Nib/feed size for kitless quesiton

[Carl Fisher]

So I've purchased what seems to be the most popular starter thread sizes for kitless beginners. 9x.75 section to body and 12x.75 cap to body

Before I plunk down $40 on another tap, is that sizing better suited to the 5mm or 6mm feed and nib? Or will it realistically hold either depending on the overall finished size of the front section?

Thanks!

 

[mredburn]

THe Bock feeds your refering to are basically 8mm (#6) and 6.5 (#5) so you will have better results in softer materials (resins) with the #5 size. I would start with the #5. For a #6 I would go to a 10 x.75 mm for the internal threads.
A 9mm tap will have the bottom of the threads at 8.25mm (9mm-.75mm=8.25) The #6 is acutually 7.9mm leaving only .35 difference between the tip of the threads. You will experience sever breakage.

Let me add I doubt it would work well even with brass or aluminum.

 

[Carl Fisher]

Perfect, that was what I was looking for. I couldn't figure the math out for some reason without having the parts in my hand.

Sounds like #5 is the way to go.

Thanks!

 

[SerenityWoodWorks]

Using a 9x.75 works fine for the #5 and #6 if your using Ebonite, Ceblo or other rubberlike based products. I dont have an issue with Alumilte but as Mike said you will get breaks and cracks if you try it with PR or other soft brittle materials.