40mm SQ Stub Axle

SKU: N/A Category: Axles Tags: Australian Made, Couplemate™ Core, stub Brand: Couplemate

Price

Price range: $53.50 through $68.85 Inc.GST

Stub Length

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Brand: Couplemate

Australian-made stub axles.

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40mm Square Stub Axle

40mm square stub axle LM or otherwise known as a standard profile.

The axle length is measured from tip to tip. The Stub Axle is supplied with a nut, washer, and split pin.

Welding a 40mm Square Stub into a 50mm tube with 5mm walls makes a good farm trailer.

Select from an electric or marine turn. An electric turn suits both electric and hydraulic backing plates, while a marine turn suits marine or unbraked axles.

How to install a stub into a hollow tube

Cut the tube to length, including the stub measurement.
Drill a hole no smaller than 12mm on all four sides. When inserted, mark the 50mm tube 25mm back from the end of the stub.
Insert the stub weld into place.
Weld the stub holes to secure the end of the stub into the tube.
Finally, the hollow axle stub must protrude past the springs and u-bolts once affixed into position.

LM Bearing Sizes are

Inner LM Bearing Sizes	ID 31.75mm	OD 59.10mm
Outer LM Bearing Sizes	ID 19.05mm	OD 45.20mm
LM Seal	ID 37.5mm	OD 59.10mm
Dust Cap	45.20mm

A 40mm Square stub axle is rated at 500kg per Stub or 1000kg per pair.

Dimensions

Tip to Shoulder, including thread 115mm
Square part 135mm

We recommend you use only Japanese Bearings.

It is common to slide 40mm stub axles into a 50sq tube and weld them into position for use on narrow trailers.

Stub Axles We Manufacture

39mm Round Stub Axle
40mm Square Stub Axle
Round Stub 45mm Axle
45mm Round PLL Stub Axle
Square Stub 45mm
50mm Round Stub Axle
50mm Square Stub Axle
Trailing Arm Suspension Stub Axle
Caravan and Boat Spare Wheel Carrier
39mm Round Spare Wheel Carrier

How undersized axles cause caravan parts to fatigue.

40mm SQ Stub Axle Guide

Ensure a structurally sound build and dependable wheel alignment by following these critical installation and welding guidelines.

✔️ The Do’s

Vee the joints: Machine a deep V-groove on the edges of the stub axle and the main axle tube before welding to ensure total weld penetration.
Verify bearing profile: Confirm if your stub has a standard Holden LM or Ford Slimline machined profile to ensure accurate bearing purchases.
Use an alignment jig: Clamp the 40mm square body firmly into an alignment jig or a straight channel to prevent warping from the intense heat of welding.
Protect machined surfaces: Wrap the precision bearing journals and thread tips in heavy leather or welding spatter tape before striking an arc.
Allow slow cooling: Let the completed axle assembly cool down slowly and naturally at room temperature to preserve structural steel strength.

❌ The Don’ts

Don’t quench the weld: Never drop a freshly welded stub axle into water or oil to cool it down, as this creates extremely brittle, hazardous steel.
Don’t ground via journals: Avoid clamping your welder’s earth lead directly to the ground-bearing surface, as this can cause internal electrical arcing pits.
Don’t weld bearing surfaces: Never weld close to or on the machined bearing journals, rubber seal tracks, or split pin holes.
Don’t exceed weight limits: Avoid overloading a single 40mm square axle setup past its safe engineering limit (typically rated up to 1000kg per pair).
Don’t use low-amp welders: Avoid structural welding with undersized DIY machines; use a high-penetration structural MIG or stick welder for reliable penetration.

Additional information

Weight	2.5 kg
Dimensions	30 × 4 × 4 cm
Stub Length	250mm, 300mm, 350mm, 400mm, 500mm
Axle Style	Stub
Bearing Profile	Holden (LM)

Our Service Lifetime Warranty

Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.

Couplemate™ is a manufacturer and vendor of high-quality towing, trailer, and caravan components. Couplemate™ Core Goods and Custom Work are guaranteed to be free of defects for the service lifetime of the product when used as intended.

Warranties are non-transferrable and Couplemate™ requires satisfactory proof of purchase prior to issuing a remedy. The full Couplemate™ Warranty Policy can be found in the Terms & Conditions: Section 8 – Consumer Guarantees & Warranty.

Warranties are in addition to your rights under the Australian Consumer Law. If something is wrong with your order, please contact our team.

60-Day Returns

After 60 years of experience, we know that life has its unpredictable moments.

All Couplemate™ orders (online, over the phone, or in-store) have a 60 day period for change-of-mind returns and exchanges. There are some items that can’t be returned and some returns may incur a 15% restocking fee.

You can view our full policy for change-of-mind returns here.