Is this hex screw generic and if so what is it

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Jdsk
Posts: 24640
Joined: 5 Mar 2019, 5:42pm

Re: Is this hex screw generic and if so what is it

Post by Jdsk »

simonineaston wrote: 2 Aug 2021, 1:40pm
the nonexistence of a universal definition
Well I'm not sure that's quite true. After a quick session, looking things up, I'm fairly clear now that bolts pass through and screws twist into.
That's a distinction that I find useful. But there are exceptions...

... what do you call the fasteners that hold the cylinder head to the block of an engine, and don't have nuts and aren't studs?

Jonathan

PS: The etymology doesn't help at all with definition or description of modern fasteners.
But of course it's always interesting.
Suffolker
Posts: 149
Joined: 5 Jul 2014, 7:04am

Re: Is this hex screw generic and if so what is it

Post by Suffolker »

Another name for these is "machine screw", which is of course a bolt-type of fastener. Then there are set screws, half and full dog, and a number of other types, and that's before getting into the different head forms (dome, countersunk etc.) and the fastening method (socket head cap screw, Phillips, Pozidrive, slotted etc.).

The most useful thing about these nowadays is that metric sizes and threads (fine and coarse) are the norm, and we don't have to worry too much about UNC, UNF, Whitworth, BSF, and so forth.
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simonineaston
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Location: ...at a cricket ground

Re: Is this hex screw generic and if so what is it

Post by simonineaston »

worry too much about UNC, UNF, Whitworth, BSF, and so forth.
I remember whe I first got interested in motorbikes and so bumped up against sundry threaded objects and the resulting dread on realising that I probably needed several sets of spanners to allow for the various thread forms. And then, along came the Japanese with their blessed fondness for metric standards - phew.
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
colin54
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Joined: 24 Sep 2013, 4:34pm

Re: Is this hex screw generic and if so what is it

Post by colin54 »

snaz wrote: 2 Aug 2021, 1:28pm
Further help appreciated ... cheers
sp :D
Hi Snaz, I've had a good look around and I can't find anything with that shallow a shoulder either (2mm from your,
picture), the screw looks like an M6 by scaling with a bit of paper off of your picture and ruler). I've knocked up something from an off-cut old threaded brake(nut) 8mm OD like the shoulder and I filed it to just over 2mm thick (to keep the threads intact), I've used a washer the same diameter as your existing low-head. I'd found a long M6 low head which I was going ask if it was any use to you to modify yourself, but it has a bit of a shank on it so it was probably no good to you anyway, hence plan B with the buttonhead screw. I've just scaled the dimensions off of your picture.
Any good to you, I could send you the low head head screw as well if you think you might use it.
Drop me an address in a PM if you think this would work for you, I quite enjoyed making it anyway, so don't worry if you don't think it will work or it's not M6(!).
P1140389.JPG
Nu-Fogey
jb
Posts: 1782
Joined: 6 Jan 2007, 12:17pm
Location: Clitheroe

Re: Is this hex screw generic and if so what is it

Post by jb »

Door bolt, crossbow bolt, nut & bolt, rifle bolt.

The thing they all share is a plain shank and a forward movement to pass through a hole (or a body) so I would think that is on the right lines for the origin.
Cheers
J Bro
snaz
Posts: 91
Joined: 6 Nov 2019, 7:35pm

Re: Is this hex screw generic and if so what is it

Post by snaz »

@johnathon
dimensions:
1. Hex head diameter = 112mm / depth=1mm
2. Shank diameter = 9mm / depth=2mm
3. Screw diameter =
Inside thread to inside thread = 5mm
Outside thread to outside thread = 6mm
4. Thread dimensions ? (not sure what this is)
The raised thread parts looks seperated by 1mm distance groves
5. Thread barrel length =
underside of shank to tip of bolt = 9mm / including 2mm depth of shank - total = 11mm

@colin54
that bolt looks very close visually . I dont need the hex head to be flat i am happy to replace it with a protruding head - its the head-shank-thread + wheel combo i need to get right - i attach 3 more images showing how the non sheard bolt hex head sits flush in the wheel (middle picture)
If i can id the M size hex bolt for sure - then i just need to id the right shank type (the bolt thread length can also be slighlty longer - isn't exactly constrained)
I'd ideally like a pair so they look the same tho - i'm afraid i wasn't very clear on interpreting your technical jargon regarding how or what you used to duplicate the bolt
"8mm OD like the shoulder and I filed it to just over 2mm thick (to keep the threads intact), I've used a washer the same diameter as your existing low-head. I'd found a long M6 low head "
If using my bolt dimensions above you think you can crack the hack - let me know - i am happy to source the parts / be linked to the parts required - (may be useful to know for future) or aquire off you - (v generous offer - thankyou) -

Are you able to id the M size from this ? is it an M5 or M6 ? Whats the difference between an M5 and M6 btw ?
Anything else let me know - inc any more feedback on the product page link
thanks again folks - appreciated
sp :o
Attachments
IMG_20210803_141050.jpg
IMG_20210803_141031.jpg
IMG_20210803_140950.jpg
colin54
Posts: 2529
Joined: 24 Sep 2013, 4:34pm

Re: Is this hex screw generic and if so what is it

Post by colin54 »

It's an M6 (your outside to outside dimension).
Judging by your original picture against the ruler the 9mm and 11mm dimension you quote is incorrect,
I've made it to the photo's dimensions, the bolt is a mm over length, you could file a bit off of the end if it bottoms out in the hole.
The shank is internally threaded, made by sawing a 2mm slice from one of these brake nuts.
P1140391.JPG
I've made a second one.
P1140409.JPG
The washer is the same width as your current screw head.
I'm fairly certain these will do you, pm with your address if you want them.
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Jdsk
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Joined: 5 Mar 2019, 5:42pm

Re: Is this hex screw generic and if so what is it

Post by Jdsk »

Exemplary helpfulness.

Jonathan
snaz
Posts: 91
Joined: 6 Nov 2019, 7:35pm

Re: Is this hex screw generic and if so what is it

Post by snaz »

@colin54

many thanks - pm sent - the axel at either end will take a mm over-length on both bolts.

cheers - as johnathan says - exemplary :D

i'll aim to update with pics !

sp
snaz
Posts: 91
Joined: 6 Nov 2019, 7:35pm

Re: Is this hex screw generic and if so what is it

Post by snaz »

@colin54

Fits like a pair of gloves - many thanks again :D
sp
Attachments
2.jpg
1.jpg
colin54
Posts: 2529
Joined: 24 Sep 2013, 4:34pm

Re: Is this hex screw generic and if so what is it

Post by colin54 »

Nice one, thanks for the update.
Nu-Fogey
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