Choosing Threading Inserts: Full vs Partial Profile for CNC Lathe Work

In cnc lathe machine workshop undoubtedly you will see most of the component assignments with some kind of threading like internal threading, external threading, tapping etc.

Of course threading on a cnc machine is not a problem because cnc gives us the flexibility we can use cnc canned cycle like cnc threading cycles or cnc G-code G33, we can even machine taper threads.

For threading on cnc lathe machine mostly threading inserts are used. Using threading inserts for threading gives us lot of benefits such as

• Easy to replace
• Less set-up time
• Accuracy
• High performance
• High productivity

CNC threading inserts are specifically made for thread turning, so therefore threading inserts have shape (profile or form) like the thread profile.

You will see two flavors if we divide the threading inserts according to the threading insert shape or profile.

• Full Profile Threading Inserts
• Partial Profile Threading Inserts

Full Profile Threading Inserts

American UN Full Profile Thread Insert

Full profile threading inserts are used for high productivity and long runs. Actually full profile threading inserts are specifically made for a specific type of thread, meaning that a full profile threading insert which is made for one thread type can’t be used for the other threading type or pitch, Why, because the full profile threading insert have the same shape and profile as the thread it is made to be machine.

CNC threading insert full profile threading insert

A plus point of the full profile threading insert is that full profile threading inserts have a larger nose-radius, so threads can be made in fewer passes, and this also means that the full profile threading insert will give us a longer run.

Full Profile Threading Inserts Pros

Full profile threading inserts actually ensure

• Proper Thread Profile
• Correct Thread Depth
• Bottom and Top Radii

Full Profile Threading Inserts Cons

There are some limitations when you select a full profile threading insert.

• A separate insert is required for each pitch and profile
• Full profile threading inserts might cut the thread-major-diameter if mishandled.

Partial Profile Threading Inserts

60° Partial Profile Thread Insert

Partial profile threading inserts can be used for various threading pitches and profiles, so now partial profile threading insert can machine different pitches and we not have to stick to a specific profile or pitch which was when we use full profile threading insert.

Partial profile threading inserts only machine the thread profile, and these inserts will never touch the thread-major-diameter, so no danger of diameter variation.

CNC Threading insert partial profile threading insert

The nose radius of the insert is sized to suit the smallest profile within the pitch range of the insert.

Partial Profile Threading Inserts Pros

• Same insert can be used for multiple pitches as long as the angle is same
• Fewer insert need to be stocked. (because one insert can used for multiple pitches)

Partial Profile Threading Inserts Cons

• Smaller insert nose radius (shorter insert life)