Rivet nuts.

[Dave Plowman (News)]

I bought similar for M3 - as I said earlier all too easy to shear off the mandrel. This type which you screw rather than compressing handles may be slightly easier, but not foolproof. Very difficult to 'feel' the correct setting, I found.

An ideal tool would have a foolproof way of setting the correct amount of 'pull' to set the rivnut *and* protect the mandrel.

Other thing is spare mandrels for those cost a lot more than for the mass produced lever types.

So saying, I've never used large ones like M10. But using a spanner etc to cut the effort down is still going to make it possible to shear the mandrel - if the rivnut is secured to the best 'tightness'

[T i m]

Thanks for the feedback Peter.

Cheers, T i m

[T i m]

On the grounds I would be only doing 'a few' I couldn't justify a good tool and it probably wouldn't be worth trying to use a cheap / bad one.

So, I would turn a mandrel that had a reasonably wide foot, with a close fitting hole for the drawing bolt and a recess turned into the face that was not quite as deep as the thickness of the rivet nut outer flange and just a fraction bigger ID than it.

The idea being is that the slightly shallow recess would ensure all the effort is applied to the rivet nut itself whilst the larger diameter of the face would help ensure everything was held true.

An HT bolt would be screwed though the mandrel and into the rivet nut and then drawn back though using a backnut and a few washers or a thrust bearing. This ensures that the rivet nut is just drawn into place with little rotational force applied to the rivet nut etc.

Cheers, T i m

[newshound]

The nice thing about the Memfast ones is that the mandrel is just a standard high tensile socket head screw, so cheap and easy to replace when they are knackered. As I explained above, although the ones relying on rotation rather than pulling are theoretically inferior, provided you put moly disulphide on the threads they are not too bad. I've never gone up as far as M10, though.

[newshound]

Correct. Some have countersunk heads, so that if you countersink the hole that they fit in you can get a flush, or almost flush, fitting. You don't necessarily need a flush fitting, for example when fitting things like Bridle racks or disability handles which are sort of like jam jar lids with the screws inboard of the lip that you pull down on to.

Some rivnuts have axial ridges under the "head" to help prevent rotation of the nut. These are particularly good if you are fixing to aluminium sheet (as long as you drill the right sized hole, so that the ridges have to deform the aluminium). Rotation of the nut when setting is more a problem with the "screw" type tools (like memfast) than the "pull" type based on pliers. But with the memfast you can reduce the risk of rotation by putting moly disulphide on the setting screw.

[Dave Plowman (News)]

Ah - right. Not the same as the wheel one I have, then. Sadly their website doesn't seem to show them that well.

[FMurtz]

Don't know what the stainless was but it worked, the bolts or screws were higher grade.

[T i m]

A spinoff thought is maybe a 'better' use for some Rivet nuts may be my upcoming wood to steel gate post swap.

They are probably ideal for mounting gate stops and hinges etc, or possibly hinge mounting 'plates' so that I can still get some level of adjustment (slotted holes)?

Cheers, T i m

[newshound]

Oh, you are going to use *posh* hinges then, not good old farmers gate types which you adjust by adding washers to the pin and/or via the nuts on the ring stud.

:-)

[T i m]

Well ... because the existing posts and gates are wooden, I used what I would describe as a 'T' hinge but with pins where you could lift the gates off but flat straps where you would fit the stud ring bolt. In fact, mine could probably be the sort of hinges you might see on a tailgate of a trailer. ;-)

I haven't really decided what to do with the gates yet (they are currently just two 6' fence panels) but I was thinking of making 4 off

6' x 3' light box steel frames and having them bi-fold so I can open them into the garden (EOT) when something is in there (trailer / car / boat etc) without needing a complete 6' free.

I was thinking of long shoot bolts to hold each section 'stiff' (possibly inside the box sections, giving me 18" left in each side when closed?)) or even a single bar that slides across the back.

There is a metal 'heel' set into the ground where the current two gates join and that takes a vertical central bolt.

Adjustable hinges (as you suggest) would make the idea of compensating for wear and load easier.

Cheers, T i m

[Andy Burns]

Keep going, you'll be talking yourself into flowdrilling next, which will give you a good reason to buy a milling machine :-)

[Thomas Prufer]

Much easier to buy a stud welder. Just stick a bolt in the machine, point it where you want it, and pull the trigger, fixed (assuming a metal substrate here, ok?)

Also available in portable, so cordless/rechargeable. Much *smaller* than a milling machine, too...

Thomas Prufer