2X4 frame for my CJ2A

I like this idea as well, but from experience I know that getting a saw to cut round holes, correctly, repeatably and with quality results is difficult with basic hand tools. Now if i had a mag drill and some real hole saws, that would change. The other problem is also chamfering the birds mouth. A grinder can make it happen, but not really nicely if I am the one doing it. When there are smaller tube for handrails or rollcages, there are jigs that can be purchased cheaply that can make this work. I just know what I am sure to screw up and big round stuff going through other things will definitely be it.

 

you can fishmouth with a chop saw. theres a calculator that will tell you the angles for the saw on pirate...

 

Here is the link http://www.pirate4x4.com/forum/shop-tools/456800-chop-saw-notching-101-pictures.html

Makes it look easy and maybe it is. I have never built a roll cage, but when I do I will try these techniques. The paper tower roll idea is killer.

Another tutorial. http://www.atomiczombie.com/tutorials/Basic Fishmouth Cutting/Basic Fishmouth Cutting.pdf

 

ive used both methods and i found the chop saw method works well the paper towel roll involves more hand grinding...http://api.viglink.com/api/click?fo...ff-Road Forum&txt=http://snip.awardspace.com/

 

All interesting methods of getting to the heart of Roll Bar / Cage building along with one of if not the most important part of that structure which is the welded joint.......If not shaped or fitted correctly all else suffers from a structural & strength prospective , notwithstanding how good a welder you may be filling gaps will never offer full strength to that joint zone. Fitting any tube at any compound angles regardless of method is in fact a work of art and very time consuming to get it correct........ ( And the common argument is , this is not a race car and will not go 200 mph.........and with all do respect to the critics all things are relative irregardless of Speed.)

Seen many different approaches over the years including the ones mentioned above.........all the way back to some of the best race car builders that I was lucky enough to come into contact with who commonly notched all of there tubing on a basic bench grinder that had two worn out rounded grinding wheels............glad those days are over.

Were all faced with choices in how we decide to accomplish things and for some that have the proper equipment the choices becomes easier......

I see you have a Mill in your shop ...........cutting those tubing angles is one of the things that machine does best.........

 

The width of my frame is dictated by the width of my new to me rear mounted gas tank. The pic says 26" but its really 25 3/4".


my work table isn't all that flat and i can't walk around it and my MIG welder is outside, so I go outside. The steel the pieces are sitting on is something I found in the dump. Its not square but is flat until the very end. I can wheel this around. I don't have any more clamps aside from woodworking, so one side at a time is going to get tacked up.

 

I agree with you. I make do with a lot of things. I just plain make it happen. I do not do anything perfect and most people ,if given some time, will probably do a better job than me. I unfortunately am not as detail oriented as some. I also have zero training. I have used my mill to make the angles when partially making a bicycle. I have end mills that are sufficient in size to produce really excellent results. This was imperative when TIG welding CrMo tube with .030 wall. The fitting of the pieces perfectly was the only way to make a nice weld. Imperfect fit, ugly blobby weld with holes. Oh yeah, make sure you either drill a hole or leave a piece open and finish weld the small hole later because the puddle will pop out on you and blow up your nice job.

Wife wanted one of those extended cargo bikes that some of the local women ride around. no way I was going to spend as much as 4 grand on one, so i made one. Found a frame in the dump, cut it up and had a buddy set it up with used stuff. Works perfect, weighs about 2 lbs more than stock and is super strong. The paint job is terrible, curtains and runs, but whatever. This was the hardest thing to weld I have ever tried. thin wall CrMo tube. Aircraft stuff. Strong, ugly, functional.

 

First tacks.

I am using .035 wire at the settings the welder has inside the cover. Those work well just about every time.

This is my MIG welder. Airco Dip Pak 200. 60% duty cycle at 200 amps. Big and old, works well. Uses a Bernard gun and consumables aren't everywhere. Its from the 80's i guess. CL for 400 bucks. The hood is a 3M speedglas, formerly Hornell I think. It was 300 bucks and worth every cent. Never get flashed and i don't have funny vision after a long day welding like the other (HF) auto darkening hoods I have used. It also has side windows so you have shielded peripheral vision.

 

Tacked up the other side.


both straight.


don't mind the trash, house project along with this pile of steel.

Both rails are now tacked on both ends and both sides.

 

I have the home depot ridged and milwaukee hole saws. they aren't great and will only get you a cut or two. One of the best ways to get a nice hole with one is to drill a 1/4 hole in the center of where you want the hole to be, take out the hole saw center pilot bit and chuck it. replace it with a piece of 1/4 drill rod and the wandering goes away. Even with my variable speed drill press its hard to get the speed low enough to cut without destroying the hole saw in steel of any real thickness.

Been busy this weekend. I will weld those rails tomorrow. My steel supplier only sells 1/8 and 1/4 thickness stuff. I wanted strap 3/16 4" wide and 2" wide. no dice. I had to order the tube in tha thickness. I think the 1/4" is too thick and the 1/8 too thin.

Tell me your thoughts.

 

Well your right if your boring holes in that tubing you'll first need to slow the spindle and feed down have it clamped tight so there is no cutting tooth to frame chatter and supply plenty of lubricant at the cut.........On cross members either a butt weld at the frame rail or bored hole is an acceptable method while neither is really stronger. Wall thickness all depends on what will be hung off the tube.

 

I plan on butt welding the same 2x4 tube for the cross member as the rails. Chamfer the edge of course. I do like the idea of the cross member going all the way through. I would do that if I had smaller square or rectangular tube and use my milling machine to cut the holes. I don't feel that is required in my case. I will also be using the front cross member to mount my radiator on and thats a lot easier on a flat area than round. I will tack those cross members on and not finish weld until the jeep is apart. I am sure to have to move them 1/2 inch or something dumb to make it all fit right.

So, 1/8 plate for straps and tapped bolt points or 1/4? tube wall is 3/16.

 

3/16" should cover most brackets......Suspension stuff on axles I like 1/4"

 

I got to welding a bit today. A disclaimer... I have no training, no classes and no one to tell me i do wrong other than when stuff doesn't work right. If you see something i don't do right, speak up. I like to learn how to do things better.

Started filling in between tacks. Weld on side, the other, next piece, turn over etc


little more


filled


get this, no warping or twisting.


next step is to go out and buy 4" wide 1/4 thick steel to plate the sides of the stacked pieces and 2" wide 1/4 to encase the open angles. They only carry 1/8 or 1/4 not 3/16. thats what I really want.

 

Buy cold rolled steel if you can..........a little more expensive but you don't have to grind off the Hot Rolled crust prior to welding on it.......the CR will be oiled so you will have to wipe it clean with lacquer thinner or a like product. Always use an abrasive wheel or light grinder in the area's that well get welded , helps to keep the weld zone clean.

 

I would so love to use cold rolled stuff. Its not available at my local steel place. This local place is also the cheapest for 40 miles. They only sell hot rolled poo, but it will work. All the places I have welded on have had the mill scale ground off and where I will plate has since been cleaned up bright and shiny. I use flap disks. I really like them. Grind and blend.

I cut out my plates for the angle step up. They are 1/4 plate 4" wide and 16" long. I used a cut off wheel to get the rough radius and then a 12" pedestal grinder to make easy work of smoothing it out.


I will probably drill a big hole on both ends and mill a 3/4 slot lengthwise to better weld these plates on.
I am up to 294.00 for the material so far.