tightening nut inserts

[pidgeon chit welder]

I have an industrial /contractors electric sawbench , the saw slide table is stopped from slipping off the bench guide by an 8 mm bolt screwed into a captive nut insert .

Today I tried to remove the stop bolt to remove the slide so I could get the bench through a door and the nut insert rotated in the guide tube at the slightest pressure. It is about 11 inches in from the end of the slide tube.

I understand how the insert would be set tight in the tube at manufacture .

So as a DIY tightener I'm after a very high tensile 50 mm long bolt and a couple of very high tensile steel nuts so I can slip the nuts on the HTSbolt , make a pack washer anvil up, screw in the bolt and then use the nuts to draw the nut insert up tight and compress the fixing sleeve onto the pack washer anvil enough to resecure it .

It's been a long long while since I used HTS bolts in anger , I seem to recall that there were greater strengths than " R " steel ..

Can any of you give me some info wrt the latest high tensile steel /alloy steel stuff and where I might buy just a few to do the job .

I have just now thought of using some 8mm concrete anchor bolts taken out of the expanding anchor ( redhead or rawlbolt ???) and their nuts , but don't know if they are a high enough tensile strength to allow me to compress the nit insert sleeve ... so your thoughts on this one as well please.

Cheers
David

 

[Paul.]

As you probably know you can buy a simple tool for doing small nutsert jobs, but I have used the method you describe many times using nothing more than an off the shelf high tensile cap screw, nuts and a couple of flat washers, a bit of lube helps on the nuts and washers, the problem with an existing nutsert is it may already be fully expanded, and trying to tighten it further may rip the thread out, you wont know until you try it,
a small tack with a tig torch is often a better method for repair, or even better replace with a new insert.

 

[Shox Dr]

or even better replace with a new insert.

...and a tack. (belt and braces)

 

[Luke]

I've used standard 8.8 bolts/machine screws before, with no issues. The thread wears if you set lots of rivnuts, but it's no real issue.