The best 3/8 crush washer depends on the bolt and sealing surface: choose an aluminum washer for a listed 3/8-inch application, or a copper washer when its 10 mm inside diameter matches the fitting. The products below include individual-size options and a broad assortment. A stainless split lock washer is included for comparison, but it is not a crush washer and should not be treated as a sealing gasket.
| Product | Best For | Material or Size Detail |
|---|---|---|
| SPEEDFX 3/8 Aluminum Crush Washer | Small 3/8-inch replacement supply | 10 washers; aluminum |
| DYNAPEX Copper Crush Washers | 10 mm ID sealing applications | Copper; 10 per pack |
| Speedway Motors Crush Washers | Aluminum washer in a five-pack | 3/8 inch or 10 mm; aluminum |
| Nuepuxo Crush Washer Kit | Multiple metric drain-plug sizes | 720 pieces; 18 listed sizes |
| Neprift Split Lock Washers | Non-sealing bolt retention | 304 stainless steel; 30 pieces |
SPEEDFX 3/8 Aluminum Crush Washers
This pack contains ten 3/8 aluminum crush washers. It is the most direct match in this selection for a buyer looking for a small supply identified specifically as 3/8-inch aluminum crush washers.
- Best for: Replacing a washer when the required size and material are confirmed as 3/8 inch and aluminum.
- Why it was selected: The product name explicitly identifies both the crush-washer type and 3/8 size.
- Limitation: The supplied product details do not state inside diameter, outside diameter, or thickness. Confirm the washer dimensions against the application before ordering.
DYNAPEX 10 mm Copper Crush Washers
DYNAPEX supplies ten copper washers with a 10 mm inside diameter, 16 mm outside diameter, and 1.0 mm thickness. The product describes them for M10 metric or banjo-bolt use.
- Best for: Buyers whose fitting calls for a copper washer with a measured 10 mm opening.
- Why it was selected: It provides exact dimensions, which help distinguish this washer from a nominal 3/8-inch part.
- Limitation: A 10 mm opening is not the same measurement as 3/8 inch. Choose it only if the specified fit and sealing dimensions match.
Speedway Motors Aluminum Crush Washers
This five-pack is described as 3/8 inch or 10 mm and lists aluminum as its material. It offers a compact quantity for buyers who need a few washers rather than a large assortment.
- Best for: A buyer whose application accepts the listed 3/8-inch or 10 mm size and requires aluminum.
- Why it was selected: The product is explicitly presented as a crush washer and states its material and pack count.
- Limitation: The provided details do not give exact inside diameter, outside diameter, or thickness. Verify fit rather than assuming the two size labels are interchangeable.
Nuepuxo 720-Piece Crush Washer Kit
This aluminum assortment contains 720 washers across 18 listed metric sizes, including M10. The product describes the washers as oil drain plug gaskets and cites controlled thickness and flatness as features intended to support sealing.
- Best for: A home garage or repair setting that regularly uses several metric drain-plug washer sizes.
- Why it was selected: Its broad size range is useful when the exact replacement size varies by job.
- Limitation: The supplied size list is metric and does not identify a dedicated 3/8-inch washer. Check the kit’s size labels and required dimensions before using it for a nominal 3/8 application.
Neprift 3/8 Stainless Split Lock Washers
Neprift’s 30-piece set contains 3/8-inch split lock washers made from 304 stainless steel. The listed inside diameter is 0.37 inch and thickness is 0.14 inch. Offset split ends are designed to provide a locking feature beneath a nut or bolt head.
- Best for: Buyers who need a 3/8-inch locking washer for a fastener assembly, not a fluid or gas seal.
- Why it was selected: It helps clarify an important search distinction: lock washers and crush washers serve different purposes.
- Limitation: This is a spring lock washer, not a crush washer. Do not use it as a sealing gasket.
Buying Guide: How to Choose a 3/8 Crush Washer
Does 3/8 inch mean the same as 10 mm?
No. Three-eighths of an inch equals 9.525 mm, while 10 mm is slightly larger. Product listings may use both labels, but that does not prove the washers have identical dimensions. Check the specified inside diameter and the requirements of the bolt, fitting, or sealing surface.
Which material should you choose?
Start with the material and washer type specified for the repair. The listed choices include aluminum and copper crush washers. Do not substitute a different material solely because its nominal size appears similar. Confirm the application’s required dimensions and material before installation.
Should you buy a small pack or an assortment?
Choose a small pack if you know the exact size and need only a few replacements. An assortment can suit a workspace handling multiple metric drain-plug sizes, but the provided Nuepuxo list does not identify a dedicated 3/8-inch size. Read the size breakdown instead of relying only on the total piece count.
How is a crush washer different from a lock washer?
A crush washer is selected for a sealing application, while a split lock washer is intended to help resist loosening in a fastener assembly. The Neprift product is explicitly a split lock washer, so it is not a substitute for an aluminum or copper crush washer.
Frequently Asked Questions
What size is a 3/8 crush washer?
“3/8” is a nominal size, but the supplied products do not all list exact dimensions. Check the washer’s inside diameter, outside diameter, and thickness where available, and compare them with the application specification.
Can I use a 10 mm washer for a 3/8-inch fitting?
Not automatically. Ten millimeters is slightly larger than 3/8 inch. Use a 10 mm washer only when its dimensions and the application requirements match.
Are split lock washers suitable for sealing?
No. A split lock washer is made for a locking function under a fastener. Select a product identified as a crush washer when a sealing washer is required.
What should I check before ordering?
Confirm the washer type, material, inside diameter, outside diameter, thickness, and required quantity. When a listing omits dimensions, compare the product’s stated size with the repair specification before purchase.