Drilling hole through a 2x4 frame

[kamaroman68]

Hey guys I received my max G frame from Art Morrison this weekend. It is constructed out of 2x4 .120 wall steel. I am working on mounting the body and have a question about drilling a 3/4 inch hole through the frame cleanly the long way. The long way meaning 4". Any suggestions would help. I am considering starting with a 6-8" long drill bit to create a pilot hole first through the 4" section. Then go back and use a 3/4 hole saw to obviously make the hole. A piece of steel tubing would then be inserted and welded then tapped. Is there a better way to do this. The frame cannot be put in a mill so thats out. Thanks for the help Chris

[parsonsj]

Here's how I'd do it:

Drill the holes as best you can with a hand drill. .750 is hard, but doable using a 1/2" drill and a stepped drill bit. Don't use a hole saw ... they wander all over the place with a hand drill.

Your idea of a long jobber pilot drill bit to get it close is good. Cut your tube that is to be welded to length, and get some tight fitting tube that fits the ID of the .750 tube. Make it a solid 24-36" in length. Use that to verify that the .750 tube is square to the frame rails using a carpenter's square. You will likely have to "move" the upper or lower hole a bit to get it square.

Also, remember that you are mounting a body ... if the bolt goes in at a slight angle (couple of degrees of error), it's no big deal. Getting the tap to go straight will be your next challenge.

Have you considered nut inserts? Properly installed, they will do the job fine with a *LOT* less work. If you're worried about them spinning, put a tack weld on it.

jp

[kamaroman68]

Thanks for the help I really appreciate it. Wish me luck Chris

[parsonsj]

One other thing to consider is making a jig. If you have access to a mill, you could make a steel or aluminum jig that wraps around the 2x4 tube and hold the sleeve square to it. The jig would take some time to make accurately, but then you'd have a better chance of getting it square. You could make two: the one for tacking the tube, and another for guiding the pilot holes, or perhaps a center punch to get the holes close to start with.

jp

[B Schein]

I would try to find a mag drill you might be able to rent one.
You defiantly don’t want to buy one for A one time use
Here is a link to what I am talking about http://www.toolfetch.com/tools/4206-1.html?id=qGN8vEvP

[Camaro Zach]

why dont you just drill the top, get a speed square and draw a line down the side, transfer to the bottom, measure to center, and drill from the bottom. And if somehow their not perfect get a 6" drill bit and connect them

[kamaroman68]

Thanks everyone for the help. I am a little more concerned with drilling the 3/4" hole. We have a 1/2 drill at work with a bubble level on it I planned on using for the initial pilot hole. I just want the 3/4 hole to be as clean as possible. I don't know where around here I could find a magnetic drill but it sure would be nice. Thanks guys Chris

[B Schein]

I know Dewalt makes a mag drill you might be able to rent on at home depot, I would try and call your local rental places as well once you use a mg drill it is hard to imagine doing something like that any other way. You can’t be drilling more that 20 holes I would guess so you should be able to do it all in one day if you can find one.

Another option that won’t be easy to find is a vacuum base drill. We have a couple at work that we bought trough Snap-On. They are designed for the aerospace industry and made by an Australian company called DrillMate. Rather expensive thought I think the base is about $900 and you all so need to have a good air drill for it. I know it is out of the question for what you are doing but man these little things are awesome.

[Matt@RFR]

Chris (and everybody), in my opinion, you're being WAY too anal about this. There's times where things need to be perfect, and there's times where things can be done in 5 minutes. This is a 5 minute job.

Layout top and bottom, center punch, drill to 1/4", drill to 3/4". Adjust holes as necessary with a die grinder. Insert tube, square, and tack. An 1/8" gap on something like this is fine.

Do you have access to a plasma or oxy/fuel torch? That's how I would do it.

Just get it over with and move on, you're not looking for ±.005 here.

[parsonsj]

Not everybody. I mentioned above to remember that he is just attaching a body, and a couple of degrees won't hurt anything.

Besides, it is fun to try and think about a fairly common fabrication problem and figure out how to make accurate holes.

jp

[CoryM]

I'm with Matt on this one. Mark it out, drill the holes by hand and just get the tube insert trued up where you want it. There is nothing wrong with being precise and careful..... but its painful to watch when its not required. ;) . You're just going to melt your perfectly round hole when you weld it anyhow. Not going to ever be known that the tube was 1/32" off center in the hole so long as the tube is in the right spot.
Having said that, its your car so build it the way that makes you comfortable. You're the one who will be looking at it and driving it.
Cheers.

[parsonsj]

Just a quick observation:

When I ask specific questions, I much prefer specific answers to the questions. I'm not much for advice about why I'm asking the wrong question. That's why I answered his question ... because that's what I want when I ask a question.

As I said above, I agree that precision isn't needed. +- 5 degrees and +- .125 would be fine for a body mount, especially when you're going to be drilling or welding tabs that correspond to the newly tapped hole anyway.

jp

[CoryM]

JP, I had my reply done before yours popped up on my screen. Was not responding to your post.
Kamaroman has had the right idea since he posted. Just drill the thing and get it welded in. Can always cut it out if its not good enough ;) .
Cheers.

[B Schein]

I hear what you guys are saying about just drill the hole and weld the inserts in. Some thing to take into account, when you are use to working with accurate equipment it hard to just drill a hole that is close enough at least it is for me. This is where the long heated battle between a machinist and weldors comes into play

I guess its a good thing I am not framing houses Id still be trying to get the framing for the footers square

[parsonsj]

No offense taken. I was just sharing one of my hot buttons.

Brian, lol! It is hard to know when to quit with wall framing. I've spent hours getting walls square and plumb, only to realize later that wood warpage made it not matter anyway.

jp

[kamaroman68]

Hey guys not to keep a war going if this is.... but I only asked the question because after spending 5 grand on a frame I really don't want to screw it up. Thanks for the different options. Chris

[parsonsj]

Not a war. Different opinions ... and you get to choose which one you want to follow!

Good luck ... maybe you can drop us a pic with how it turned out?

jp

[B Schein]

Yeah like John said no war just varying opinions on how to do things. I just wanted to trough out some of the options for doing this in a very precise way, because that is what I used to do full time for a living and know do part time and full time in the summers while I am finishing my degree.

As my girlfriend will tell you I am very attentive to detail as a machinist, and it carries over in to my everyday life it drives her crazy how I notice every little detail, but that is what my job is and it is hard to turn it off once I leave work

[Matt@RFR]

it is hard to turn it off

That's an understatement! I'm a machinist, CAD designer and a weldor/fabricator. The hardest thing for me to do is to work in four decimal places, and to ±1/8" all in the same day. With that said, I would pay someone who knows when to be perfect and when not to be MORE than I would someone who works towards perfection no matter what. There's a time and a place for everything...the trick is knowing when and where.

[B Schein]

There's a time and a place for everything...the trick is knowing when and where.

Very true I Know what you are saying, Its just hard to apply.