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
In a 6" kurt vise, with jaws made from 1x3 alum (trimmed to
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
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
Calculate the "squish" on the rubber part, and machine the clearance
Should work great..
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.
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.
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
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.
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
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
I've never seen one myself, so all I could do is type what I
remember of the description.
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.
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.
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???
Joe Agro, Jr.
Automatic / Pneumatic Drills: