What bolt type please? - Page 1
Forum section: electronics / general

author: eti
author_rank: Super Contributor
timestamp: June 23, 2022, 01:47:50 am
content: I'm not a bolt and fastener expert, so I'm delegating this to someone who hopefully is. Can someone identify the thread and bolt type of this, please?Many thanks

author: beanflying
author_rank: Super Contributor
timestamp: June 23, 2022, 02:03:22 am
content: Not easy to do accurately from a Pic but based on a thread count over 10mm using your ruler it is just under 13 threads for 10mm so around 0.8mm pitch.Diameter is roughly 5mm based on rotating the same scale so what you get is an M5 thread being most likely.So use that same method your end to check it and do some simple math.Also lash out and buy a cheap set of Digital Calipers and even a set of pitch gauges wont set you back very much.

author: Brumby
author_rank: Unknown
timestamp: June 23, 2022, 04:50:48 am
content: Yep, I agree with Bean - M5 0.8mm pitch.Here's a random M5 bolt I had at hand:Mine is a hex head. Yours looks like a round head. Material looks like it could be brass.

author: Zoli
author_rank: Frequent Contributor
timestamp: June 23, 2022, 04:58:45 am
content: M5X0.8 and 10-32(UNC)are interchangeablehave limited interchangeability in real life(I've done it countless times). Judging on the shape of the of the screw, I tend for 10-32; but as I've said, they're interchangeable.Edit: corrected statement.

author: eugene
author_rank: Frequent Contributor
timestamp: June 23, 2022, 03:33:36 pm
content: I count 12 threads per cm, not 13, and it looks smaller than 5 mm diameter to me. I'm nearly certain that it's a 10-32 screw, 7/8" long. The head is smaller than a typical pan head (probably came from something mass produced.) If the space for the head is small diameter and a pan head won't fit, a fillister head might.And I disagree that M5x0.8 and 10-32 are interchangeable. Maybe in soft plastic where you can force a new set of threads, or with narrow nuts that only have a few threads, but generally, no.

author: Zoli
author_rank: Frequent Contributor
timestamp: June 23, 2022, 04:35:59 pm
content: Quote from: eugene on June 23, 2022, 03:33:36 pmThe deepest hole where I've done the change was 20mm(~3/4" ) deep in stainless steel(316); and it was a good(not tight or lose) fit. Now, I cannot speak about longer treads, or anybody else experience, but in this particular case, considering the location of the OP, I would recommend the M5X0.8X20. IIRC, long time ago I've looked up the tolerances, and one extreme case(min10-32 hole -> max M5X0.8 screw ) the sizes are within each other ANSI tolerances. And if there's any problem, you always can play tag (by chasing threads)

author: TimFox
author_rank: Super Contributor
timestamp: June 23, 2022, 05:33:23 pm
content: 1/32 inch = 0.7938 mmThe 0.00625 mm mismatch would be one full pitch in 160 turns = 128 mm = 5 inch.

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 23, 2022, 05:51:41 pm
content: What is it from?Looks to me like cheap furniture hardware, which is usually metric. M5 is a good bet.At least around me, anywhere that sells bulk hardware has a rack with nuts and studs in all the common threads, for matching up mystery parts.

author: Zoli
author_rank: Frequent Contributor
timestamp: June 23, 2022, 06:31:42 pm
content: Quote from: TimFox on June 23, 2022, 05:33:23 pmIf you need to swap screw+thread that long, you have a bigger problem on your hand.But thank you anyway to calculate the theoretical limit; I prefer the practical limit, which in real life means interchangeable for me(at least for 20mm~3/4").

author: Ian.M
author_rank: Super Contributor
timestamp: June 23, 2022, 06:42:03 pm
content: Hopefully it is out of something reasonably modern so M5 coarse pitch is the likely candidate. However if its out of vintage equipment, read this and weep!https://www.jrcengineering.com/technical-support/whitworth-and-other-british-threads/

author: jpanhalt
author_rank: Super Contributor
timestamp: June 23, 2022, 06:59:00 pm
content: The Whitworth profile is a very good profile, particularly for fine threads, threads in cast iron, and threads in stamped sheet metal. It is still used. In fact, a have a modern, made in China horizontal bandsaw with a Whitworth thread 1/2" bolt. Another use is by the Royal Microscopical Society for microscopes (https://threadingtoolsguide.com/en/blog/thread-in-microscopy-the-microscope-object-thread/#:~:text=RMS%2DGewinde,indicated%20in%20inch%20or%20inch).There really is no need to take a gratuitous dig at any system that is not metric.

author: Uunoctium
author_rank: Frequent Contributor
timestamp: June 23, 2022, 07:33:54 pm
content: left = UNC 8/32right = M5

author: jpanhalt
author_rank: Super Contributor
timestamp: June 23, 2022, 07:41:12 pm
content: Is that a coarse M5? Those threads are nowhere nearly the same. I would expect a 0.8 mm to be closer (1/32 = 0.794 mm).

author: Uunoctium
author_rank: Frequent Contributor
timestamp: June 23, 2022, 08:17:47 pm
content: An very useful site in German for imperial screws.http://www.astro-electronic.de/screws.htm(I ordered there a lot of different types to complete an Gigatronics RF sweeper - previous owner threaded in housing all what he found on his workbench. And with help of the hints from this site all of the new ones fit!)At bottom:"Wie kann man ein unbekanntes Gewinde bestimmen?"(How to determine an unknown threading)

author: Ian.M
author_rank: Super Contributor
timestamp: June 23, 2022, 08:56:25 pm
content: Quote from: jpanhalt on June 23, 2022, 06:59:00 pmMy comment "read this and weep!" wasn't intended to denigrate non-metric threads, but was intended to point out the large number of different standardized thread systems that have been in use in the UK in the past century or so, making quick identification without precision measurement tools far from certain. Then you've got the problem of sourcing the part, in the UK, in whatever thread you've identified . . .

author: beanflying
author_rank: Super Contributor
timestamp: June 23, 2022, 09:18:01 pm
content: Quote from: eugene on June 23, 2022, 03:33:36 pmAs it is likely a rolled thread it will be a smaller diameter than nominal regardless. 10-32 as a guess without is being of US origin equipment would be fairly unlikely in the UK where it is 'maybe' a 2BA (31.4 TPI - only an Englishman could make that up)This is really why spending $20-30 on calipers and pitch gauges make sense. Metric would still be a place to start and easy to get and try.

author: Benta
author_rank: Super Contributor
timestamp: June 23, 2022, 09:27:20 pm
content: Certainly not metric.I also count 12/cm, giving a pitch of ~0.833 mm. Could be anything. The head is really odd.What did it come out of?EDIT: found it.It's aBodmer threadfor old/historic optical instruments. That also explains the strange head and the thread angles.https://www.gewinde-normen.de/en/bodmer-thread.html

author: TimFox
author_rank: Super Contributor
timestamp: June 23, 2022, 09:50:52 pm
content: Quote from: Zoli on June 23, 2022, 06:31:42 pmThat was my point. You will never see a thread engagement of several inches, and 3/4" is rare.

author: eti
author_rank: Super Contributor
timestamp: June 23, 2022, 11:08:04 pm
content: Quote from: BrokenYugo on June 23, 2022, 05:51:41 pmIt's from a frying pan (the picture) but I needed one for my saucepan, which rusted right through; thankfully I found out when it was empty, emerging from the dishwasher!Thanks to everyone for your help. I now have a replacement from a mechanical engineer neighbour!

author: Benta
author_rank: Super Contributor
timestamp: June 23, 2022, 11:21:15 pm
content: I feel @eti made a fool out of everyone here. Frying pan, indeed!You're on my block list.

author: eti
author_rank: Super Contributor
timestamp: June 24, 2022, 01:54:45 am
content: Quote from: Benta on June 23, 2022, 11:21:15 pmWhat you on about?:~ I had a broken ^saucepan^~ I asked for help with regard to bolt type~ I removed bolt from my *frying pan* and it fitted the bracket of the ^saucepan^, therefore that's the bolt you see pictured.Not sure why you're blocking me, but feel free, you have free will; I shall miss all the potential for your visits, cups of coffee and banter. Oh well!

author: eti
author_rank: Super Contributor
timestamp: June 24, 2022, 02:01:01 am
content: As regards the suggestions that I buy thread gauges… nope. I was repairing a saucepan, not planning to put them into mass production. Thanks to everyone for the help. Appreciate it a lot.

author: beanflying
author_rank: Super Contributor
timestamp: June 24, 2022, 02:31:16 am
content: Given a bunch of our bench gear is sourced from around this rock and multiple different standards of fasteners guessing wrong will cost you $ and more time so a Lifetime tool for under $10 just worth it to have in to kit. Digital Calipers should just be a given, Lidl and Aldi drop them several times a year or buy a metal set of evilbay. This doesn't mean you will ever use a tap and die set but you can know what nut or bolt you need to buy.Like in Oz the UK has a really mixed bag of 'standards' dating back in time. On instrumentation BA in particular was common going back into my Father's time and I still have his Tap and Die set. UNF and UNC even now are still as common as muck and still specced in some cases. As an Model Aircraft nutter for plenty of decades it was also 'common' for get 2-56, 4-40 etc threaded items out of the USA.One thing this thread has shown is there is a difference between 5'ish mm -3/16" diameter bolts and 0.8mm (31.75 TPI), is not 32 TPI and is also not 31.4 TPI or any of the other likely 5 or 6 others in and around that pitch before you get to anything more custom. Add to that classes of fit tolerances (these also vary around this rock) making diameter a bit useless as a guide.