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tooling for repeat punching of holes accurately on Ironworker

Hitting these one at a time ...good luck on accuracy. How are you going to balance 20' out in the air and keep everything straight?
We hit 10' steel and towards the end things get weird.
Do you have a press brake?
You putting in 60 some holes per channel?
Taking your .002 and 1/8 figures from first post .125/.002=65
Since we have no idea if this is a one shot deal or it repeats...... UniPunch tooling in a brake would be the way to go.

Buy used c frames off 'bay and the tooling isn't that expensive, buy as much as you can, more tools less hits better accuracy.
We had a big job in stainless steel, setup 8 frames in a row. Had matching panels that fitted together. holes were .187 you could put pins in any hole and it all lined up.
Course your frame fixture must be right.

one shot deal? once you have a good fence then just make a " loose catch" that you hook into the last hole punched and locate it somewhere on the ironworker.
So punch first hole, slide over stock, use catch to stop bar, punch ,,,repeat...a whole bunch of times Catch bar/thing does not have to be fastened to anything ,just use it to index the stock.
 
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If I had to make more than two or three of these I would take some time to accurately make a full length pattern with round holes that are spaced to no more than 1/2 the desired accuracy, preferably better than that. Make it so that the work pieces can be attached to it, probably with built in clamps. Then have a pin on the iron worker that is a close fit in those holes. You probably will need some outboard supports too.

That should make it easy and fast to make individual parts and you can use that pattern to insure that all the present and future parts will be interchangeable.

And you may need to do the operation in a temperature controlled environment.
 
If these are for the same fence you needed the forged tapers for, you are way overthinking this.
How many do you need? If its less than ten or so, just lay em out with a tape measure and a center punch. Takes less time than all this chin wagging about jigs.
Welding square bar thru square holes in channel is a pretty modern, cheap way to mass produce fence panels, but its based in mig welding from the bottom, where the weld wont show, and it fills the gap ofsloppy oversized punching.
commercially, you can buy the prepunched bar.
stuff like this https://www.tsdistributors.com/store/p/714-Square-Hole-2-x-1-x-1/8-Bar-Channel.aspx
its not what you use for high end fencing.
just lay out the holes, punch em, and weld em.
do edwards ironworkers have a creep mode for the punch, so you can register on a center punch mark?
(edit- looks like they dont. You get what you pay for, i guess. Better ironworkers have a setting where you can creep the punch down and it will stop when you take you foot off the pedal. This allows you to register the punch on the center punch dimple, then punch the hole. Looks like edwards is like a mechanical ironworker- you hit the pedal, and it cycles, period.)
 
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Please read post #10.

dkmc was quoting an example where the error was 0.001" over 100 holes. That is the numbers his math was based on and it was totally correct.

Now, if you use a different set of numbers, such as the OP's numbers, then you will get a different result.



No.

2 tenths times his 65 holes is 13 thou total. He added an extra zero by mistake or he's just an idiot.
 
as long as the flat plate is on the bottom, and the channel is open face up on top, it should work, but on many ironworkers, you may need to remove either guards or the stripper assembly. Vertical clearance can be an issue, and some machines have removable tables so the bottom die can go up inside inverted channel. Depends on the make .
I sometimes punch the first hole, then put a bolt thru it, or use clamps at both ends. Or even tack weld em together, then grind apart at the end.
 
Drill .25 hole at center of first knockout. Install .25 dowel pin (or suitable locating geometry to drop into matching holes). Make locating fixture that dowel pin drops into for each location. Move dowel pin to first hole, punch, move to next hole, punch, repeat until done. Go back and punch first hole.
 
I got a local fabricator to punch 1"holes in 1/2 thick .....by scribing and centre punching he got 002 positional accuracy for 10 to 15 holes.....These were .the side pieces of hydraulic presses..........If the holes in the beams didnt match the sides,it was always my drilling of the beams at fault............my presses used the traditional 3 pins either side ,the Chinese ones use only one pin either side,and the beam rests on it........This requires very large holes that weaken the side members.
 
What if you had a die block with the square die opening and a pilot hole set on center to center of the progression. Punch the hole and advance the bar to the pilot hole. The pilot locates in the punched hole.
Roger
 
You really need +/-.0002 locational tolerance? Just 10°F over 20' amounts to a change of .030 in thermal expansion/contraction. That's patently absurd to even begin with a design criteria like that. The tooling requirements alone will make this, at best, difficult and the OP wants to use an ironworker to pop the holes? Even with a taper piloted, guide railed, multi-gimmicked, progressive stamping die that 20 foot length is going to be warped/cupped/bowed enough to throw that .0002 end to end location out the window. Tolerance stacking has already been thoroughly discussed and makes this even more ludicrous. Several thoughts come to mind as to what this is ultimately for, and several more for where project parameters like this are inspired. I would only suggest that the target be re-visited with more realistic factors in mind. Just a suggestion.
 








 
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