TomB Posted December 18, 2007 Share Posted December 18, 2007 The rivnuts I want to put into my new bulkhead panels are 7mm shank diameter. The holes I have drilled are 8mm diameter. Will a rivnut when pulled close up the 0.5mm gap each side of it or have I ruined by new panels by not being patient & buying a 7mm drill??? 😳 Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted December 18, 2007 Support Team Share Posted December 18, 2007 I think it unlikely that the rivnuts will fill the hole adequately ☹️ but it might depend on the amount of stress that will be applied to whatever you are fixing to the bulkhead. Would it be possible to put an M7 washer behind the bulkhead and fix the rivnut through that? Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
TomB Posted December 18, 2007 Author Share Posted December 18, 2007 Balls. Its for the ECU mounting. Dont see why a 7mm washer couldnt be put behind it. That would allow the rivnut to grip the washer tight and hold it all together. Right, Im off out a lunch to get some M7 washers & a 7mm drill! Not the first time impatience might have got the better of me! Link to comment Share on other sites More sharing options...
Sheds Moderator Posted December 18, 2007 Share Posted December 18, 2007 TomB, you need a 7mm hole. The washer trick will be fine but M7 washers - good luck! I bet you end up with something similar, maybe an imperial size. 1/4 UNF has a nominal major dia of 6.35mm, so you'll cram a 7mm rivnut through with luck. You can solve this with the rubber rivnut affairs. I was flogging some a while back, but the sale stalled. Link to comment Share on other sites More sharing options...
TomB Posted December 18, 2007 Author Share Posted December 18, 2007 Ive got some nice big M6 washers which I can put in the vice & open up to M7 with my new shiny M7 steel drill bit, then use under the rivnuts. Ill get it right on the vertical bulkhead! Link to comment Share on other sites More sharing options...
Roger Ford Posted December 18, 2007 Share Posted December 18, 2007 M7 washers Those are 1.5mm, which seems a bit thick. 1.1mm here and they're cheaper (smaller pack, but I imagine 25 is enough. Drilling out washers isn't easy - it's hard to grip them tight enough in a vice so they don't spin or get crushed. Edited by - Roger Ford on 18 Dec 2007 13:36:24 Link to comment Share on other sites More sharing options...
TomB Posted December 18, 2007 Author Share Posted December 18, 2007 Another solution would be to drilled out an ali disk from my old panel & turn into an ali M7 washer. Or buy some M7 washers like roger says. Link to comment Share on other sites More sharing options...
I.Mupferit Posted December 18, 2007 Share Posted December 18, 2007 I wouldn't worry too much Tom. We use Rivnuts all the time in my factory and they will expand to fit larger holes as I know only too well when some of the guys have picked up the wrong size drill. One tip I would offer is to put a smear of Loctite around the shoulders of the Rivnut before inserting it in the hole. That will help fix it in place. Brent (aka Arfur Nayo) 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
Area Representative Crudders Posted December 18, 2007 Area Representative Share Posted December 18, 2007 Are you using M4 or M5 fixings Tom? If M5, the large flange (snigger) ribbed (chortle) threaded inserts that came in my AVK Threaded Insert Kit courtesy of RS Components (same as Brent's as it happens) require a 7.6mm hole, which is as near to 8mm as makes no difference. RS sell them separately @ about a tenner + VAT for a bag of 100. Oh, and Brent's Loctite tip is a good one which I've used myself on many occasions Crudders Link to comment Share on other sites More sharing options...
millsn Posted December 18, 2007 Share Posted December 18, 2007 I'm not convinced it needs to close the gap up. As long as you can stop it spinning until it bears down on the mating parts that you are bolting to the riv nut it should flare out enough to prevent pullout. The torque out is limited by the friction between the surface of the part you are bolting to it, not the grip to the parent (skin panel) material Link to comment Share on other sites More sharing options...
I.Mupferit Posted December 18, 2007 Share Posted December 18, 2007 Btw, the RS Components Rivnuts that Crudders refers to have a splined outer surface that grips much better on to the parent metal thus avoiding the problems often associated with the cheap and nasty 'smooth' type. Coupled with Loctite, we have never had one start to spin on the dozens of jobs completed in my factory. Tom, if you are using M5, and you only need a few, drop me a blatmail with your address and I'll pop some in the post. As Crudders says, they need a 7.6mm hole which is very close to your 8mm. Brent (aka Arfur Nayo) 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
Irrelevant Posted December 18, 2007 Share Posted December 18, 2007 In my experience, rivnut holes in thin ally need to be right - especially if you use steel rivnuts as these have a tiny outer lip. ALly rivnuts tend to have a larger outer lip. Washer trick is useful - used it many times on rear wing mounts. You could always use bigger rivnuts I spose. I often use a bit of JB Weld (good stuff) round the back of a rivnut to help hold it in place - bit like Brent does with his loctite. Once the barstewards start spinning, they're a real pain in the 🙆🏻 Link to comment Share on other sites More sharing options...
TomB Posted December 19, 2007 Author Share Posted December 19, 2007 Hi Brent, Ill blatmail you Link to comment Share on other sites More sharing options...
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