Tap Size For Adding Socket Head Set Screws To KIK Cyclinder

[Klaiviel]

Hey, I am trying to build a practice lock using a random Schlage KIK cylinder I have laying around. I would like to add socket head set screw's on the top of the bible to allow for easy pin changes. What size tap would you recommend using? I have seen people do this before so I know it is possible. Based on my dial caliper measurements the pin diameter seems to be .115" and the diameter of the pin stack seems to be .125", it seems odd to me that there is a 10 mil gap between the pin and the pin stack, I am unsure if that is a the standard gap or not. Anyways based on my measurement of .125" I would think that would be equal to the drill size on a tap so based on this chart http://en.wikipedia.org/wiki/Drill_and_tap_size_chart I would go with a #8-32 tap despite their being an 11 mil difference because if I am not mistaken when you fall in between two tap sizes you go with the larger one. Is this correct? Thanks.

[Ortin468]

The math sounds right to use the #8-32 tap. Start the holes with a normal tap, and finish with a bottoming tap. Try to keep the depth of the thread even across all the pin holes. This way the spring pressure is even across the stacks. Do not go very far in, just enough to keep them in since its a practice cylinder. Later on for a more advanced practice session, make the threads deeper, and set the screws at different heights so you can vary the spring pressures.

[Klaiviel]

Thanks for the advice.

[Klaiviel]

Well I went with the #8-32 tap and I have an update. Here is the finished product: I apologize for the low-res my camera is terrible. The #8-32 tap ended up being close enough to work; for caps I used #8-32 socket head set screws 1/8" long that accept a 5/64" hex wrench. As far as how much of an improvement they make; I can repin a pin stack in about 15 seconds which is a huge improvement over doing it the old fashioned way, so I think it was well worth it for a practice lock. Now I am off to practice DigitalBlue's method of SPP as I have neglected SPP for far to long and I feel like I have hit a brick wall in terms of not being able to advance any further with just raking. Anyhow just wanted to show the final product.