Macsim 3/8 x 12" Cup head BOLT & NUT Zinc Plated
Macsim 3/8 x 12" Cup head BOLT & NUT Zinc Plated
In stock
Postage on this one is $9.95 anywhere in Australia, and it ships from Strathalbyn in 1 to 2 business days. Free postage on orders over $200.
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- Real local people
- Trade-grade fixings
- Ask us the size
A grade 4.6 zinc-plated coach bolt and nut that holds framing and fences tight.
This is a 3/8 inch cup head bolt, 12 inches long with the nut included, for bolting timber to timber or timber to steel on fence posts and retaining walls.
The square neck under the dome bites into the timber as you tighten, so the bolt doesn't spin while you do the nut up. It's grade 4.6 with a zinc plated finish, which is fine for general outdoor use, but it's imperial sizing, so check it against the one you're replacing because a metric nut won't go on it.
If you're not sure of the size, bring the old bolt into the shop and we'll match it up, and if you need a box of them for a bigger job just let us know.
You'll want a 10mm auger to drill through the timber for it, and a 3/8 inch bit for the steel side.

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The bolt specs
- Type: Cup head coach bolt and nut
- Diameter: 3/8"
- Length: 12"
- Head: Cup head (carriage head)
- Drive: Square neck, tighten by the nut
- Measure: Imperial
- Grade: 4.6
- Finish: Zinc plated
- Includes: Matching nut
Why it holds
- Square neck stops the bolt spinning as you tighten the nut
- Domed head sits smooth with no sharp edge to catch on
- Zinc plating holds off rust through general outdoor use
- Comes with the matching nut, so no hunting for a pair
- Sized for framing, fencing, posts and retaining walls
- Grab the exact length you need without buying a whole box
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
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Built to handle our weather
Colorbond and steel chosen to stand up to local heat, wind and rain.
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Everything for the whole job
Panels, posts, cement and fixings in one place so you're not chasing bits.
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Help to get it right
We'll talk through sizes and what you'll need before you commit.