I have an old house with glass door knobs. The bathroom knob no longer
works properly. I bought a new replacement and when I removed the old
knob, I noticed that the bore in the door is way too small for the new
knob assembly. Should I get out a hole saw and cut a new hole? Looks
like I can really screw this up if I'm not careful.
Bore a better hole, but clamp a board on the door and start your
drilling through that to keep it from wandering off where it doesn't
belong. Two boards, one on each side would be best so there won't be a
splintery breakthrough. Measure carefully, and mark well before you
start. God luck.
The clamp-on jigs are for 2 1/8" hole saws - most definitely bigger
than what the OP needs for his antique reproduction knob set.
Joe had it right. Drill the correct size hole in two pieces of scrap
plywood, clamp one on either side of the door with the holes centered
on the existing hole, and have at it with the drill. The escutcheon
will mask minor errors.
The replacement knob is a mordern knob that I got at Home Depot. The
old glass knob is loose and the latch has a lot of slop. Feels like
someday the knob will fail to turn the latch mechanism and I (or
someone else)will get locked in the bathroom if it breaks.
We would all be glad to help, but I think we need more
Is the old lockset a cylinder lock or a mortise lock?
If it is a cylinder lock with the hole in the door face too small:
Bore the correct size hole in a scrap piece of plywood. Have
the scrap piece large enough to be able to clamp it to the door
face above and below the old hole. Carefully position the plywood
for proper backset of the new lock. Let the hole in the scrap
guide the drill into the door. A thin scrap on the back side of
the door will prevent splintering as the bit goes through.
If it is a mortise lock, the problem is quite different.
I hope I guessed the problem about right, if not, clarify and ask
Keep the whole world singing . . .
How much bigger a hole do you need? One way to enlarge a hole and keep it
round and centered with vertical sides is to use a router bit that is larger
in diameter than the bit shank. Extend the shank far enough through the
hole so that the shank rides on the top portion of the hole thus cutting
only a bit more than the bottom half; turn work over and repeat. When the
last cut in the hole is the correct diameter, use a bit that cuts the same
size as the shank to finish the cut.
As an example, if you start with a 3/8 bit on a 1/4 shank, you will enlarge
the hole diameter by 1/8 with each cut. Whether or not you can get an
exactly sized new hole this way depends on the sizes of starting hole and
desired finished size; with a 5/16 bit on a 1/4 shaft you can get to within
1/16 regardless of starting hole size.
That was my first impression as well. OP has not posted back, so far,
that I have noticed. If these are in fact old-style locksets, the
backset will be wrong as well, I suspect.
I'd be looking on-line for repro knobs, or take out the entire assembly
and start visiting salvage houses, as well as the oldest locksmith in
town (sometimes, they keep junk boxes in the back room). In the short
term, I'd steal the knob assembly off another door, to get the bathroom
usable and buy some time.
On Sun, 13 Feb 2011 07:39:39 -0800 (PST), finiteguy
A woman might have wanted glass knobs.
Some even have roses embedded in them.
There used to be a wrecker's yard not far from where I lived that
had everything you might want "old."
Probably some source in your area.
There's places on the net selling old stuff too.
Prices are probably steeper than you'd find in a salvage yard.
1947 was a good year. A very good year.
From your limited description it sounds to be like you might have an old
mortise style lock. Replacing that with a modern 2-3/8 backset lock is a
big job that involves adding a filler plug to the door before you drill
My advice would be to find another mortise lock if yours is broken. The
glass knobs, the shafts and setscrews can be purchased at any full service
I can and will describe the procedure in detail if you want to proceed.
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