How to cope tubing on the radius????

Anyone figured out a good way to do this without a fancy mill or something?

I have a tube notcher but you can't cope a radius on that.

I have a drill press with a x and y adjustment on it but keep going through hole saws because there is a slight amount of play on the axis adjument slides.

This really sucks.

Any help is greatly appreciated.

Grinder?

hinkley

use a piece of straight tube as a pattern. Wrap some heavy paper stock around the notched tube and trace a pattern on the paper. Cut the pattern out and then you can wrap it around other tubes and mark them with a Sharpie. Then cut a V notch for a rough cut and angle grind to fit. Keep some paper patterns around for 90°, 60° & 45° joins when your tubing notcher won't work.

Actually,a sawz-all is perfect for this,thats what we always used for custom cuts!

here is a program that lets you input your tube sizes and angle of the joint and then you print out a paper stencil of the notch. I like to then tape that stencil onto the tube and spray white spray paint at it, then take the stencil off and grind or cut until all the white paint is gone:

http://home.tallships.ca/mspencer/winmiter.html

I used to use a program possibly like the on BrettM recommended ( I didn't look at his), before we got a mill. It's at <www.geeks.casaforge.com/code/miter-orig.pcgi>
Printed it out, traced it on the tube, bandsaw it close then right angle ground it. TOO MUCH WORK !!!!
Guy

NO NO NO...All too much work!!!

Seriously, that's what I came up with also. I'm going to try to make it easier by plasma torching the rough shape, then cleaning it up with a grinder.

Thanks.

I'm about to start my cage and the guy I'm working with (who's builds race car chassis) told me to use a portable band saw. Not close enough for TIG welding but fine for MIG.

kid4lyf said:

I'm about to start my cage

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Yeah, thats about right.
Are you running AvGas now too?
I saw you break a u-joint on an ABS HP30 axle last year.
I knew then that a cage was the next logical step for you.
:laugh2:

kid4lyf said:

I'm about to start my cage and the guy I'm working with (who's builds race car chassis) told me to use a portable band saw. Not close enough for TIG welding but fine for MIG.

Click to expand...

I like my tubing to fit alittle better than that. I'll use a bandsaw to get close, then torch and grind.

Thanks.

bgcntry72 said:

Yeah, thats about right.
Are you running AvGas now too?
I saw you break a u-joint on an ABS HP30 axle last year.
I knew then that a cage was the next logical step for you.
:laugh2:

Click to expand...

Just ripped the LP system off one of the forklifts. Installing next week.
Found a great set of axles off a CAT 992 loader that should work great if I get wheels with the right backspacing. (Mogs are so last year)

I usually get a close with the plasma then finish on the belt grinder.

helped build a tig welded tube chasis for a small formula car, used a tubing notcher and assorted files.

thewrath said:

helped build a tig welded tube chasis for a small formula car, used a tubing notcher and assorted files.

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It's little tidbits of info :idea: like this that make the internet so awesome! :worship:

flexj said:

Anyone figured out a good way to do this without a fancy mill or something?

I have a tube notcher but you can't cope a radius on that.

Click to expand...

Well.... I use a fancy mill (cnc) for the uber complicated ones - but most often I used the old hole saw notching jig... With some finish tuning with the grinder

You say you have a notcher - why won't it work? what radius are you trying to get?

The only trick to a hole saw is to go slow - my 400 rpm d-handle drill is too fast to be correct... But it works ok

If you are using a 1.75" bi-metal hole saw your rpm for mild steel should be ~217rpm; for 4130 alloy you should be ~152rpm

For 2" cutters you numbers go mild ~190rpm; alloy ~133rpm

Use coolant - rather than oil since you are fighting heat from excessive surface footage rather than a lubricity problem (most oils will reach their smoke point and be relatively useless if being used for cooling effect)

Beyond that I often just hand fishmouth the really low angle tubes (less that 25-30 degrees off the joining tube) - it just take practice and patience

HTH

Matt

PS - for those who care - the example rpms were done with 100sfm (surface feet/ min.) for mild and 70sfm for alloy- with hss you can go as high as 150 - 180sfm but tool steels often suffer heat damage easily...

The way I took the original post is that he's trying to fishmouth the end of a curved tube. Straight tubes clamp into the notcher just fine, but you can't use the typical notcher close to a bend in the tubing. The last curved piece I had to fit, was for a 90° join, so I just chucked a 1 3/4" into the drill bit. Anything other than a 90° join on a curved tube; you just have to do by hand.

MaXJohnson said:

The way I took the original post is that he's trying to fishmouth the end of a curved tube. Straight tubes clamp into the notcher just fine, but you can't use the typical notcher close to a bend in the tubing. The last curved piece I had to fit, was for a 90° join, so I just chucked a 1 3/4" into the drill bit. Anything other than a 90° join on a curved tube; you just have to do by hand.

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Yeah, what he said

Anyone familiar with the pipemaster products?. They are profiles replicators for various dia's of tube. Works like nothing else.

http://www.pipemastertools.com/

Even with cuts on a radius you can use the reverse end of the pipemaster.

Then plasma and grinder as needed. Although my new favourite tool for cutting tube is the bandsaw.

flexj said:

I like my tubing to fit alittle better than that. I'll use a bandsaw to get close, then torch and grind.

Thanks.

Click to expand...

I wouldent use an oxy-acetaline torch to help notch, it could easily over heat the metal and cause it to become britle and crack or rip the tube above the weld...

I keep a 45 bend to help me visualize and plan my projects. I marked the bend start with a ring of tabe (sharpies rub off over time). I notched the end of the bend so I can easily transfer the notch using a sharpie, then cut it on the chop saw and grind out the remaining material.

I also keep a 90 bend that has the start and finish bend's marked, this is not notched.

Sample 45 is sitting on my PS tire in this pic. Some of those notches were completely different then my sample, like the upper stinger supports, (of axix notch on a bend).
Notching is no fun.


I love the way it looks to have notch on the end of a 45..