Welding on nuts without damaging them

[joshuabardwell]

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!

 

[bcp]

Run a tap through the nuts.

Bruce

 

[Katahdin]

A couple thoughts, 1) use weld-nuts, which are designed to be welded on. Or 2) put a brass bolt through the steel nut that you're welding. The brass and steel won't bond and it may keep the nut from warping.

 

[gwdixon]

Run a tap through the nuts.

Bruce

Agree with bcp. Use a tap to ream out the nuts.

I have also had success using a impact wrench with larger nuts and bolts. Lube the bolt and run it back and forth several times.

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.

 

[RobertBrown]

You could try the heavy 3/8" nuts, for a 5/8" wrench.....might help. I've successfully welded nuts but never that small 5/8" thread and larger.

 

[joshuabardwell]

Here are some pics of the project.



One side weld. 3/32" E7014.



Other side weld. The second side is a lot neater, I think because the electrode had burned down shorter. If you look at the first side, you'll see it gets a lot better towards the end of the weld.



Top plate. I beveled the plates with a small landing to help with penetration. You can see where I undercut the landing on the top weld, whereas the bottom weld stayed entirely within the bevel.



"Bad" side -- after grinding flat. Small slag inclusion towards the end of the weld.



"Good side" -- after grinding flat. Some undercutting, but otherwise, I'm pretty happy with this bead.



After welding, I beveled all the edges, both for safety and because I thought it looked nice. Not sure how I should have done this if I wanted it absolutely flat. Maybe no bevel? Or another pass?



Finally, I drilled 1/2" holes.

 

[joshuabardwell]

Run a tap through the nuts.

Good suggestion! But I don't have a tap.

 

[gwdixon]

Good suggestion! But I don't have a tap.

Taps are not that expensive. In fact, if you are going to weld and fab you need a whole set. Harbor Freight has horrible ones for cheap but they work for a few holes if carefully done. They are better than not having any.

That opens another option - tap the holes in the plate instead of welding nuts on the back. One less step and guaranteed to work.

 

[k0ua]

Agree with bcp. Use a tap to ream out the nuts.

I have also had success using a impact wrench with larger nuts and bolts. Lube the bolt and run it back and forth several times.

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.

I agree, but also a couple of other things, The larger the nut the easier to weld and less likely to be so heat distorted. You can also tack one side let cool, and tack again. Also try just a little less heat (amps). A single tap and a tap handle is not a whole lot of money. You don't have to buy a whole set. Now the best solution. Dont stick them on, TIG them on.. much better control of the process and much better results.. NOT that you cant stick weld small nuts, because you can, and I have done it several times. But given the choice if I had the TIG torch I would use it. On your welds on the plate, you can weave across the puddle a bit and just touch the "toes" of the weldment. This will fill in the gap by making a wider weld bead. I applaud your efforts for tackling the project and getting better all the time.:thumbsup:

James K0UA

 

[Scooby074]

I cover a bolt's threads in grease then thread that into the nut to be welded. Weld the nut on going easy on the heat (enough so that the nut is well stuck however) then back out the bolt once it cools a bit. Works for me.

Most important thing is making sure the bolt is centred in the bore of the hole. If it's off centre, it will be a bear to get in and out.

 

[joshuabardwell]

Now the best solution. Dont stick them on, TIG them on.. much better control of the process and much better results..

See, that's what I said to my partner! I need a TIG torch for this job! She just rolled her eyes. Frankly, I plan to keep practicing stick for a bit before I spend any more money branching out into another process. I have a tendency to do the first 10% of learning on a subject, and in the mean-time buy the first 50% of equipment. Then I move on to the next subject. I've been trying to flip that ratio around.

 

[joshuabardwell]

That opens another option - tap the holes in the plate instead of welding nuts on the back. One less step and guaranteed to work.

That is tempting, and if I had a tap set, that's probably what I would have done. I confess I do like the visual effect that having the nuts there would have--so in his little toddler brain, he's seeing bolts going into nuts and associating them. Not that he's not going to figure that all out anyway, mind you.

 

[crazyal]

Try to weld the just the steel plate and just get the puddle to touch the nut. Since the nut is not much mass it will heat very easily. Also unless you need to bonded to the steel well just weld it on two sides. If you use a bold to hold the nut make sure to center it and only tighten finger tight (avoid putting stress on the nut). Watch out for splatter. Any on the threads will damage them and if not removed will ruin the threads. Avoid welding stainless nuts if possible. Stainless will gall so even the slightest distortion will ruin the threads. Finally go on ebay and buy some weld nuts, much easier to weld and they aren't expensive.

 

[Dr Dave]

You can make a thread chaser with a bolt, cut 3 or 4 angled cuts in the bolts with a hack saw. When I weld nuts on to a plate, I use a short bolt, coat threads with anti splatter tip paste, run the bolt threw the plate, hand tight. Tack on 3 sides and remove bolt. Nice project for a young mind, they are never too young to learn.

Dave

 

[Grumpy Old Man]

I suggest you buy the kid more accident insurance because he will sooner of later drop it ,step on it ,fall on it ,or throw it thru a window , spend $5.00 and go to walmart and buy him something he won't hurt himself with , My kids at that age ( they are in their 30's now ) would have killed the dog swinging the block of steel on the chain !:2cents:

 

[RoyJackson]

I'd just tack the nuts on...and I'd use TIG welding...easier to concentrate the heat.

 

[LD1]

As others said, TIG is the way to go for attaching nuts that small. And MIG is not bad either.

Are you just tacking them on? Or trying to weld them in full (IE: practicing??) Cause if it were me, I just tack a couple of spots on each nut since it isnt going to be load bearing.

Also, I think 110a is a bit too hot for a small 3/8 nut. With 3/32 rod, I'd probabally run around 65-70a on a DC machine. Maybe a tad more on an AC machine.

 

[Shield Arc]

If you think welding a steel nut on is tough, try welding an aluminum one.
Not necessarily a nut, but pipe insert.

 

[joshuabardwell]

I suggest you buy the kid more accident insurance because he will sooner of later drop it ,step on it ,fall on it ,or throw it thru a window , spend $5.00 and go to walmart and buy him something he won't hurt himself with , My kids at that age ( they are in their 30's now ) would have killed the dog swinging the block of steel on the chain !:2cents:

Well, you sure do live up to your name! :laughing: If a five-dollar Wal-Mart toy would keep him out of my tool box, you better believe I'd do it. He doesn't want plastic tools. He wants the real thing, like his dad has. At this point, my fallback plan is to try to keep him away from tools that can actually injure him, and keep him using them places where he's not going to knock any holes in the wall or what-have-you. As for dropping it, stepping on it, falling on it... if that's the worst thing that happens to him in any given day, I'll call it a win. I turn my back for two seconds and he's climbing up a ten-foot ladder propped against the wall, or climbing the cattle racks on my trailer, or trying to stick a screw into an electric socket. I don't let him do those things, but I have to let him do something with himself or he'll just go crazy with boredom. So he gets to carry around the mallet if he wants to, and if he drops it on his foot, his foot might bruise, but it'll heal, and he'll be okay, and next time maybe he won't drop it. We had a hard time "teaching" him about the electric fence, but we used the same philosophy. We can shoo him away from it all day long, but let him touch it and get shocked a time or three, and he'll keep himself away from it just fine. And he does. Shoot! He reaches over to pick grass or sticks out from the wires and each time, his mom and I cringe, but he's figured it out just like the pigs have, which parts he can and can't touch without getting shocked. My point is that if something is actually dangerous or deadly (guns, knives, a hot wood stove, woodworking chisels, a circular saw), then I'm going to keep it away from him, but if it is only mildly injurious, I'm happy to let him figure it out, even if it means he gets hurt sometimes.

As for throwing it through a window... well, he hasn't quite got the coordination to throw things yet, but if he starts picking up the habit, then I'll reassess his access to heavy projectiles.

 

[Grumpy Old Man]

Well, you sure do live up to your name! :laughing: If a five-dollar Wal-Mart toy would keep him out of my tool box, you better believe I'd do it. He doesn't want plastic tools. He wants the real thing, like his dad has. At this point, my fallback plan is to try to keep him away from tools that can actually injure him, and keep him using them places where he's not going to knock any holes in the wall or what-have-you. As for dropping it, stepping on it, falling on it... if that's the worst thing that happens to him in any given day, I'll call it a win. I turn my back for two seconds and he's climbing up a ten-foot ladder propped against the wall, or climbing the cattle racks on my trailer, or trying to stick a screw into an electric socket. I don't let him do those things, but I have to let him do something with himself or he'll just go crazy with boredom. So he gets to carry around the mallet if he wants to, and if he drops it on his foot, his foot might bruise, but it'll heal, and he'll be okay, and next time maybe he won't drop it. We had a hard time "teaching" him about the electric fence, but we used the same philosophy. We can shoo him away from it all day long, but let him touch it and get shocked a time or three, and he'll keep himself away from it just fine. And he does. Shoot! He reaches over to pick grass or sticks out from the wires and each time, his mom and I cringe, but he's figured it out just like the pigs have, which parts he can and can't touch without getting shocked. My point is that if something is actually dangerous or deadly (guns, knives, a hot wood stove, woodworking chisels, a circular saw), then I'm going to keep it away from him, but if it is only mildly injurious, I'm happy to let him figure it out, even if it means he gets hurt sometimes.

As for throwing it through a window... well, he hasn't quite got the coordination to throw things yet, but if he starts picking up the habit, then I'll reassess his access to heavy projectiles.

I hope that posting is a joke because you can't teach kids the same way you do pigs ! :laughing: I can appreciate what your saying but I just noticed you live here in Knoxville and some people around here are a bit overzealous on child protection rules:hissyfit: I'm sure you know what I'm talking about ,but at 17 months they don't get to pick what they are allowed to play withullinghair: and even if it's just "mildly injurious " you could go to jail !:yuck: