View Full Version : Thread Pitch?

Frank Downey
08-15-2006, 12:40 PM
I'm in the process of buying an internal threading boring bar.The problem that I have is that I'm going with a Kennametal laydown LT system and the inserts that I can chose from has a 1.0 and 1.5 thread pitch.I'm only going to be threading coarse threads and in std. sizes.App. 3/4" to 1 1/2" bolt sizes.Any pitch sizes would be greatful.Thanks

08-15-2006, 02:03 PM
Frank, not sure what you're looking for?

Frank Downey
08-15-2006, 02:08 PM
looking for the correct insert that i need is it the 1.0 or the 1.5

08-15-2006, 02:52 PM
So, all you're going to do is Metric 1.0 or 1.5mm?

I guess I'm cornfused too. :eek:

08-15-2006, 03:28 PM
I'm not sure either but if you're asking what is the best pitch for machining bolts of the 3/4 to 1-1/2 inch size you will probably want something closer to the standard pitch of a 3/4 inch bolt in a coarse thread. When you finally get to the 1-1/2 inch bolt you'll be at a fine pitch for that diameter.

a 1mm pitch is 40th American (actually .039371) which is 25.4 threads per inch. Thisi s much to fine for the bolt sizes you specify. A 1.5 mm pitch is 16.93 threads per inch (TPI) and is still fine for those diameters but a better choice. A larger metric pitch, say 2 to 3 mm is better yet.

Rob Dee

08-15-2006, 05:07 PM
Can you offer more information? I have looked at Kennametal LT Laydown tooling in a couple of catalogs, and see no reference to 1 vs 1.5 pitch. There is something regarding (I think) the helix angle and that may have to do with the pitch of coarse vs fine threads. The inserts do come specific to a range of thread counts.

08-15-2006, 06:25 PM

Like others, I'm a little confused by your question.

With the laydown type insert you can get a general purpose insert that'll cut anywhere from something like 8 tpi (threads per inch) to 16 with the same insert. You also get inserts that are called full profile, where a different insert is required for each different thread pitch.

I'm guessing your question may be based on the fact the dealer you're working with only happens to have the 1.0 & 1.5 in stock. Those are metric inserts full profile types, since you mention 3/4 and 1-1/2 I'll assume you're aren't working much in metrics so those wouldn't be a good choice for you.

With the popular laydown style insert system there's a wide variety of inserts readily available from dealers. J&L Industrial and MSC are a couple online places that'll have them. When buying be sure to find a dealer who'll sell in less than box quantity, that way you won't be forced into buying full boxes of ten.

08-16-2006, 10:07 PM
Hi! If you look at the Iscar threading inserts, You only have 2 insert sizes....the small inserts will cut any thread ( 60 degree thread) up to about 8 TPI... the larger inserts will cut the deeper course threads....Kenametal should have a similar system.