Is this hex screw generic and if so what is it

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snaz
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Joined: 6 Nov 2019, 7:35pm

Is this hex screw generic and if so what is it

Post by snaz »

Hi

I sheard a hex screw - see photo - is it generic type and if so what is it -can anyone link me to a replacement online ?



cheers
sp
Attachments
hex screw id.jpg
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 »

No, it's not a standard screw (or bolt) because it has that stepped down part under the head.

Why is the part at the lower right that shows the damaged hex socket separate from the screw above it?

Where's it from?

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

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

Post by snaz »

Jdsk wrote: 1 Aug 2021, 6:02pm No, it's not a standard screw (or bolt) because it has that stepped down part under the head.

Why is the part at the lower right that shows the damaged hex socket separate from the screw above it?

Where's it from?

Jonathan
see this - its from a brompton folding bike third party telescopic rear wheel

sp
1.jpg
Jdsk
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Re: Is this hex screw generic and if so what is it

Post by Jdsk »

The unthreaded shank under the head sits in the wheel and the thread engages in the round black shaft pointing to the left??

Jonathan
colin54
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Re: Is this hex screw generic and if so what is it

Post by colin54 »

Measure the width and length of the screw,it looks like M5 or M6 (?), I used the search term ; shoulder socket screw/ bolts and came up with this on ebay, there were others using similar search terms including the word allen, screw, bolt, shoulder etc.
https://www.ebay.co.uk/itm/283048140832 ... 3431396522
Not quite the same but , I forget what the term is for that type of head on a screw.
I'd be surprised if it's not a generic part of some sort, I would think the diameter and depth of the shoulder is a standard somewhere depending on the size of the screw and the pulley that spins on it.
Good luck.
Edit, a bit more info here :-
https://shop4fasteners.co.uk/fasteners/ ... crews.html
Last edited by colin54 on 1 Aug 2021, 7:15pm, edited 1 time in total.
Nu-Fogey
Jdsk
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Re: Is this hex screw generic and if so what is it

Post by Jdsk »

You definitely need to know the thread.

If you can't find the exact fastener would it work with a sleeve over the part of the fastener that sits in the wheel?

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

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

Post by snaz »

@johnathon - yes

im wondering if i could just source a genric M5 or M6 hex screw and substitute the shank part with a couple of washers / sleeve as j says ?
The wheels are supposed the fix loose to enable free turning - do you know if washers / sleeves come in generic sizes and if so what size i should look for - the shank diameter looks to me abput 8mm and the thickness 2 mm

what thinks ya'll ?

cheers again
sp
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 »

We could look for some stainless steel tube that would fit. Can you convert those dimensions into a wall thickness and an outside diameter for tubing?

Jonathan
Last edited by Jdsk on 1 Aug 2021, 7:28pm, edited 1 time in total.
colin54
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Re: Is this hex screw generic and if so what is it

Post by colin54 »

Here's the exact description of your type of screw, best I can find ; 'Metric Low Head Socket Shoulder Screw'.
Not difficult to bodge of course, but this is what the OP's looking for I think, as per his original question, pricey, but there may be cheaper using the above search term on ebay etc.
Good luck.
.
https://www.accu.co.uk/en/572-low-head- ... der-screws
Nu-Fogey
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 »

colin54 wrote: 1 Aug 2021, 7:28pm Here's the exact description of your type of screw, best I can find ; 'Metric Low Head Socket Shoulder Screw'.
Well done.

Now we need the thread and dimensions of the original.

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

Post by simonineaston »

With regard to the choice of screw or bolt, mentioned upthread, I have to say that I used to be rather in favour of using bolt whenever the item under discussion exhibited no taper - screws, I thought, are those pointy things you use in wood-work. However all is not plain sailing. So from the OED:
▶ noun
A short, slender, sharp-pointed metal pin with a raised helical thread running around it and a slotted head, used to join things together by being rotated so that it pierces wood or other material and is held tightly in place.
The phrase sharp-pointed strongly suggests that screws (as opposed to set-screws) are most definitely tapered. Perhaps more importantly, a bolt turns out to be quite something else:
▶ noun
A large metal pin, in particular:
• a bar that slides into a socket to fasten a door or window.
• a long pin with a head that screws into a nut, used to fasten things together.
The defining charactersistic of a bolt appears to be that it goes through something - thus a bolt could well hold two bits of a bike together, but only if it passes right through them and then uses a separate nut to squeeze eveything together. As in 'nut & bolt' whereas 'nut & screw' doesn't seem right. I looked carefully at my bike just now and although I can see several 'set-screws', doing their special job of adjustment, I can also see some 'bolts', passing through components and tightening into a nut at the other side. As for the rest of the threaded items of which there are plenty, I guess they must be 'screws' even though they aren't tapered! In summary, although I'm content that I know what a set-screw and a bolt is, I'm still not exactly sure what a screw is...
PS the etymology of the word screw turns out to be quite - how shall I say? - biologial and mostly unrepeatable on these family-friendly pages... :lol:
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Jdsk
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Re: Is this hex screw generic and if so what is it

Post by Jdsk »

simonineaston wrote: 2 Aug 2021, 12:29pm With regard to the choice of screw or bolt, mentioned upthread, I have to say that I used to be rather in favour of using bolt whenever the item under discussion exhibited no taper - screws, I thought, are those pointy things you use in wood-work. However all is not plain sailing.
Absolutely not. As in the recent discussion which documented the nonexistence of a universal definition:
viewtopic.php?p=1624632#p1624632

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

Post by snaz »

Nouns aside 8) ...

What else do you need from me to resolve this ? Also looking at the link posted above :
https://www.accu.co.uk/en/572-low-head- ... der-screws
Thanks for finding that ! However not being very bolt savvy - i wasnt very sure which of those bolts would be the one to select. There are 43 pages of bolts to naviagte. Also the shank part in the picture seems much longer than the one in my picture and some of the bolts cost half as much just for a single item - as the entire wheel set price was ....

Further help appreciated ... cheers
sp :D
Jdsk
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Re: Is this hex screw generic and if so what is it

Post by Jdsk »

From your original: thread size, and dimensions of the screw and of the shoulder under the head.

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

Post by simonineaston »

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.
The etymology of the word screw appears to imply pressure, that is to say, when operated the screw has to tighten up into whatever it is going into, whereas the origin of the word bolt appears to suggest passing through, that is to say, it needs something else (often a nut) to keep it in place. That would fit nicely with the idea of both wood-screws (obs) and set-screws, which turn into an object in order to adjust or set its position relative to another piece and are tightened. In the case of a screw that should remain adjustable, for example in a derailleur mechanism, the screw may not be fully tightened, but remain in place by spring pressure. All other threaded cylinders, which tighten into an object are screws too. They're only bolts if they pass through.
I will re-read the posts you kindly linked to, J :-)
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
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