Metric threaded bottom hole d=D-P.
D is the major diameter of the thread, P is the pitch
d=D-P is medium carbon and plastic materials, etc.
d=D-(1.1—1.2)P Aluminum alloy, cast iron and other soft materials
Choose a method with a large hole and a small axis when you cooperate, try it yourself
Metric thread (MM teeth)
Tooth depth=0.6495*tooth distance P
(tooth angle 60 degrees)
Inner Tooth Aperture =
Nominal diameter-1.0825*P
M20x2.5-6H/7g (right hand)-(single thread)-(metric coarse thread)
(Nominal diameter 20mm) (Pitch 2.5mm)
(Internal thread fit grade 6H)
(External thread fit grade 7g)
picture
Left-Double-M20x1.5 (Left Hand)-(Double Thread)-(Metric Fine Thread)
(Nominal diameter 20mm) (Pitch 1.5mm)
American thread
(unified thread)
Tooth depth=
0.6495*(25.4/teeth per inch)
(tooth angle 60 degrees)
3/4-10UNC-2A
(UNC Coarse Teeth)(UNF Fine Teeth)
(1A 2A 3A External tooth tolerance level)
(1B 2B 3B internal tooth tolerance level)
UNC American Unified Standard Coarse Thread
3/4" OD, 10 threads per inch
External teeth 2-level tolerance fit
Pipe Thread (Imperial PT)
Tooth depth =
0.6403*(25.4/teeth per inch)
(tooth angle 55 degrees)
PT 3/4-14 (tapered pipe thread) tapered pipe thread, taper ratio 1/16
3/4 inch works, 14 threads per inch
pipe thread
(PS straight thread) (PF fine thread)
Tooth depth =
0.6403*(25.4/teeth per inch)
(tooth angle 55 degrees)
PS 3/4-14 (Straight pipe thread)
PF1 1/8-16 (Straight pipe thread)
(fine teeth)
straight pipe thread
3/4 inch works, 14 threads per inch
1 1/8" works, 16 threads per inch
Pipe thread (US NPT)
(tooth angle 60 degrees)
NPT 3/4-14 (tapered pipe thread) tapered pipe thread, taper ratio 1/16
3/4 inch works, 14 threads per inch
trapezoidal thread
(30 degrees metric)
TM40*6 nominal diameter 40mm pitch 6.0mm
trapezoidal thread
(29 degree Acme thread)
TW26*5 outer diameter 26mm, 5 threads per inch
square thread
Calculation of car teeth
Consider the conditions Calculation formula
Conversion between metric and imperial threads Number of threads per inch n = 25.4 / Pitch P
Pitch P = 25.4 / threads per inch n
Because of the speed determined by the workpiece material and the tool, the speed N = (1000 peripheral speed V ) / (circumference p * diameter D )
Because of the speed determined by the machine structure
The effect of rapid movement of the tool holder Maximum turning speed N = 4000/ P
Add WeChat: Yuki7557 to send a macro program tutorial
Influence of acceleration and deceleration of rapid movement of the tool holder
Calculation of cutting point and retracting point
(Calculation of incomplete teeth) Minimum cutting distance L1
L1 = (pitch P ) * (spindle speed S ) / 500
Maximum tool retract distance L2
L2 = (pitch P ) * (spindle speed S ) / 2000
Tooth depth and root diameter d Tooth depth h =0.6495 * P
Root diameter d = nominal outer diameter D - 2 * h
Example: Car-made outer teeth 3/4"-10UNC 20mm long
Conversion between metric thread and imperial thread pitch P = 25.4 / (number of inch threads n)
P = 25.4 / 10 = 2.54mm
Because the workpiece material and
The speed determined by the tool Outer diameter D = 3 / 4 inches = 25.4 * (3/4) =19.05MM
Speed N = (1000 peripheral speed V) / (circumference rate p * diameter D )
N = 1000V / pD = 1000 * 120 / (3.1416*19.05)
=2005 rpm (rev/min)
Because of the speed determined by the machine structure
The effect of rapid movement of the tool holder Maximum turning speed N = 4000 / P
N = 4000/2.54 = 1575 rpm
Comprehensive workpiece material tool and mechanical structure
Determined speed N = 1575 rpm N = 2005 rpm
Choose the lower speed of the two, that is, 1575 rpm
Influence of acceleration and deceleration of rapid movement of the tool holder
Calculation of cutting point and retracting point
(Calculation of incomplete teeth) Minimum cutting distance L1
L1 = (pitch P) * (spindle speed S) / 500
L1 = 2.54*1575/500=8.00mm
Minimum tool retract distance L2
L2 = (pitch P) * (spindle speed S) / 2000
L2 = 2.54*1575/2000=2.00mm
Tooth depth and root diameter d Tooth depth diameter d = nominal outer diameter D-2*h =19.05-2*1.65 = 15.75mm
