Lathe - Internal threading tool DIY or purchased?

[bill70j]

what is your take on internal threading? DIY? purchase?

• if DIY - how did you make it - got any pictures to show for it? any tips or things you'd do differently?
• if purchases - which one are you using ? what is it's benefits (insert type and whatnot)?

I use bars that accept HSS ground bits, like Tom shows, as well as tool holders for threading inserts.

For small diameter bores, I have a 1/4" bar and a 5/16" bar. I grind the bits from either round or square HSS blanks.
For larger diameter bores, I have 8, 10, and 12mm bars that take an 11mm IC insert, an a 16mm and 5/8" bar that take a 16mm IC insert.

I prefer the inserts simply because they are easier to use and seem to stay sharp forever. I use the HSS bits for smaller diameter bores.

Here is a pic that shows the 8mm bar with the 11IC insert and the 5/8" bar with the 16IC insert. It also shows the 1/4" bar with a bit ground for ACME threads and the 5/16" bar with a bit ground for 60 deg threads.

 

[magicniner]

These days I use Iscar MGCH 06 and MGCH 08 bars with LH threading inserts and thread from the bottom of the hole outwards on most jobs.