How Nuts and Bolts Are Made Commercially

Good demonstration of the cold heading process, which is mostly used on smaller sized fasteners. The bolts the showed the heading op on were grade 8, so pretty strong bolts. Most people are not familiar with the plate rolling method of creating threads, but it is the most efficient for this type of fastener. Formed threads are inherently stronger than cut thread because of the compression and cold working of the metal. Those hex cap screws (proper name for that type of "bolt") still would be heat treated, then probably zinc plated. There are other rolling methods, but that is probably the predominant method. Socket head cap screws are made in a similar manner.

Nut are generally worked hot due to the extreme changes in size and shape, but some manufacturers use collapsible taps so there is no reversing of the spindle required.

Thanks for the link. Brings back memories of a HoloKrome training film I sat through in 1979 on how they made their products.
 
Nice video of "How it's Made". Now on to the Euro instructional video in order to become rich!!!:rofl:
 
Nelson, just think for a common one inch bolt and nut, thats a couple + hr job, resting my back and
finding stock are not included.
 
That was very interesting. I've read before where the filers and artisans of the time before screw-cutting lathes would make their threads by transferring parallel lines at a slight angle (just like that cold forming die) to the work-piece and then start carving. I'll bet that there is a little known and interesting story as to how the cold forming process came to be.
 
The narrator made a mistake with the forming of the hole in the nut. A die does not make the center hole, a punch does. Punches are male, dies are female.
 
At the very end, they show the bolt being stress tested... My uncle was a metallurgist and as a kid, I visited his office several times and witnessed that same test. I saw some 1" bolts get pulled apart and when it cuts loose, it makes a bang louder than a large caliber gunshot and depending on the metal, makes a bright flash. When the test is done, you stand behind a wall with a bullet-proof window. You wouldn't want to be anywhere near that test when that bolt cuts loose.

Very cool video. I had no idea threads were cold formed... The "How's it made" videos can be pretty addictive!

Ray
 
Great Vid...I never would have thought the bolt threads were pressed instead of a rod
being run through a die. Probably faster pressing them.
 
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