Technical Information
Screw Thread Defi nitions
resultant angle
3.5º
2.5º
1.5º
insert size (iC) toolholder 16mm ex. RH/in. LH
ex. LH/in. RH SM-YE3-2P
SM-YI3-2P SM-YE3-1P
SM-YI3-1P SM-YE3
SM-YI3
22mm ex. RH/in. LH
ex. LH/in. RH SM-YE4-2P
SM-YI4-2P SM-YE4-1P
SM-YI4-1P SM-YE4
SM-YI4
insert size shim size (D)
0.5º
-0.5º -1.5º
SM-YE3-1N
SM-YI3-1N SM-YE3-2N
SM-YI3-2N SM-YE3-3N
SM-YI3-3N
SM-YE4-1N
SM-YI4-1N SM-YE4-2N
SM-YI4-2N SM-YE4-3N
SM-YI4-3N
shim ordering code
Slanted Shim Kit
Because you might occasionally need different shims than those
supplied with our standard toolholders, we strongly recommend
that shim kits be readily available in every tool shop.
ordering code contains slanted shims
3x 16mm ABY3 SM-YE3-2P, 1P, 1N, 2N, 3N
SM-YI3-2P, 1P, 1N, 2N, 3N
4x 22mm ABY4 SM-YE4-2P, 1P, 1N, 2N, 3N
SM-YI4-2P, 1P, 1N, 2N, 3N
The Helix Angle
Example:
d = 48,06mm (1.892")
p = 3,175mm ( .125")
q
p
d
= Helix angle
= pitch
= pitch diameter
q = arctan
* starts
( p /
) = 1.13°
Screw Thread Defi nitions
1. Major diameter — The largest diameter of a straight screw
thread. This applies to both internal and external threads.
2. Pitch diameter — On a straight thread, it is the diameter which
passes through the thread profi les at such points which make
the thread width of the groove equal to one-half of the basic
pitch. On a “perfect thread,” this occurs at the point where the
widths of the thread and groove are equal.
3. Thread angle (included) — The included angle between
the individual fl anks of the thread form.
nut
major diameter
pitch diameter
lead angle
minor diameter
4. Minor diameter — The smallest diameter of a straight screw
thread. This applies to both internal and external threads.
5. Lead angle — On a straight thread, the lead angle is the angle
created by the helix of the thread at the pitch diameter with
a plane perpendicular to the axis.
lead
thread angle
included
6. Lead — The distance a screw thread advances axially in one
revolution. On a single start, the pitch and lead are identical.
The lead is equal to the pitch times the number of starts.
7. Pitch — The distance from a point on a screw thread to a
corresponding point on the next thread measured parallel
to the thread axis.
pitch
crest
root
screw
8. Crest — The outer most surface of the thread form which
joins the fl anks.
widia.com
NOTE: Threads per inch (TPI) not shown:
The number of threads per inch measured axially.
The terms pitch and TPI are often used interchangeably. TPI = 1/pitch
F79
9. Root — The inner most surface of the thread form which
joins the fl anks.