I bought some new door hardware to retrofit into an existing mortise lock door. The lock itself is a bit larger than the old lock, so I need to enlarge the mortise in the door. I’ve only got one shot, so I don’t want to mess up. How would you do it?
I do not have a drill press, but I do have one of those small (kinda junky) press thingys that attaches to an electric hand drill. Should I use that with a forstener bit? Should I just use chisels and get on with it?
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Replies
I'd use a sharp chisel to enlarge a hole. I put a block under the door to keep it from moving and sit on an upside down plastic bucket.
My point is, get comfortable and take your time. It should be fine if you take your time.
Will Rogers
I'd just use chisels.
One tip - clamp a pair of 1X or 2X blocks on either side of the existing mortise (imagine you're temporarily sistering a pair of supports to the door edge) to keep the mortise sides from blowing out into the door face.
With a pair of sistered supports - if you clamp them flush with the edge face - you now have a wider bearing surface, so you'd have better luck if you want to use a router to clear out the bulk.
I've never had luck dropping a Forstener bit into a partially drilled out space.
-t
You can also drill it. First, using a Forstner bit, drill a hole thru a piece of 3/4 plywood (about 3" x 9") using the drill size you need. This will be your guide that you position over the old mostise, and tack in place with 4d nails or something similar. Re-position the guide as needed to elongate the hole.
This might be a good excuse to buy a Multimaster.
Lots of good suggestions; clamping a couple of cheeks to the door to prevent blowing out the side of the mortise is a particularly astute one.
Once you've done that, I would suggest you cut a plug of pine (or some other softwood) to fit the existing mortise. Stuff that in there so it won't move, then layout your new mortise and either drill it with a forstner bit and your gizmo or use a plunge router and a straight bit.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
Hi rasher,
I bought some new door hardware to retrofit into an existing mortise lock door. The lock itself is a bit larger than the old lock, so I need to enlarge the mortise in the door.
It sounds like you're doing exactly what I did to my new office door about six weeks ago.....if that's the case I only had to do a "little" sizing and shaping....took out about 1/8" here and there......used a barrel shaped sanding attachment on my dremel tool. Took about 15 minutes and had the slickest, smoothest doorknob hole you've ever seen in a 100 year old + mortise and tenon heart pine door.
Another door I did was all new modern style hardware mounted in the old location, picked up a hole saw kit from the local home depot made by black and decker.....it was comprised of a platics guide that sandwiched the door where the knob went...two screws held it in place on the door edge....the holes the screws created are the same holes the latch screws would go in later....the sandwiched guide kept the hole saw from jumping all over the place. Drill halfway through both sides and pop out the resulting plug, then use the second smaller hole saw to drill the latch through the end of the guide. Remove the guide and use a small chisel to clean out the edges for the latch.
Pedro the Mule - easy as one two three power sand
another method is to drill your hole dia thru a piece of ply.
Then clamp the ply to the face of the door where you want your hold and you have a guide for your hole saw.
Put another piece to waste on the other side to prevent the blowout.
If i have it right that this is what you're doing??
I think the OP is trying to enlarge a DEEP rectangular hole on the edge of the door, not a wide round hole through the faces of the door.
That was my impression as well.
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Aha!
hole saw the size of the current hole screwed into the inside of a hole saw of the desired size...
guide and hole size all in one..
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Sharpen a 3/4" & 1-1/2" chisels and go at it. I've done this several times. If you had multiple doors then a lock mortiser would be the ticket.
mike
Cheeks and chisels--that's my vote.
I've got a couple of lock mortisers, so I'm spoiled. If it's just the one door, cheeks and chisels.
By the way, I don't think a forstner bit would be long enough to reach the entire depth of the mortise, and they may be difficult to control.
Edited 4/30/2009 4:56 pm by doorboy
You need to go 4 -7/16" deep for most new mortise locks, I think you are correct that forstner bits may be too short. A bottom cutting mortice chisel would come in handy. I never owned one , but made a half decent one out of a large screwdriver. I heated the screwdriver to a red heat about 1- 1/2" from the end,then bent it to a 90° angle in a vice.I ground it to about a 45° angle. I don't bother honing as it is not tool steel and won't take a sharp edge. I have only touched it up with a file a couple of times,only used maybe 6 times in 20 years.Although not exactly a quality tool it does the job of cleaning the bottom of the mortise.
mike
Rasher,
You're trying to do a job without the right tools.
That's it,
WSJ
Gee, I certainly appreciate your helpful productive comments... <cough cough>But let's see, I have chisels, and a plunge router, and I guess I have some blocks of 2x4s sitting around to make some shoulder reinforcements and a couple of clamps. I also have lots of useful advice from the others here, so I guess I'm probably good.Thanks to the rest of you for your advice. Especially the shoulder reinforcement comment.I especially like the hole saw within a hole saw idea, although it's not useful for my current application. That's just a genius idea and I can't wait to try it out some time.
Rash,
Sorry to come in your opinion that way. Lot's of DIYer's here who lack the proper tools., but based on what you posted, just block it out, and cut it with your router.
Again sorry, my apologies
WSJ