ASME/ANSI B18.21.1 Internal Tooth Lock Washers
Ningbo Teng Qi Fasteners Co., Ltd. is a reliable ASME/ANSI B18.21.1 Internal Teeth Lock Washers supplier, we specialize in providing high-quality locking solutions for customers who require secure and durable fastening performance. With extensive experience in stainless steel fastener manufacturing, we focus on strict control of raw materials, production processes, and dimensional accuracy to ensure every internal teeth lock washer meets international standard requirements. Our washers feature precisely formed internal teeth that provide effective locking performance, helping reduce fastener loosening caused by vibration and mechanical movement.
Different from general washer suppliers, we provide more than standard products by offering flexible solutions for various industrial applications. We can supply ASME/ANSI B18.21.1 Internal Teeth Lock Washers in stainless steel materials such as AISI 304 and AISI 316, with customized sizes, surface treatments, and packaging options available according to customer needs. Supported by professional quality inspection and export experience, our internal tooth lock washers are widely trusted for their corrosion resistance, stable performance, and long service life in industries including machinery, automotive, electrical equipment, construction, and industrial manufacturing.


Specification:
ASME/ANSI B18.21.1 covers the dimensional and physical requirements for tooth lock washers used with inch-series fasteners. Internal Tooth Lock Washers are available in #3 to 1” sizes, with inward-facing teeth designed to engage around the fastener head during tightening. Hardness is particularly important for tooth lock washers because the teeth must maintain their shape and engage the mating surfaces during tightening. Excessive deformation can reduce the mechanical locking effect.
| Item | Specification |
|---|---|
| Standard | ASME/ANSI B18.21.1 |
| Product Type | Internal Tooth Lock Washer |
| Size Range | #4-1-1/4““ |
| Tooth Configuration | Internal Radial Teeth |
| Carbon Steel Hardness | 40-50HRC/392-513HV |
| Stainless Steel Hardness | ≥88HRB Annealed/20-45 HRC Hardened |
| Material | Carbon Steel,Stainless Steel |
| Surface Treatment | Bright Pickling,Zinc Plated, Black Oxidation |
| Mating Fasteners | Inch-Series Screws,Nuts |
Dimension Chart of ASME/ANSI B18.21.1 Internal Tooth Lock Washers:
The ASME/ANSI B18.21.1 dimension chart provides the key measurements for selecting an Internal Tooth Lock Washer for an inch-series fastener. In addition to the nominal washer size, the inside diameter, outside diameter, thickness, and internal tooth configuration determine how the washer fits beneath the fastener head and within the available mounting space. For applications with limited clearance around the fastener, the outside diameter is particularly important because the locking teeth remain within the washer perimeter. The inside diameter should provide sufficient clearance for the mating fastener without excessive movement.

| Mon | #2 | #3 | #4 | #5 | #6 | #8 | #10 | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | 9/16 | 5/8 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/4 |
| d max | 0.095 | 0.109 | 0.123 | 0.136 | 0.15 | 0.176 | 0.204 | 0.267 | 0.332 | 0.398 | 0.464 | 0.53 | 0.596 | 0.663 | 0.785 | 0.927 | 1.06 | 1.192 | 1.325 |
| d min | 0.089 | 0.102 | 0.115 | 0.129 | 0.141 | 0.168 | 0.195 | 0.256 | 0.32 | 0.384 | 0.448 | 0.512 | 0.576 | 0.64 | 0.769 | 0.894 | 1.019 | 1.144 | 1.275 |
| dc max | 0.2 | 0.232 | 0.27 | 0.28 | 0.295 | 0.34 | 0.381 | 0.478 | 0.61 | 0.692 | 0.789 | 0.9 | 0.985 | 1.071 | 1.245 | 1.41 | 1.637 | 1.83 | 1.975 |
| dc min | 0.175 | 0.215 | 0.245 | 0.255 | 0.275 | 0.325 | 0.365 | 0.46 | 0.594 | 0.67 | 0.74 | 0.867 | 0.957 | 1.045 | 1.22 | 1.364 | 1.59 | 1.799 | 1.921 |
| h max | 0.016 | 0.016 | 0.018 | 0.02 | 0.022 | 0.023 | 0.024 | 0.028 | 0.034 | 0.04 | 0.04 | 0.045 | 0.045 | 0.05 | 0.055 | 0.06 | 0.067 | 0.067 | 0.067 |
| h min | 0.01 | 0.01 | 0.012 | 0.014 | 0.016 | 0.018 | 0.018 | 0.023 | 0.028 | 0.032 | 0.032 | 0.037 | 0.037 | 0.042 | 0.047 | 0.052 | 0.059 | 0.059 | 0.059 |
ASME/ANSI B18.21.1 External Teeth Lock Washers
DIN7349 Stainless Steel Heavy Clamping Sleeves Washers
Stainless Steel DIN128B Wave Spring Lock Washers
Stainless Steel DIN137A Wave Spring Washers
Black Oxidation DIN2093 SeriesA Disc Spring Washers
Zinc Plated DIN434 Double Grooved Square Taper Washers
DIN5406 Rolling Bearings Stainless Steel Lock Washers
Application of ASME/ANSI B18.21.1 Internal Teeth Lock Washers:
Compact Mechanical Assemblies
Internal tooth lock washers are suitable for small mechanical assemblies, mounting points, covers, brackets, and component fasteners where space around the bolt or screw head is limited. The inward-facing teeth provide the locking interface without extending beyond the washer’s outer perimeter.
Appliances and Consumer Equipment
They can be used in appliances, electrical equipment, control devices, and consumer products where compact fastening hardware is preferred. The relatively small outer profile can help keep the locking washer within the footprint of the fastening point.
Panels, Covers and Access Components
Internal tooth lock washers are also suitable for removable panels, access covers, equipment housings, and service components secured with inch-series screws or bolts. They can provide additional resistance to fastener rotation while maintaining a compact installation profile.
