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SAE J499-2014: Parallel Side Splines for Soft Broached Holes in Fittings
SAE J499-2014 addresses parallel side splines used in soft broached holes in fittings. This standard covers four-, six-, ten-, and sixteen-spline configurations and provides dimensions, tolerances, and torque capacity data. It is important to note that the standard has been stabilized and is considered technically obsolete for new designs; engineers should consult ANSI B92.1-1970 for new applications.
⚠️ SAE J499 has been stabilized and is considered obsolete for new designs. For new applications, consult ANSI B92.1-1970 — Involute Splines and Inspections Standard.
Overview and Scope
This standard specifies dimensions for parallel side splines in soft broached holes in fittings. The dimensions apply only to the broached hole; the shaft dimensions depend on material, heat treatment, and machining methods to achieve the required fit. The standard includes three fit types: A (permanent fit), B (slide when not under load), and C (slide under load). Tables provide values for large diameter (D), small diameter (d), tooth width (W), tooth depth (h), and single-key torque capacity (T) for each nominal diameter and fit.
Spline Configurations and Fit Types
Tables 2 through 5 in the standard give dimensions for 4, 6, 10, and 16 spline fittings. An example for a 1-inch nominal diameter six-spline fitting is shown below:
| Nominal Dia | Fit Type | D min | D max | W min | W max | d min | d max | T (in-lb/in) |
|---|---|---|---|---|---|---|---|---|
| 1″ | A (Permanent) | 0.999 | 1.000 | 0.248 | 0.250 | 0.899 | 0.900 | 143 |
| 1″ | B (Slide, no load) | 0.999 | 1.000 | 0.248 | 0.250 | 0.849 | 0.850 | 208 |
| 1″ | C (Slide, under load) | 0.999 | 1.000 | 0.248 | 0.250 | 0.799 | 0.800 | 270 |
Dimensions are in inches; torque values are per inch of bearing length at 1000 psi side pressure.
Engineering Design Considerations
Tolerances: The standard allows radii on corners of splines not exceeding 0.015 in, and spline parallelism must be within 0.006 in per foot of length. Tolerance selection for large and small diameters depends on whether the fit is based on the large diameter, small diameter, or solely on the spline sides.
Torque Capacity: The theoretical torque capacity is calculated using:
T = 1000 × N × r × h × L
where N is number of splines, r is mean radius (D/2 minus h/2), h is tooth depth, and L is bearing length. This assumes 1000 psi pressure on the spline sides. Engineers should apply safety factors for actual loads.
🛠️ The torque capacity formula is theoretical, based on 1000 psi side pressure. Always consider safety factors and verify under operating conditions.
Manufacturing: No allowance is included for radii or clearance in the tabulated dimensions. Allowance must be made for machining and heat treatment. The shaft dimensions must be designed to achieve the desired fit, considering material deformation.
Frequently Asked Questions
1. Can SAE J499 be used for new designs? No. The standard is stabilized and technically obsolete. ANSI B92.1-1970 is recommended for new designs.
2. What is the difference between fit types A, B, and C? Type A is a permanent fit; B is for sliding when not under load; C is for sliding under load. The dimensions and tolerances differ accordingly.
3. What is the torque capacity formula? The formula is T = 1000 × N × r × h × L, giving inch-pounds per inch of bearing length at 1000 psi side pressure.
4. What are the key dimensional tolerances? Radii ≤ 0.015 in, parallelism ≤ 0.006 in/ft. Diameter tolerances depend on the fit basis.
For complete details and all tables, refer to the full SAE J499-2014 document.
