299108-1 · Cap & socket
Nickel-plated brass cap-and-socket components for the canvas side of a snap.
Sea-Dog Canvas Snap Fasteners: Cap, Socket, Stud & Tool Guide
Repairing a boat cover or canvas enclosure starts with identifying which half of the fastener needs replacing. Sea-Dog makes cap-and-socket combinations for the fabric, screw-mounted studs for the attachment point, turnbuckle-style hardware and extensions for hard-to-reach snaps. This guide puts the available styles and sizes side by side.
Understand which canvas fastener you need
Cap and socket assemblies
The canvas-side options are 299108-1 with a 1/4-inch cap and 299109-1 with a 5/16-inch cap. Their cap dimensions are not identical.
Screw-mounted stud styles
Choose #8 or #10 sheet-metal screw gauge and match the 3/8- or 5/8-inch screw length. The stud is the fixed-side connection.
Turnbuckles and extensions
299116-1 uses a two-screw turnbuckle base. Add-A-Snap extensions 299201B-1 and 299202B-1 can help with hard-to-reach cover snaps.
Setting tools
299190-1 includes a die wrench and three removable dies for compatible fasteners; do not use it on heavy-duty stainless snaps.
Cover side
Cap + socket
299108-1 or 299109-1
Mounting point
Screw-on stud
299111-1, 299112-1 or 299113-1
Sea-Dog canvas snap MPN and size chart
Use this manufacturer's reference to identify the design and dimensions before opening the corresponding store product. Catalog-set quantities should be confirmed against the listing's actual sales unit.
| Sea-Dog MPN | Component | Key size or description | Manufacturer reference |
|---|---|---|---|
| 299108-1 | Cap & socket | 1/4-in cap; socket | 6 caps and 6 sockets per manufacturer set |
| 299109-1 | Cap & socket | 5/16-in cap; socket | 6 caps and 6 sockets per manufacturer set |
| 299111-1 | Screw-on stud | #8 sheet-metal screw × 3/8 in | 6 studs per manufacturer set |
| 299112-1 | Screw-on stud | #8 sheet-metal screw × 5/8 in | 6 studs per manufacturer set |
| 299113-1 | Screw-on stud | #10 sheet-metal screw × 5/8 in | 6 studs per manufacturer set |
| 299116-1 | Snap turnbuckle | Two-screw mounting base | 2 per manufacturer set |
| 299190-1 | Installation tool | Die wrench and 3 removable dies | Aluminum/steel; not for heavy-duty stainless snaps |
| 299201B-1 | Add-A-Snap extension | Black; drawing A 1-1/2 in; C 11/16 in | Drawing B 1 in; nylon/nickel-plated brass |
| 299202B-1 | Add-A-Snap extension | Black; drawing A 2-1/2 in; C 1-1/2 in | Drawing B 1 in; nylon/nickel-plated brass |
Add-A-Snap extension dimensions
Black 299201B-1 has manufacturer drawing A/B/C dimensions of 1-1/2, 1 and 11/16 inches. Black 299202B-1 has A/B/C of 2-1/2, 1 and 1-1/2 inches. These letters refer to the manufacturer's own drawing labels, not interchangeable hole-cutout dimensions. Check the original fastener arrangement.
The 299190-1 setting tool is intended for compatible canvas snaps and is not recommended by Sea-Dog for heavy-duty stainless canvas fasteners.
Select the right components for the repair
- Identify the existing canvas-side and fixed-side components. A cap-and-socket set does not substitute for a screw-mounted stud.
- Match cap height or stud screw diameter and length. A #10 × 5/8-inch stud is not the same mounting fastener as a #8 × 5/8-inch stud.
- For a shrunk cover whose snaps no longer reach, compare the exact extension dimensions; the 299201B-1 and 299202B-1 are different sizes.
- Check the individual product listing for the quantity supplied before ordering. The table's set quantities are from Sea-Dog's manufacturer catalog.
Sea-Dog canvas fastener product cards
Choose from the specific fastener parts and tools below. Each image links directly to the matching product in this store.
299109-1 · Cap & socket
A taller 5/16-inch cap option with the matching socket components.
299111-1 · Screw-on stud
A snap stud mounted with a short #8 sheet-metal screw.
299112-1 · Screw-on stud
A longer #8 screw-mounted stud; the 5/8-inch screw differs from 299111-1.
299116-1 · Snap turnbuckle
Two-screw-base turnbuckle-style canvas fastening component.
299190-1 · Installation tool
Canvas snap tool with interchangeable dies; not designed for heavy-duty stainless snaps.
299201B-1 · Add-A-Snap extension
Short black Add-A-Snap extension for hard-to-reach canvas fastening points.
299202B-1 · Add-A-Snap extension
Longer black Add-A-Snap extension with different A and C drawing dimensions.
More Sea-Dog and Bimini hardware
Sea-Dog Bimini top caps and inserts  · Sea-Dog boat snap hooks and swivels
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