not boat related - help identifying a machine screw size

[Wittenham]

I am regularly in awe of the expertise on tap in this forum so I am hoping to lean on someone who can tell me what i need to order to replace two of these machine screws.  Is there enough info in these photos?

 

 

[OldGoat]

I'm going to start the bidding at M6 x 30 - 'cos I've just bought a pack to do some 'T' shaped hinges and they look similar (my tape measure looks similar to yours.

Happy to be corrected, though!

 

whoops - M6 x 25mm.....

Edited July 20, 2021 by OldGoat

[Bee]

I guess they are 25mm long, M8 pan headed screws, Screwfix probably has them in boxes of 100 and B&Q in little poly packets., take one along to compare or you will end up with lots of wrong sized nuts and bolts like I have.

Edit to add, see what I mean? Old Goat has got a kitchen draw full of wrong sized nuts and bolts just like me!

Edited July 20, 2021 by Bee

[Wittenham]

thanks, and is it necessary to figure out a thread count, or would that be standard?  This came out of a kitchen drawer unit, if that adds anything.

[David Mack]

Old Goat may well be right, but to check measure the diameter across the threads. For M6 this should be fractionally less than 6mm.

 

M6 threads have a pitch of 1.0mm, so if you hold the threaded section against the edge of the tape the thread ridges should match the mm markings.

[Tony Brooks]

3 minutes ago, OldGoat said:

I'm going to start the bidding at M6 x 30 - 'cos I've just bought a pack to do some 'T' shaped hinges and they look similar (my tape measure looks similar to yours.

Happy to be corrected, though!

 

whoops - M6 x 25mm.....

 

That is my thought, as its bright probably fairly new and courser than UNF

[David Mack]

Or might be M5 (5mm diameter) with a thread pitch of (I think) 0.8mm.

 

Assuming of course that it is a metric thread.

1 minute ago, Tony Brooks said:

 

whoops - M6 x 25mm.....

 X 20mm.  Thread length on pan head screws is measured from the bottom of the head.

[Jen-in-Wellies]

5 minutes ago, David Mack said:

Or might be M5 (5mm diameter) with a thread pitch of (I think) 0.8mm.

 

Assuming of course that it is a metric thread.

M5 I think. Measured the pixel count just now. 6mm on the scale is 56 pixels. The thread looks to be 46 pixels across. Very approximate, but enough to give an idea. 6 threads is 45 pixels, which again suggests it is not M6, but something smaller. Standard M5 threads are on a 0.8mm pitch, which ties in reasonably well.

Jen

Edited July 20, 2021 by Jen-in-Wellies

[David Schweizer]

My I suggest that the OP tries to find someone who has a digital vernier and a set of pitch gauges, determining the thread size would not then be down to guesswork.

[OldGoat]

I suggested M6 because it's a popular size - whereas M5 is often used for electrical stuff - but hey there are so may posibilities!

 

[matty40s]

1 hour ago, Wittenham said:

I am regularly in awe of the expertise on tap in this forum so I am hoping to lean on someone who can tell me what i need to order to replace two of these machine screws.  Is there enough info in these photos?

 

 

M5 x 25 pan head pozi....

I think

 

Edited July 20, 2021 by matty40s

[nb Innisfree]

I've just removed and measured a pan head machine screw from one of our kitchen drawer handles - M4 x 0. 7 x 25mm.

 

ETA: Gaairman kitchen units btw.

Nod to Stan Boardman there. 

Edited July 20, 2021 by nb Innisfree

[Tracy D'arth]

25mm X M4 for sure.

[Slim]

To start with it's 20mm in length.  Measurement is from below head for a pan screw.. 5mm thread at a guess. 

[Iain_S]

My vote goes to M4. Diameter looks less than 5mm against the tape, and counting threads gave 14 per centimetre, which gave a pitch of 0.71mm, which is close to M4 pitch of 0.7mm

[Jen-in-Wellies]

I've taken the liberty of extracting a couple of bits of tape measure and laying them over the major diameter and threads of the screw,, with no scaling then blowing up the detail. Definitely M5, not M4, or M6. Definitely 10 turns makes 8mm, so 0.8mm pitch.

Jen

[matty40s]

Buy a packet of M4, M5 and M6 nuts, see which one fits, then you can buy 2 of those...

Where are you based, nip into your local boatyard, they will probably give you 4 FOC

[Jen-in-Wellies]

5 minutes ago, matty40s said:

Buy a packet of M4, M5 and M6 nuts, see which one fits, then you can buy 2 of those...

Where are you based, nip into your local boatyard, they will probably give you 4 FOC

Another option is if you have a 5mm drill bit and a drill to hand. Make a hole in a bit of wood. If the screw will push in snug it is M5. If there is a lot of slop it is M4. If it won't fit at all it is M6.

Edited July 20, 2021 by Jen-in-Wellies

[john6767]

For me that looks 20 long and my guess for the size is M4.  Is there a prize?

[David Schweizer]

Well there are some pretty inventive suggestions being put forward, and with the exception of the one being offered by Matty40, none of of them will provide a definitive answer.

[nb Innisfree]

1 hour ago, David Schweizer said:

Well there are some pretty inventive suggestions being put forward, and with the exception of the one being offered by Matty40, none of of them will provide a definitive answer.

We did try, perhaps we shouldn't have bothered. 

[Wittenham]

thanks all, again, amazing level of knowledge and engagement.  I have ordered a pack of M5 20mm.... let's see what happens.

 

Now, I need to dig out that old large bolt that I need to replace and post a photo of that.

[blackrose]

Buy yourself a cheap vernier caliper. Its a lot easier and more accurate for measuring something like that than a tape measure and takes the guesswork out.

 

I bought this from Lidl for about a tenner and despite the price it's actually pretty good.

 

 

 

Edited July 21, 2021 by blackrose

[billh]

15 hours ago, blackrose said:

Buy yourself a cheap vernier caliper. Its a lot easier and more accurate for measuring something like that than a tape measure and takes the guesswork out.

 

I bought this from Lidl for about a tenner and despite the price it's actually pretty good.

 

 

 

Yes, these are very useful and appear accurate. However, you must remember to take out the battery between uses, when you press the "off" button it doesn't actually switch off , though the screen goes blank and  so,after a few days, the battery goes flat. Keep the battery in the little holder made for it in the case

[David Schweizer]

44 minutes ago, billh said:

Yes, these are very useful and appear accurate. However, you must remember to take out the battery between uses, when you press the "off" button it doesn't actually switch off , though the screen goes blank and  so,after a few days, the battery goes flat. Keep the battery in the little holder made for it in the case

 

I have two digital Verniers, one is a cheap Aldi/Lidl purchase, the other is a really good (expensive) Moore and Wright one. I always leave the battery in, and it usually lasts several years. I would suggest that either the vernier is faulty, or you are using poor quality  batteries.