| Tapping
Screws (Type A, AB, B) |
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Type
A point: A thread forming screw for use in thin metal .015
to .050 thick. Used with drilled, punched or nested holes in
sheet metal, resin impregnated plywood, asbestos combinations,
among others. Not recommended for new design. |
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Type
AB point: A thread forming screw combining locating point
of Type A with thread size and pitch of Type B. Normal limitations
of type B apply. |
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Type
B point: A thread forming screw for use in heavier metal
.050 to .200 thick. Larger root diameter with finer thread
pitch for light and heavy sheet metal non-ferrous castings,
plastics, impregnated plywoods, asbestos combinations, and
other materials. |
| Thread
Cutting Screws (Type 1, 17, 23, 25, F) |
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Type
1 point: A thread cutting screw with single flute for general
use. Produces a fine standard machine screw thread for field
replacement. |
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Type
17 point: A thread cutting screw for wood with a coarse
tapping screw thread and a special long sharp point fluted
to capture chips. |
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Type
23 point: A thread cutting screw in the fine thread series
offering maximum thread cutting area and excellent chip clearing,
with minimum tightening torques. |
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Type
25 point: A thread cutting screw similar to type 23 point
except with coarse Type B thread. For plastics and other soft
materials with large chip clearing and cutting edges. |
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Type
F point: A thread cutting screw with machine screw thread
with blunt tapered point, having multi-cutting edges and
chip cavities. For heavy gauge sheet metal, aluminum, zinc
and lead die castings, cast iron, brass and plastic. |
Thread
Forming Screws (Type C, CA, Tri-Round, Lo-Driv)
Screws for Plastic (Tri-Round, Round) |
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Type
C point: A thread forming screw with either coarse or fine
pitch machine screw thread and blunt tapered point. Eliminates
chips and permits replacement with standard screw in the field.
Higher driving torque required. Usable in heavy sheet metal
and die castings. |
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Type
CA point: A thread forming screw with either coarse or
fine pitch machine screw thread. Same as Type C except with
a Gimlet point. The locating point works better than Type C
where holes between two adjoining pieces of sheet metal may
be somewhat misaligned. |
|
|
Tri-Round: A
thread forming screw in mostly coarse machine screw threads.
Three vertexes perform a roll-forming process to form mating
threads. Much better thread forming than Type C or CA, and drives
with less torque. |
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Lo-Driv: A
thread forming screw in mostly coarse machine screw threads.
The point and body design requires low end-load for starting
and low drive torque for seating. The full 360 degree body above
the point provides excellent strip-to-drive ratios. |
