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Air powered closer for post vise ideas?

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Investigating an idea I saw a while ago [and can't find] for an air powered post vise closing mechanism that would leave both hands free when opening/closing my post vice. Mine is a modular Kinyon style that I may modify some more to open/close hands free, if possible.

Built by my friend Bill Cottrell.

Anyone care to share your thoughts?

TIA

Dave

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I have seen air brake cans used as actuators for clamps, air on and diaphram releases the actuator and air off and the spring applies the actuator. The bigger the can the stoughter the spring.  

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Ray Clontz, the tire hammer guy, built a foot pedal actuated one from an 18 wheeler brake can. If you put more than a couple psi to it, it would crush anything in the jaws and warp the vise itself!

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You can get custom air cylinders built by Bimba.  All depends on what pressure you are running and what force you are looking for. That will determine the diameter of the bore and then you just have to figure out an approximate length.  Small diameter cylinders are rather affordable.  I don't know how larger ones are.

Foot operated directional air valve and you are good to go.  I would put a ball valve in to shut off the air supply to the system so it is not always under pressure.  McMaster has a few foot valves but they are not cheap.  They also have different air cylinders and don't look too bad.  I think they use Bimba iirc but don't quote me on that.

I'm not familiar with your vise.  Searches seem to hit more hammers than vise of that style.  It is just a matter of securing the cylinder to the non-moving jaw and then attaching the rod to the moving jaw. 

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There was also a design in the old Blacksmith's Journal from 15 years back or so.  Smaller cylinder mounted vertically between the legs and used some sort of 4 bar linkage.  

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Hi all , not air powered , but I came across this yesterday while playing down the YouTube rabbit hole .

Dale Russell

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Emert Studebaker had a commercially made air actuated vise in the old log cab in studebaker blacksmith shop. I don't think I would trust my fingers with such things...(Though now that I think about how many times I have closed a vise with my knee working the bar AND the sewing machine knee operated rheostat I wonder if I could come up with a chain drive closer...)

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It's a good idea and easy enough to make. Only thing I would be concerned is the speed. Closing a vice with air pressure would make it rather snappy, with unintended consequences depending from the speed of the closing jaw. Further away, more speed. Kind of dangerous. I suppose you can tame the speed with a regulator ... not sure.

One way to make it safer would be to use an air motor attached to the screw. So you wizz it in and out by air pressure but slow it down a lot. You can adapt an air ratchet wrench for that. 

I would prefer hydraulic any day with a foot pedal. 

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You can get flow adjusters that go on the air ports of the cylinder and use those to restrict flow for a slower close and open.  It would allow you to adjust close and open speed separately.

We use them at work when we use cylinders for cycling.

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The air wrench sounds like the answer for me, been concerned about fingers getting in there, and could operate that thru a foot switch, I think?

Thanks to everyone for the ideas and thoughts. As a blacksmith I always love the idea of having a free hand!

I happen to have an air ratchet for sale right this minute- will go remove that item now and give this some more thought.

Will post some pics as I work this through and figure it out or not, either way. I always wonder what happens to ideas that pop up and then seem to get lost out in the ozone somewhere :)

You guys are the best!

Thanks again,

Dave

 

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The problem with an air wrench is that you won't be able to change the direction "hand's free" so it might defeat the purpose of the whole thing.  The idea is great for simplicity but might not quite get you where you want to be.

Happily spending your money for you, I'd go with an air over hydraulic intensifier--simple construction system where you get hydraulic pressure from an air line (and easily adjustable for pressures via the input air pressure).  An example is https://www.bimba.com/Products-and-Cad/Safety--Production/Inch/BoostersIntensifiers/Air-to-Air-to-Hydraulic-Intensifiers/Intensifiers but there are some I see on e-bay at appropriate prices.  Then I'd use a hollow hydraulic cylinder over the screw..or over an extension out of the back attached to the screw..similar to this https://www.amazon.com/TEMCo-HC0001-Hydraulic-Cylinder-Warranty/dp/B06XKK8YD4 with the hole an appropriate size and a spring return.  Fab with that would be easy.  Just add a good air foot pedal, backing plate for the cylinder,  and you're good to go.  It's quite similar to a lathe air collet closer but the hydraulic part shrinks the size down to something appropriate for a vise and gives you the longer stroke needed for a vise.  I didn't dig into those links so they are just a rough example.

Going with the air over hydraulic intensifier eliminates the "snap" problem both ways.  Hydraulic flow is much easier to control and throttle and there are simple throttles available that you could slow the closing operation for good control but free-flow the opening (return line) so it opens faster. 

And...don't skimp on the foot pedal.  Good ones aren't that expensive and are worth it. 

 

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Yes, Kozzy, you are correct however I think it would be way too powerful. A vice is not a press and only needs to hold, not to crush. Your way is feasible of course and pressure can be limited in many different ways.

I would give the air wrench a go for now. Cost is very low and reversing direction is a matter of getting to the little valve with a small lever attached to the pedal. Press to clamp, release to unclamp ... or ... press once to clamp and press again to release. 

If then you decide to go gargantuan, you can always make a monster vice and adapt a truck air brakes to action it :P

or if you go lazy ... buy one readymade http://www.heinrichco.com/savise.htm

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I disagree with vises not needing to generate much force. I agree they don’t always need to but sometimes you need to crank down to keep something from moving due to odd shapes, beating on things, or twisting things using much leverage.

Think about a typical post vice with an18” handle and a 1.5” screw with 6TPI. 40 lbs of force on the end of that handle will generate about 4000 lbs of clamping force directly inline with the screw (the jaws are offset so the force is perhaps half that). I know that we don’t always tighten the screw that tight but sometimes we push that hard so I used it.

To directly compare, an air cylinder or bellows/air bag as used in suspension, etc, would need an effective piston face surface area of 40”sq if using 100psi shop air. That would equate to roughly a 7” diameter air cylinder. This is if the cylinder is directly closing the vise and there are no lever linkages, screws, etc that increase mechanical advantage.  This is why folks would use an air brake actuator, because they are of a large enough diameter and can be found as scrap if you search.

Controlling the closing speed is a piece of cake by using flow controls on the exhaust side of the cylinder, and also using a soft start valve. You control the exhaust because otherwise the piston will actuate jerky jerky due to friction and seal stiction. I have built a lot of manufacturing equipment using pneumatics and that’s how it’s done for commercial usage.

As some stated you can use a rotary actuator (actually air motor with gearbox) on an existing screw vise, and again play with air flow to control closing speed. A regulator isn’t of much use because you need the pressure to drive the actuator to provide enough force, so instead you leave pressure high and reduce the flow volume.

For safety you can rig dual switches, so that if say you don’t depress a second switch with your knee the actuator won’t work. This can prevent unintended closing on hands etc.

Best

steve

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I ordered an electric  impact wrench since I sold my compressor- duh..

When that gets delivered I will head back out to the shop and do some more looking and playing with the rough design I now have in my head and see what is or isn't going to work. Will get some pics for a follow-along for those who may be interested in where this is going.

I did rough out a return spring and have an idea for mounting that, too, at least for the moment.

Still quite concerned about my fingers- had them quite a while now and kind of like the way they work, sure don't want any changes is that department :)

Guess I will go see if there is an estimated delivery date yet.

Thanks again for all the input!

Dave

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You could attach a worm gear to your vice screw and attach the gear to a small washing machine motor via pulleys. Easy to change the ratio of the pulleys if they are too fast or too slow. 

Seen some worm gear reducers on ebay us for very cheap, around $30 or so

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Greetings Dave, 

        You might consider a caulking foot vise . I have 3 and use them all the time. They work well for brushing hot stock and for repositioning stock and tools for the treadle hammer. They are also very useful for upsetting. Just a thought. 

FORGE ON AND MAKE BEAUTIFUL THINGS 

JIM

 

 

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Will check out the new suggestions as you folks keep pitching them out here for me. I value every one.

 

Great place and great guys here! A million thanks to you, too, Glenn, for a terrific site!!

Dave

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