How to Measure an Inline Handle for Replacement

Replacing an inline window handle need not be difficult if you measure correctly first. Whether you are a trade fitter or a keen DIYer, understanding how to check the size, spindle and screw positions will make selecting a replacement simple and prevent returns. This guide covers step-by-step measuring, common variations of the inline window handle, and practical tips to ensure a correct match first time.

What is an inline window handle and why accurate measurement matters

An inline window handle is a slim handle style fitted close to the frame that operates shootbolts or multi-point locks in casement and tilt-and-turn windows. Tradespeople will know that dimensions vary by manufacturer: the backset, screw centres and spindle length must match. Accurate measurement reduces downtime on site, avoids damage from forcing components, and saves money on returns and call-backs.

Tools and preparation

Before you start, gather basic tools and check the condition of the existing handle. For measuring an inline window handle you will need:

• A steel rule or tape measure with millimetre graduations
• A set of feeler gauges or a vernier caliper for precise thickness checks
• A spirit level to ensure the handle is not twisted on its backplate
• A small torch to inspect screw recesses
• A camera or phone to take reference photos before removal

If the handle is seized, apply a small amount of penetrating oil and carefully free the spindle before forcing measurements; this preserves the internal gearbox and makes measuring easier.

Key measurements to take

There are four critical measurements when measuring an inline window handle: overall length, backset, screw centres and spindle size. Record each measurement in millimetres and double-check to avoid ordering the wrong component.

1. 1Overall length: Measure from the tip of the handle to the end of the backplate. This helps verify the replacement style will sit correctly on the frame.
2. 2Backset: This is the distance from the face of the handle backplate to the centre of the spindle hole. The backset is often the most critical measurement when replacing an inline window handle.
3. 3Screw centres: Measure the distance between the fixing holes, centre to centre. Common centres are 43mm, 70mm and 92mm; confirm the specific value for your handle.
4. 4Spindle length and section: Measure the thickness of the spindle plus the exposed length. Most spindles are 7mm square, though some use 8mm; check the section and overall length to ensure engagement with the gearbox.

Removing and measuring the spindle correctly

To measure the spindle accurately remove the handle and extract the spindle where possible. Note whether the spindle is fixed to the handle or removable; many modern inline window handle spindles are removable. If you cannot remove it, measure the visible length carefully and include the thickness of the backplate in your calculation. Always note the spindle profile as square, D-shaped or splined, because even correct lengths fail to engage if the profile does not match.

Common variations and site checks

Inline window handles come in various configurations: single spindle, double spindle, and handles with locks. On site, check for the following common variations before ordering replacements:

• Locking mechanism: Is the handle key-locked or push-button? A locking inline window handle requires matching key type and cylinder backset.
• Non-standard screw centres: Some older frames use unusual screw centres; measure on both sides to confirm symmetry.
• Spacer and washer requirements: Modern UPVC frames sometimes need thin spacers behind the backplate; record any spacers when removing the handle.
• Corrosion or wear: If the spindle shows significant wear, order a new spindle together with the handle to guarantee smooth operation.

Installation tips and testing

When you have the correct inline window handle, follow these practical installation tips to ensure reliable operation:

• Fit the spindle and handle loosely at first; align the handle with the shootbolt or lock mechanism before tightening fixings.
• Use threadlocker on screws in high-usage windows, particularly in commercial units; avoid over-tightening which can warp the backplate.
• Check operation through the full travel twice: lock and unlock, and operate any tilt-and-turn action to ensure the handle does not foul the frame.
• Keep original parts until you confirm the replacement works; this allows a simple swap back if an error has occurred.

Troubleshooting and when to seek help

If the replacement inline window handle feels stiff, binds, or the spindle does not engage, inspect the gearbox and keep plate orientation. Misalignment of the spindle by a few millimetres can prevent engagement. For complex multipoint locks, or where the frame or locking gearbox is damaged, it is often quicker and safer to involve an experienced installer. They can assess whether a lockcase replacement is necessary in addition to the inline window handle.

Correct measurement is the key to a successful inline window handle replacement. Take clear photos, measure carefully in millimetres, and check spindle profile and screw centres before ordering. With accurate measurements and the right tools, tradespeople and DIY enthusiasts can fit replacements quickly and reliably.

Recommended Products

Based on this article, you may find these products helpful:

• TSS Cockspur Window Handles
• TSS Offset UPVC Window Handles
• ERA Universal Inline Window Handle
• In-Line Window Handle - White
• Multipoint Gearbox GU Old Style