Welding Nuts - OK Fab guys, chime in.

[hotrod56]

I frequently weld nuts behind a bracket, braces, or to conceal it (perhaps in the frame). I usually weld all sides of the hex to the part, but perhaps I seem to over do it. I am concerned about the heat and temper of the nut from welding but also the strength restricting of the nut when you crank on the bolt that goes with it (stops it from spinning). Here is a commercial seatbelt blind tab. They only weld a few of the corners. It looks too light in the weld department to me but I am not sure.


What are your guys thoughts? Any articles?

[minendrews68]

look at the welds on the nut to the plate. That's not going to hold anymore than if you had put the same amount of weld on the piece your currently welding a nut to. It looks like spot welds at most. I would think what your currently doing is ok, or put only the spot welds you see in the picture on your piece.

[Motorcitydak]

Do not forget that the proper application of a bolt is to provide a clamping load. They are to squeeze different pieces together with such force that they cannot move. The welds just need to hold that nut in place, let the fastener work the way it should and clamp down the load. Something to keep in mind is that a 1/2 inch bolt torqued to 100ft/lb provides 10,000 pounds of clamping load.

[hotrod56]

Thanks. I imagine that the big question is how much of a weld will it take to hold 100ft/lbs of torque. Putting heat into the nut bothers me also. I usually start with a hardened nut but dont know if that makes any difference after the weld heats it up.

[raustinss]

Yes heat will effect the nut...as a fabricator anytime I've built something engineered or not the drawings have never asked for anything more then 2 or 3 wrench "flats". it's worth the few minutes to also run a tap thru the nut after its cooled it will help clean it the threads as the heat will slightly distort the threads...good luck

[renegade6]

Flange nuts are good to use for this purpose, gives you a little bit more area to weld on.

[IMPALA MAN]

I don't know guys, I have always just screwed the bolt into the nut. Then welded the nut. Let it all cool and the bolt comes out with ease. I've not ever had to chase a thread after doing it this way.

[raustinss]

I don't know guys, I have always just screwed the bolt into the nut. Then welded the nut. Let it all cool and the bolt comes out with ease. I've not ever had to chase a thread after doing it this way.

Yes you are correct, I should have stated that sometimes it isn't feasible in a work environment. I.e stainless stuff or if there is a bunch of pieces with numerous nuts to be welded. It then can sometimes be cheaper to chase the threads with a "speed" tap on a cordless drill

[parsonsj]

I have always just screwed the bolt into the nut. Then welded the nut. Let it all cool and the bolt comes out with ease. I've not ever had to chase a thread after doing it this way.Me too. The most important thing to do is let it completely cool down. If you get impatient and try and remove the bolt while still hot, you can cause the threads to gall. Especially with aluminum or SS.