For a door manufacturer ordering TOPTEK sash mortise locks, the family name is only the starting point. Select the centres, backset and furniture interface together. EN72SL has 72 mm centres; EN85SL has 85 mm centres. Those numbers describe handle-to-cylinder spacing, not the distance from the door edge.
One useful distinction affects real quotations: a 55 mm backset is listed for EN72SL, while the EN85SL schedule lists 45, 50 and 60 mm. Moving to 85 mm centres does not preserve every backset choice. Confirm the full model before releasing the door machining drawing.
First confirm that the door needs a sash function
A sash lock combines a latch and a deadbolt. For these TOPTEK models, the handle operates the latch; the cylinder operates the latch and deadbolt. This is the function described in TOPTEK’s Certificate of Constancy of Performance No. 2649-CPR-26002201, issued on 4 June 2026.
Do not assume that operating the lever retracts a projected deadbolt. If the project requires the handle to release both bolts, select the appropriate function from the EN mortise lock range before comparing dimensions. The right geometry cannot correct the wrong operating function.
Match the model to the two dimensions
The certificate’s model schedule gives the following combinations. Backset is measured from the specified forend reference to the operating axis; centres are measured vertically between the lever follower and cylinder axis. Use the corresponding drawing to confirm both datums.
| Family | Centres | Backsets and complete model references |
|---|---|---|
| EN72SL | 72 mm | 40: EN4072SL; 45: EN4572SL; 50: EN5072SL; 55: EN5572SL; 60: EN6072SL; 65: EN6572SL; 70: EN7072SL; 80: EN8072SL; 100: EN10072SL. All backsets in mm. |
| EN85SL | 85 mm | 45: EN4585SL; 50: EN5085SL; 60: EN6085SL. All backsets in mm. |
For example, a door designed around 55 mm backset and 72 mm centres points to EN5572SL. If the designer changes the furniture to 85 mm centres, there is no corresponding 55 mm-backset model in this schedule. Resolve the door and furniture arrangement before accepting a substitute. This avoids sending one dimension to the door factory and another to the hardware supplier.
Check the furniture and forend before cutting the door
The current product specifications distinguish more than centres. EN72SL lists a 235 mm-high forend and 8 or 9 mm square follower options. EN85SL lists a 240 mm-high forend and an 8 mm square follower. Both families list 20, 22, 23 and 24 mm forend widths, with round or square ends.
Choose one actual configuration rather than treating these options as interchangeable. Match the lever spindle to the selected follower and the faceplate to the prepared door edge. Check case depth, fixing positions, cylinder cut-out and strike geometry on the model drawing. Equal backsets do not establish replacement compatibility.
The EN72SL product page is the starting point for its family. For an existing door, the replacement measurement guide helps collect the additional dimensions without assuming the old case and new case share a footprint.
Keep the selected code on the quotation and documents
The twelve complete model references above appear in the dated TOPTEK certificate. Request the applicable certificate, Declaration of Performance and drawing for the selected model through the certification resource centre. For a fire-resisting door, the proposed doorset and installation must also fall within the applicable evidence; the family name alone does not establish that scope.
Keeping one full code across the quotation, sample and purchase order makes later changes visible. A finish change and a change from EN5572SL to EN6085SL are different decisions: the latter changes both backset and centres and needs coordinated door preparation.
Request the matching sash lock configuration
Send the required centres, backset, spindle size, forend shape and width, plus a door or existing-lock drawing. Include the quantity and market requirements. TOPTEK’s commercial door hardware team can discuss the corresponding set. Request the model drawing and quotation for your sash lock configuration.
Frequently Asked Questions
Is a 55 mm backset listed for EN85SL?
The referenced model schedule lists EN85SL backsets of 45, 50 and 60 mm. A 55 mm backset is listed for EN5572SL with 72 mm centres.
Can a 9 mm spindle be assumed for both families?
No. EN72SL lists 8 and 9 mm square follower options, while EN85SL lists an 8 mm square follower. Match the spindle to the ordered configuration.