Welding on nuts without damaging them

[joshuabardwell]

I got the nuts welded on.



I used a combination of the tips presented here. Using the bolt to hold the nut in place while welding was genius. Not sure why I didn't think of that to begin with. I built a small puddle on the base metal and then tried to draw it over to the nut. In the past, when I've done this, I've had problems with wiping the weld metal up the face of the nut, but not heating the nut enough to get it to penetrate, but it worked okay this time. All three nuts are secure and the bolts turn freely. Up next: paint.

 

[gwdixon]

I got the nuts welded on.

I used a combination of the tips presented here. Using the bolt to hold the nut in place while welding was genius. Not sure why I didn't think of that to begin with. I built a small puddle on the base metal and then tried to draw it over to the nut. In the past, when I've done this, I've had problems with wiping the weld metal up the face of the nut, but not heating the nut enough to get it to penetrate, but it worked okay this time. All three nuts are secure and the bolts turn freely. Up next: paint.

Also, next time you do a project like this, leave the bolts through the nuts during the weld. That will support the nuts from getting so out of round due to heat warping. Just spot weld or tack three of the six faces to lessen the HAZ.

Why, thank you, thank you. Rarely is genius recognized in one's lifetime. :cloud9:

 

[john_bud]

No, not my nuts. :laughing:

I'm making a toy for my 17-month-old son. He loves playing with wrenches and nuts and bolts, so I figured I would make him a plate of metal with some captive bolts and a box wrench on a chain, so he can turn the bolts but neither they nor the wrench could get separated. It's a pretty rudimentary project, and once upon a time, I would have made it out of wood, but I'll take any chance I can get to practice welding.

My idea was that I would drill holes in a plate, then weld nuts over the holes, then put bolts through the nuts, then weld washers onto the end of the bolts to prevent them from being removed. The problem I ran into was, after welding the nuts on, the bolts wouldn't go all the way through two out of the three of them. At first, I thought maybe a little slag or dust got into the threads, but upon closer inspection, they looked like they might be warped or distorted from the heat. For perspective, I used 3/32" E7014 at about 110 amps, DCEP. The base plate is about 3/16" to 1/4" thick and the bolts and nuts are 9/16" (3/8" diameter thread).

As a workaround, I am considering putting the bolts through the plate and then welding the heads of the bolts to the back of the plate, but I really like the idea of having the bolts being turned through the plate, compared to having the nuts being turned up and down the bolts, so I'd rather find a way to affix the nuts to the plate without damaging them. I suppose I could just break down and use JB-weld, but I didn't buy a welder just go turn around and JB-weld something, now did I!

Before you present this to your child, what provision are you making to keep the bolts from being swallowed?

 

[joshuabardwell]

Before you present this to your child, what provision are you making to keep the bolts from being swallowed?

Please refer to the text you quoted:

then weld washers onto the end of the bolts to prevent them from being removed.

 

[CNC Dan]

you could also weld nuts on the other end of the bolts to make them captive. Just remember to atach the ground clamp to the bolt, not the plate, or you could weld the bolts in.

 

[joshuabardwell]

you could also weld nuts on the other end of the bolts to make them captive. Just remember to atach the ground clamp to the bolt, not the plate, or you could weld the bolts in.

That is a mighty fine tip, there Dan. Normally, I clamp to the table and set the work piece in. I think what you are getting at is that the air gap between the threads of the nut and the bolt may be sufficient to create an arc and melt them together?

 

[LD1]

I think what you are getting at is that the air gap between the threads of the nut and the bolt may be sufficient to create an arc and melt them together?

Thats correct.

Same reason to never weld "through" a bearing or bushing or any moving parts that you want to keep moving.

 

[CNC Dan]

That is a mighty fine tip, there Dan. Normally, I clamp to the table and set the work piece in. I think what you are getting at is that the air gap between the threads of the nut and the bolt may be sufficient to create an arc and melt them together?

exactly. same thing with bearings as another poster said. But not even an air gap realy. Just too small of an area for the amount of current.

You may have had a workpiece "stick" to your welding table if it was an odd shaped piece that was resting on just a few points. That was the effect you want to avoid in moving parts.

If you had to do it, tighten the nut /bolt to increase contact.

If you were worried about an iffy connection or bearing and wern't sure what side to ground on, use an extra ground clamp to ground both sides. A set of jumper cables will work in a pinch.