Diameter of imperial machine screws

In summary, the conversation is about someone trying to buy imperial machine screws and bolts online but is confused by the given diameters. They are specifically looking for a 5/32 inch diameter screw, but it does not appear in the list provided. The participants suggest looking up the diameters in a machinist handbook and clarify that below 1/4", the diameter is given in numbers while above 1/4", it is given in inches. The second number indicates the number of threads per inch. The conversation also touches on the rarity of a 5/32 inch size and the possibility of it being an old British part.
  • #1
temujin
47
1
Dear Forum,

I am currently trying to buy some imperial machine screws and bolts online, and I am confused with how the diameter is given.

The website I am seaching (boltdepot.com) gives me these diameters but I don´t understand what is meant by i.e. "2-56"

2-56
4-40
6-32
8-32
10-24
10-32
12-24
1/4-20
5/16-18
3/8-16
1/4-28

Can anyone help me? I am specifically looking for a 5/32 inch diameter screw but this does not appear here. Anyone suggesting a different good site for buying fasteners online, preferably located in europe?


best regards
t.
 
Engineering news on Phys.org
  • #2
Below a 1/4" they are just given numbers, a #8, #10 etc - the diameter is d=0.06" + (#*0.13")
or you to look up the diameters in a machinist handbook
Above 1/4" the first number is the diameter of the bolt in inches.

In both cases the second is the number of threads per inch, so a 'quarter-20' is 0.25" diameter and a thread pitch of 0.05"

5/32 isn't a standard US size, it's almost a #7 - which is also rare.
Is this an old British part ? in Which case it might be whitworth.
 
Last edited:
  • #3
Thanks,

It is definitely an US part.

My local store here thought it was a 5/32 and I believed them. Might even be a #7 as you say. I probably need to measure it myself...

Edit:
With respect to the list in my first post, does 2-56 then mean screw #2 with 56 threads per inch? and "4-40" is #4 with 40 tpi?

regards
t.
 
  • #4
temujin said:
With respect to the list in my first post, does 2-56 then mean screw #2 with 56 threads per inch? and "4-40" is #4 with 40 tpi?
Correct - I clarified my post a little
 
  • #5
Thanks.t
This helped a lot.

t.
 

1. What is the standard diameter of imperial machine screws?

The standard diameter of imperial machine screws is measured in inches and ranges from 0.06 inches to 0.75 inches.

2. How is the diameter of imperial machine screws determined?

The diameter of imperial machine screws is determined by measuring the distance across the widest part of the screw's thread, also known as the major diameter.

3. Are there different types of diameters for imperial machine screws?

Yes, there are different types of diameters for imperial machine screws, including coarse and fine thread diameters. Coarse thread diameters are more commonly used for general purpose applications, while fine thread diameters are typically used for more precise and delicate work.

4. Can the diameter of imperial machine screws be converted to metric measurements?

Yes, the diameter of imperial machine screws can be converted to metric measurements by using a conversion chart or calculator. However, it is important to note that there may be slight variations in the conversion due to rounding or manufacturing tolerances.

5. Are there any special considerations when selecting the diameter of imperial machine screws?

Yes, when selecting the diameter of imperial machine screws, it is important to consider the application, the material being fastened, and the strength and load requirements of the screw. It is also important to choose a diameter that will fit properly in the corresponding nut or hole without causing damage or excessive stress.

Similar threads

Replies
22
Views
744
  • Mechanical Engineering
Replies
3
Views
2K
  • Mechanical Engineering
Replies
18
Views
917
  • Precalculus Mathematics Homework Help
Replies
4
Views
747
  • Electrical Engineering
Replies
4
Views
638
  • Mechanical Engineering
Replies
6
Views
918
  • Mechanical Engineering
Replies
15
Views
654
Replies
7
Views
3K
  • Mechanical Engineering
Replies
2
Views
1K
Replies
2
Views
3K
Back
Top