0.800-36 AMO AMO (microscope objective) External Thread Specifications
0.800-36 AMO (external) · 0.8000-36 AMO
ASMESTD: ASME B1.11SOURCE: Table 2 · p. 7TYPE: External (bolt/screw)CLASS: Only class
Thread profile
0.800-36 AMO (external): solid line = maximum material profile, dashed = minimum material, hatched = tolerance zone, dotted = full-form British Whitworth thread. Drawn to scale; values in inches.
Limits of size, class Only class
| Dimension | Basic | Max | Min | Tolerance |
|---|---|---|---|---|
| Major diameter dCrest of the objective thread; tolerance minus | 0.8000 | 0.7941 | 0.7911 | 0.0030 |
| Pitch diameter ESets the fit; maximum = basic − allowance G | 0.7822 | 0.7804 | 0.7774 | 0.0030 |
| Minor diameter KMaximum set by the allowance; the minimum is an extreme set by the tool form, not toleranced and not gaged | 0.7644 | 0.7626 | 0.7552ref. | |
| Allowance GOn the pitch, major and minor diameters | 0.0018 |
Dimensions in inches. Values are those of the standard (ASME B1.11); calculated cells follow the standard’s formulas. Where the standard prints a value that differs from its formula, the printed value is shown with a note.
Engagement, design sizes and gage tolerances
Length of engagement
- Minimum
- 0.125 in
- Usual
- 0.125 in
- Maximum
- 0.375 in
Design sizes (Table 1)
- Design major diameter
- 0.7941 in
- Design pitch diameter
- 0.7804 in
- Design minor diameter
- 0.7626 in
- Extreme limit from the tool flat geometry
- 0.7552 in
- Allowance on the major and minor diameters G
- 0.0018 / 0.0018 in
Lead, flank and gage tolerances
- Lead variation of the thread
- not given in the standard
- Half-angle variation of the thread
- not given in the standard
- Gage lead tolerance ±
- 0.0002 in
- Gage half-angle tolerance ±
- 0° 20′
Recommended gage dimensions (appendix), calculated against the printed values
| Gage | Symbol | Description | Formula (as printed) | Printed | Formula value | Difference | Agrees? |
|---|---|---|---|---|---|---|---|
| "Go setting" thread plug gage (A-Go) | Dg Max | Major diameter, maximum | De Max | 0.7941 | 0.7941 | 0 | yes |
| "Go setting" thread plug gage (A-Go) | Dg Min | Major diameter, minimum | Dg Max − 0.0004 | 0.7937 | 0.7937 | 0 | yes |
| "Go setting" thread plug gage (A-Go) | Eg Max | Pitch (effective) diameter, maximum | Ee Max | 0.7804 | 0.7804 | 0 | yes |
| "Go setting" thread plug gage (A-Go) | Eg Min | Pitch (effective) diameter, minimum | Eg Max − 0.0002 | 0.7802 | 0.7802 | 0 | yes |
| "Not Go setting" thread plug gage (A-Not Go) | Dg Min | Major diameter, minimum | De Max | 0.7941 | 0.7941 | 0 | yes |
| "Not Go setting" thread plug gage (A-Not Go) | Dg Max | Major diameter, maximum | Dg Min + 0.0004 | 0.7945 | 0.7945 | 0 | yes |
| "Not Go setting" thread plug gage (A-Not Go) | Eg Min | Pitch (effective) diameter, minimum | Ee Min | 0.7774 | 0.7774 | 0 | yes |
| "Not Go setting" thread plug gage (A-Not Go) | Eg Max | Pitch (effective) diameter, maximum | Eg Min + 0.0002 | 0.7776 | 0.7776 | 0 | yes |
| "Go" thread ring gage (G-Go) | Eg Max | Pitch (effective) diameter, maximum | Eg Max "Go" A Plug | 0.7804 | 0.7804 | 0 | yes |
| "Go" thread ring gage (G-Go) | Eg Min | Pitch (effective) diameter, minimum | Eg Min "Go" A Plug | 0.7802 | 0.7802 | 0 | yes |
| "Go" thread ring gage (G-Go) | Kg Max | Minor diameter, maximum | Dn Min − 2hb | 0.7644 | 0.7644 | 0 | yes |
| "Go" thread ring gage (G-Go) | Kg Min | Minor diameter, minimum | Kg Max − 0.0004 | 0.764 | 0.764 | 0 | yes |
| "Not Go" thread ring gage (G-Not Go) | Eg Min | Pitch (effective) diameter, minimum | Eg Min "Not Go" A Plug | 0.7774 | 0.7774 | 0 | yes |
| "Not Go" thread ring gage (G-Not Go) | Eg Max | Pitch (effective) diameter, maximum | Eg Max "Not Go" A Plug | 0.7776 | 0.7776 | 0 | yes |
| "Not Go" thread ring gage (G-Not Go) | Kg Min | Minor diameter, minimum | Ee Min − p/3 | 0.7681 | 0.7681 | 0 | yes |
| "Not Go" thread ring gage (G-Not Go) | Kg Max | Minor diameter, maximum | Kg Min + 0.0004 | 0.7685 | 0.7685 | 0 | yes |
| "Go" thread plug gage (C-Go) | Dg Min | Major diameter, minimum | Dn Min | 0.8 | 0.8 | 0 | yes |
| "Go" thread plug gage (C-Go) | Dg Max | Major diameter, maximum | Dg Min + 0.0004 | 0.8004 | 0.8004 | 0 | yes |
| "Go" thread plug gage (C-Go) | Eg Min | Pitch (effective) diameter, minimum | En Min | 0.7822 | 0.7822 | 0 | yes |
| "Go" thread plug gage (C-Go) | Eg Max | Pitch (effective) diameter, maximum | Eg Min + 0.0002 | 0.7824 | 0.7824 | 0 | yes |
| "Not Go" thread plug gage (C-Not Go) | Dg Max | Major diameter, maximum | En Max + p/3 | 0.7945 | 0.7945 | 0 | yes |
| "Not Go" thread plug gage (C-Not Go) | Dg Min | Major diameter, minimum | Dg Max − 0.0004 | 0.7941 | 0.7941 | 0 | yes |
| "Not Go" thread plug gage (C-Not Go) | Eg Max | Pitch (effective) diameter, maximum | En Max | 0.7852 | 0.7852 | 0 | yes |
| "Not Go" thread plug gage (C-Not Go) | Eg Min | Pitch (effective) diameter, minimum | Eg Max − 0.0002 | 0.785 | 0.785 | 0 | yes |
| Tolerance in lead | ± in. | 0.0002 | |||||
| Tolerance on half-angle of thread | ± deg min | 0° 20′ |
The standard’s paragraphs
Our explanation of each paragraph is still to be written; the standard’s own text is not reproduced on this site.
| Paragraph | Topic | Printed page | Explanation |
|---|---|---|---|
| — | Title | explanation to be written | |
| — | Errata | explanation to be written | |
| — | Errata | explanation to be written | |
| — | Foreword | 2 | explanation to be written |
| 1 | General and historical | 5 | explanation to be written |
| 2 | General and historical | 5 | explanation to be written |
| 3 | General and historical | 5 | explanation to be written |
| 4 | General and historical | 5 | explanation to be written |
| 5 | General and historical | 5 | explanation to be written |
| 6 | General and historical | 5 | explanation to be written |
| 7 | Terminology | 5 | explanation to be written |
| 8 | Specifications: basic form of thread | 5 | explanation to be written |
| 9 | Specifications: design form of thread | 5 | explanation to be written |
| 10 | Specifications: lead of thread | 6 | explanation to be written |
| 11 | Specifications: classification | 6 | explanation to be written |
| 12 | Specifications: nominal sizes | 6 | explanation to be written |
| 13 | Specifications: allowances | 6 | explanation to be written |
| 14 | Specifications: tolerances | 6 | explanation to be written |
| 15 | Specifications: lengths of engagement | 7 | explanation to be written |
| 16 | Specifications: limits of size | 7 | explanation to be written |
| 17 | Specifications: thread designation | 7 | explanation to be written |
Notes
- One thread only: 0.800-36 AMO, single start, one class (paras. 10-12). Lead and half-angle variation of the thread, tensile stress area, root radius tolerance and taper: not given in the standard (the pitch diameter tolerance already includes lead and angle errors, para. 14; no taper). Gage lead ±0.0002 in. and half-angle ±0°20′ belong to the Appendix gages. Grey italic = extreme minimum minor diameter (Table 2 note b), reference only. Allowance G = 0.0018 on pitch, major and minor diameters (paras. 13, Table 1 notes b, c). Tolerances run in the minus direction from the design size (para. 14).
Mates
0.800-36 AMO (external) screws into a thread of the same standard at the same size and pitch. The standard mating internal thread is class Only class. Check the fit with the standard pair →
Working out the mating options…
Different pitch or a different thread family never mate; the fit check runs over both tolerance zones.
All values for 0.800-36 AMO (external)every column of the workbook row
| Designation | 0.800-36 AMO (external) |
|---|---|
| Decimal designation | 0.8000-36 AMO |
| Threads per inch | 36 |
| Thread form | AMO (truncated Whitworth, 55°) |
| Series | AMO |
| Series name | Microscope objective |
| External / internal | External |
| Class | Only class |
| Nominal size | 0.800 |
| Pitch P (in.) | 0.02777778 |
| Basic major dia D (in.) | 0.8000 |
| Size category | Only size |
| Source table | Table 2 |
| Printed page | 7 |
| Major dia max (in.) | 0.7941 |
| Major dia min (in.) | 0.7911 |
| Major dia tolerance (in.) | 0.0030 |
| Major dia status | Toleranced (Table 2) |
| Pitch dia allowance G (in.) | 0.0018 |
| Major dia allowance (in.) | 0.0018 |
| Basic pitch dia E (in.) | 0.7822 |
| Pitch dia max (in.) | 0.7804 |
| Pitch dia min (in.) | 0.7774 |
| PD tolerance (in.) | 0.0030 |
| Basic minor dia K (in.) | 0.7644 |
| Minor dia max (in.) | 0.7626 |
| Minor dia min (in.) | 0.7552 |
| Minor dia status | Max 0.7626 is toleranced by allowance only. Min 0.7552 is an extreme set by the tool form (Table 2 note b), not toleranced and not gaged |
| Minor dia allowance (in.) | 0.0018 |
| Table 1 design major dia (in.) | 0.7941 |
| Table 1 design pitch dia (in.) | 0.7804 |
| Table 1 design minor dia (in.) | 0.7626 |
| Extreme limit from tool flat, geometry (in.) | 0.7552 |
| Whitworth radius r, not used (in.) | 0.0038 |
| Lead variation ± (in.) | not given in the standard |
| Half-angle variation ± | not given in the standard |
| Gage lead tolerance ± (in.) | 0.0002 |
| Gage half-angle tolerance ± | 0° 20′ |
| Lead angle at basic PD (deg) | 0.6476 |
| Lead angle (deg min) | 0° 39′ |
| Tensile stress area As (sq in.) | not given in the standard |
| Thread angle (deg) | 55 |
| Flank angle (deg) | 27.5 |
| Sharp V height H (in.) | 0.026680 |
| Basic thread height hb (in.) | 0.017787 |
| Design thread height k (in.) | 0.015734 |
| Crest truncation U (in.) | 0.002053 |
| Crest flat Fc (in.) | 0.006767 |
| Root flat Fr (in.) | 0.004630 |
| Sweep cut: start diameter (in.) | 0.794100 |
| Sweep cut: tip diameter (in.) | 0.762632 |
| Sweep cut: depth (in.) | 0.015734 |
| Sweep cut: profile width at start diameter (in.) | 0.021011 |
| Sweep cut: tip flat width (in.) | 0.004630 |
| Crest flat as modelled (in.) | 0.006767 |
| Length of engagement min (in.) | 0.125 |
| Length of engagement max (in.) | 0.375 |
| Length of engagement usual (in.) | 0.125 |
| Check against formulas | OK: Table 2 maxima equal the Table 1 formulas; tolerances = max − min; minor min reproduced from the p/12 tool flat |
| Notes | One thread only: 0.800-36 AMO, single start, one class (paras. 10-12). Lead and half-angle variation of the thread, tensile stress area, root radius tolerance and taper: not given in the standard (the pitch diameter tolerance already includes lead and angle errors, para. 14; no taper). Gage lead ±0.0002 in. and half-angle ±0°20′ belong to the Appendix gages. Grey italic = extreme minimum minor diameter (Table 2 note b), reference only. Allowance G = 0.0018 on pitch, major and minor diameters (paras. 13, Table 1 notes b, c). Tolerances run in the minus direction from the design size (para. 14). |
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ASME B1.11: Microscope Objective Thread. Source: workbook data (2026-10-10). Confirm against your licensed copy of the standard before use.