• Macsim Cup Head Bolt and Nut 3/8" x 3" Zinc Plated
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Macsim 3/8 x 3" Cup head BOLT & NUT Zinc Plated

Macsim 3/8 x 3" Cup head BOLT & NUT Zinc Plated

50 in stock

$2.00 AUD
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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.

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Bolt specs

  • Type: Cup head (carriage) bolt with matching nut
  • Diameter: 3/8"
  • Length: 3"
  • Thread: Imperial coarse
  • Grade: 4.6 general-purpose mild steel
  • Finish: Zinc plated
  • Head: Domed with square neck
  • Best suited to: Timber fixing, indoor or sheltered

Why a cup head

  • Square neck locks the head so it won't spin while you tighten the nut
  • Comes with its matching nut, ready to fix
  • Smooth domed head leaves nothing sharp poking out of the timber
  • Zinc coating keeps surface rust off in dry, covered spots
  • Grade 4.6 steel suits general fence and deck framing
  • Imperial sizing matches existing holes and older timberwork

Shipping and Returns

We pack and send your order with care, right here from our Strathalbyn store. Most parcels leave within 1-2 business days, and you'll get tracking as soon as it's on the way. If you're local, you can choose click-and-collect or our delivery service at checkout.

If something arrives damaged or not quite right, let us know within 14 days and we'll sort it quickly. You can return unused items in their original condition for a refund or store credit. For safety reasons, we can't accept returns on gas bottles, cut materials, or custom orders.

We're here to make things easy, so if you ever have a question about your delivery or a return, our team is only a call away.

Why you'll love shopping with us

  • Trade-grade, job-tested

    This gear is selected for daily use on real job sites, not light-duty or one-off projects.

  • Right gear, first time

    We help you get the correct product and spec upfront so you’re not redoing work later.

  • In and out fast

    Call ahead and we'll set your order aside so you spend less time at the counter.