4-40 phillips pan head screw

Many of Mr. Ma’s products use American-made threads. But recently, Mr. Ma received a 4-40 phillips pan head screw delivered to him by Shi Shi Tong. Then, Mr. Ma told us that the size of the screws does not meet his assembly requirements. Why?

During the actual assembly, Mr. Ma found that some of the threads could be screwed in, but some of the threads were screwed in and found to be small. After Mr. Ma gave us feedback, we told Mr. Ma whether it was possible to tell the thread diameter of the small screw that was found after the assembly.

Mr. Ma told us that it is 2.70mm. In the drawings given by Mr. Ma, it is marked with #4-40-2A, and the diameter of this thread is converted into metric: 2.69-494mm-2.82448mm, 2.70mm is within this tolerance. Later, Mr. Ma told us that the proper thread diameter for assembly is 2.72mm-2.81mm.

After Mr. Ma finished talking to us, we were aware that Mr. Ma might have given the wrong 4-40 phillips pan head screw, or the size of the hole in their product was a little larger, resulting in a smaller diameter of the thread. The assembly does not match. Then we said this to Mr. Ma. Mr. Ma said that he would carefully check where the problem occurred and tell us the result.

After a few days, Mr. Ma told us that the size of the threaded part of the drawing he gave last time was wrong, not #4-40-2A, but #4-40-3A, let’s do some 4-40 phillips pan head screw sample for him.

After receiving the samples, Mr. Ma found that the assembly was indeed consistent. Then let us give him mass production.

If you want to customized 4-40 phillips pan head screw  please send an email: annie.li@szsst88.com