[How do I?] Square Hole ?

[hman]

I don't have a great idea on how those greenlee punch tools work. And the accuracy here is really going to matter.

I don't know about Greenlee ... but here's a vintage chassis punch I have squirreled away. Note that the pull bolt has square shanks of two sizes, to keep the punch and die aligned with each other. But there's nothing there to align the edges of the hole with the sides of the sheet metal being punched - probably the best you can do is to use a carpenter's square to align the side of the punch vs. the edge of the metal. Position on the sheet metal is set by the position of the 3/8" bolt clearance hole - probably good to about ±0.010"

 

[RedOak]

Yes, exactly. Some of those punch tools work with a center bolt that squeezes two dies together, I'd you had that style, you could use a hole drilled with the mag drill (then not moving said drill!) to center it.

I've used manual "knockouts" before, Erich, but I'm not sure if the Greenlee 731, for example, uses the same principles. I've looked at a few photos, on the other hand, and I'm pretty sure that it works by drawing a hardened die through the work piece and into a hardened "receiver," which my years working on our heavy equipment would have me referring to as a "bushing." Regardless, a pilot hole large enough to accommodate the threaded piece that draws the die through the steel sheeting would have to be drilled first, which is where our mag drill would shine.

You know, the more thought that I give this, the more I believe that it could be done: assuming that the mag drill and the work were fixed into position via a proper jig.

 

[RedOak]

I don't know about Greenlee ... but here's a vintage chassis punch I have squirreled away. Note that the pull bolt has square shanks of two sizes, to keep the punch and die aligned with each other. But there's nothing there to align the edges of the hole with the sides of the sheet metal being punched - probably the best you can do is to use a carpenter's square to align the side of the punch vs. the edge of the metal. Position on the sheet metal is set by the position of the 3/8" bolt clearance hole - probably good to about ±0.010"
View attachment 377532

Yes, John, I think that this is pretty much the same principle employed by the Greenlee 731 that I'm presently considering for the task at hand. Here's a photo of the unit and, once again, it looks like a die that's drawn into a bushing via a threaded action.

 

[brino]

I am a little late to this party, I've been away for almost a week. It's great to see so many great ideas coming forward!

to satisfy the pass through theory you could drill holes for round tubing the id of the square tubing and pass the round through the square - welded no one will know but you unless your engineer puts it on the scale. - or use short round tubing stubs as the pass through.

@deakin, I think you are saying

1. drill round holes in the upright,
2. put round tubing thru those holes that fits the square tube ID,
3. weld the round tube in place, and
4. put the square tub over the round tube and weld that in place

Is that right?
Great idea!

It gets rid of all this square hole idea.

-brino

 

[Shiseiji]

Yes, good point. Regardless, the square holes formed in Step 1 of the proposed procedure will have to be centered fairly precisely in their own right, aye?

Part of the idea of using "something" with a square hole to put inside the tubing is that a simple jig, cee clamp, vise-grips, whatever would hold the reference bar that goes through the square hole in the proper place while the washer is tac welded. So the round washer is loose by design so the reference bar through the hole will be placed exactly where it's called for. The "washer" could be square to get close as long as it's not pulled against the weld inside the tubing.

 

[RedOak]

I am a little late to this party, I've been away for almost a week. It's great to see so many great ideas coming forward!



@deakin, I think you are saying

1. drill round holes in the upright,
2. put round tubing thru those holes that fits the square tube ID,
3. weld the round tube in place, and
4. put the square tub over the round tube and weld that in place

Is that right?
Great idea!

It gets rid of all this square hole idea.

-brino

Hi Brino ~

If you have a clear understanding of this "great idea," please elaborate on it...because I don't. Why is this much different than simply welding the square tubing together? I'd really like to learn why this is such a great plan.

Have a good one ~ Red

 

[RedOak]

Part of the idea of using "something" with a square hole to put inside the tubing is that a simple jig, cee clamp, vise-grips, whatever would hold the reference bar that goes through the square hole in the proper place while the washer is tac welded. So the round washer is loose by design so the reference bar through the hole will be placed exactly where it's called for. The "washer" could be square to get close as long as it's not pulled against the weld inside the tubing.

Thanks for coming back, Ron. Once again, I'm thinking that the tolerances involved in sizing the components involved with this particular idea would have to be pretty tight, correct?

You see, in the post that you quoted at 12:51 PM today, I was thinking out loud about how one might make use of a "knockout" die, like a Greenlee 731, to cut squares out of 0.065" thick strips of mild steel. Well, that is pretty simple, on its face, but the tricky part is ensuring that the larger annular cutter employed by our mag drill cuts evenly around the "square hole" to form a washer with a centered hole in it.

In my mind, this means that the mag drill and the strip of steel that will render the washer we're discussing will have to be secured in place from the beginning to the end of the process. After that is accomplished, a very precise "pilot hole" -- that will allow the knockout cutter's drive bolt to pass through it -- will have to be cut via the mag drill. Needless to say, the knockout cutter assembly will then be used to cut the square hole. At this point, we end up with a [fixed] strip of steel with a square hole in it. From there, the annular cutter in the mag drill will be changed to the appropriate [larger] size and the subsequent slug that the annular cutter leaves behind will be our magic "square hole washer."

Is this making any sense at all?

 

[deakin]

I am a little late to this party, I've been away for almost a week. It's great to see so many great ideas coming forward!



@deakin, I think you are saying

1. drill round holes in the upright,
2. put round tubing thru those holes that fits the square tube ID,
3. weld the round tube in place, and
4. put the square tub over the round tube and weld that in place

Is that right?
Great idea!

It gets rid of all this square hole idea.

-brino

sorta. since the cust wants to see sq tubing you would slide the round tubing through the square ( to so call support it) then just weld the sq tubing as you would had you punched sq holes in the 2x2

 

[Weldingrod1]

Here's another thought: get some strips of steel plasma cut so the width matches your big tubing. When they burn them, have all the square holes burned at the same time. Drill clearance holes in your big tubing. Tack weld the square hole strips on WITH the small tubes in place for alignment. Weld a lot...

Sent from my SM-G892A using Tapatalk

 

[RedOak]

Here's another thought: get some strips of steel plasma cut so the width matches your big tubing. When they burn them, have all the square holes burned at the same time. Drill clearance holes in your big tubing. Tack weld the square hole strips on WITH the small tubes in place for alignment. Weld a lot...

Sent from my SM-G892A using Tapatalk

That is another interesting idea, but I think that it would require someone who can weld better than I can, sir. It's one thing to weld around a small component like a 1" x 1" square tube and another to weld a large piece onto the main uprights. Yeah, it all requires welding, but my "part time" welding experience is telling me to keep the welding on the 0.065" to as small an area as possible. Please bear in mind that the customer's design [presently] calls for all of the metal in the rack to be exposed. Thanks very much for the idea.