Why not standard size treads?

[alxe24]

I will try my hand at kitless and my brother in law who works at at machine shop will wife me some taps and dies they don't use any more but are standard size single entry.
To start playing I think that should do, I will find the closest equivalent and give tha a try.
Can someone tell me what would be the closest pitch to the .75 and also for educational purpose why is everyone using triple lead on mm?
Thanks a lot.
Alex

 

[Paul in OKC]

I will try my hand at kitless and my brother in law who works at at machine shop will wife me some taps and dies they don't use any more but are standard size single entry.
To start playing I think that should do, I will find the closest equivalent and give tha a try.
Can someone tell me what would be the closest pitch to the .75 and also for educational purpose why is everyone using triple lead on mm?
Thanks a lot.
Alex

Triple starts are used so you have a 'fast' screw for putting on/taking off the cap. (Not having to unscrew several turns) If you just used a coarse thread for the same purpose it takes too much material thickness for that. As far as .75 would equal aprox. 34.5 threads per inch. In a standard size tap and dies of the size needed for pens there isn't anything close. You can get special taps through places like MSC and such with 30 or 32 tpi.

 

[Displaced Canadian]

I haven't done much with threading, but The ones I have made have used fine thread ones that you can get anywhere. I have found that NAPA dies work better than most. If you are making the whole thing you could use any size you wanted to.

 

[KenV]

By "standard" you are suggesting that the inch-pound system is or should be the standard.

Most of our pen components, and major pen manufacture is metric based. The good news is that you can get started making your own components with a few readily available metric taps and dies.

I have noted that some times free things are not worth the prece.

 

[alxe24]

Thanks for the answers. I figure that after I try my hand at treading and get a bit familiar to kitless pens it can take the dive and spend the money on the right taps and dies, I guess if I can get a set the right size that cost me $0 that shoul do for now.

 

[KenV]

A "right tap and die" can be single start and cost $10-$20. NAPA or a similar auto store is a good source. Say a 12 by 0.75 for a cap thread, and one for which ever feed you decide to use.

Most of the NF and NC threads will not leave enough "meat" and you will be fighting cracks and breakage.

Good luck.