Feronerie & Configurator
There are two main ways of fixing a handle to a door: wood screws (which bite into the thickness of the door from one side only) and through bolts (which pass all the way through the door and are locked on the opposite side with a nut or threaded insert).
Wood screws work exactly as they do on a cupboard or a shelf: they enter the material, the thread cuts into the wood fibres and creates resistance through friction. The problem appears over time — wood moves, expanding and contracting with the seasons, the opening-and-closing cycles apply repeated loads, and the thread cut into the wood fatigues and gradually gives way.
Grip from one side only, into the thickness of the door. Holding strength limited by the quality of the wood and the available thickness.
Basic fixing
Pass completely through the door. Secured with a nut on the opposite side — incomparably higher pull-out resistance.
Permanent fixing
Modern interior doors are manufactured with a rebate — a raised step on the door leaf that overlaps the frame for sealing and sound insulation. This constructional detail creates a specific problem when handles are fixed with wood screws.
In concrete terms: if the door has a 12 mm rebate and the total door thickness is 40 mm, on one side the handle is fixed normally into 28 mm of material, while on the other the screw grips only 8–10 mm. That is the side that fails first.
The symptoms are progressive: at first the handle has a slight play, then the fixing becomes weaker and weaker until the rosettes move visibly, and eventually the handle can be pulled off with one firm press — damaging the door surface around the hole as well.
For the first few months, the handle seems solid. The thread in the wood starts to fatigue, but nothing is visible yet.
Under pressing or twisting, the rosette has 1–2 mm of play. The screws no longer grip firmly in the wood.
The rosette comes off, pulling splinters of MDF or lacquer from the door with it. The repair is expensive — or impossible without repainting.
The through bolt works on the principle of a complete mechanical joint: a bolt passes through the door from one face to the other, and the nut (or threaded insert) on the opposite side creates a clamp that holds the rosette firmly against the door surface.
| Criterion | Wood screws | Through bolts |
|---|---|---|
| Pull-out resistance | 200–400 N (depending on the wood) | 1,500–3,000 N (limited by the door material) |
| Behaviour over time | Loosens with every cycle | Stays constant — the nut does not fatigue |
| Risk on rebated doors | High — minimal grip on one side | Zero — both rosettes are mechanically locked |
| Compatibility with hollow-core doors | Limited — few fibres to grip | Excellent — the bolt passes through regardless of the core |
| Repairability | Difficult — the hole is damaged | Easy — just replace the bolt and nut |
Although through bolts are superior in every situation, there are door types where the difference is critical:
The most frequent problem case. The rebate dramatically reduces the thickness available for wood screws on one of the faces.
Very high risk without through bolts
MDF fibres are less cohesive than solid wood. Wood screws loosen faster — within 2–3 years under heavy use.
High risk without through bolts
The internal honeycomb structure offers minimal support for screws. Without through bolts, the fixing is precarious from day one.
Through bolts: mandatory
Installation is straightforward and requires no special tools — every Enger set includes everything you need.
Standard thicknesses are 35 mm, 40 mm and 45 mm. Order the through-bolt set for the corresponding thickness — the bolt should be 5–8 mm longer than the door thickness.
Use the template included in the pack. Drill with an 8 mm bit at exactly the indicated distance (rosette centre distance, usually 72 mm).
Fit the lower rosette, insert the drive spindle, then pass the bolts through the holes from the inside towards the outside.
Tighten the nuts until the rosette sits firmly on the door — without forcing. Fit the outer rosette that covers the mechanism. Nothing looks any different from a classic handle.
All Enger handles in the Aprile, Stile and Sterk lines are available with the through-bolt fixing option. The set includes stainless steel bolts, brass threaded inserts and rosettes with calibrated holes — everything pre-set for a fast installation.
Classic line with square or round rosettes. Through bolts are included as standard in every finish.
Modern slim line. The thin rosette (5 mm) makes the through-bolt fixing even more elegant — the bolt stays completely hidden.
If you are not sure what door thickness you have or which through-bolt set fits, the LC Design team can guide you — we are the official Enger distributor in Romania and we know how to adapt the solution to every situation.
Enger handles with through bolts — installed once, for the entire lifetime of the door.