[W7OWC]

Hello,
I am hoping someone could give me some pointers on this. First off I am building a CNC mill, nothing too fancy 30X20 cut area. Moving gantry etc. I mainly want it for cutting .5 and less aluminum plate to make parts to weld. I have finished the base all .25' wall steel tubing fit and welded with 70ES2, no problems. Now I am working on the gantry, pretty much the sam as the Base all .25' wall tube except the part for the Y axis BallScrew, because of the dimensions of the ball screw in relation to the Linear slides I am having to build up the Stepper mount and Ballscrew on a piece of .12 wall 3X1 tubing. In order to align the Motor shaft and the Ballscrew I have to put a 14mm spacer under the Ball screw bearing blocks at each end of the screw.

I had to do the same thing on the X axis (the base) but I welded the spacer which measure 2.5"X1.5"X14mm (yeah it has been fun going back and forth between metric) to the .25 wall tube, I didn't have any warp issues doing that.

But when I tried welding the same space tot eh .12" wall tube it warped! about 1/4 for 8' of run. I am TIG welding everything this joint I had welded at 180 amps, 3/33 70S2 filler concentrating the arc mostly on the 14mm block but getting enough wetting to dip filler on the .12 tube.

Obviously this didn't work so well.

So now I am wondering if I TIG brazed the spacer/block to the .12 wall tube (all new metal) I wouldn't have the warp issue?

What should my settings be? I did a test run on the old piece 100 amps tight arc and some 1/8 SIB ( 1/8 is all I had on hand). it seemed to turn out OK but I was welding to a warped piece of metal so I could really tell if I had new distortion after welding.

are my settings correct?

TNX
Sorry I have taken any photos

[Rick_H]

That tube will most likely pull regardless...I back bow tubing at times clamped tight to the welding table to help it distort straight. You need to clamp it very tight, keeps the heat on the thicker material and quickly wash it over to the tube while adding filler.

Just nature of the beast, it will always move...

Pictures would be a big help

[W7OWC]

I figured that it would pull but I need to try and minimize this as much as possible. Here are some pictures of what I am doing.

Here is the new pieces. the filler rod is
1/8"

New Pieces

IMG_0367.JPG (54.87 KiB) Viewed 382 times

This is the one I tried welding that warped. I cut the welds out with a mill and knock the spaced of, thus the waffle marks of the first hammer I hand in sight. After dong this I used it to test the brazing idea, problem is it was already warped. This is on it the 2nd or 3rd tig I have ever TIG Brazed, I think I got good bonding, but need to take a grinder to is and see.

IMG_0368.JPG (55.23 KiB) Viewed 382 times

IMG_0370.JPG (52.78 KiB) Viewed 382 times

Here is the new Piece on top of some 1" MIC6 tool plate. I have used the tool plat to clamp other projects too when I wanted things to align up nicely on one side or suck heat out when doing thin AL work. Do you think this would help with my distortion issue?

IMG_0371.JPG (39.77 KiB) Viewed 382 times

[kiwi2wheels]

If the tube is straight between the spacer blocks, machine the spacer blocks to the required height dimension from the tube base after welding.

You need to remove the mill scale from the blocks and tube whatever weld process you will use.

[Poland308]

If it's just a spacer block then just do 2 or three small 1 inch long welds to hold it in place.

[W7OWC]

I think I will stick with two welds, nothing across the face of the tube. That is where I got into trouble the first time. the spacer will eventually get drilled and tapped so I can bolt the ball screw bearing blocks to them so there is a small amount of force applied but nothing I dont thing a couple of 1 to 1 1/2" brazed weld couldn't take.

Thank you guys