Dear Maxime,
Good Day!
Regarding the samples of pan framing screw we send to you, were from the production line which we offer to another customer in America.
Does the fact that it is grey phosphate instead of black phosphate makes a difference for penetration ? → For this, we think that is not the main cause of it~
We found that there are some different between our samples and yours!
The TPI of yours is #7-20, which is different from ours is #7-16, we think it may be the main cause to make the difference of penetration.
Now, my boss is preparing for new die of the new screw samples, and it will take around 30 days to run the production line. After we finish it, will send you samples to testing
Also, we found samples from yours there is serration under the head, but none of ours. In order to check the samples which meet your requirement, we want to confirm do you need serration or not?
Thanks for your attention on all above, and look forward to hearing your comments soon ~