Self clinching nuts and studs

[tsbParticipant @tsb]

[tsbParticipant @tsb]

Can anyone give me any advice on using self clinching nuts and studs in aluminium and steel material. Can they be manually fitted or do you need some sort of special press. Any advice or where to look would be very appreciated

[Clive HartlandParticipant @clivehartland94829]

Fine threads should not be used in aluminium, general practice is to fit a coarse thread insert with a locking device which has a fine thread inside it. The fixing I have seen is a thread collar with grooves on the outside which have rectangular pins driven down into the grooves and into the soft aluminium.

There is a method using a clinch nut/thread where a compressable sheath is pulled up tight to lock it up but has the problem of rotating after some time. I believe these clinch nuts/threads can go up to 12mm from as low as 3mm.

Rivetwise have a flush fitting female thread clinch nut.

Clive

[MuzzerParticipant @muzzer]

tsb, when you say "self-clinching" do you mean PEM studs and inserts? If so, you need suitable tooling to insert them properly as they deform the sheet metal and cause it to flow back into grooves in the inserts to retain and seal them. Never tried to use them without the correct tooling but I could imagine it might not be too difficult to make something that would work.

Steel requires much higher forces, as it is a lot less ductile.

If it's for your own hobby use they are hardly going to come after you. Patent protection is to prevent you profiting from copying their IP, not for using it for your own purposes.

Interesting articles here and here.

Edited By Muzzer on 12/01/2016 12:26:07

[Anonymous]

I've used lots of the PEM nutserts in aluminium (1050A) and copper. I fitted them using a flypress, but no fancy tooling just a plain cylinder to apply pressure. I wouldn't want to rely on the method for production but it worked fine for prototyping.

Andrew

[KWILParticipant @kwil]

I have used self clinching nuts both commercial and home made with good results. Best for simply holding parts together and the mating faces can be flush fitted. I usually fit using a ballbearing to flare and compress the cylindrical part where it passed through the parent metal. Commercial nuts with their axial teeth hold better for rotational strength, then if you are merely holding two plates together, then a spanner can be applied to those made from hexagonal stock.

[WindyParticipant @windy30762]

The ones I used in sheet metal for the car body trade some had hexagonal shanks for similar holes to resist turning if the bolt or screw was removed a lot.

One or two hexagonal holes in sheet metal could be filed to do a lot a punch is better.

Edited By Windy on 12/01/2016 15:36:13

[KWILParticipant @kwil]

Forgot to add "Hank Bushes" TR Fastenings

**LINK**

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Muzzer on 12/01/2016 12:21:55:

tsb, when you say "self-clinching" do you mean PEM studs and inserts? If so, you need suitable tooling to insert them properly as they deform the sheet metal and cause it to flow back into grooves in the inserts to retain and seal them. Never tried to use them without the correct tooling but I could imagine it might not be too difficult to make something that would work.

.

Further to Muzzer's note PEM has this quite informative 'handbook'

MichaelG.

[HughEParticipant @hughe]

Used PEM studs and clinch nuts a lots over the years, always had them inserted using correct tooling. I can highly reccommend them. The only failure was using aluminium ones (4mm) that shear easily, SS should have been called up on the drawing. Avdel also available with special tool for fitting from RS and Farnell, but mind your fingers.

Hugh

[VicParticipant @vic]

You don't mean a nutsert do you? I have a kit like this.

**LINK**

[tsbParticipant @tsb]

Thank you for the information. It is the Pem studs and inserts I was looking for. Would engineering shops stock this sort of fastener or would I have to go direct to Pem, for a few to sample

[Enough!Participant @enough]

I've bought small quantities of PEMs (studs and nuts) from eBay in the past. Installed them with simple, shop-made tooling using a bench-vice. Works for me with small inserts (#4, #6 UNC). Commercial tools may make a stronger installation but mine were not highly stressed and things hold themselves together anyway after assembly.

Using simple tooling, you may not get them absolutely flush – a few thou proud (although I've seen that with commercial installation too). If that's important to you …. for example, in one case I installed PEM-Studs through the front panel of an electronic enclosure which would afterwards be covered with a thin overlay …. you can try using an end-mill to put a small (5-10 thou) counterbore on the hole before installation. Rub a bit of filler in if you're painting. Or skip the counterbore and just sand of the proud part.

PEMs can be a bit fiddly without proper tooling. It's do-able but you wouldn't want to bother unnecessarily. In certain cases though, they're a lifesaver and well worth the effort.

[HughEParticipant @hughe]

Vic ,

You are correct I should have said Avdel nutserts. Have broken the tool a couple of times trying to put SS ones into 3 mm ali .

[VicParticipant @vic]

I've found nutserts easy to fit with the supplied tool but they are sensitive to material thickness. I suppose they sell different nutserts for different thickness material?

[Michael GilliganParticipant @michaelgilligan61133]

According to p9 of the little PEM Handbook that I linked earlier:

"In just three easy steps, self-clinching fasteners can be installed with any parallel acting press that can be adjusted to optimum installation forces."

MichaelG.

.

P.S. In extremis, I have seen them inserted using a good caphead screw and some spacers … but I wouldn't like to guarantee performance to specification.

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