Working out a screw size?

Stew

Stew

Well-Known Member
Hi guys,

Hoping someone can help! :)

I need another one of these screws on the right of the picture:

P1050804.jpg


(The one on the left is a 1-72 thread size)

Changing the bolt it goes into isn't really an option I want to attempt at this stage and I don't have another screw that fits here.

How can I work out what size it is?

An outer measurement gives this:

P1050805.jpg


I have a feeling I need to measure the diameter at the bottom of the threads, which is something I can't do!
 
you need a thread pitch gauge it measures the size of the screw or bolt and how many threads per inch.
The 1-72 is a size 1 with 72 threads per inch this is considered a fine thread.
Do a internet search on thread pitch and buy a gauge there only a few bucks .
Hope this helps.
 
It's from a Spyderco Pride.

Pivot and two back bolts.

This:

P1040773.jpg


Changing to this:

P1050767-1.jpg
 
Go to your local hardware store and in the bolt and screw section most will have a guage you can screw it into to check the size,then buy several.
Stan
 
Where was the knife made? If it wasn't made in the USA, it may be a metric thread ( maybe a M3 x 0.5 ?, 3mm = 0.1181 in.). If I remember correctly, the 4-40 and M3 x 0.5 are very similar in diameter, but the pitches are different.

One thing I did before I got a pitch guage, is to use another screw that has a known pitch as a guage. I just tried different ones until they meshed up just right.

Ric.
 
SBuzek said:
Go to your local hardware store and in the bolt and screw section most will have a guage you can screw it into to check the size,then buy several.
Stan
Click to expand...

If only I could Stan. :D The UK isn't as good for that sort of thing.
 
baddog said:
Where was the knife made? If it wasn't made in the USA, it may be a metric thread ( maybe a M3 x 0.5 ?, 3mm = 0.1181 in.). If I remember correctly, the 4-40 and M3 x 0.5 are very similar in diameter, but the pitches are different.

One thing I did before I got a pitch guage, is to use another screw that has a known pitch as a guage. I just tried different ones until they meshed up just right.

Ric.
Click to expand...

Being a Spyderco it may have been USA made or may not (helpful, i know) I don't know if they restrict to Imperial bolts even if made overseas.
 
Have you tried an electronics supply place? I found a electronics supply/surplus store and they had a lot of small screws used for electronics assembly. Great place to scrounge around. I got some SS 1-72 x 0.5 in button heads, got 25-30 for less than a dollar.

So for you dogs in the SF Bay Area here's the link to their site: Halted they are in Santa Clara. They also have metric sizes too.

There is also a place near by called Olanders, they have an excellent selection of fasteners too, they cost a few cents more but they are new. I've gone in there with a odd screw and they were able to size it and also had replacements in stock.

Ric
 
You must log in or register to reply here.
Back
Top