Best hole saw size for notching, when mig welding?

singlehanded

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I will be notching 3/4 and 1 inch and 1 1/2 inch dom tubing. What is the corect hole saw to use on each one to get a desired gap for mig welding.
THANKS..................
 

singlehanded

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will it leave a gap? I think I used 1 5/8 last time I did my bed, but there wasnt really a large enough gap as I would have liked. Will 1 1/2(hole saw) on 1 1/2 tubing increase or decrease the gap.
 

GFC

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ok..... you do not want to have to weld ANY gaps. as for hole saws, if you are fitting a 1 3/4 in. tube up against a tube of equil size, use a 1 3/4 in. hole saw. when fitting a piece of 1 1/2 in. tubing up against a 1 3/4 in tube, also use a 1 3/4 in. hole saw. when fitting a 1 1/2 up against a 1 1/2 use a 1 1/2 in hole saw............. catch my drift?

sorry that it isnt a very clear pic
 

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singlehanded

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but you do want some gap when mig welding and no gap when tig welding. or else you will end up with a larger uglier weld mig welding material that is touching. Am I right or have I been told wrong.....
 

drtdevil93

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a very small gap is good for mig. the problem is there wont be an equal gap all around. i usually use a 1.5" holesaw for a 1.5" tube, and grind around the edges to make a v-shape when its assembled.

erik
 

GFC

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grinding a V is hardly a "gap". thats basic prep work before welding
 

In_the_works

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The attractiveness of a bead has a lot more to do with the skill of the welder as opposed to the presence of a gap or lack thereof. I usually prefer to have the tubes fit up against each other as tightly as possible.
 

Ryan B

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If there is a gap in the joint that means you are filling that with the welder. If there is no gap I think you are going to get better penetration between the two pieces you are joining because you aren't wasting any of the heat and material from the weld were there's no material. right?
 

TRDshaunTRD

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You do not want a gap when fitting pieces together. The smaller the gap the stronger the conection.
 

FABRICATOR

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If you are that concerned with joint preparation and strength, why Mig weld it?
 

Ryan B

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If your life depends on that joint, like in a seat mount or something, then weld prep should be a big deal no matter what your welding with.
 

FABRICATOR

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That was not my point at all. Explained another way...To insist that a special fit is needed for Mig welding, is not congruent with the choice to use Mig welding.
 

Kbach66

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Anyone have a good source for 2.5" ID galvanized pipe. I'm going to be cutting out all the DOM chassis/cage and starting over on my truck. From the website Jeff posted, it seems like I've been going at it all wrong. I'm thinking about selling my bender and notcher as well, seems like I should be able to rebuild it all without any bends and notches!!
 

Josh_K

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Ya, there's going to thousand's of dollars worth of fab tools for sale in the classifieds soon. I wish I would have thought about doing it the "better way" before I bought my bender, a full set of dies, Tube notcher, plasma cutter,,,on and on.
 

MNotary

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Early 90's at Crandon. ... All the GOB cars had iron pipe cages on the OUTSIDE of the car.... ssooooo cooooolll.... And there was a 100 of them...... I think some of the Class 13 (now Sport 2) had a little Iron pipe in them too....
 

michael_loomis

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you silly people ... you dont want to use galvanized pipe !!!!


use ABS ...ITS MUCH LIGHTER !!!
 
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