felt like adding something nice to the family: here's my fishmouthing methid i discussed on fathacks sweet exhaust post. layout the angle the tubes will intersect then make a cardboard template of the tube to cut (i use folders) draw your cut on the template to the best of your ability. then begin t******* the template
keep the template over the tube to hold shape while test fitting the trace the outline onto the tube to cut, i usually mark the bottom and alignment marks so i can get back to my starting point as well add a healthy dose of deathwheel to the tubing removing as much as you can down to the lines testfitting after initial cut, definitely needs some work still here's the final grind with a toosie roll in my right angle tool add some JB Weld and Voila' check for penetration, this was 3/4 of the way finish welded
the hard part is doing large wall tubing, the template only gives you the outside profile. the air grinder is the only way to go in terms of shaping the wall to sit on the face of the other tube. hope this helps somebody. at work we just use the mittler tube prep machine with a roughing end mill. but who has $4500 for that?
I know everyone won't be able to do this but I bought an old horizontal mill for $100 when I started to build rollcages for a living. Went to Sears and got a 3/4 hp electric motor and belt from the auto supply. We were using 1 3/4" tubing so I found a machine shop in town that used 2"O.D. X 4" end mills. They would resharpen the mill cutters until they reached 1 3/4"O.D. then give them to me with a fresh sharpening job. Stopped at a used Industrial machine sales business a half hour from home and bought a used mill vice with a swivel base. Attached vice to the mill table and presto instant muti-angle tube notcher. Its quite similar to the Mittler setup for less than $400. I've done literally thousands of notches with the ol war horse and it just keeps plugging along. Frank
Another way to quickly do this is to use a floor-mounted belt sander. Hold the end that you're fishmouthing up to the belt, while using your other hand to push the other end down toward the floor. Do this a few times, quench it, rotate the tube 180 degrees, and keep going. It sounds crude, but some very nice dragsters have been built this way. Dave http://www.roadsters.com/
i was offered a job at riley and scott in indy after college as a fabricator, thats how they did it for most joints in their world sports car roll cages. i've used a 6" bench grinder but eventually the stone will come apart from all of the side loading... the lathe trick is pretty smooth, i've even seen a toolpost modified to rotate in 2 directions to do compound miters.
Harbor Freight pipe & tubing notcher For $62.99, how can you beat this?? You don't even need a drill press, just a hand drill & a table to mount it on. WWS
I think they meant mill, not lathe. Although I just had a thought: How about putting the end mill for the desired tubing OD in a collet and mount a machining vise onto the cross slide instead of the tool post. This will take some more thinking... Now you can adjust the vise to the desired angle, put the tubing piece in there and go to work. Just might work...
I use a tubing notcher. When you've used it to notch hundreds of tubes, it becomes easier to make the cut "spot on" the first time... and needing nothing more than a quick "de-burr" with the Makita. To get my angles right, I have one of those adjustable angle dealies (like you have pictured)... and I put a shorter piece of tube where the real one is going to go... and then set the "angle dealie". Once set, I use it to set my notcher. Reguardless... I really like to see these other methods... so thanks for sharing. Has anyone ever seen that site where they have a program that makes your templates? Seems like a lot of work, but the site is interesting none the less... Sam.
yeah the lathe trick is to mount a roughing end mill in a collet in the chuck. then make a tool post that holds a tube. the problem is you are stuck with only 1 axis to miter, and you can only do a depth that doesn't cause an interference between the tube and the jaws of the chuck. i really hate that drill press setup, only because i had some bad experiences with one before. of course with that bit of knowledge i should hate jagermeister too, but i don't.
sorry... forgot to add that mittler sells a hydraulic setup that pierces the tube like a ch***is punch. looks pretty slick but i've never used one.
It can be done cheaper with a little more work. After making the template, described in the post, take a hacksaw blade after clinching in a vice, and hand cut the tube. after the hacksaw cut, your angle grinder or diegrinder will smoothe the cut to a more refined cut. Your rat tale file can be used to deburr and fine tune the cut to the desired shape. Jim
all these examples are for joining two straight tubes, aside from freehand, what do you all do when fitting curved tube? Paul
i'm not feeling what you're asking here. like joining two bends to where they would share common volume? that would take some noodling. if you're asking about a bent tube going into another tube, like an engine bar on the front of a doorslammer ch***is just make the template really short so its doesn't have to follow the radius. can you put up a pic of what you mean?
Nice piece of tech but I agree with Sam. The joint jigs are a cool tool that is really easy to learn. My good pal Randy built one for about $15 that I borrow all the time.
I think that that's great work, stolen mojo. Plus, you figured out how to add more than one picture per post! I'd nominate this for Tech O'Matic. --Matt
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