Holding multiple parts in a single pair of jaws

Holy Shit... ON topic???
Holding things like a row of balls, rods (held in the vertical) etc for drilling/tapping (8 or 10-32), ie operations with no big forces/torques
involved.
In a 6" kurt vise, with jaws made from 1x3 alum (trimmed to <3", if req'd), I figger I could put 8-10" jaws on, to hold 8 or so 1" balls (or rods/whatever), for tapped holes about 1/2" deep.
I figger the quickest/dirtiest way to do this, without going fixture-crazy, is to put some kind of compressible-ish material on the movable jaw, so that all pieces would be held "tight enough". If the V's in the fixed jaw were accurate, accuracy should still be perty good?
What material would be good for this? I'm thinking *wood* might even be doable, no?
In principle, a die spring in the moveable jaw, at every part location, with whatever adapter is req'd for the part geometry, would do this, but this would be like being a real machinist -- I think.....
Do others try these type of things in production, or do y'all stick with the real expensive multiple vise/fixture ditties discussed recently?
--

Mr. PV'd

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On Jan 20, 6:34pm, "Proctologically Violated"

You can get some rubber/neprene and glue it in with #M weatherstrip and trim adhesive. Remember, the fixed jaw does the holding and Locating, the rubber is just for adding pressure. MSC/McMaster for the rubber strip. Maybe 40-60 durometer. 1/16" thick, or 1/8" depending on the squished surface area.
I've had up to 40 1/4" 303 SS rods held in a 5" X 2" bar, in the 4th axis all held in by brass tipped 1/4-28 set screws. Change the set scers out at Any signs of getting rounded in the hex. Get good ones to begin with too. In an earlier post, I was making some really small parts, and actuall skimmed a rubber band down to .020" by .035' with a razor blade, and held it to the movable jaw with super glue. Parts were small enough to need a microscope to inspect.
If going out to 10" wide, maybe 1.25" or 1.5" thick bars, for support.
Calculate the "squish" on the rubber part, and machine the clearance to suit. Should work great..
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req'd),
fixture-crazy,
that
with
the
Delrin works fairly well for this but suggest the entire detail should be captured under compressive force so as to avoid failure due to plastic deformation.
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On Jan 20, 6:34pm, "Proctologically Violated"

Actualy, Mite eBite clamps are pretty awesome for some fixtures too. I've made several plates with multiple pockets in them for maybe 16 parts at a time, with a MiteeBite for each pocket. The pocket provides the reference positions. Don't forget to provide clearance radiuses for the possible saw burrs. IOW, one project was thousands of little bars, all cut off, then into the fixture. The ends fo the bars fit into pockets with a relief for where the burr might be, it got machined off, but there was clearance to load it trouble free.
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Proctologically Violated wrote:

WTF???
Well, I've used 1/16 rubber sheet of a fairly firm durometer, hardwood, but most often use thick cardboard. Like cereal box cardboard. That might not work so hot on the balls due to the small contact area, but works great for anything with a flat face. For balls, hardwood or delrin should work, at least within a 6" wide jaw, probably out to 8". Going much further than that, I've found the jaws spring and don't clamp well at the ends. Cheap fix for that is a couple C or Kant Twist clamps.
Jon
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Proctologically Violated wrote:

I generally stay away from what you're suggesting, just because the odds of something slipping just often enough to ruin your whole day, every day, are very close to 100%.
For a cost-effective alternative, try http://www.carrlane.com
Look at Toggle Clamps, and then Push-Pull types. These are cheap and reliable. You put a row of them on a plate, clamp the plate in the bottom of your vise, and then use the clamps to hold the workpieces individually against the back vise jaw. For round or spherical work, make the back jaw a soft one with vee's cut in it.
This is also, usually, a quicker and more error free way to clamp things, since you don't have to hold them all at once, with fingers, nose, tongue, and duct tape, trying to keep them all in place while you close the vise.
And, of course, since the whole apparatus is on a plate that drops into your vise, setup time for repeats is usually in the range of maybe thirty seconds. Can't beat that with a stick.
KG
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Use a strip of 80 grit emory cloth. Stuff comes in 1" wide rolls, perfect for a curt vice. If its a production run, drop 2 drops of super glue on the back to keep it in place on the moveable jaw.
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The emory sounds neat, plus I have rolls of it. Emory on wood et al might be the ticket, if there is slippage with the wood itself. Also, emory cut from sheets to cover the whole part, if longish, or just wider rolls.
Super Glue: As in CrazyGlue? That stuff is such a ripoff, at least on the retail level. Rubber cement is a lot more versatile, cheap, etc. Plus, you can get quite the buzz off it. :)
In my case, there is no real stress on the parts, no buried/heavy cuts, everything is of a secondary-type deal.
Also, I don't know how long I'll be doing the production, before I farm parts out, so I really want to keep things as simple as possible . In fact, I have formulated PV's Law XXVI: The more intricate/expensive/time consuming the fixture is to make, the faster the part design will change, requiring a new fixture to be made.
--

Mr. PV'd

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Similar to KG's plan, make a couple of aluminum fixtures to swap out in the vise. Load parts in one fixture while the other is running. Something simple like a clamp for each two workpieces with a bolt between them.
Fred
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On Jan 20, 4:34pm, "Proctologically Violated"

This is one of those gray areas. Hard jaws can't really hold more than two parts, and soft jaws are (gasp!) soft. The durometer of the jaw material should be selected after evaluating the forces you plan on applying. Wood had a tendency to split under pressure, and as others mentioned soft materials can allow part movement. Here's an idea based on a thing described to me once. Get a steel block and mill a cavity in the back. Drill it full of holes nicely reamed to a perfect size. Put an ejector pin in each hole, big ends inside the cavity. Fill the cavity with grease and screw a backing plate on to keep the grease where you put it. I forgot to mention a couple of holes to screw it into the vise. Put your porcupine in the vise, and as you close on irregular shapes the pins will push back into the holes until the grease creates hydraulic pressure on the pins. I've never seen one myself, so all I could do is type what I remember of the description.
Later,
Charlie
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On Tue, 20 Jan 2009 19:34:03 -0500, "Proctologically Violated"

I used plugs of fibroflex, drilled into the jaws, a couple of times. The trick is to modify the jaws so the parts are fixed by one jaw and clamped by the other. Always strive for three bearing points. A square or rectangular part might benefit from clamping over two adjoining sides and the opposite corner. The thicker the plugs, the better the balance in clamping force - as a bonus fibroflex is great for killing bad vibes.
--

-JN-

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http://www.youtube.com/watch?v=byk2ehTqtA0

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Top posted 'cause it's pretty:
We don't do a tremendous amount of drilling/tapping of small parts this way, but if the forces are not too great to cause movement of the part, we use a simple V-Jaw vice and sometimes a sheet of aluminum if it's a steel part or even cardboard if it is a part that allows for it.
PV - As a side note, did you get my private E's lately???
Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com Flagship Site: http://www.Drill-N-Tap.com
V8013-R

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