MiataMark
Club Retro Rides Member
Posts: 2,954
Club RR Member Number: 29
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screw threadsMiataMark
@garra
Club Retro Rides Member 29
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I've bought a new seat (Sparco) for my MX5 and like an idiot forgot to buy the seat fixing bolts, as a temporary measure I thought I was bound to have some bolts hanging about. The screw spec is M8 12.9 1.25 25mm (M8 8mm thread, 12.9 high tensile, and 1.25 screw thread? 25mm long). I tried some M8 bolts I have (Screwfix) and they don't fit the thread so I'm guessing the high tensile screws use a closer thread?
I can't find a supplier open on a Saturday (unless I go to Merlin at Castle Combe).
Or am I missing something?
Ignore this , I'm an idiot the M8 bolts I have do fit (well they're too long) so will get some shorted ones from Screwfix tomorrow so I can mock up the seats while I wait for some proper high tensile bolts to arrive.
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Last Edit: Aug 2, 2019 17:06:50 GMT by MiataMark
1990 Mazda MX-52012 BMW 118i (170bhp) - white appliance 2011 Land Rover Freelander 2 TD4 2003 Land Rover Discovery II TD52007 Alfa Romeo 159 Sportwagon JTDm
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they don't need to be 12.9, a standard 8.8 would suffice (12.9 is hard to find in smaller sizes) they're still strong.
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screw threadsDeleted
@Deleted
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12.9 will only be available in socket head capscrew. 8.8 is the beginnings of hi tensile 10.6 is better 1.25 is standard metric M8 thread
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Last Edit: Aug 2, 2019 18:07:47 GMT by Deleted
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Dez
Club Retro Rides Member
And I won't sit down. And I won't shut up. And most of all I will not grow up.
Posts: 11,710
Club RR Member Number: 34
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screw threadsDez
@dez
Club Retro Rides Member 34
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Anything greater than 8.8 is entirely unnecessary.
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MiataMark
Club Retro Rides Member
Posts: 2,954
Club RR Member Number: 29
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screw threadsMiataMark
@garra
Club Retro Rides Member 29
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1990 Mazda MX-52012 BMW 118i (170bhp) - white appliance 2011 Land Rover Freelander 2 TD4 2003 Land Rover Discovery II TD52007 Alfa Romeo 159 Sportwagon JTDm
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If you need to comply with FIA regs, isn't 12.9 specified (don't have the regs to hand to check) ? Trackdays I dare say you could use aluminium.
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MiataMark
Club Retro Rides Member
Posts: 2,954
Club RR Member Number: 29
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screw threadsMiataMark
@garra
Club Retro Rides Member 29
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If you need to comply with FIA regs, isn't 12.9 specified (don't have the regs to hand to check) ? Trackdays I dare say you could use aluminium. Aluminium sounds expensive I'm sure tie-wraps would do Although I don't need to comply with FIA regs for the sake of <£5 I'll use the proper bolts.
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1990 Mazda MX-52012 BMW 118i (170bhp) - white appliance 2011 Land Rover Freelander 2 TD4 2003 Land Rover Discovery II TD52007 Alfa Romeo 159 Sportwagon JTDm
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I almost said nylon but thought that might be a bit much :-)
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i looked up the MSA blue book to double check before posting yesterday, and the only wording is min 8mm fasteners, I have been involved in building a few rally cars couple have been through logbooking process recently without issue with the seats.
harness eye bolts are specified to the letter though.
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Interesting - I thought either Article 253 or FIA 8855 specified the bolts for seatmount-to-seat as 12.9 8mm min but it doesn't, I've just checked - it just says 8mm min so to the letter of the regs 8mm nylon would suffice... 8.8 8mm min are specified for mount-to-car.
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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screw threadsslater
@slater
Club Retro Rides Member 78
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Aug 12, 2019 12:07:01 GMT
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I think you will find theres a more general regulation covering aluminium fasteners in there somewhere. The regs tend to do that sort of thing..
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