Rim Locks - whats the critical measurement?
Rim locks or more commonly known as Rim Night Latches or even more common ‘Yale Locks’
Today I am going to give you all a quick guide on how to measure a rim lock for the most critical measurement that you will need when wanting to replace a ‘Yale Lock’
The critical measurement is the back set.
This is the measurement from the leading edge of the door to the centre of the key hole.
In the UK there are two measurements.
First is 40mm and then 60mm these measurements are called in our industry narrow and the latter standard.
Typically you will find narrow Yale locks fitted to doors that may have glass in them. The idea is that the frame/wood around the glass may not be that thick to accept a standard Yale Night Latch.
Another thing to watch out for also is the narrow style may be fitted where the door has a thick door stop and in this case you may find the door stop could protrude onto the cylinder itself if the door is inward opening.
The standard should be the considered choice every time in reality and on any door that is of solid construction this should be the considered choice.
As normal there are exceptions, abate a distant memory now but there are locks out there that have odd measurements. We have to accept any thing that was fitted pre decimal would of course be imperial measurements, so of course it would be obvious that this measurement would be out by todays standards. The other is our friend Mr. Chubb.
They did a range of locks that had a completely different back sets compared to the standardisation of the 40mm and 60mm. The Chubb Rim Lock in question the Chubb 4L70 draw back latch. This lock has a measurement of 50mm for its back set.
Which means in plain English, that if you don’t want to modify your door you have to stick with this lock.
So there you go, this is a short article as articles go but a very relevant one and I hope that I managed to help you understand the critical measurement for Rim Locks, or Rim Nightlatches, or simply Yale Locks …. :-)
Head of the tech department
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