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.
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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, alu - minum, 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 diecastings. |
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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. |