Macsim Cup Head Bolt and Nut 3/8" x 4" Zinc Plated

A cup head bolt earns its keep the moment you go to tighten the nut. The square shoulder under the smooth domed head bites into the timber and grips, so the bolt holds still while you work from the nut side.

It's a Grade 4.6 zinc-plated bolt that comes with its matching nut, made for timber-to-timber and timber-to-steel jobs like deck frames and fence rails. The rounded head sits neat against the surface with nothing sharp to catch on.

Worth knowing. Zinc plating suits sheltered and indoor spots. For a fence line or anything out in the weather for years, galvanised holds up better. Slip a washer under the nut so it pulls up tight without chewing into the timber.

Full sizes and specs are in the tabs below. If you're not sure which length you need, give us a call or pop in and we'll get you sorted.