made a nutsert / rivnut / rivet nut tool

[ned]

Hi, ya necessity did its magical thing again, I had to made this on saturday to complete a job im working on.

I didnt see a design like this online, I'm posting it here in the hope that others looking for similar will come across it.

The basic idea of a rivnut is that the top 7mm of the rivnut crumples / deforms and this is what creates the bond with the parent metal.

Trying to use a spanner is a kak idea and will just lead to fustration.

You start by welding two nuts together, make three of these, then weld them around three central nuts. The first one I made , one of the sides fell off due to the high pressures i was exerting on it, so make sure its well and truly melted together.


MK I: one of these broke off, really you need three bolts in the middle to increase the surface area available for welding. you can see below i only used two for the central part, later i improved this.

the gap beween the rivnut and the tool body is for a metal plate to sit in.
This is what the bolts press into / against when you are using it. See bottom pic.

The two bolts are needed becuse if you use one you will strip the threads on the nuts, or the bolts, whichever gives first. Use grade 8.8 bolts and nuts.

you can see the metal plate in this pic.

the metal plate below is part of the tool, the bolts are pushing against this to deform the rivnut. I think the plate is 5 or 6mm, needs to be fairly hefty.

hope this is useful to someone sometime. Once its sorted its a very effective tool. fun to use.

 

[awemawson]

Very cunning Ned.

I have a pliers type for smaller threads up to about M6 but the bigger ones are a pain particularly in confined spaces. If you made the thread that the Nutsert screws on a bolt screwed into yet another nut, you could unscrew it without having to rotate the entire structure when in confined spaces

 

[123hotchef]

great idea like it

 

[ned]

interesting. I actually stripped the threads on the central bolt , so I grinded it off and then built up the walls of the triangle so that i could weld on and grind off bolts of different sizes.


Bit long winded...., but it works!

 

[armalites]

I was struggling with how it was pulling the rivnut against itself but I've just realised the plate in the last picture is part of the tool not the thing the rivnut is being inserted in.

 

[ned]

yes, thast it, its part of the tool. ill edit my speil to explain that better. You could drill out the center and then fit different sized bolts , using washers to make it stay.

 

[Bill Edwards]

Interesting idea, for when there's enough space.

You've done well welding two nuts together, usually when you do this the welding pulls them about so that the threads don't line up and it doesn't work.

Using two spanners is a real PITA, the little pop riveter style are OK to about M5 but hard work after that, plus cheap ones bend and break.
The more expensive tools are great to use but of course, expensive. Getting ones that go about 8/10mm gets really pricey.

I guess your one will work very nicely with an air ratchet or impact wrench. I may copy it for the big sizes.

 

[Sean]

i put a washer over the insert then an oversized nut( that clears the thread in the bolt). 2 greased washers then fit an allen bolt in the insert. hold the oversized nut with a spanner and give the allen bolt a burst with the rattle gun
I managed to strip the thread on the insert tool and so resorted to the above bodgery its surprisingly quick as the stack comes off as a oner when you reverse the screw gun, fit the next insert to the stack on the rattle gun and insert in next hole.

 

[ned]

Sean I tried that and endured spectacular failures, so I had to think of something else.

Bill yes on welding the two bolts together, one of them was fine but two of them required re-tapping to make them workable.

An impact gun wont work, i found the best way was to give one bolt a half turn, the next bolt a half turn, and so on in sequence, in order to keep it level and keep the rivnut at 90 degrees.
Its easy though, your only deforming it 4mm in the case of M8's, and rewarding when it goes well.

If I was to do it again, i might in fact, i would get 4 of these below in an M12 size, and weld three of them around a central one.
Then use whatever sized bolt suited the rivnut, down through the middle shaft.

 

[ned]

just found out they are called coupling nuts.

 

[MrFluffy]

Or you could approach it a different way and use a piece of steel stock thick enough to take the larger threads. Drill in a radial pattern & tap appropriate size.
Either way works the same, just if you have a bit of steel (like a offcut of a old lathe cabinet, that has been donating to my projects for years that has) to hand it works out quicker.
Good idea, I have the hand version and it gets a bit hard to pull after m6, so I may make one from a bit of stock.

 

[ned]

hiya ) dont know what a radial pattern is, please post pics if you do make one

 

[Wozzaaah]

It does look like a lot of effort winding 3 bolts in bit by bit?
I just used a setscrew, nuts, washers, grease, a combi and a ratchet spanner and fitted loads in no time. Once the thread on the screw started to look tired I just used a new one.
Nice little welding project though.

 

[ned]

not really because you only have to squeeze the rivnut 3 or 4 mm for it to deform, so that equates to three turns of the spanner on each nut, which isnt much at all.
Each nut takes 1 minute or so

i ordered five of those nuts i linked to above for the princely sum of 4 euros. will update this when i make the next one.

 

[arther dailey]

Nice one Ned

 

[Sean]

Once the thread on the screw started to look tired I just used a new one.
Nice little welding project though.

why I used the Allen bolt they are usually 12.9
this was for a quite a few M6 ones

 

[armalites]

i ordered five of those nuts i linked to above for the princely sum of 4 euros. will update this when i make the next one.

£3.37 for 10 in Toolstation

http://www.toolstation.com/shop/p35943?table=no