Page 86 - THREADING CATALOG

USER GUIDE
THREAD TURNING FLTB-2A & 2B Thread Size Minimum Minor Diameter American Standard Buttress

Internal Threading Limitations
Thread Designations
Threads
Nominal
Per Inch
When only the designation BUTT is used, the thread is a
Inch
MM
“pull” type buttress (external thread pulls) with the clearance
1.600
8
1-3/4
40.64
flank (45˚) leading and the pressure flank (7˚) following.
1-5/8
1.505
38.23
10
When the designation PUSH-BUTT is used, the thread is a
1-1/2
1.400
12
35.56
push type buttress (external thread pushes) with the load
29.85
1-1/4
1.175
16
flank (7˚) leading and the 45˚ clearance flank following.
20
1-1/16
1.002
25.45
Whenever possible this description should be confirmed
by a simplified view showing thread angles on the
drawing of the product that has the buttress thread.
FLTB-3A & 4A Internal Threading Limitations
Threads Nominal Minimum Minor Diameter Always remember that the position of
your holder and direction of your feed will
Per Inch Thread Size Inch MM determine the lead angle on the insert.
4* 2-1/2 2.200 55.88
5 2-1/4 2.010 51.05 External Buttress (45˚ lead) Thread
6 2 1.800 45.72 counterclockwise rotation
8 1-3/4 1.600 40.64
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.
chuck
RH insert
FLTB-3B & 4B Internal Threading Limitations 45˚ Lead
FLTB-2RB
Threads Nominal Minimum Minor Diameter FLTB-3RB LH holder FLEL
Per Inch Thread Size Inch MM FLTB-4RB RH holder FLSR
feed
4 *2-7/8 2.575 65.41 45˚ clearance angle of this buttress thread becomes the leading angle in
5 2-3/4 2.510 63.75 this application.
6 2-3/8 1.175 29.85
8 2-1/8 1.975 50.17 Internal Buttress (45˚ lead) Thread
10 1-7/8 1.755 44.58 counterclockwise rotation
12 1-5/8 1.525 38.74
16 1-1/2 1.407 35.74
20 1-7/16 1.378 35.00 RH bar
* FLTB-4B insert only 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
ISCAR
84