Punching Holes

[rthibeau]

I need to punch holes in 1" square tube to mount 1/2" square pickets. What is the best way to do this? There will be four pieces of the square tubing to be pierced with 16 holes each for a decorative railing.

[Nick]

You may want a low speed, high torque drill.

[JPH]

Howdy!!

all depends upon what shape you want the holes to be...round or square...round is easier by a longshot...

JPH

[rthibeau]

I apologize for not being clearer. The holes are to put the 1/2" square pickets through, so they should be..1/2" square plus a touch. The holes will be in 1" square tubing - if I hot punch the tube distorts. My thought is to drill 1/2" holes and then heat and drift them square. Is there a better way?

[Rich Hale]

You need a broach; You can make one, a half inch square pice of hardenable tool steel,,,I would use S-7 or H-13 as they work really well for long time. But a piece of spring steel sized to shape will do also...taper it from half on all four sides to about 3/8" square. Now you could just punch it through a drilled hole , but like you stated it will distort the metal a lot. It needs teeth to cut, you can make them. Heat the shaped piece and cut into it at a bit of an angle with a hot cut chisel so it lifts one tooth up from the square. Do this from the small end to the half inch sized end. Do this on all corners, you do not want large teeth,,just enought to enlarge the hole where your corners will be. One tooth will cut a little,,the next will enlarge the cut a bit more etc. When you have it all cut heat treat it and give it a try on scrap. Your new broach and the steel can be cool while you work. To minimize distortion make the tool with a rather long taper so the teath will only have to cut a small amount atwith each bit they take. Maybe a 8" long taper for a tool that size. May take some experimenting..good luck

[sandpile]

RTHIBEAU--I built a railling like you are talking. I ended up making round holes(drilled)in one side of the tubing and splitting the fullered ends of the stakes and doing a suicide joint. The next railling was simply WELDED with 3/32nd rod, and ground out. Grin.

Chuck

ps. I have your steel ready to mail.

[rthibeau]

sandpile: "splitting the fullered ends of the stakes and doing a suicide joint". I'm not familiar with that procedure, could you elaborate please?

[6013]

Rthibeau, why not just cut a few corners and make the project go faster?

Make a square bolster block to fit inside the tubing. Drill the holes, insert the bolster into the tube. Make a corner chisel (think wood working corner chisel) and with the bolster for support, just cut a few corners and a round hole becomes a square hole.

[JPH]

Howdy...

Here's an even easier way......drill 1/2 round hole....drift in 1/2" round into the square tubing and butt these up against the top/bottom rail and weld in place...???

JPH

[Chris Pook]

Alot of shops making those railings these days use c channel for the cross rails, then they are easy to punch.

[yesteryearforge]

assuming this is 16 gauge wall thickness drill a 1/2 " hole and run a 1/2 square file through it [ it will only take a few strokes per hole as your are only cutting the corners ] when the file goes all the way thru you are at 1/2 ".
haven't done it on tubing but it worked well on 3/8 flat bar so should work even easier on thin wall tubing.

[ThomasPowers]

I've seen punched channel in Wrought Iron fences---*real* wrought iron fences so that nowdays goes back 100 years or more...

If I had to have the hollow I'd punch two channels and then weld them together...

Thomas

[lefthand forge]

Hi, I suggest you drill a round 1/2 inch hole, then use a jigsaw w/a fine metal cutting blade to make the corners. I'ts faster than the file (which was going to be my other suggestion). The mandrel and cold chisel idea would also work, But I don"t think I would drill a hole, or make a corner chisel. Just use a one inch strait cold chisel and four cuts.

Hope this helps
John :)

[frogvalley]

Drill 1/2 inch round holes. Round the square rod to 1/2 inch diameter and insert. You can buy a clapper die/spring swage to do this or you can eyeball them with a grinder(not the best way) or use top and bottom fullers. You know, like a dowel joint. Mig weld in place with a very small bead or tack and no one will notice.

I would buy a 1/2 inch spring swage and fit it under a power hammer.

Square holes are a pain, so if you must create a tube with them, then use C channel and a punched flat bar welded in the bottom to hold the pickets. That way the weld is on the bottom, cleaner, and less likely to get water in it if your only tack or stitch welding. I don't do any railing work with less than 1/4 in stock with holes for the pickets and topped with one or more bars of different profiles. In the past I have used square holes for pickets, but now use only round holes with doweled pickets or round pickets with or without any squared bits.

Why tube anyway? There certainly was very little "wrought iron" tube. Solid flat bar punched is better, with a top rail its darn purty too. Tube would not be traditional nor as strong. Of course I might use my plasma cutter to make the holes, but that ain't traditional either.

[rthibeau]

Thanks for all the information and suggestions. The square tubing and square pickets is because this job is to replace an existing railing with one of the same design and style. I think it will be easier to convince the customer to have round pickets and use solid bar, either square or flat. Then it's just straight drilling. Traditional is not the focus on this one.