A dedicated 5/8-inch copper crush washer is the most direct choice when you need a washer for a 5/8-inch or 16 mm opening; the DYNAPEX 10-pack is specifically listed for that size. For mixed repairs, consider a copper assortment that includes M16, or a smaller kit that lists 5/8 inch. The options below include dedicated and assorted copper washers, plus one clearly identified brass alternative for flat-washer applications.
| Product | Best for | Size information |
|---|---|---|
| DYNAPEX Copper Crush Washers | A specific 5/8-inch sealing washer | 5/8-inch or 16 mm ID |
| 110-Piece Copper Washer Kit | Common inch-size repairs | Includes 5/8 inch |
| Magicave Copper Washer Kit | Broad metric-size coverage | Includes M16 |
| AKOSN Copper Washer Kit | Mixed-size metric projects | M5–M14 assortment |
| Fastenere Brass Flat Washers | Non-sealing flat-washer use | 5/8-inch brass |
DYNAPEX 5/8-Inch Copper Crush Washers
Best for: Buyers who need a specific copper crush washer rather than a mixed assortment. The product is listed as a 10-pack with a 5/8-inch or 16 mm inside diameter and is identified for M16 metric or banjo bolts. That makes it the most directly targeted option in this list for a 5/8-inch copper sealing-washer search.
Why it was selected: Its stated size and crush-washer purpose closely match the keyword. Choose this if you have confirmed that the washer’s inside diameter and application match your fastener.
Limitation: The supplied product details do not specify outside diameter, thickness, or copper grade. Check those dimensions against the part you are replacing before ordering.
110-Piece Copper Washer Kit
Best for: Home repairers who want several common inch sizes on hand. The kit includes 110 copper flat washers in six listed sizes: 1/4, 5/16, 3/8, 7/16, 1/2, and 5/8 inch. It provides 10 washers in the 5/8-inch size and comes in a transparent storage case.
The listed features describe copper material, heat resistance, corrosion resistance, and a bearing surface intended to work with matching screws, nuts, and bolts. Choose this kit if you need 5/8-inch washers along with smaller inch sizes for other jobs.
Limitation: It contains only 10 pieces in the 5/8-inch size, and the listing does not provide detailed thickness measurements.
Magicave 330-Piece Copper Washer Kit
Best for: Buyers who work with a range of metric fasteners and may need an M16 washer. The 330-piece kit lists 12 sizes, including M16, and is described for automotive, plumbing, and mechanical use. Its features identify the washers as copper flat sealing crush washers.
Choose this assortment if your measurement calls for M16 and you also want other sizes from M5 through M20. The listing says the washers are intended to distribute load and serve as sealing replacements, including for oil drain plug applications.
Limitation: The listing names M16, not a specific 5/8-inch washer dimension. Metric and inch sizes should not be treated as interchangeable without checking fit.
AKOSN 325-Piece Copper Washer Kit
Best for: Projects that use metric washers from M5 to M14, rather than a confirmed 5/8-inch or M16 size. This 325-piece assortment contains 10 sizes and is described as red copper, with features including heat resistance, electrical conductivity, and corrosion resistance.
The listing describes the washers as suitable for automotive, motorcycle, marine, electronic, and mechanical tasks. It also says the design distributes pressure and can help reduce leaks or loosening when paired with matching fasteners. Choose it for varied smaller metric jobs.
Limitation: The listed size range stops at M14, so it does not specify a 5/8-inch or M16 washer. It is not the right choice when that exact size is required.
Fastenere 5/8-Inch Brass Flat Washers
Best for: Buyers who need a 5/8-inch flat washer for load distribution or surface protection and are open to brass rather than copper. This product contains 10 plain-finish, Grade 360 brass flat washers. The listed uses include spreading a fastener’s load, acting as a shim, and helping protect a surface.
This is included as a size-related alternative, not as a copper crush washer. Choose it only when a standard brass flat washer suits the application.
Limitation: It is brass, not copper, and the product information describes a flat washer rather than a crush-style sealing washer. Avoid it if your job specifically calls for a copper sealing washer.
Buying Guide: Choosing A 5/8-Inch Copper Washer
Does 5/8 inch refer to the inside diameter?
Check what the measurement describes. The DYNAPEX product states a 5/8-inch or 16 mm inside diameter, while the other inch-size kit lists a 5/8-inch washer without giving detailed dimensions. Compare inside diameter, outside diameter, and thickness with the washer being replaced or the fastener specification.
Should you choose a crush washer or a flat washer?
Choose a crush washer when the application calls for a compressible sealing washer, such as a specified fluid connection. A plain flat washer primarily provides a bearing surface, spreads load, or protects material. Do not assume a flat washer will provide the same seal as a crush washer.
Is M16 the same as 5/8 inch?
They are close in nominal measurement, but the labels do not guarantee identical fit. A 5/8-inch measurement equals 15.875 mm, while M16 refers to a metric nominal size. Verify the required washer dimensions and fastener before substituting one for the other.
When is an assortment kit a better choice?
An assortment makes sense when you need several sizes for ongoing repairs. The 110-piece kit includes a labeled 5/8-inch size; the Magicave kit includes M16 among its metric sizes. The AKOSN kit covers smaller metric sizes through M14, so it is not a direct 5/8-inch choice.
Frequently Asked Questions
Which listed product is specifically identified as a 5/8-inch copper crush washer?
The DYNAPEX 10-pack is listed as 5/8 inch or 16 mm ID and specified for M16 metric or banjo bolts.
Which kit includes 5/8-inch copper washers?
The 110-piece kit lists 5/8-inch washers and includes 10 of that size.
Does the AKOSN kit include a 5/8-inch washer?
Its listed sizes run from M5 through M14, so the product details do not identify a 5/8-inch or M16 washer.
Can a brass washer replace a copper crush washer?
Not automatically. The listed Fastenere product is a brass flat washer, not a copper crush washer. Use it only if the application allows that material and washer type.