mark260463 Posted April 10, 2005 Share Posted April 10, 2005 I am just about to fit my petty strut and have a query re the bolt size that mounts in the foot well. I know the size should be 7/16th UNF, however this just spins in the bush - I have bent the trim panel back as far as I can to get a good look and it does not appear to be either spinning or cross threaded. I have tired an M10 metric and it goes in fine ? 1) Has anyone come across this or got any views? 2) Do Arch use an M10 similar bush elsewhere on the car and could have got them mixed up ? Mark 20 years with no points then I buy this bloody thing Link to comment Share on other sites More sharing options...
Tony C Posted April 10, 2005 Share Posted April 10, 2005 The one on my 2003 SV is M10 x 1.25 (I measured 11mm dia on the "top" of the thread and 10mm dia on the "bottom" - if you know what I mean 😬 ) it's that upon which I'm basing the M10, the thread gauge showed 1.25 BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery) Link to comment Share on other sites More sharing options...
mark260463 Posted April 10, 2005 Author Share Posted April 10, 2005 Tony Thanks - yes that makes perfect sense, interesting (mine ias a 2004 R400) maybe they are going metric after all, makes sense as the top bolts are metric. Mark 20 years with no points then I buy this bloody thing Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted April 10, 2005 Area Representative Share Posted April 10, 2005 I think you'll find that it it is a UNF thread! I'd be very cautious anout going from the tread guage! 7/16UNF is 20 tpi, which works out a 1.27mm pitch! Too close to check with a thread guage unless you've a long thread guage! you'd be looking for less than .4mm over the normal 15mm of a thread guage! Mark, are you sure its a 7/16 UNF bolt that you're using? What size spanner fits it? Link to comment Share on other sites More sharing options...
V7 SLR Posted April 10, 2005 Share Posted April 10, 2005 If it helps, it's the same thread as the seatbelt mountings. Link to comment Share on other sites More sharing options...
simonbell Posted April 10, 2005 Share Posted April 10, 2005 I`m pretty sure it`s 7/16" UNF Simon Bell - Caterham 7 Duratec R I`ve seen the future.....and it`s powered by duratec Check out the website here Link to comment Share on other sites More sharing options...
Englishmaninwales Posted April 10, 2005 Share Posted April 10, 2005 Mine was 7/16'' UNF, but was tight. Link to comment Share on other sites More sharing options...
mark260463 Posted April 10, 2005 Author Share Posted April 10, 2005 Guys Having stripped the car - it is without doubt M10 As I said the 7/16th UNF just pushed straight through the hole. It may be that Arch brazed the wrong one in - but who cares now I know what it is Mark 20 years with no points then I buy this bloody thing Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted April 10, 2005 Area Representative Share Posted April 10, 2005 But 7/16UNF is bigger than M10. So its either smaller than 7/16UNF, or bigger than M10 *confused* An M10 bolt may APPEAR to fit, but may only just be catching in the socket! Link to comment Share on other sites More sharing options...
Mr Locust Posted April 10, 2005 Share Posted April 10, 2005 Mine had powder coat in the thread and needed the thread cleaning out. Definitely not 10mm on mine. Most likely 7/16"unf as others have said as chassis fittings are generally UNF. Ian Green and Silver Roadsport 😬 Link to comment Share on other sites More sharing options...
Tony C Posted April 11, 2005 Share Posted April 11, 2005 Just checked and metric thread size is the male thread diameter - so the bolt that fits my Petty Strut, being 11mm diameter is NOT an M10. I'm trying to discover how a 7/16" UNF bolt is physically measured - anyone know? If one bolt you have runs in OK and one doesn't - use the one that fits 😬 BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery) Link to comment Share on other sites More sharing options...
Tony C Posted April 11, 2005 Share Posted April 11, 2005 Just checked and metric thread size is the male thread diameter - so the bolt that fits my Petty Strut, being 11mm diameter is NOT an M10. I'm trying to discover how a 7/16" UNF bolt is physically measured - anyone know? If one bolt you have runs in OK and one doesn't - use the one that fits 😬 BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery) Link to comment Share on other sites More sharing options...
Tony C Posted April 11, 2005 Share Posted April 11, 2005 Bother - sorry 😬 BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery) Link to comment Share on other sites More sharing options...
mark260463 Posted April 11, 2005 Author Share Posted April 11, 2005 OK Final result. After talking to Bruce at Arch. They fit 7/16th, and then after fitting they are all run through with a tap to clean them out - so even if a "rougue" M10 had got bthough the tapping process would have identified it. So - with a great deal of courage I tapped mine and yes, it was 7/16th and not M10. I did a load of experimnenting first and yes an M10 bolt would appear to go corretclty into a 7/16th nut, but not quite. Thanks to all those who contributed..............just goes to show that perfection and persistance counts when fitting safety items. Mark Mark 20 years with no points then I buy this bloody thing Link to comment Share on other sites More sharing options...
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