Repairing a fence for my daughter and I had to use Hilti bolts, drilling into concrete. I've never used the things before and they don't come with instructions. I figured it's simple enough, drill the holes, remove the nuts, fit the metal plate, replace the nuts on the protruding threads and tap the bolts into the holes. Of four bolts, three failed with stripped threads and were absolute swines to get back out. What's the secret? Don't whack them in too hard? Whack them in really hard? Screw the nuts down tight before tapping them home, leave the nuts on the ends of the threads? What? Any clues folks, the damn things are expensive and I've four more to do tomorrow as well as the three I lost today. Thanks for any pointers.
What exactly do you mean by Hilti bolts? Do they look like these
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I figured it's simple enough, drill the holes, remove the nuts, fit
Not sure what you mean by 'metal plate'?
If they are sleeve anchors, these will fail if you whack them in too hard - either the nut distorts or the thread becomes damaged - or both. Net result is that the sleeve spins as you try to tighten them. Leave the nuts on when you tap them in to protect the thread, use a wooden block to protect the thread/nut. Tap rather than whack :-)
Important to drill the hole the right diameter (I assume you have) and the right depth and clear the dust out.
Sleeve anchors are cheap as chips from places like Toolstation or Screwfix - M10 x 100 for example are £5+ for a pack of 6 in Wickes, but £2.52 for 10 at Toolstation.
Even better, forget sleeve anchors & use masonry bolts
In my book a Hilti Bolt is synonymous with a Rawl bolt, i.e. a traditional shield anchor.
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?option=com_content&task=view&id=19&Itemid=25>> I figured it's simple enough, drill the holes, remove the nuts, fit
Whatever he's bolting down with the anchor, presumably.
Not sure how OP managed to strip threads!
To the OP:
The technique for a shield anchor is firstly to drill the correct size and depth of hole.
Next, get all the dust and crap out of the hole. Try not to blow into it unless you have goggles on.
Next, make sure the "expanding" part of the anchor is loose, otherwise the anchor won't go in the hole.
The anchor should slide easily into the hole. If it doesn't, undo the nut sufficiently that it protects the threads on the end of the bolt and then gently tap the anchor into the hole until the body of the anchor is flush or slightly recessed. This is by way of a playful love-tap. If you have to force it, then either the hole's too small or you didn't clean the crap out.
Remove the nut and washer; offer up the plate (or whatever) to the projecting stud; replace the washer and nut.
Tighten the nut by hand. The anchor should bite before the nut is too difficult to tighten by hand. If the whole anchor rotates in the hole, then you have to assist the anchor to get started. Using a pair of Mole grips, pliers or somesuch to stop the bolt from rotating whilst you use a spanner on the nut should get the action of the anchor started.
Once friction has got a start, you can tighten the nut with a spanner, socket or (my favourite) a ratcheting ring.
Brilliant! Many thanks for the responses. Dave guessed closest and sorry, I was a little vague - end of a long, wet, hard day and just crawled from a Radox bath prior to staggering off to bed. They're rawbolts, just I've always known those sort of fittings collectively as "Hilti bolts" - from the days when I'd watch the shop floor fitters using them. The thread which is stripping is at the bottom of the bolt itself, where it passes into the last component, shaped sort of like an old Apollo crew capsule. Yes, the holes are correct size, dust is out and, initially force wasn't used. When the nuts wouldn't tighten I used gentle force and when that didn't work, ended by hammering them down. If I'd know about masonry bolts I'd have used them, but as I've now got four 10mm holes I think I'm stuck with what I've got - although I will be getting new items from the local Screwfix. Many thanks again.
Thanks to your reponses I bought replacement fixings from Screwfix - £4.40+ for five as opposed to Focus, which is much closer, who charged £9+ for two. A dry fit proved that the bolt was too long - I'm unable to drill deeper - but hacksawing 1/2" off sorted it and this time the things worked perfectly. Metal plate bolted down solidly and fence repair complete. Everyone's advice much appreciated, pints all 'round ;->
M8 x 10 - 85762 Looks as if I could have gotten cheaper too, but it was early and all I could think of was I already had holes drilled of a set size and just wanted to get back and finished, so obviously wasn't thinking clearly/fast enough (no change there then).
I'm a recent convert to the epoxy or polyester resin anchors. I had a piece of machinery (*) that repeatedly pulled out of a concrete floor despite very sizable expanding anchors - problem totally solved by a tube of polyester anchor fixing and a length of ordinary studding, and existing hole size was easily accomodated.
I have my bathroom basin and bog cistern hanging on SS studding resin'd into the very weak "thermashite" wall. Gives me complete confidence in them not falling off... So easy and relatively inexpensive these days. If you improvise with the dust blowing you need one mastic gun to suit the cartridges and one bit of tube to blow or hoover from the back of the hole (very important).
I've also used it to put studs in when adding a vertical column half a brick wide (bricks on end for convenience, stud in every mortar joint) and for repairing the house foundation strip (5 heavy studs at random angles in the edge of the old strip before fitting the hole with string concrete).
I Have used the fancy studs, but as Andrew says, ordinary studding (steel or SS) works just as well.
If alignment of studs is critical, I have perviously made up a wood locator for one job (angle and height of studs critical for porcelain bog cistern, and the studs were neither level or perpedicular, by design!!). 2x4" screwed to wall, drill right through into the wall using the item to be fixed as the template, remove wood, enlarge hole in wall, clear hole, inject resin, refix wood, shove studs in. Remove wood when firm but not fully set (or the wood may end up stuck!), pare off excess resin, perfect job.
Would have actually been harder to use screws/plugs and guarantee a mm critical fit (if the holes are a bit off, the stud can move a bit in the resin).
Well things have changed and it's a whole new world out there. This week I also discovered hammer fixings - mind you, nobody thought to tell me they were just that and not really meant to be "screwed" home. Oh well, I'm (re) learning. Things were so much more simple when it was just rawlplugs and hammer drills and supascrews where considered hi-tech....
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