Buy Open End Wrenches Online in Australia
AIMS Industrial's open end spanner range is 100% Stahlwille — the German-made precision hand tool line built for workshops where jaw tolerance still matters after ten years of daily use. The range covers single open end spanners in large industrial sizes, everyday double open end spanners in metric and imperial, thin-jaw electricians' spanners for panel and instrument work, ready-made sets, and AS Drive open-ended inserts for Stahlwille's torque wrench system. Open end (U-shaped) jaws engage two flats of a hex fastener from the side rather than lifting over the head, which makes them the right call wherever a ring spanner or socket can't be placed — hydraulic and pneumatic line fittings, recessed bolts, and any job where you need to slide a spanner on and off sideways rather than straight down. We've put together a Types of Spanners Guide: Types, Sizes & Selection if you'd like more detail before you buy.
Quick Reference — Stahlwille Open End Spanner Range
| Type | Sizing | Best for |
|---|---|---|
| Single open end spanner | Metric, 24 mm to 95 mm (one size per tool) | Large structural and flange fasteners beyond standard double-end range |
| Double open end spanner — metric | 4 x 5 mm to 17 x 19 mm (two sizes per tool) | Everyday workshop and maintenance fastener work |
| Double open end spanner — imperial | 1/4" x 5/16" to 1-1/8" x 1-5/16" AF | Imperial-threaded plant, imported equipment, older machinery |
| Electricians' double open end — metric | 3.2 mm to 14 mm | Thin-jaw access to small fasteners in switchboards, panels, instrumentation |
| Electricians' double open end — imperial | 3/16" to 9/16" AF | Same thin-jaw access on imperial-threaded control gear |
| Open end spanner sets | 6 to 14-piece, metric or imperial, various size ranges | Kitting out a bench, van, or apprentice toolbox in one purchase |
| AS Drive open-ended inserts (SW731 series) | 7 mm to 41 mm | Torque-controlled work with a compatible Stahlwille torque wrench body |
For sockets and ring spanners in the same fastener range, see our ring spanners, combination wrenches and sockets collections.
The Stahlwille range at AIMS
Single open end spanners — large-format, one size per tool
Where a double-ended spanner runs out of range, Stahlwille's single open end spanners pick up from 24 mm through to 95 mm, each tool sized to one flat dimension only. These are the ones you reach for on large flange bolts, structural connections, and heavy plant fasteners where a compact double-ended jaw simply isn't built wide enough. Chrome-plated finish throughout for corrosion resistance in workshop and field conditions.
Double open end spanners — the everyday workshop tool
The double open end spanner is the one that lives in every toolbox — a different flat size at each end, so one tool covers two of the sizes you use most. AIMS stocks the metric range from 4 x 5 mm right through to 17 x 19 mm, and a full imperial range from 1/4" x 5/16" up to 1-1/8" x 1-5/16" AF for imperial-threaded plant and equipment. Buy singles to fill gaps in an existing kit, or start with one of the sets below.
Electricians' double open end spanners — thin-jaw precision sizes
Stahlwille's electricians' range uses a slimmer jaw and head profile than the standard double open end line, built for the small fastener sizes found in switchboards, control panels, and instrumentation — metric from 3.2 mm to 14 mm, imperial from 3/16" to 9/16" AF. The thin head gets into terminal blocks and enclosures where a standard-profile spanner is too bulky to seat properly on the fastener.
Open end spanner sets
Rather than building a kit size by size, AIMS stocks Stahlwille open end sets ready to go — 6-piece value packs, 8-piece sets (including one bundled with a mechanics glove), 10-piece and 12-piece sets spanning 6 x 7 mm to 30 x 32 mm, and a 13-piece electricians' set from 5/32" to 9/16" AF. A set is the most cost-effective way to equip a new bench, van, or apprentice — singles are there afterwards to replace whatever size sees the most wear.
AS Drive open-ended inserts — for torque-controlled work
The SW731 series are open-ended insert tools, not standalone spanners — they lock into a compatible Stahlwille AS Drive torque wrench body so a fastener that needs open-end access can still be tightened to a checked, repeatable torque figure rather than by feel. AIMS carries the SW731/10 insert (7 mm to 19 mm) and the SW731/40 insert (13 mm to 41 mm), covering small-to-mid and mid-to-large fastener sizes respectively. If you're speccing a torque-controlled build and need to confirm insert-to-body compatibility, our team can check the pairing before you order — see our torque wrenches range for compatible bodies, or get in touch below.
Open end vs ring vs combination — choosing the right jaw
Open end is the fastest tool on and off a fastener because the jaw slides in from the side — no need to lift the spanner clear and drop it back over the head, which matters when a fitting is against a wall, inside a recess, or on a hydraulic or pneumatic line where the tubing itself blocks a straight-down approach. The trade-off is torque capacity: an open jaw only contacts two flats of the hex, so under heavy load it's more prone to rounding a soft or worn fastener than a ring spanner or socket, which contact all six flats. A combination wrench splits the difference — ring end for breaking a tight fastener loose or final torque, open end for the fast runout once it's moving. If a job is purely about speed on fasteners that are already at correct torque and easy to reach, open end alone does the job; if you're breaking loose anything that's been seized or over-torqued, reach for the ring end or a socket first.
Metric and imperial — reading the across-flats sizing
Open end spanners are sized to the across-flats (AF) dimension of the fastener head, not the thread diameter, which is why metric spanner sizes look larger than the bolt's nominal size. As a rough guide for standard metric fasteners: M5 = 8 mm AF, M6 = 10 mm, M8 = 13 mm, M10 = 17 mm, M12 = 19 mm, M14 = 22 mm, M16 = 24 mm, M18 = 27 mm, M20 = 30 mm. Imperial spanners are marked directly in fractional inches (AF) and don't convert cleanly to metric sizes, which is why AIMS stocks the two ranges separately rather than as a single mixed set — check what's actually stamped on the fastener or bolt head before ordering rather than assuming from thread size alone. If you're not sure which range a job needs, send us a photo of the fastener and we'll confirm the size.
Companion ranges at AIMS
Open end spanners cover one part of the fastening job — for the rest of the kit, see ring spanners for full-contact torque work, combination wrenches for the open-end-plus-ring hybrid, sockets for enclosed-head fastener work, and torque wrenches for the bodies that pair with the AS Drive inserts above.
Order from AIMS
Need help matching a spanner size, a set, or an AS Drive insert to a specific torque wrench body? Call our team on (02) 9773 0122, reach out via contact us, or send through your fastener list for a quote — we'll confirm sizing and get pricing back to you fast.
People Also Ask — Open End Spanners
Q: What's the difference between an open end spanner and an open end wrench?
Nothing — they're the same tool. "Spanner" is the term used in Australia and the UK; "wrench" is the American term. Both describe a U-shaped jaw tool that engages two flats of a hex fastener from the side.
Q: What is the difference between an open end spanner and a ring spanner?
An open end spanner has U-shaped jaws that slide onto two flats of a fastener from the side, which suits restricted access and fittings you can't lift a tool straight over. A ring spanner fully encircles the fastener head, contacting all six flats for better torque transmission and less risk of rounding the head — but it needs axial clearance to drop over the fastener first.
Q: What are the across-flats (AF) sizes for common metric fasteners?
As a general guide: M5 = 8 mm, M6 = 10 mm, M8 = 13 mm, M10 = 17 mm, M12 = 19 mm, M14 = 22 mm, M16 = 24 mm, M18 = 27 mm, M20 = 30 mm. Double open end spanners are sized in pairs, so an 8 x 9 mm or 17 x 19 mm spanner covers two of these sizes in one tool.
Q: When would I need a single open end spanner instead of a double-ended one?
Single open end spanners come into play at the large end of the size range — Stahlwille's single-ended line runs from 24 mm up to 95 mm, where a compact double-ended head isn't built wide enough or strong enough for the fastener. They're the right choice for large flange bolts and heavy structural connections rather than everyday maintenance work.
Q: What's an electricians' spanner, and do I need the thin-jaw version?
An electricians' spanner uses a slimmer head and jaw profile than a standard open end spanner, sized for the small fasteners found in switchboards, control panels, and terminal blocks. If a standard spanner is too bulky to seat properly inside an enclosure or against adjacent terminals, the thin-jaw electricians' version is the one that fits.
Q: What is an AS Drive insert tool, and why isn't it a spanner on its own?
An AS Drive insert (Stahlwille's SW731 series) is an open-ended head that locks into a compatible Stahlwille torque wrench body rather than being used by hand on its own. It lets you apply open-end access to a fastener while still working to a checked, repeatable torque figure — useful anywhere torque needs to be verifiable, not just "tight".
Q: Should I use the open end or the ring end to break a tight fastener loose?
Use the ring end (or a socket) to break a seized or over-torqued fastener loose, since full six-flat contact spreads the load and is less likely to round the head. Once it's moving freely, the open end is faster for the remaining turns.
Q: Why does AIMS only stock Stahlwille in this range?
We stock what holds up under real workshop use rather than carrying every brand for the sake of range — Stahlwille's jaw tolerances stay tight and the chrome finish holds up over years of daily handling, which is why it's the brand we've settled on for open end spanners. If you need a specific brand we don't currently stock, ask us — we can usually source it.