Accurate SS tube marking guide

[scratchedup]

Working on 2 1/2" SS exhaust tubing.

I have pieces that I need to cut a perfect 90 on. The pieces have curves and flanges on them. The cut will usually be just past the curve on a straight section but some will be in the curve.

Is there a tool or a method to mark the perfect circle around the curcumference so I can then cut it using a 3" die grinder/cutter?

THX

 

[sanddan]

A hose clamp will help.

 

[LXCam]

If you want it dead on use a large disc grinder. I build custom cai's and I cut the just a hair over and flatten them with my combo unit. Also you'll find the dimension will vary between your straight piece and where you're talking about cutting the 90. That's were the tube will have stretched and shrank slighty. Its not much, but more then enough to piss you off if you're attempting a seamless transition. If that's what your after, you'll need to do a relief cut length wise on the larger piece ans shrink the od to match. Do that on the side you won't be able to see. I also suggest a adjustable mandrel to work any oblong issues you run into.

 

[Kevin54]

A hose clamp is a great way to mark it. Plus you can leave it on and run your saw blade against it. Or you can use masking tape. Just don't wrap the tape tight right away. Leave it sort of just a light tack and bring the tape around until it matches itself, then push the tape down. Or if you have a pipe that slides over what you are cgoing to mark out, slide a piece that you know has a square cut over your pipe and either use it to mark a line or use it as a guide.

 

[scratchedup]

Why didnt i think of this.....super simple. THX

 

[scratchedup]

If you want it dead on use a large disc grinder.

ARE U SAYING CUT IT WITH A LARGE GRINDER?

I build custom cai's and I cut the just a hair over and flatten them with my combo unit.

WHAT IS A COMBO UNIT?

Also you'll find the dimension will vary between your straight piece and where you're talking about cutting the 90. That's were the tube will have stretched and shrank slighty. Its not much, but more then enough to piss you off if you're attempting a seamless transition.

If that's what your after, you'll need to do a relief cut length wise on the larger piece ans shrink the od to match.
DO U HAVE ANY PICTURES OF THIS?

Do that on the side you won't be able to see. I also suggest a adjustable mandrel to work any oblong issues you run into.

Do you have a commercial shop.....website?

 

[steel 35]

Cut off disks on a grinder work very well but there are better ways and here is my combo; Works very well for cleaning up errors.

 

[scratchedup]

Cut off disks on a grinder work very well but there are better ways and here is my combo; Works very well for cleaning up errors.

So its a combo belt sander and 90 angle disk sander/grinder?

I have a cold cut saw that is great but it is very limited to straight cuts on straight stock.

 

[steel 35]

Mine is and I am sure thats what was mentioned prior. I bet the cold cut saw is nice.

 

[OccupantRJ]

So its a combo belt sander and 90 angle disk sander/grinder?

I have a cold cut saw that is great but it is very limited to straight cuts on straight stock.

If you take a piece of flatbar and make a clamping arrangement to attach the bent tubing to it in the correct position, you can then make the cuts on the cold saw.

 

[scratchedup]

If you take a piece of flatbar and make a clamping arrangement to attach the bent tubing to it in the correct position, you can then make the cuts on the cold saw.

Yes I agree. It's just that the set up can get pretty involved. And the saw is very powerful. Can be a little nerve wrecking

 

[LXCam]

Do you have a commercial shop.....website?

I cut with a porta band, then clean up with a disc sander like what you'll find on a combo unit that also has a 6" x 48" belt sander. And to answer the last question yes I do. But not being a vendor here don't feel it right discussing or showing my products. But when I get to a real computer, ill post a couple pictures. I like coming here to relax and get a kick out if all the other like minded nuts jobs.

 

[racingtadpole]

For marking rounds, I use a strip of 2" wide 3/16" insertion rubber. Pliable enough to follow the shape even on a bend, solid enough that it maintains shape to give a straight line.
Slightly off topic, sadly the pipe welder that taught me that was killed when he got lazy one day and didnt test for gas in a trench. Climbed in the hole, got into position and lit up an arc...

Never thought about using a hose clamp, add that one to the ever growing list of stuff I've learnt here.

 

[scratchedup]

This is one of the pieces to cut just right of the green tape. As you can see it would be pretty hard to get the piece on a saw.

 

[Kevin54]

This is one of the pieces to cut just right of the green tape. As you can see it would be pretty hard to get the piece on a saw.

Would you happen to have a large pipe cutter? With that I mean like the tubing cutters where you have one sharpened wheel like you cut copper tubing with? If you have a large one, you could also use that.

 

[scratchedup]

Would you happen to have a large pipe cutter? With that I mean like the tubing cutters where you have one sharpened wheel like you cut copper tubing with? If you have a large one, you could also use that.

Great idea. That was what I was thinking originally. I do not currently have one big enough for this.

 

[bullnerd]

1) Bandsaw and some scraps of wood for spacers will make quick work of that and most any tubing work.

2) belt or disk sander.

Both can be found on CL all day long.

I have two delta 6x48"s just like the one pictured,one of them was 45$.

Do yourself a favor,if your going to be doing alot of this type of work try to pick them up.

Oh and I use the masking tape as mentioned.

 

[LXCam]

Here's a 4" unit for a super charger. Not exactly hard to make, but it's the only raw pictures I have. As for lining up my pieces. I use a scrap piece if tubing about 1" wide. I cut out 3/4" on one side. Them drill a 1/2" hole in the center directly opposite of the section I removed. Then I use two hose clamps to clamp the two pieces of tube together. If needed and like you'll see below, I'll pie cut the tube if the OD of both sections aren't perfectly matched. This allows me to line up thee tubing and tack weld them.

 

[scratchedup]

LZCam-
Is this what you are suggesting?

This was done on my ipad while traveling so....

 

[LXCam]

Exactly.

Oh and please, its just Cam. I have no imagination for forums names and won't remember it even if I did. Thanks

 

[scratchedup]

Exactly.

Oh and please, its just Cam. I have no imagination for forums names and won't remember it even if I did. Thanks

Well if you came up with this clamp idea your a rock star...if there is any such thing any more.

 

[NASTYZEN]

Hose clamp. Thats brilliant Kevin.
A tube cutter will make a near perfect 90 deg. cut every time. No mess,takes less than a minute to execute. But, it also deforms the edge of the tube inwards, reducing the edge diameter a little. A bit of a pain when you segment assemble for headers.
I just make a small mark where I need the cut. Execute with the bandsaw or some times cut off wheel on my handheld grinder and dress the cut on my belt sander.

 

[racingtadpole]

You may find that, depending on the quality of the tube cutter, the cutting wheel doesnt last very long trying to cut stainless with it.

 

[Rentawrench]

Watch this for ideas

 

[trboxman]

There are tube sawing guides made for this purpose. Google "tube saw guide" and you'll see a bunch.

 

[Mr.N]

A tube cutter will make a near perfect 90 deg. cut every time. No mess,takes less than a minute to execute. But, it also deforms the edge of the tube inwards, reducing the edge diameter a little.

Yes it works great! I usually use them just for marking, and cut with a 4.5" grinder or band saw. I have a pipe cutter with four large cutting wheels, I have used it to mark bent tube.


Also a simple piece of paper wrapped around the tube works great for a 90 degree cut.

 

[LXCam]

Well if you came up with this clamp idea your a rock star...if there is any such thing any more.

Well I'm not to sure about the rock star deal, most of the time folks use a 7 letter word in reference to me . But the truth is that idea was nothing more then desperation being the mother of invention. I tried a few different methods that worked like heavy wall cradles and different clamps, but this was the quickest and most effective of the bunch. I'm beyond **** with finish quality. All these units are powder coated, so metal finish had to be perfect, no body filler allowed. It may not look like it, but there are three welds on each of the side tubes.

 

[scratchedup]

 

[bullnerd]

Slickness.

 

[scratchedup]

...little more challenging

 

[bullnerd]

Stretchy tape over the top and down the sides.

 

[LXCam]

Kickass stratchedup!. As for the other piece, I'm with the guys who voted on a couple tack welds.

 

[scratchedup]

Kickass stratchedup!. As for the other piece, I'm with the guys who voted on a couple tack welds.

THX
Figuring, cutting, grinding, sanding more grinding....it's my meds.

Yes I agree. A couple of tacks. Just have to trust my welder.

I picked up a Miller Dynasty 200 a while back ...just have not had the time to learn.

 

[LXCam]

Hell man, there's no better time then the present. Practice on some scrap.