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How to identify a metric thread?
I want to replace some damaged bolts. I know they are metric thread,
but don't know what size they are. What dimension do I need to measure to determine this please? Thanks David |
How to identify a metric thread?
Lobster wrote:
I want to replace some damaged bolts. I know they are metric thread, but don't know what size they are. What dimension do I need to measure to determine this please? Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. -- Grunff |
How to identify a metric thread?
Grunff wrote:
Lobster wrote: I want to replace some damaged bolts. I know they are metric thread, but don't know what size they are. What dimension do I need to measure to determine this please? Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Thanks - looks like 4.5mm, which I don't believe! (don't have anything other than a ruler on me to measure it tho). I've just found a nut which matches it - this takes an 8mm spanner. That should define a specific thread size too, shouldn't it? Thanks David |
How to identify a metric thread?
On Wed, 22 Mar 2006 14:50:04 +0000, Grunff wrote:
|Lobster wrote: | I want to replace some damaged bolts. I know they are metric thread, | but don't know what size they are. What dimension do I need to measure | to determine this please? | | |Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Or a bit of undamaged shaft, 10mm is M10 It is also a good idea to get another bolt of the thread you thing it is, and check that the thread pitch is the same, by matching the two threads together. ############### \/\/\/\/\/\/\/\ \/\/\/\/\/\/\/\ ############### Roughly like that, works OK even on mangled bolts I have lots of Whitworth, Unified, BSF, BA etc. bolts which I keep in case I need them ?sometime? -- Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst* method of accessing usenet. GG subscribers would be well advised get a newsreader, say Agent, and a newsserver, say news.individual.net. These will allow them: to see only *new* posts, a killfile, and other goodies. |
How to identify a metric thread?
Lobster wrote:
Thanks - looks like 4.5mm, which I don't believe! (don't have anything other than a ruler on me to measure it tho). I've just found a nut which matches it - this takes an 8mm spanner. Most likely M5. That should define a specific thread size too, shouldn't it? No, it doesn't define it - it just hints at it :-) You can have different head sizes for a given screw size. M5s commonly have 8mm heads, but not always. -- Grunff |
How to identify a metric thread?
Dave Fawthrop wrote: On Wed, 22 Mar 2006 14:50:04 +0000, Grunff wrote: |Lobster wrote: | I want to replace some damaged bolts. I know they are metric thread, | but don't know what size they are. What dimension do I need to measure | to determine this please? | | |Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Or a bit of undamaged shaft, 10mm is M10 How is that different to measuring the outside of the thread? It is also a good idea to get another bolt of the thread you thing it is, and check that the thread pitch is the same, by matching the two threads together. If you're going to go getting, I'd rather get a nut and try it for size. MBQ |
How to identify a metric thread?
On Wed, 22 Mar 2006 15:24:24 +0000, Dave Fawthrop
wrote: I have lots of Whitworth, Unified, BSF, BA etc. bolts which I keep in case I need them ?sometime? Foolish boy, everyone knows the keeping of such bolts is to ward off the need for them. If you have them you will never need them, if you don't you certainly will. -- Peter Parry. http://www.wpp.ltd.uk/ |
How to identify a metric thread?
The message
from Dave Fawthrop contains these words: |Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Or a bit of undamaged shaft, 10mm is M10 Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. -- Skipweasel Pay no attention to the man behind the curtain. |
How to identify a metric thread?
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How to identify a metric thread?
On Wed, 22 Mar 2006 16:13:37 GMT, Guy King wrote:
|The message |from Dave Fawthrop contains these words: | | |Measure the diameter of the bolt, to the outside of the thread. 10mm | is M10. | | Or a bit of undamaged shaft, 10mm is M10 | |Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. I just thought of that as well, so a bolt with a thoroughly mashed up rolled thread is difficult to identify. -- Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst* method of accessing usenet. GG subscribers would be well advised get a newsreader, say Agent, and a newsserver, say news.individual.net. These will allow them: to see only *new* posts, a killfile, and other goodies. |
How to identify a metric thread?
On Wed, 22 Mar 2006 17:12:26 +0000, Chris Bacon
wrote: |Lobster wrote: | I want to replace some damaged bolts. I know they are metric thread, | but don't know what size they are. What dimension do I need to measure | to determine this please? | |Measure the diameter, which will tell you something - then |the pitch. If you've really got 4.5mm then the pitch should |be 0.75mm (coarse) or 0.5mm (fine). Measure a number of |threads to get a more accurate figure. You could go to a |hardware shop, if you know of a good one, and compare the |thread of what you've got with the ones they stock. Better to buy a huge box of various Metric nuts, bolts, washers etc. next time Lidl have them, then you always have something roughly right in stock. -- Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst* method of accessing usenet. GG subscribers would be well advised get a newsreader, say Agent, and a newsserver, say news.individual.net. These will allow them: to see only *new* posts, a killfile, and other goodies. |
How to identify a metric thread?
Dave Fawthrop wrote:
On Wed, 22 Mar 2006 17:12:26 +0000, Chris Bacon wrote: |Lobster wrote: | I want to replace some damaged bolts. I know they are metric thread, | but don't know what size they are. What dimension do I need to measure | to determine this please? | |Measure the diameter, which will tell you something - then |the pitch. If you've really got 4.5mm then the pitch should |be 0.75mm (coarse) or 0.5mm (fine). Measure a number of |threads to get a more accurate figure. You could go to a |hardware shop, if you know of a good one, and compare the |thread of what you've got with the ones they stock. Better to buy a huge box of various Metric nuts, bolts, washers etc. next time Lidl have them, then you always have something roughly right in stock. Yep I've got a reasonable collection, for that very reason (I found a matching nut in there!); however this is actually a specific need for countersunk socket screws rather than bolts, and I don't have those. And as each bolt in my 'collection' isn't stamped with its size, that makes me none the wiser as to which I need! As it is, I wanted this info to include in a Screwfix order today, and as I see they don't go below M6 for these, that's unfortunately a non-starter. So a trog down to my local nuts'n bolt emporium, ie with the old bolt, is called for anyway. Thanks David |
How to identify a metric thread?
The message
from Dave Fawthrop contains these words: |Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. I just thought of that as well, so a bolt with a thoroughly mashed up rolled thread is difficult to identify. Still reckon the best way is to take it to a shop and mesh threads with other bolts till you find a match. Or, better yet, an industrial fastener specialist. There's one in most towns if you know where to look. -- Skipweasel Pay no attention to the man behind the curtain. |
How to identify a metric thread?
On Wed, 22 Mar 2006 19:08:42 GMT, Guy King wrote:
|The message |from Dave Fawthrop contains these words: | | |Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. | | | I just thought of that as well, so a bolt with a thoroughly mashed up | rolled thread is difficult to identify. | |Still reckon the best way is to take it to a shop and mesh threads with |other bolts till you find a match. | |Or, better yet, an industrial fastener specialist. There's one in most |towns if you know where to look. Ours local Bolt and Nut specialist is *very* amiable -- Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst* method of accessing usenet. GG subscribers would be well advised get a newsreader, say Agent, and a newsserver, say news.individual.net. These will allow them: to see only *new* posts, a killfile, and other goodies. |
How to identify a metric thread?
In article ,
Lobster wrote: Yep I've got a reasonable collection, for that very reason (I found a matching nut in there!); however this is actually a specific need for countersunk socket screws rather than bolts, and I don't have those. And as each bolt in my 'collection' isn't stamped with its size, that makes me none the wiser as to which I need! Get a cheap set of taps and dies from a local market or Ebay, etc. They may not be much use for what they're meant to do but are ok for identifying threads. -- *Never kick a cow pat on a hot day * Dave Plowman London SW To e-mail, change noise into sound. |
How to identify a metric thread?
Dave Plowman (News) wrote:
In article , Lobster wrote: Yep I've got a reasonable collection, for that very reason (I found a matching nut in there!); however this is actually a specific need for countersunk socket screws rather than bolts, and I don't have those. And as each bolt in my 'collection' isn't stamped with its size, that makes me none the wiser as to which I need! Get a cheap set of taps and dies from a local market or Ebay, etc. They may not be much use for what they're meant to do but are ok for identifying threads. I saw a 'thing of purpose' for this recently, I used it in the shop to check that the thread of an elusive ceramic tap fitting I was buying was the same as the original. It was just a metal sheet with mabye 20ish threaded holes in it. Designed for plumbing fittings but there were alot of holes, I imagine it had some ordinary metric threads in there. And did I buy one - no! I'm going to regret that one day.....but now at least I know where to get one from should the need arise. -- Holly, in France Gite to let in Dordogne, now with pool. http://la-plaine.chez-alice.fr |
How to identify a metric thread?
The message
from "Dave Plowman (News)" contains these words: *Never kick a cow pat on a hot day * Never kick a camel turd at all if the SOE have been in the area. -- Skipweasel Pay no attention to the man behind the curtain. |
How to identify a metric thread?
On Wed, 22 Mar 2006 19:17:43 +0000, Dave Fawthrop
wrote: On Wed, 22 Mar 2006 19:08:42 GMT, Guy King wrote: |The message |from Dave Fawthrop contains these words: | | |Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. | | | I just thought of that as well, so a bolt with a thoroughly mashed up | rolled thread is difficult to identify. | |Still reckon the best way is to take it to a shop and mesh threads with |other bolts till you find a match. | |Or, better yet, an industrial fastener specialist. There's one in most |towns if you know where to look. Our local Bolt and Nut specialist is *very* amiable Our local Industrial Fastener Specialist I.F.S. is very expensive. Best go there and get them to identify the thread and order the screws from Maplin/Farnells/RS etc. DG |
How to identify a metric thread?
Lobster brought next idea :
I want to replace some damaged bolts. I know they are metric thread, but don't know what size they are. What dimension do I need to measure to determine this please? Thanks David Some have their size stamped upon the head of the bolt. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
How to identify a metric thread?
Lobster wrote:
Grunff wrote: Lobster wrote: I want to replace some damaged bolts. I know they are metric thread, but don't know what size they are. What dimension do I need to measure to determine this please? Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Thanks - looks like 4.5mm, which I don't believe! (don't have anything other than a ruler on me to measure it tho). 4.5 mm is close enough to 5 mm to get it wrong. How certain are you that you have metric threads? At this difference, parallax errors are quite large. You might have a 5 mm thread, but are reading it a little too small at 4.5 mm. Find a bolt that you are certain of its size and compare diam. and thread pitch, as someone else has mentioned. 4.8 mm is 3/16 of an inch and that is too close to 5 mm to be sure either way. Dave I've just found a nut which matches it - this takes an 8mm spanner. That should define a specific thread size too, shouldn't it? 8 mm is the same as 5/16 th of an inch, so beware until you know what thread you are seeing. Dave |
How to identify a metric thread?
Guy King wrote:
The message from Dave Fawthrop contains these words: |Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Or a bit of undamaged shaft, 10mm is M10 Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. In the year 2006 when was the last time you saw a cut thread? I'll bet it was a long time ago. Cutting a thread costs a lot more than rolling them. Dave |
How to identify a metric thread?
Lobster wrote:
I want to replace some damaged bolts. I know they are metric thread, but don't know what size they are. What dimension do I need to measure to determine this please? I often need to identify threads, without even knowing whether they are metric or not. So I use this chart. The bit you want would be somewhere in the middle. The diameter is the width to the outside of the thread, and that may be slightly smaller than on the chart. Also count the distance that 10 threads take, to work out the pitch. Type Size Dia Inch TPI Dia mm Pitch mm BSW 5/32 0.15625 32 3.97 0.79 MF 4 0.157 50.80 4 0.5 M 4 0.157 36.29 4 0.7 BA 3 0.1614 34.84 4.10 0.73 M 4.5 0.177 33.87 4.5 0.75 BA 2 0.185 31.35 4.70 0.81 BSF 3/16 0.1875 32 4.76 0.79 BSW 3/16 0.1875 24 4.76 1.06 MF 5 0.197 50.80 5 0.5 M 5 0.197 31.75 5 0.8 BA 1 0.2067 28.25 5.25 0.90 BSW 7/32 0.21875 24 5.56 1.06 BSF 7/32 0.2188 28 5.56 0.91 BA 0 0.2362 25.38 6.00 1.00 MF 6 0.236 33.87 6 0.75 M 6 0.236 25.40 6 1 UNEF 1/4 0.25 32 6.35 0.79 UNF 1/4 0.25 28 6.35 0.91 BSF 1/4 0.25 26 6.35 0.98 BSW 1/4 0.25 20 6.35 1.27 UNC 1/4 0.25 20 6.35 1.27 BA British Association BSF British Standard Fine BSW British Standard Whitworth M Metric Coarse MF Metric Fine UNC Unified Coarse UNEF Unified Extra Fine UNF Unified Fine TPI Threads Per Inch |
How to identify a metric thread?
In message , Dave
writes Guy King wrote: The message from Dave Fawthrop contains these words: |Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Or a bit of undamaged shaft, 10mm is M10 Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. In the year 2006 when was the last time you saw a cut thread? I'll bet it was a long time ago. Cutting a thread costs a lot more than rolling them. By another 9p / packet in the budget -- geoff |
How to identify a metric thread?
raden wrote:
In message , Dave writes Guy King wrote: The message from Dave Fawthrop contains these words: |Measure the diameter of the bolt, to the outside of the thread. 10mm is M10. Or a bit of undamaged shaft, 10mm is M10 Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. In the year 2006 when was the last time you saw a cut thread? I'll bet it was a long time ago. Cutting a thread costs a lot more than rolling them. By another 9p / packet in the budget Not yet seen the budget :-) or :-) So I don't know. Other wise, I'll understand that better in the morning Dave |
How to identify a metric thread?
"Guy King" wrote in message ... .... Still reckon the best way is to take it to a shop and mesh threads with other bolts till you find a match.... The best way is a shadowgraph machine, but taking it to a shop is a lot cheaper if you don't already have a shadowgraph. Colin Bignell |
How to identify a metric thread?
nightjar
"Guy King" wrote in message ... ... Still reckon the best way is to take it to a shop and mesh threads with other bolts till you find a match.... The best way is a shadowgraph machine, but taking it to a shop is a lot cheaper if you don't already have a shadowgraph. What a good idea. As it happens, the department next door has something like that. A backlit or frontlit item can be magnified up to 100 times and displayed on a screen. This is what I need to tell the difference between Whitworth and Unified threads. If it works well I'll make my own shadowgraph just for that purpose. |
How to identify a metric thread?
The message
from Dave contains these words: Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. In the year 2006 when was the last time you saw a cut thread? I'll bet it was a long time ago. Cutting a thread costs a lot more than rolling them. Funnily enough, last week. I was looking for M10 bolts and needed one with a cut thread 'cos I didn't want the shank undersized - and found some in B&Q. Which might explain why they were so sodding expensive. -- Skipweasel Pay no attention to the man behind the curtain. |
How to identify a metric thread?
On Wed, 22 Mar 2006 21:50:42 +0000, Derek ^
wrote: |On Wed, 22 Mar 2006 19:17:43 +0000, Dave Fawthrop wrote: | |On Wed, 22 Mar 2006 19:08:42 GMT, Guy King wrote: | ||The message ||from Dave Fawthrop contains these words: || || |Only on cut threads. Rolled threads will be about 9mm for a 10mm thread. || || || I just thought of that as well, so a bolt with a thoroughly mashed up || rolled thread is difficult to identify. || ||Still reckon the best way is to take it to a shop and mesh threads with ||other bolts till you find a match. || ||Or, better yet, an industrial fastener specialist. There's one in most ||towns if you know where to look. | |Our local Bolt and Nut specialist is *very* amiable | |Our local Industrial Fastener Specialist I.F.S. is very expensive. Ours Bradford Bolt and Nut has a *huge* range of fastenings, and tools, many times that of the sheds. All competively priced. | |Best go there and get them to identify the thread and order the screws |from Maplin/Farnells/RS etc. The Bradford Maplins is now very poor. Haven't used Farnell for years. -- Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst* method of accessing usenet. GG subscribers would be well advised get a newsreader, say Agent, and a newsserver, say news.individual.net. These will allow them: to see only *new* posts, a killfile, and other goodies. |
How to identify a metric thread?
The message
from Dave Fawthrop contains these words: The Bradford Maplins is now very poor. Sadly they all are. They've gone the way of Halfords - bling and toys. -- Skipweasel Pay no attention to the man behind the curtain. |
How to identify a metric thread?
"nightjar .uk.com" nightjar@insert my surname here wrote in message ... "Guy King" wrote in message ... ... Still reckon the best way is to take it to a shop and mesh threads with other bolts till you find a match.... The best way is a shadowgraph machine, but taking it to a shop is a lot cheaper if you don't already have a shadowgraph. A digital camera works quite well if it has a decent macro mode. I would expect a scanner to work too, you would need a reference like a ruler to measure the real sizes. What's wrong with buying and trying a couple of nuts/bolts? |
How to identify a metric thread?
"dennis@home" wrote in message k... "nightjar .uk.com" nightjar@insert my surname here wrote in message ... "Guy King" wrote in message ... ... Still reckon the best way is to take it to a shop and mesh threads with other bolts till you find a match.... The best way is a shadowgraph machine, but taking it to a shop is a lot cheaper if you don't already have a shadowgraph. A digital camera works quite well if it has a decent macro mode. I would expect a scanner to work too, you would need a reference like a ruler to measure the real sizes. What's wrong with buying and trying a couple of nuts/bolts? I have to go out to buy bolts. The shadowgraph is in my workshop. I also have sets of thread form gauges, but haven't used them since getting the shadowgraph machine. Colin Bignell |
How to identify a metric thread?
In article , Derek ^
wrote: Our local Industrial Fastener Specialist I.F.S. is very expensive. Best go there and get them to identify the thread and order the screws from Maplin/Farnells/RS etc. Which will make IFS even more expensive. What you are suggesting is immoral. Taking advantage of a supplier who provides a service, with no intention of purchasing from them. When the IFSs of this world have all closed, you will be whining that there is nowhere to go that has a clue. -- AJL |
How to identify a metric thread?
Dave Fawthrop wrote:
Chris Bacon wrote: |Lobster wrote: | I want to replace some damaged bolts. I know they are metric thread, | but don't know what size they are. What dimension do I need to measure | to determine this please? | |Measure the diameter, which will tell you something - then |the pitch. If you've really got 4.5mm then the pitch should |be 0.75mm (coarse) or 0.5mm (fine). Measure a number of |threads to get a more accurate figure. You could go to a |hardware shop, if you know of a good one, and compare the |thread of what you've got with the ones they stock. Better to buy a huge box of various Metric nuts, bolts, washers etc. next time Lidl have them, then you always have something roughly right in stock. These selections are of very limited range. Something "roughly right" won't do for many things. |
How to identify a metric thread?
Guy King wrote:
The message from Dave Fawthrop contains these words: The Bradford Maplins is now very poor. Sadly they all are. They've gone the way of Halfords - bling and toys. Sad indeed.. I called into the Manchester branch the other day to find they didn't even have a component counter! If I wanted any resistors etc I'd have to order them! The place seemed more like a small branch of Toys 'R Us. Mathew |
How to identify a metric thread?
|
How to identify a metric thread?
On Thu, 23 Mar 2006 10:18:44 +0000, "Andy Luckman (AJL Electronics)"
wrote: Which will make IFS even more expensive. What you are suggesting is immoral. Taking advantage of a supplier who provides a service, with no intention of purchasing from them. They weren't competetive. When the IFSs of this world have all closed, you will be whining that there is nowhere to go that has a clue. FWIR the price of the screws at IFS was about 3-4 times the price in B&Q (It was in the days when you used to weigh them out yourself). So they only got my business *once*. AAMOF, I was expecting a specialist supplier to be significantly cheaper than B&Q. DG |
How to identify a metric thread?
In article ,
Nick wrote: The best way is a shadowgraph machine, but taking it to a shop is a lot cheaper if you don't already have a shadowgraph. What a good idea. As it happens, the department next door has something like that. A backlit or frontlit item can be magnified up to 100 times and displayed on a screen. This is what I need to tell the difference between Whitworth and Unified threads. If it works well I'll make my own shadowgraph just for that purpose. You could scan it if you have a half decent scanner and compare to known thread profiles and sizes. -- *If you remember the '60s, you weren't really there Dave Plowman London SW To e-mail, change noise into sound. |
How to identify a metric thread?
In article ,
dennis@home wrote: A digital camera works quite well if it has a decent macro mode. I would expect a scanner to work too, you would need a reference like a ruler to measure the real sizes. If I scan something like a PCB on my ancient Epson GT-9500 and output it as a bitmap file to Draw on my even more ancient Acorn RPC I get an exact sized copy that (after treatment) can print out as a transparency to manufacture an exact reproduction. I dunno just how accurate it is in micron terms but would certainly be far more than adequate for things like mass produced thread measurements in the normal sizes. -- *The statement above is false Dave Plowman London SW To e-mail, change noise into sound. |
How to identify a metric thread?
"Dave Plowman (News)" wrote in message ... In article , dennis@home wrote: A digital camera works quite well if it has a decent macro mode. I would expect a scanner to work too, you would need a reference like a ruler to measure the real sizes. If I scan something like a PCB on my ancient Epson GT-9500 and output it as a bitmap file to Draw on my even more ancient Acorn RPC I get an exact sized copy that (after treatment) can print out as a transparency to manufacture an exact reproduction. I dunno just how accurate it is in micron terms but would certainly be far more than adequate for things like mass produced thread measurements in the normal sizes. Some of the newer CIS scanners aren't particularly good for 3D items. |
How to identify a metric thread?
In article .com,
Mathew Newton wrote: The Bradford Maplins is now very poor. Sadly they all are. They've gone the way of Halfords - bling and toys. Sad indeed.. I called into the Manchester branch the other day to find they didn't even have a component counter! If I wanted any resistors etc I'd have to order them! The place seemed more like a small branch of Toys 'R Us. Given that all 'shop' suppliers of electronic components have also disappeared it's not surprising. It's sad, but home construction of electronic things is no longer popular as a hobby. Maplin have high cost high street shops and can't afford to stock low moving products in them. -- *I will always cherish the initial misconceptions I had about you Dave Plowman London SW To e-mail, change noise into sound. |
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