Page 95 - Turning_catalog_INCH_2022_45_P691-914

USER GUIDE

FLTB-2A & 2B Internal Threading Limitations American Standard Buttress THREADING
Threads Nominal Minimum Minor Diameter Thread Designations
per Inch Thread Size Inch MM When only the designation BUTT is used, the
8 1-3/4 1.600 40.64 thread is a “pull” type buttress (external thread
10 1-5/8 1.505 38.23 pulls) with the clearance flank (45˚) leading
and the pressure flank (7˚) following.
12 1-1/2 1.400 35.56
16 1-1/4 1.175 29.85 When the designation PUSH-BUTT is used, the thread is a
push type buttress (external thread pushes) with the load
20 1-1/16 1.002 25.45 flank (7˚) leading and the 45˚ clearance flank following.
Whenever possible this description should be confirmed
by a simplified view showing thread angles on the
FLTB-3A & 4A Internal Threading Limitations drawing of the product that has the buttress thread.
Threads Nominal Minimum Minor Diameter
per Inch Thread Size Inch MM Always remember that the position of
your holder and direction of your feed will
4* 2-1/2 2.200 55.88 determine the lead angle on the insert.
5 2-1/4 2.010 51.05
6 2 1.800 45.72 External Buttress (45˚ lead) Thread
8 1-3/4 1.600 40.64 Counterclockwise rotation
10 1-5/8 1.505 38.23
12** 1-1/2 1.400 35.56
* FLTB-4A insert only
** 16 or 20 threads per inch can be cut providing minor diameter
is 1.375 or larger.

FLTB-3B & 4B Internal Threading Limitations chuck RH insert
Threads Nominal Minimum Minor Diameter 45˚ Lead
FLTB-2RB
per Inch Thread Size Inch MM FLTB-3RB LH holder FLEL
FLTB-4RB
4 *2-7/8 2.575 65.41 feed RH holder FLSR
5 2-3/4 2.510 63.75 45˚ clearance angle of this buttress thread becomes the leading angle in
6 2-3/8 1.175 29.85 this application.
8 2-1/8 1.975 50.17
10 1-7/8 1.755 44.58 Internal Buttress (45˚ lead) Thread
12 1-5/8 1.525 38.74 Counterclockwise rotation
16 1-1/2 1.407 35.74
20 1-7/16 1.378 35.00
* FLTB-4B insert only RH bar
A_ -FLER
feed
LH insert
chuck 45˚ Lead
FLTB-2LB
FLTB-3LB
45°
FLTB-4LB
45˚ clearance flank of this buttress thread becomes the leading angle in
this application.
American Standard Buttress
1/2 d play P
nut
0,1632 P 0,0627 P

0,3 P 0,3 P
0,8906P
0,3 P
0,0826 P 1/2 d2 play
45˚
7˚ 0,1632 P
1/2 d1 play screw
Use: fittings and pipe couplings

785