Temporary joining methods

Woodscrews

Nuts and bolts

Types of screws

Knock-down fittings Screenshot 2020-12-10 at 3.03.07 PM

Neat strong method of joining timber and they can be removed easily

They are classified by length, gauge (diameter) type of head and material

Have a tapering head Screenshot 2020-12-10 at 2.49.13 PM

Countersunk – are the most common; finish flush with the surface; available plated in zinc and nickel.

Round head – usually japanned steel, and used to fix metal fittings outdoors, e.g. hinges, bolts, guttering and downpipes.

Raised countersunk – usually made of chrome-plated steel or brass, and used where appearance is important.

Twinfast – have two threads, which gives them greater holding power in manmade materials such as chipboard, MDF and blockboard.

GCSE Screw question Screenshot 2020-12-10 at 2.54.37 PM

Nuts and bolts are used to clamp two pieces of material, usually metal, together. They provide a mechanically strong method of joining materials.

Nuts and bolts are usually made of steel or brass. Steel nuts and bolts can be coated with zinc or chrome to increase resistance to corrosion and improve their appearance.

Bolts are available with hexagonal and square heads; however, hexagonal is the most common.

Bolts have a parallel thread, which can be for all or part of the length. The most common thread form is ISO metric.

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Nut and bolt specifications

Bolts are available in in a standard range of lengths up to 150 mm, and diameters up to 25 mm.

Nuts are screwed onto bolts and provide the clamping force.

Wing nuts are designed to be tightened and undone by hand.
Locking nuts are used to prevent the nut becoming loose due to vibration.

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Knock-down (KD) fittings are used extensively in the manufacture of flat-pack furniture.

The advantages of using KD fittings over more traditional joining methods are:

They are ideal for use with manufactured boards such as chipboard and MDF.

They offer increased efficiency and accuracy through the use of drilling jigs.

They reduce the space needed to store completed pieces in the warehouse.

The number of items per load can be increased when transporting.

Customers can fit larger items in their cars and assemble them at home.

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Hinges, locks, catches and stays Screenshot 2020-12-10 at 3.06.22 PM