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techtalk:ref:tools032 [2022/03/27 05:35] – [Measuring Threads In General] hippysmack | techtalk:ref:tools032 [2024/01/23 01:55] (current) – hippysmack | ||
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Panhead screws / hex bolts / cap screws etc. are measured from under the head to the end. \\ | Panhead screws / hex bolts / cap screws etc. are measured from under the head to the end. \\ | ||
Flat head screws, tapered shanks under the head, are measured for overall end to end length (head is assumed to end flush with fastened piece). \\ | Flat head screws, tapered shanks under the head, are measured for overall end to end length (head is assumed to end flush with fastened piece). \\ | ||
+ | |||
+ | | Measuring length ((composite of photos used with permission)) | ||
+ | |{{: | ||
|SAE thread gauge: ((photos by Hippysmack))||Tap/ | |SAE thread gauge: ((photos by Hippysmack))||Tap/ | ||
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====== Pitch to TPI Conversion Table ====== | ====== Pitch to TPI Conversion Table ====== | ||
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The table below is a reprint from THA ((https:// | The table below is a reprint from THA ((https:// | ||
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====== US Nut/Bolt Threads ====== | ====== US Nut/Bolt Threads ====== | ||
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US threads generally have 3 numbers although the last can be left off unless required. \\ | US threads generally have 3 numbers although the last can be left off unless required. \\ | ||
The first number is a whole number and/or fraction, the second number is the threads per in (TPI), followed by the length in inches. \\ | The first number is a whole number and/or fraction, the second number is the threads per in (TPI), followed by the length in inches. \\ | ||
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====== Metric Nut/Bolt Threads ====== | ====== Metric Nut/Bolt Threads ====== | ||
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Metric bolts are written down as an " | Metric bolts are written down as an " | ||
The first number is the diameter, the second the thread pitch, and the third the length in millimeters. ((http:// | The first number is the diameter, the second the thread pitch, and the third the length in millimeters. ((http:// | ||
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|**24mm**| | |**24mm**| | ||
+ | **Methods of measuring in pics**: \\ | ||
Metric screw thread OD can be deduced by using an imperial (US) scale caliper using the chart above. \\ | Metric screw thread OD can be deduced by using an imperial (US) scale caliper using the chart above. \\ | ||
Your measurements may not be an exact match to the dims above but will be close enough to make a judgement on the metric counterpart size. \\ | Your measurements may not be an exact match to the dims above but will be close enough to make a judgement on the metric counterpart size. \\ | ||
- | {{: | + | {{: |
====== Common Brake Line Threads ====== | ====== Common Brake Line Threads ====== | ||
Most brake systems use flared fittings since they have strong metal to metal connections. \\ | Most brake systems use flared fittings since they have strong metal to metal connections. \\ | ||
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====== NPT Pipe Threads ====== | ====== NPT Pipe Threads ====== | ||
- | NPT stands for National Pipe Thread. Descriptions are commonly used as either straight (NPS) or tapered (NPT). ((DR DICK of the XLFORUM | + | NPT stands for National Pipe Thread. Descriptions are commonly used as either straight (NPS) or tapered (NPT). ((DR DICK of the XLFORUM |
Pipe thread sizes do not refer to any physical dimension. \\ | Pipe thread sizes do not refer to any physical dimension. \\ | ||
NPT has flattened peaks and troughs where BSP is rounded. NPT has a thread angle of 60º where BSP is 55º. \\ | NPT has flattened peaks and troughs where BSP is rounded. NPT has a thread angle of 60º where BSP is 55º. \\ | ||
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** Little known fact**: \\ | ** Little known fact**: \\ | ||
- | All iron heads pipe threads used in cases, rocker boxes, and oil pumps are straight female thread, fitted with tapered thread male fittings.((DR DICK of the XLFORUM | + | All iron heads pipe threads used in cases, rocker boxes, and oil pumps are straight female thread, fitted with tapered thread male fittings.((DR DICK of the XLFORUM |
This holds true for Evo Sportsters also. \\ | This holds true for Evo Sportsters also. \\ | ||
- | * The sizes in the chart below are the major dia of the male straight thread (as the pipe OD is the major). \\ And the major dia. of a tapered male thread at it's big end. ((DR DICK of the XLFORUM | + | * The sizes in the chart below are the major dia of the male straight thread (as the pipe OD is the major). \\ And the major dia. of a tapered male thread at it's big end. ((DR DICK of the XLFORUM |
- | * The tapered thread has it's diameter reduced on a taper of .0625" per inch of thread length. Almost all hardware store fittings will be tapered thread.((DR DICK of the XLFORUM | + | * The tapered thread has it's diameter reduced on a taper of .0625" per inch of thread length. Almost all hardware store fittings will be tapered thread.((DR DICK of the XLFORUM |
^{{techtalk: | ^{{techtalk: |