so it would clear the jaw protrusion. The rest lies flat on the top of the vise block. My vise also has big cap screw heads protruding proud on the block but I decided to not relieve for those or there would be little left of the bar to lay flat on. So my range is limited between them, but that's going to be fine.

The overly complicated part comes with the clamping mechanism. Its funny how you take a POS hardware store clamp for granted. I wanted a shoe that would clamp tight & accurate & in line as much as possible with the stop area. That means the foot has to be able to free rotate about the threaded screw. If its fixed to the screw the whole assembly skates sideways as the shoe makes contacts & torques against the surface. There is a reason why clamp feet are designed this way. Many commercial clamp shoes have a ball in socket which nice but easy to replicate. Some are just a cup with a peened over end. So I machined what looks like a big thumbscrew with 1/4-28 TPI threads & tapped the end of the screw 4-40. A flathead 4-40 screw gets loctited in there so it always resides behind the face of the shoe via the countersink but just enough clearance so the shoe can rotate. It works!
 
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PeterT

Ultra Member
Premium Member
#5
And then I discovered it 'almost' works as a side clamp. But the shoe isn't making full contact. I need more notch relief and maybe deeper stop finger. I'll see if its worth the bother once I run this one.
But I'm happy with how it locks in position in the intended mode. very positive.
 

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trlvn

Active Member
#6
A picture is worth a thousand words--I wasn't really getting it from your description.

BTW, your photos are really good!

Craig
 

PeterT

Ultra Member
Premium Member
#7
I made a shorter length stop finger just to give me more options around different parallel heights. I put a nylon washer between the brass foot & end of the clamp screw. And finally the blackening treatment on the bar parts which came out blotch free this time. I think there is something beneficial to those scuff pads as a surface treatment, methanol wipe to remove any oils, handle with rubber gloves etc. Another Duh moment - I don't have to put the clamp rotated on the outside, it can just position it upright on the other side of protruding cap screws. The more I play with this, the more I like it. Its so quick to set up & very positive grip, stays put.
 

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PeterT

Ultra Member
Premium Member
#10
Just the usual generic blackening stuff, I find its all the same, just different price. I flattened the (1018) steel with wet-o-dry on a plate so there was no surface coating anywhere, all shiny metal. Then the maroon colored scotch pad on all the surfaces so it was uniform matt finish. I have a hunch this is helpful over machined or sanded finish, kind of an even micro surface texture like what primer provides to paint. Then a de-greaser spritz & wipe with paper towel. Any oil or cutting fluid has to be off & maybe needs repeating. I've used acetone, brake cleaner, high % alcohol... seem the work similarly. Just avoid generic thinners which can have oils within them. I gave this one a methanol spritz by accident, picked up the wrong bottle.

Then when dry a dip in the blackening solution. These parts used maybe an inch or less liquid in a new paper coffee cup so I could angle the cup & get more contact on the longer piece swapping it end for end. I remove & let it sit for a minute to kind of dry, light rub with paper towel, look for any blotch or miss spots. Repeat a few times. The liquid is light blue to begin with, it goes a tan color but is still active. If its dark its less active. Better to toss it & use fresh stuff vs adding to it. After maybe 5 min dry I gave it a super light rub with paper towel just to take away the kind of chalky excess & then into a bath of WD-40. It kind of soaks into the black. Then blot & repeat. I don't know why WD-40 works but it does. It kind of takes on this semi-sealed look, not glossy but not dry matt. I haven't experimented with other oils or the special 'sealer' that you can buy as part of the blackening kit. I'd be interested to know if it works better than WD-40 (but not interested enough to pay for it yet haha). Use new rubber gloves through the process because A) the cleaners & chemicals re not good for your skin B) I think handling the metal with natural oil on your fingers might be part of what makes blotching.

I'm also intrigued by the heat & oil dip method but I just cannot get nice consistency with a torch & its a rigmarole. Maybe if I had a mini oven & could just let arrive to a predictable temp soaked through the whole part. The chemical blackening isn't as tough or very deep but OTOH my lathe stops see perpetual swarf & oil & cutting fluid & they are hanging in not bad at all.
 

Janger

(John)
Administrator
Premium Member
#11
And the magic ingredient is WD-40. That’s weird Peter. So no heating of fluids? No sodium hydroxide cleaning? No distilled water rinse?
 

PeterT

Ultra Member
Premium Member
#12
Correct on all the above. Room temperature and I have tried the heat gun pre-heat too. Someone told me the sealer they sell has some paraffin or some kind of wax like constituent but I haven't tried it. Maybe WD-40 is thinner and absorbs in more, but still has a bit of oil carrier. Next time I'm going to try a plain low visc machine oil & try same coupons both ways.