Balustrade Timber Insert

What a balustrade timber insert is for

A timber insert is a 316 stainless (A4) sleeve with a coarse thread on the outside that cuts into a pre-drilled hole in timber, a countersunk head with a 6mm internal hex drive, and an M6 metal thread inside, 30mm long. Hobson describes its timber inserts as a quick, easy, no mess solution for fixing wire rope balustrading into timber posts, quick to install after pre-drilling, and says the internal thread allows any combination of Hobson metal thread balustrading accessories to be fitted.

Hobson publishes no pull-out or load rating for them. A wire balustrade is a safety barrier, so the post, the fixings, the wire, its spacing and its tension come from the balustrade system maker, the designer or an engineer, and the insert is used only where that design calls for it.

Right hand or left hand?

The right hand insert (Hobson thread type RHT, code HXTI16CRM06) has an ordinary M6 thread that a standard right hand fitting screws into. The left hand insert (LHT, code HXTI16CLM06) is its mirror: a left hand thread tightens anticlockwise, so it only accepts a fitting with a left hand M6 thread, and a standard (right hand) M6 stud, bolt or eye screw will not go into it. Otherwise they are the same: M6, 30mm long, countersunk, 6mm hex drive, 316 stainless.

Match the insert to the hand of the fitting that goes into it. Hobson makes its timber inserts in left and right hand threads, and its balustrade fittings also come in both hands: our swage terminal range includes M5 and M6 left hand threaded studs and a left hand lag screw terminal alongside the standard right hand ones. In our range, the left hand M6 fitting that suits the left hand insert is the M6 left hand swage stud for 3.2mm wire rope (ask us: our balustrade wire is 2.5 and 4.0mm).

Hobson does not set out a balustrade method for the inserts in its documents. As general mechanics (not from Hobson), opposite threads at the two ends of a part let one turn draw both ends together, as in a turnbuckle. Use the left hand insert only where the balustrade system or its designer calls for a left hand fitting, and order the matching right hand insert for the other hand.

Balustrade timber insert dimensions

One size, M6, in both thread directions. Select a row to open it in the selector.

What screws into it

• •Right hand insert: Hobson metal thread balustrade fittings with a right hand M6 thread, such as 316 stainless M6 swage studs for 2.5 and 4.0mm wire (our 316 balustrade wire comes in those sizes), and for 3.2mm wire rope (ask us), and 316 stainless metal thread eye screws in M6 (30 and 55mm long).
• •Left hand insert: a fitting with a left hand M6 metal thread. In our range that is the M6 left hand swage stud for 3.2mm wire rope (ask us).
• •Swage terminals, eye screws, wire and tensioners each have their own page; check the thread hand and size of each part before ordering.
• •Threaded inserts for wood (zinc alloy timber insert nuts, M4 to M10, zinc yellow) are a different product: for furniture, joinery and jigs indoors, not for an outdoor stainless balustrade.

How to fit a timber insert

1. Follow the balustrade system's drawings for post size, hole positions and wire spacing, and mark the hole square to the face of the post.
2. Pre-drill the hole: Hobson says the insert is quick to install after pre-drilling. Hobson publishes no pilot hole size or edge distance for the insert, so take them from the balustrade system's instructions, or call us on 1300 03 03 63.
3. Drive the insert in with a 6mm hex key or 6mm hex bit in the internal hex drive, keeping it square, until the countersunk head is seated flush in the timber.
4. Screw the metal thread balustrade fitting into the insert (a left hand fitting tightens anticlockwise) and tension the wire to the system maker's instructions.
5. Stainless threads can gall: the article Hobson publishes describes galling as the cold welding of clean stainless surfaces under load, worse with fine threads, tight clearances, no lubrication, dirt and over-tightening. Keep the threads clean, turn steadily and do not over-tighten.

316 stainless outdoors and near a pool

The inserts are 316 (A4) stainless, the same grade as our swage terminals and balustrade wire. Hobson's corrosion guide for metal connectors calls for stainless steel 304 or 316 (or hot dip galvanising) where a fixing is exposed to the weather, lists 304 or 316 for exposed work in seaspray, coastal and low corrosion zones, and 316 only within 2m of a pool edge, so 316 is the grade the guide lists for exposed and pool-side fixings. That covers the finish only: the balustrade system maker or designer's specification still decides whether this insert is used.

Hobson's article on stainless myths adds two cautions: 316 is not made to sit in seawater, and even 316 can visibly corrode in severe coastal spots where salty spray builds up, so stainless keeps its finish where it is washed by rain or cleaned as part of maintenance; wash the balustrade down. Keep carbon steel tools and filings off it, since carbon steel contamination is a usual cause of rust spots on stainless.

A balustrade is a safety barrier

Hobson publishes no pull-out, load or breaking rating for these inserts. A wire balustrade stops people falling, so it must meet the National Construction Code, and the post size, timber, insert positions, wire size and spacing and how tight the wires are come from the balustrade system or the designer or engineer, not from the fitting. Use the insert only where that design specifies it. It is not rated for lifting and must not be used to lift or suspend loads.

Balustrade timber inserts in Adelaide

Allmat supplies left and right hand 316 timber inserts, swage terminals, eye screws, tensioners, balustrade wire and accessories to builders, deck and stair builders and balustrade installers across Adelaide and South Australia. Add the inserts to a quote with the wire and terminals for each run, and we will price the lot.

Questions