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Inserting interior lock set

How do you cut out the wood on a door for a lock set? Door is new, solid MDF (?) board and I have ordered lock set from Rejuvenation to match lock sets in sold oak doors from 1917.

Thank you

A. Spruce
Re: Inserting interior lock set

It varies, depending on the door and the lock set, but generally it is a 2-1/8" hole through the face and a 1" hole for the bolt. Schlage and Yale brands have been known to need smaller holes, so follow the instructions with the lock set.

Tip: When boring through the face of the door, bore from both sides, this will prevent tear out. If using a standard hole saw, drill from one side until your pilot bit penetrates the back, then switch to the back and bore forwards. It is a toss up whether you bore your bolt hole first or after the handset hole, I tend to do the bolt first because when you break through into the handset hole, it can blow out a lot of material, weakening the door a bit. Is it a big deal, no, but if you tend to be anal retentive like I do, then you don't like the mess, so bore the bolt first and the handset second.

The instructions with the handset should tell you all this, but for the bolt, you centerline the door edge when you bore. The set back for the handset hole is generally 2-3/8" for an interior door, 2-3/4" for an exterior door, again, verify your measurements with the instructions.

Re: Inserting interior lock set

Are you needing a cylindrical hole for the knob and plunger like today's doors or are you speaking of a mortise-style lockset where the mechanism fits a slot on the edge of the door? Likely the latter if from 1917 so I'll start there. First locate where the set will go. If you're using an existing door jamb, align the set with the existing strike in the jamb. To create the 'mortise' takes a bit of doing. Generally, you drill a set of overlapping holes using a bit that matches the thickness of the lockset (or 1/16" wider if there's wood enough), then clean it up with sharp chisels. Be very careful drilling- it's super-easy to go on an angle and drill through the surface of the door! Also do not drill too high or low- there needs to be wood to catch the screws which hold the lockset in place. Test fit as you go until the lockset goes in easily. Don't force it or you may split the door or crack it on one side. Re-check for strike alignment and when that is good, trace the outer flat portion of the lockset to the door with a sharp knife. Clean out to the needed depth to make the lockset flush with the edge of the door. There should be a template with the lockset, but if not you can use the lock itself to locate where the knob-shaft (keyhole and locking knob too if appropriate). Again use the proper size drills and leave wood for mounting any escutcheons. When drilling here, stop when the tip of the bit pokes through the other side, then use that hole to center the bit and drill from the other side. This will reduce the chance of chipping the door face. The rest should be obvious.

Most new cylindrical locksets use a 2 1/8" hole but some older ones don't- 1 3/4" is a common 'odd' size but there are others. Drill for the knob first with a holwesaw or forstner bit, again stopping to drill from the other side. Locate and drill for the plunger. Mortise for the plunger plate and install the lockset. Rather simple and easy in comparison to a mortise set, huh?

In the old days when holes were bored with a brace and bit by hand, installing a mortise set was a lot of work, and what with the cranking motion it was much easier to ruin a door, so these were left for only the experienced carpenters to do- kourneymen need not apply! Today's power tools make the job a lot easier to do well but you must still pay careful attention to drill alignment. That is still the key to doing this job well. Also be gentle when chiseling- many small bites, not one big one that may split out a face. Chisels should be very sharp; you really need that here. And when you drill the overlapping holes, you need to lap about 1/3 a diameter or the drill point may break out toward the already drilled hole, and that is a real bugger to work with after that- you won't make that mistake twice! Forstner bits are best for this work, but with much care sharp spade bits will work (and a holesaw for cylindrical knob holes).

For new cylindrical locksets you can buy a jig that screws to the door which will locate and align the boring tools for the holes- they make the job super-simple, fast, and nearly foolproof- but you can do just fine without them. I only use my jig for a housefull of doors, one or two I can do just as fast and just as well with a tape and a square.


Re: Inserting interior lock set

Nothing to add except that the lock set comes with a template - precision is important for perfect fit and good operation of the lock. Use the template to mark your drilling points.

Re: Inserting interior lock set

I installed a rather elaborate lockset and escutcheon system a few years back that required drilling 9 holes of which 7 needed precise location. I used the template, then checked the given dimensions then double-checked because the door cost about a months of my wages and I wasn't about to mess it up!


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