Threaded Screws 2

[dawgfan22]

Does anyone know the pros and cons of fine threaded screws to course threaded?

 

[CorBlimeyLimey]

http://www.google.ca/search?hl=en&q=fine+threads+vs+coarse+threads&btnG=Google+Search&meta=

 

[Heckler]

Tapping Handbook

Coarse Threads vs. Fine Threads

Coarse Threads:

For most applications, course threads offer these advantages:

Easier and faster assembly, providing a better start with less chance of cross threading.

Nicks and burrs from handling are less liable to affect assembly.

They are less likely to seize in temperature applications and in joints where corrosion will form.

Less prone to strip when threaded into lower strength metals.

More easily tapped in brittle materials and or materials that crumble easily.


Fine Threads:

Fine threads may make for a superior fastener for applications with specific strength or other requirements.

They are about 10% stronger that coarse threads due to their greater cross-section area.

In very hard materials, fine threads are easier to tap.

They can be adjusted more precisely because of their smaller helix angle.

Where length of engagement is limited, they provide greater strength.

Thinner wall thickness can be used because of their smaller thread cross section.





Heckler
Sr. Mechanical Engineer
SWx 2007 SP 3.0 & Pro/E 2001
XP Pro SP2.0 P4 3.6 GHz, 1GB RAM
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(In reference to David Beckham) "He can't kick with his left foot, he can't tackle, he can't head the ball and he doesn't score many goals. Apart from that, he's all right." -- George Best

 

[eromlignod]

I agree with Heckler's post. I would just add that coarse threaded fasteners are also generally easier to obtain from a hardware store or rural supplier, making them preferable for field maintenance. The exception is 10-32 UNF, which, for some reason, is commonly available...and, of course, 0-80 UNF, which has no coarse-series equivalent anyway.

Don
Kansas City