What is a Cup Washer?A cup washer is a small lightweight washer with a concave shape that serves as an insulative, decorative, and supportive accessory for bolts and screws. They feature a bowl-like central depression that allows for a snag-free grip when tightening a bolt or a screw head.

These types of washers act as countersunk elements or surface mounts. But what are they made of? And how can you use them? Let’s take a closer look.

How Cup Washers Work

Cup washers generally work to support, insulate or add a cosmetic finish to screws and bolts. They often include features such as electrical terminal cut-outs and decorative snap-on caps. Those made for surface mount purposes resemble pet water bowls with a dished center and raised sides.

This design offers a good bearing surface for a screw with the head sitting inside the concave area. The raised sides protect against potential shorting hazards in electrically live applications.

Cup washers for flash mounting also have a dished center but flanged sides. They feature internal contours idea for flat-headed bolts and screws or countersunk. It allows them to lay flush with the material surface.

Cup washers Applications

Cup washers often appear in electrical applications to provide support and insulation for screws and bolts. They may also get used as a cosmetic finish on fasteners in various applications from plumbing to construction.

Cup washers work great for many different types of projects, but they are instrumental in the following industries and applications:

  • Automotive
  • Construction
  • Electrical
  • Plumbing

Material Options for Cup Washers

Cup washers are available in many materials, each with its benefits. We at Minneapolis Washer and Stamping craft cup washers from light gauge metals such as low carbon steel and brass to ensure their quality and longevity. Other materials include:

  • Spring Steel
  • Stainless Steel
  • Copper
  • Aluminum
  • Plastic

At the customer’s request, we can plate a basic or standard cap washer with Zinc & Yellow, Galvanized, Zinc & Clear, Black Oxide, Phosphate & Oil, and Nickel or other finishes for additional rust resistance.

Cup Washer Specifications

Since every project is unique, you’ll often use a variety of bolt sizes. That’s why our cup washers come in various sizes and finishes. Here are some specs:

  • OD 1.2500 + .015 – .015
  • OD 1.6250 + .015 – .015

If your next project requires a little extra support or insulation for your screws and bolts, consider using cup washers. Their lightweight design and durable materials make them up for almost any task.

At Minneapolis Washer and Stamping, we got you covered with a wide selection of cup washers in different materials, sizes, and finishes. Browse our selection today and request a quote. If you’re a resident or business in US, make sure to contact us today.

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