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. |
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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. |
