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

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

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

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

MichaelG.

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

**LINK**

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.

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?