What and where can I find this screw/bolt?

mohammed

mohammed

Member
Region
United Kingdom
Hi all,

I am looking for this screw but not sure if it's completely custom or if it's a standardised size.

Long story short, I need three of these two of the original ones have been stripped so I can no longer open them.

I know a size 3 allen key open them though.

Any help will be appreciated!
 

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No such thing as a custom sized screw, at least not for anything built in the last 50 years that I could afford! Lots of odd stuff around, though, like whitworth threaded bolts.
 
Looks right to me! The hex size is slightly smaller, but no doubt you have that tool too!
 
Unfortunately the one I ordered wasn't the same size, the head was smaller and the threaded part was too long.
 
What about the thread size? That's the most important parameter. Head size only matters for the wrench or screwdriver. Head shape matters, but that's a different story. If the shaft, the threaded part, is longer, maybe it still works. Have you tried it?
 
retiredNH said:
What about the thread size? That's the most important parameter. Head size only matters for the wrench or screwdriver. Head shape matters, but that's a different story. If the shaft, the threaded part, is longer, maybe it still works. Have you tried it?
Click to expand...
Basically the shaft was too thin so the screw didn't sit correctly. The width of the head was also a few mm off so didn't cover the whole area where the screw goes in. I'm not sure of the extract terminologies so do excuse me! :)

Attached is an old picture of where the actual screws go in for reference.
 

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I assumed that you measured your old bolts with calipers. Your sketch shows that the threaded part had an OD of 4mm, which would make it an M4 bolt.

If you're guessing at the size, you're probably guessing wrong. Double check with a pair of calipers

Secondly, flat head cap screws are measured from the top of the head to the bottom of the bolt. Your sketch indicated 8mm of thread and 4mm of head. That would be a 12mm bolt. Check with who you ordered it from and make sure they are measuring it the same way. Also double check your sketch. Are you sure about your head height?

Screen Shot 2022-05-28 at 9.15.20 AM.png


Lastly, different suppliers can have different head diameters. It shouldn't make that much of a difference. If you are trying to achieve a flush fit, like you had with the old one, you will have to check that the head height and the head diameter are the same as your old screws. Slightly more work to source, but not impossible.
 
Why don't you just take the one good screw/bolt that you have to a good hardware store and match it up? I've done that many a time. the staff is always very helpful. It's impossible to match these things up just from a picture.
You also need to pay attention to thread pitch.
Don't bother measuring. Just take one to a store.
 
retiredNH said:
Why don't you just take the one good screw/bolt that you have to a good hardware store and match it up? I've done that many a time. the staff is always very helpful. It's impossible to match these things up just from a picture.
You also need to pay attention to thread pitch.
Don't bother measuring. Just take one to a store.
Click to expand...
I am going to second what @retiredNH said. I just checked McMaster, and standard flat head cap screws have a much smaller head than what your sketch indicates. If so, that is a unique size head, and it could be challenging to find.

Screen Shot 2022-05-28 at 9.34.15 AM.png
 
mikeschn said:
I assumed that you measured your old bolts with calipers. Your sketch shows that the threaded part had an OD of 4mm, which would make it an M4 bolt.

If you're guessing at the size, you're probably guessing wrong. Double check with a pair of calipers

Secondly, flat head cap screws are measured from the top of the head to the bottom of the bolt. Your sketch indicated 8mm of thread and 4mm of head. That would be a 12mm bolt. Check with who you ordered it from and make sure they are measuring it the same way. Also double check your sketch. Are you sure about your head height?

View attachment 124520

Lastly, different suppliers can have different head diameters. It shouldn't make that much of a difference. If you are trying to achieve a flush fit, like you had with the old one, you will have to check that the head height and the head diameter are the same as your old screws. Slightly more work to source, but not impossible.
Click to expand...
The sizes in the sketch are pretty accurate, I used a ruler several times just to make sure! I will double check again and feedback but I'm very sure the sizes are correct.

Regarding the head height, yes I'm very sure I measured it correctly, it was about a third of length of the total screw this is why I asked if it's a standard size but after searching online, I couldn't find anything similar.
 
retiredNH said:
Why don't you just take the one good screw/bolt that you have to a good hardware store and match it up? I've done that many a time. the staff is always very helpful. It's impossible to match these things up just from a picture.
You also need to pay attention to thread pitch.
Don't bother measuring. Just take one to a store.
Click to expand...
I've been to a few stores but none had this type. I've got a few more to check but getting to them is a chore but I defo need to get my a** in to gear!
 
Opps, I deleted the last photo, because that was the dimension of a socket head cap screw, not a flat head...
 
Another option is to just get an M4x10, knowing the top will be recessed about 2mm instead of flush with the surface. Then if you know someone with a 3D printer, you could print some plugs.
Screen Shot 2022-05-28 at 9.56.16 AM.png
 
mohammed said:
Good suggestion!
Click to expand...
Maybe not so good, unless you know it's the proper thread size - diameter and pitch. The head diameter is the least critical parameter you have. Even length is not so important - you could pad with washers unless you insist in perfect cosmetics.
Then again, there are companies that will sell you whole assortments of these things for not that much money. Sounds like you already purchased the wrong diameter based on measurements....
 
retiredNH said:
Maybe not so good, unless you know it's the proper thread size - diameter and pitch. The head diameter is the least critical parameter you have. Even length is not so important - you could pad with washers unless you insist in perfect cosmetics.
Then again, there are companies that will sell you whole assortments of these things for not that much money. Sounds like you already purchased the wrong diameter based on measurements....
Click to expand...
From the sound of it, @mohammed has the right dia and pitch. 🤔
 
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