Page 383 - Carmex - Inch Catalog 2022

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Mill-Thread Technical Section

Tool Selection

For indexable and solid carbide Mill Threads

The following chart provides a fairly accurate visual selection tool for Internal Threading.

The chart is suitable for the following thread forms: ISO, UN, WHIT, NPT, NPTF, BSPT and PG.

4 5 6 7 8 9 10 11 12 13 14 15 16 18 20 22 24 26 28 30 32 34 36 38 40 44 48 52 58 64

Any tool with a small cutting diameter can produce larger diameter threads.
Example: Internal thread 11/4 x 16UN:
Find a Milling Tool to produce d=1.25 Internal
right hand UN thread with a thread pitch P=16/1
As can be seen from the chart above, the two red lines
intersect at a selected tool with a cutting diameter of D=.79
Chosen toolholder: SR0790 H21
Insert: 21 I 16 UN MT7

1.25

16/1

If you need assistance, please call your local
distributor and ask for help in selecting the appropriate
tool as well as for a CNC program to suit your CNC milling
machine.

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