dan9090 Posted October 19, 2008 Share Posted October 19, 2008 I'm still pretty new to getting my hands dirty repairing or modding my truck and everytime I do (and need to replace a bolt/nut) I do get confused over what I need. I dont know the difference between UNC / UNF etc and I dont fully understand the grading system used on the bolt heads, imperial/metric etc. Can this all be summarised by someone more knowledge than me? Fed up of paying individual prices everytime I need a bolt I was hoping to buy a bulk pack of rated/graded bolts for future use but will wait to see what responses come to this thread first! Quote Link to comment Share on other sites More sharing options...
Warthog Posted October 19, 2008 Share Posted October 19, 2008 This may help? http://www.boltscience.com/pages/info.htm Mark Quote Link to comment Share on other sites More sharing options...
secondjeremy Posted October 19, 2008 Share Posted October 19, 2008 By and large at the end of the 1930's the British motor industry was using the BSF (British Standard Fine) thread standard for its fixings. Other parts of industry used BSW (British Standard Whitworth) threads but the head sizes were simialr even if they had different size designations and the BSW head sizes had been re-calibrated. One of the exceptions was Morris engines which used what was essentially a metric thread with BSF head. This is another story. BSF threads are quite fine and so considered not the best for fixings in soft alloy castings - so its common to find a BSW thread used there. All was happy until about 1948 when it was universally decided that the UK should standardise on the American Unified threads (UNFine and UNCoarse) The more common is the UNF thread which is finer than BSF and has smaller heads with the head being measured across the flats (AF) In 1948 the Land Rover hatched and being the latest technology it used BSF threads for most applications. In the late 50's or early 60's it was decided that the UK should now standardise on the Metric thread system - so the series 2 Land Rover was introduced with Unified (UNF) threads. In fact they seem only to have been applied to the new bits - so you find plenty of BSF threads which were left there to remind mechanics of their youth when they worked with BSF all the time unless they were dealing with a Morris. Now we come to a first - which was the original Range Rover 4 speed gearbox - you know the one - on which it was virtually impossible to change gear - which was the British motor industry's first encounter with Metric threads - which now largely rule the world. Well almost - the USA still sticks to imperial sizes and its Unified system. For sizes etc why not download the Zeus tables linked at the top of the tools and fabrication forum. Many details on Namrick site - including hardness at the end. http://www.namrick.co.uk/browse.asp?PCID=14 Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted October 19, 2008 Share Posted October 19, 2008 In simple terms Numbers on bolt heads show the steel strength 8.8 std then 10.9 12.8 etc etc, An M on the head means metric BSF UNF BA and other fine threaded bolts and nuts when intermixed, or if you are rummaging about in that "Bucket" on the floor are next to impossible to get the right F nut for the F bolt in your F hand, They all SEEM to be correct, then you try to do them up and F me is it the thread slightly damaged or has 'one' the wrong F nut ? 10 nuts later much swearing and you may still try that 1st one that you threw across the garage in a complete paddy as it may have been right, or your ham fisted attempts to get that F B of a F nut to fit with a couple of tweaks with a pair of spanners means you have now invented a F USFBSF-F-Boll*xedNPT F Thread, Stupidly you may even throw that now F bolt back into the bucket to amuse you 7 months into the future when you pick it up and go AH HA just the job I was looking for ................... Whitworth, (BSW) and UNC (anglo saxon words do seem appropraite) are often in places next to impossible to get the new bolt and nut into, They also seem to all match for one and 4/7th of a F turns after you get under / in there and try, they fly slighlty better due to there extra weight. Nylocs with blue should be Metric, or as I sometimes say after about 30 mins rummaging "F Metric B Thread". These are definately metric (unless you have previously shoved it somewhere and wound in that NPT BSF manchester bycycle F threaded bolt that F all seem to fit..... and you then returned the Blue Metric screwed nut to the 'fun bucket' for future fun - ie now..... White isn't metric, ....but you will still belive it sometimes it F is .....and try for hours mumbling..... Allen bolts are even more 'fun' when you cross thread them. The super F high tensile shaft means hours of fun and swearing trying to cut with a broken bit of hacksaw in an unbelivably ludicrously tight space, you only just nipped it up a tad now its F solid, and wobbly, won't do up and worse won't F unfo - trying to get bolt croppers in that won't f fit cos there no enough room just makes you go purple and scream inside. Metric Bolts and Imperial spanners mean either a bolt head F jammed so F tight you can't get the F off, or that "loose" fit where on final tighening grunt the spanner will round off the head of the bolt and smack you around the head / ear Torx screws are the invention of the devil when he understood his first attempt of allen bolts wasn't as bad as he thought, "MetricInch" universal cr*p for fitting both metric and imperial is universally F horrible as it doesn't seem to fit either too well under force - but there is a magnetic attraction to your shins, boney bits and tender bits including knuckles fingers and lips Next to a full AF Metric and whitworth socket set the next most useful thing is a Spanner set for the same, and next the these a Anglegrinder, bolt croppers and hacksaw blades However the most importnat key things are a decent tin of bandages, TCP and beer HTH Nige Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 19, 2008 Share Posted October 19, 2008 A handy thing to have around, both for fixings and also things like hydraulic fittings, is a thread identification kit. A basic vernier calliper can also help with any number of tasks. If you're making stuff, try to stick to metric. Namrick do party packs of nuts & bolts, or you can hit Screwfix and buy a pack of 50 or 100 of each of several popular sizes for not too much money - I can't remember exactly but I stocked up something like 100 each of M6 and M8 bolts in 20mm, 30mm, 50mm, nuts, nylock nuts, and washers. Bigger stuff you probably don't want to bulk buy, and smaller stuff is not much use on most LR related projects. Another good general rule is to get a decent wall-drive socket set, these will often fit metric & imperial sizes and being hex rather than 12-point they get a better grip and are less likely to round heads off. If you need spanners, buy a metric & imperial set as trying to undo one with the other doesn't often end well. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted October 20, 2008 Share Posted October 20, 2008 In simple termsNumbers on bolt heads show the steel strength 8.8 std then 10.9 12.8 etc etc, An M on the head means metric BSF UNF BA and other fine threaded bolts and nuts when intermixed, or if you are rummaging about in that "Bucket" on the floor are next to impossible to get the right F nut for the F bolt in your F hand, They all SEEM to be correct, then you try to do them up and F me is it the thread slightly damaged or has 'one' the wrong F nut ? 10 nuts later much swearing and you may still try that 1st one that you threw across the garage in a complete paddy as it may have been right, or your ham fisted attempts to get that F B of a F nut to fit with a couple of tweaks with a pair of spanners means you have now invented a F USFBSF-F-Boll*xedNPT F Thread, Stupidly you may even throw that now F bolt back into the bucket to amuse you 7 months into the future when you pick it up and go AH HA just the job I was looking for ................... Whitworth, (BSW) and UNC (anglo saxon words do seem appropraite) are often in places next to impossible to get the new bolt and nut into, They also seem to all match for one and 4/7th of a F turns after you get under / in there and try, they fly slighlty better due to there extra weight. Nylocs with blue should be Metric, or as I sometimes say after about 30 mins rummaging "F Metric B Thread". These are definately metric (unless you have previously shoved it somewhere and wound in that NPT BSF manchester bycycle F threaded bolt that F all seem to fit..... and you then returned the Blue Metric screwed nut to the 'fun bucket' for future fun - ie now..... White isn't metric, ....but you will still belive it sometimes it F is .....and try for hours mumbling..... Allen bolts are even more 'fun' when you cross thread them. The super F high tensile shaft means hours of fun and swearing trying to cut with a broken bit of hacksaw in an unbelivably ludicrously tight space, you only just nipped it up a tad now its F solid, and wobbly, won't do up and worse won't F unfo - trying to get bolt croppers in that won't f fit cos there no enough room just makes you go purple and scream inside. Metric Bolts and Imperial spanners mean either a bolt head F jammed so F tight you can't get the F off, or that "loose" fit where on final tighening grunt the spanner will round off the head of the bolt and smack you around the head / ear Torx screws are the invention of the devil when he understood his first attempt of allen bolts wasn't as bad as he thought, "MetricInch" universal cr*p for fitting both metric and imperial is universally F horrible as it doesn't seem to fit either too well under force - but there is a magnetic attraction to your shins, boney bits and tender bits including knuckles fingers and lips Next to a full AF Metric and whitworth socket set the next most useful thing is a Spanner set for the same, and next the these a Anglegrinder, bolt croppers and hacksaw blades However the most importnat key things are a decent tin of bandages, TCP and beer HTH Nige Oh, GOD that is so accurate! I thought it was just me!! G. Quote Link to comment Share on other sites More sharing options...
Justin_T Posted October 20, 2008 Share Posted October 20, 2008 Thats really useful, thanks. Quote Link to comment Share on other sites More sharing options...
Mark Posted October 20, 2008 Share Posted October 20, 2008 I have a slightly different philosophy to most regarding nuts and bolts... That is, that if a 1/4 UNF bolt came out of a hole, then a 1/4 UNF bolt should go back in it... Yes, M6 is a reasonable replacement, can be stronger, cheaper and more readily available, but next time when I go to undo it I will know that a 7/16 AF spanner/socket fits that bolt, and invariably the other 4 used to hold on whatever it is I am taking off. It has served me well, as when I restored my IIA I stuck to this rule, and I now know there are No Metric nuts and bolts on that vehicle whatsoever. Granted there is still the motley collection of UNF/UNC/BSF/BSW and (believe it or not) BA threads that it left the factory with, but I only ever have to take and Imperial socket set/spanners with me which cuts my tool kit in half. just a thought... It's not been mentioned yet, but the ratings on the bolts (8.8, 10.8, 12.9 etc) refer to a combination of the breaking strain, and the point at which the bolt starts to deform irreversibly as a percentage. That is an 8.8 bolt will break at 800 Nm per mm^2 and start to deform at 80% of it's breaking strain. The higher the percentage, the less warning you will have that it is going to break - ie the material is more brittle. In the case of 12.9 bolts, they deform less, but you have to but an awful lot more force into them to get them to deform in the first place.... hope that helps. Mark Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 21, 2008 Share Posted October 21, 2008 Ha Ha Nige, very funny because it is all true. I still remember my yoof trying to fix bicycles with BSW and AF spanners until I found out that the Industry had managed to come up with a completely different 'bicycle' thread. And as for bl@@dy BA which (believe it or not) has spanner sizes in inches but the threads are metric, but not any metric known on this planet. What always amazed me in all this time is that the world has managed to standardise on only two threads, one being the Metric spark plug sizes and the other is..... A correct guess gets a banana, or at least a picture of one (There may, of course be other standards that I have not come across yet) Quote Link to comment Share on other sites More sharing options...
Mark Posted October 21, 2008 Share Posted October 21, 2008 7/16 UNF on Seatbelt mounts? Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 21, 2008 Share Posted October 21, 2008 You are right (I think) but that's not the one I was thinking of. As a clue, this standard thread goes back to 1890..... Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted October 21, 2008 Share Posted October 21, 2008 ... And as for bl@@dy BA which (believe it or not) has spanner sizes in inches but the threads are metric, but not any metric known on this planet. "In 1864 in America, ... Around the same time metric thread standards were being adopted in continental Europe with a number of different thread flank angles being adopted. For example the German Loewenherz had a thread flank angle of 53 degrees 8 minutes and the Swiss Thury thread an angle of 47.5 degrees. The standard international metric thread eventually evolved from German and French metric standards being based upon a 60 degree flank angle with flat crests and rounded roots. " "BA Thread Form: This thread was used for small diameter threads (below 0.25 inches diameter). The thread has radiused roots and crests and has a flank angle of 47 degrees and a half degrees. The thread size varies from BA number 23 (0.33 mm diameter with a pitch of 0.09 mm) to BA number 0 (6mm diameter with a pitch of 1 mm). Relative to the Whitworth thread the depth of the BA thread is smaller size for size. The thread form is now redundant and has been replaced by Unified and Metric threads." So, blame the Swiss :-) Information from pages on the site http://www.boltscience.com/index.htm? Quote Link to comment Share on other sites More sharing options...
Mark90 Posted October 21, 2008 Share Posted October 21, 2008 What always amazed me in all this time is that the world has managed to standardise on only two threads, one being the Metric spark plug sizes and the other is..... Camera tripod fixing screw, 1/4" BSW. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 21, 2008 Share Posted October 21, 2008 Another standard I reckon. But my LR doesn't have a camera mount Quote Link to comment Share on other sites More sharing options...
Mark90 Posted October 21, 2008 Share Posted October 21, 2008 I'd be suprised if it had spark plugs Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 21, 2008 Share Posted October 21, 2008 Schrader valves on tyres, just about the only universal standard. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 21, 2008 Share Posted October 21, 2008 Schrader valves on tyres, just about the only universal standard. Quote Link to comment Share on other sites More sharing options...
Drillerjoskin Posted October 21, 2008 Share Posted October 21, 2008 Schrader valves on tyres, just about the only universal standard. D'oh, beat me to that one!!! Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 22, 2008 Share Posted October 22, 2008 I'd be suprised if it had spark plugs Well LR obviously think the TD5 has eight spark plugs if you RTF Genuine Manual. They don't say which of the cylinders has two plugs and which have one though. Maybe this is why the standard toolkit comes with a plug spanner Quote Link to comment Share on other sites More sharing options...
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