Adjustment of locks and lock furniture

A common call for a locksmiths attendance will be a door failing to latch closed or being difficult to open, either by handle or key. In some cases lockouts occur.

Wooden doors

There are several possibilities for this age, wear or shrinkage of a door which still swings freely may require some adjustment to the striking plate. The door may have dropped causing the bolt or latch to catch at the bottom of the striking plate, The door may have dropped because of worn hinges. Firstly find the cause. Check for worn hinges and replace if required. Second for a dropped door with a binding bolt(s) file the metal on the bottom edge of the striking plate, or move it down and refit, plugging holes and making good afterwards. It may be necessary to take off the striking plate to file, therefore relocation may be a better option. If the bolt or latch is tight on its fastening face or does not enter the striking plate you may again need to file or move the striker. If the door rattles when fast­ened by the spring bolt, the striking plate should be set further back on the jamb This will normally mean moving the strike. A hole to be plugged properly should be drilled and a well fitting plug glued in. There is another method, quick and convenient at times if not very workman­like, of dealing with door rattle caused by too much clearance in the striking plate for the spring bolt. This is to peen the metal, that is, force some of it into the bolt hole by hammering near edge of the strike The striking plate must be removed for this operation. It is best to use a peening hammer, that is, one with a ball head or a wedge shaped end to the head and something to serve as an anvil is needed.

The section D-D has been peened.

The section D-D has been peened.


If rattle is due to the loose fit of the spring bolt in the forend of the lock, it may be necessary to get the bolt replaced or a new lock fitted. ­Occasionally a spring breaks. If you do not have a duplicate in stock, the broken spring can be replaced by something similar from your spares kit. However should the problem re-occur in the ‘ guarantee ‘ period the customer may well look to you for a replacement lock to be fitted with no added labour costs The spring bolt of a lock may fail to strike easily for one or more of several reasons. Overspringing may be the cause and in some locks or the bevel of the bolt is not at a favourable angle Adjusting the face of the bolt and the lip of the striking plate and perhaps bending the lip of the striking plate may be a cure. If the latchbolt of a lock does not spring out when the lock furniture works freely, the cause may be a broken or faulty spring in the lock or the handle. Alter­natively, dirt, rust or a stiffly working part may be the reason. in such cases the locks and furniture should be removed and overhauled. Sometimes the bolt fails to spring out fully because unsprung lever handles are fitted which are too heavy for the springs inside the lock. The remedy is to replace the handles with others which have their own springs to return the handles to the horizontal position without help from the lock. ­



PVCu doors

Similar problems occur with PVC doors, although by far the most common problem is a door incorrectly fitted at installation. The whole stability of these doors is the correct fitting initially into the opening then the glass into the frame. The glass should be packed with special plastic packers in such way as to make the glass a solid unit within the frame of the door before the trim is refitted. It is possible these packer have slipped if not correctly fitted but most likely is that they were never placed there on installation. A quick remedy is to gently lift the lock side with wooden blocks and a steel bar taking care not to damage the surface. When the door is latching correctly arrangements can be made to repack the door. On occasions the frame may have moved because of insufficient fixings, again packing and new fixings should cure the problem. In a large number of cases the original poor fitting may have caused damage to the lock either by the parts binding or the excessive force the occupiers have had to use to lock the door. The locksmiths should ascertain the current condition of the lock and advise accordingly, should the customer decline a new lock against advice this should be recorded on the jobsheet and signed by the customer.­

Aluminium doors

As with the PVC door but adjustments are not so easily undertaken. In most cases the door sections are screwed together with steel screws which will have rusted, extreme care should be used before dismantling any ali door, or you may end up with a pile of pieces and a gap to fill before bedtime! The locks are sometimes more difficult, 50mm sashlocks were common in rear doors whilst 50mm cylinder operated sashlocks were common in main entrance doors. Common faults in the older Union 22 series were weak latch follower which snapped, symptoms were – able to open from the outside with a key but not on the inside with the handle – remedy new lock. On the 50mm sashlocks the follower spring would break falling behind the bolt stopping it from withdrawing and clearing the strike, a sharp blow with a rubber hammer sometimes worked whilst turning the key, a strong magnet would also lift the spring clear through the ali door. Broken lever springs were also a common problem leaving a lever lifted high, a wire probe pulling them down usually worked. When removing any ‘mortice fitted’ lock beware, the so called captive nuts fitted into a slot in the door section often go slipping to the bottom of the door. Unless you wish to spend half an hour with a bent coat hanger fishing for them I suggest you take action to prevent them running off. A 2mm hole and a pop rivet stem should trap them and the hole will not be noticed. On some older doors the Chubb (Usually 3G220) lock was offset the longer Chubb keys had to be used to open from the outside.­­­ ­

Taken from ‘The Encyclopaedia for Locksmiths’ By Mick Friend.
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