chasing threads

[babyblues]

Do any of you cut your own threads? If so how do you do it? Do you do it on a wood lathe or a metal lathe? I'm thinking I want to learn how to cut threads in plastic. I'd like to experiment with making some pens of my own design where I can cut the threads on the inside of the cap and the outside of the lower barrel.

 

[Kalai]

Hi Jason, I have made some on turned box's and the tools I use can be bought at most wood turning supply companys but I think the size is to big for pens but you might be able to make your own using a tap and die in the size you need, I have done this before too but not on pens, aloha.

Kalai

 

[loglugger]

This has been kicked around a couple of times but I can't seem to find it. Anyone know how.
Bob

 

[Monty]

As Bob said, this has been discussed lightly before. You can use a standard tap and die, but these are single cut and as such you would need to rotate the cap several complete turn before the threads would hold well. The threads on the pens are usually 4 start threads, meaning that there are 4 positions on the pen where the threads will engage resulting in you needing to rotate the cap about one complete revolution to hold tightly. A tap & die set like this will cost in the neighborhood of $300-$400.
The other alternative is to become proficient with a metal lathe and use it to cut the 4 start threads, but there is probably a large learning curve for this method.

 

[KenV]

Or CNC milling with a thread mill (think of a tap with all the teeth ground off but one, spinning very fast and working in three dimensions plus a rotary table.