Anvil
An anvil is a receiving metal fitting for a striking tool or press machine that supports a component from below and stabilizes its position and shape when attaching press fasteners or eyelets to fabric.
Contents6 sections
Definition and role
An anvil is a jig that supports the lower side of a component when attaching press fasteners, eyelets, cap and close posts, and similar items. Force is applied from above with a setting tool or upper die, and the recesses or projections in the anvil shape the component correctly by closing it. In English, it is called an anvil.
The term base is also used, but it may refer not only to the metal anvil that receives the component, but also to the mounting base attached to the hand press body or to an auxiliary part used for removal work. When ordering, confirm the intended use and compatible components.
Structure and compatible components
A typical anvil is a metal cylindrical or disc-shaped part with holes, recesses, steps, and projections on the surface to receive the hook head or eyelet edge without damage. It serves to properly deform the leg while protecting the surface finish of the component.
An anvil is not a general-purpose item that can be used alone; in many cases, it is a dedicated part matched to the type, size, and leg shape of the press fastener or eyelet. Select the upper setting tool and the lower anvil as a pair, and match them to hand setting, hand press, foot press, or air press methods.
- For press fasteners, use a receiving surface suited to each part, such as the cap, spring, stud, and eyelet.
- For eyelets, choose an anvil that matches the outer diameter, leg length, and whether a washer is used.
- For plastic snaps, there are methods that use a dedicated base or urethane receiving part.
How sizes are indicated and how to select
Anvil sizes are generally indicated by the nominal diameter of the compatible button or eyelet, or by the compatible product number. The outer diameter of the anvil alone cannot determine compatibility, so selection is based on the type, size, and combination of the parts to be attached.
Even with the same apparent diameter, if the part leg diameter, back shape, or post-clinching shape differs, the recess shape of the anvil will also differ. Reusing parts of different standards can cause surface damage, deformation, or insufficient clinching, so it is important to match the specified parts and setting tools.
Installation method and work precautions
When installing, check the front and back of the fabric and the orientation of the part, and pre-punch holes if necessary. Set the anvil on the lower side and the compatible setting tool on the upper side, place the part and fabric so they do not shift, and apply force vertically. In mass production, using a press makes it easier to keep the impact conditions consistent.
If the fabric is too thin, the part may rotate or pull out easily; if it is too thick, the leg length may be insufficient and proper clinching may not be possible. Perform trial settings taking into account fabric thickness, interfacing or seam allowance overlaps, and part leg length, and check pull-out strength and fit condition.
For metal parts, attention is also needed for rust caused by moisture or sweat, plating discoloration, and verdigris on brass parts. For applications that touch the skin directly, confirm nickel-free specifications, and for products that undergo needle detection, manage whether the metal parts are needle detector compatible in the specification sheet.
Differences from similar terms
A setting tool refers to the rod-like tool or upper die that is applied to the upper side of the part to transmit force, whereas an anvil receives the part from below. In practice, both may be referred to collectively as setting tools, so clarify whether the upper die or lower die is being referred to.
A washer is a product part placed on the back side of eyelets and similar items to reinforce the fabric. An anvil, on the other hand, is a jig used for installation work and normally does not remain on the product. A packing is also a product part used to hold or cushion components, and its role differs from that of an anvil.
Frequently asked questions
Do I need an anvil for each press fastener size?
In many cases, yes. With press fasteners, the receiving surface differs not only by size but also by the shape of the cap, spring, and other parts, as well as the leg specification. Combine the specified upper setting tool and lower anvil for the part being used, and always test on scrap material.
Can I attach press fasteners without using an anvil?
If you strike on a hard surface that does not match the part, surface scratches on the cap, distortion of the part, and insufficient clinching are more likely to occur. A dedicated anvil is a necessary jig for stabilizing the part and clinching it into the specified shape. Use compatible items for both hand setting and press work.
Can a base for plastic snaps be shared with a metal anvil?
As a rule, no. Plastic snaps have dedicated bases designed to suit the shape of the resin parts and their susceptibility to damage, and in some cases urethane receiving parts are used. Since their shape and hardness differ from those of metal anvils, use the specified combination.
