What are those strange screws used for locks?

Page 1 of 3  

Installing a lockset today (el cheapo Kwikset entry w/deadbolt), I noticed they included two of those weird screws in the hardware package. I worked out that they were intended to hold the passage lock strike to the jamb.
They're regular flat-head wood screws, except that the threads just under the head change from coarse to fine, almost like a machine screw.
Does anyone know the purpose, or the rationale of using these screws? I've often seem them in lock installations, but nowhere else. Are those fine threads supposed to grip the wood better?
D "puzzled" N
--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 10 Mar 2010 19:12:37 -0800, David Nebenzahl

They're finely spaced but not more shallow than the other threads, right?
I haven't seen them but from your description, I think the screw is meant to screw in quickly most of the way, and then slowly but with more staying power for the last bit.
But does that really solve any problem. AFAIK, there is no risk of a lock strick screw coming out head first. The problem, as when someone kicked in my door the first summer I lived here, is that the wood behind the jamb isn't thick enough sideways, or the screws aren't long enough to spread the load when the door is kicked. The heads of my strike screws didn't move to the side at all. but the door jamb cracked, probably more than a half inch, and then sprang back all but a quarter inch.
And when I got home, 8PM on a summer Sunday evening, the door was ajar. But I never found anything missing, not the new car radio still in the box on the basement workbench, not the fancy home burglar alarm, still in boxes on the bedroom floor, and not even the cookies on the kitchen table.
All I can imagine is that the dog next door, which I hated because its barking woke me up in the morning and wouldn't let me get to sleep at night, barked when he heard the noise and scared away the burglar. :)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It's a very inexpensive and quick thing, but have you considered removing the screws of your strike plate and replacing them with 3" ones that reach well through the casing and into the crip? On some of my exterior doors, the strike plate for the deadbolt has an inner reinforcing plate with long screws provided for just this purpose. Once installed, the adjustable strike plate is screwed on over top of it.
--
Nonny


Luxury cars now offer a great seating option for politicians.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/11/2010 10:05 AM Nonny spake thus:

I'm not the one you asked, but in my installation there was no need for such substitution. The lock kit came with extra-long screws to use to secure the deadbolt strike. (No adjustable 2-piece strike in this case, though.)
--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nonny wrote:

I've done that on a lot of my doors in the past. Also a few long screws on the hinges.

I've used long heavy duty strike plates that combine the latch and the dead bolt holes into one piece. I've seen the wrap around piece of sheetmetal for on the door to strengthen the latch and deadbolt but never used one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you're going to use long screws for security, you should also shim between the casing and the frame so the screws don't screw up the casing. ;-) It'll make the assembly stronger, too.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
installed, the adjustable strike plate is screwed

. . . or use common sense and an oversized pilot hole to prevent racking. I never warped a casing when I drilled an oversized "slip" hole for the screw and then didn't overtighten it.
--
Nonny


Luxury cars now offer a great seating option for politicians.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

As long as...
It's still stronger if shimmed. The screws won't bend as easily.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There's no argument there. The problem is how to shim an already trimmed-out door casing. It's a big job getting the trim off to insert shims. Perhaps the person could inject a filler to bridge the space between casing and crip? IMHO, many of the trim guys I've known shim BOTH sides of the casing when installing a door, including the area by the strike plate for just this reason. YMMV
--
Nonny
When we talk to God, we're praying,
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 11 Mar 2010 17:31:54 -0600, " snipped-for-privacy@att.bizzzzzzzzzzzz"

What do you mean by casing? I don't see how longer screws could screw up anything if they are put in all the way.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If there is no shimming behind the jamb where you are inserting the screw, the screw will pull the jamb into the framing when it it tightened...or at least try to pull it in. I'm trying to recall if I shimmed behind the striker plates in all the doors I did way back when but can't.
Harry K
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Harry K wrote:

My first exterior door installation, also my only one, the latch side of the opening was so darn square that I just put it directly against the framing and only shimmed on the hinge side. Seems to work well. Is anything wrong with that approach?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No reason that I can think of.
Harry K
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 12 Mar 2010 07:53:18 -0800 (PST), Harry K

I see what casing means. Thanks. Yeah, I wouldn't have done that. I would have seen the problem in advance. As I recall there was shimming in the door jamb but I added extra wood beyond jamb, the shimming, and what the shim was against. I must have taken off the door molding, but maybe I did something else too, since that wouldn't have exposed much.
There have been two strings of burglaries at different times since that summer, but amazingly they caught both of the thiefs. In one case, he stole a check and they caught him when he tried to cash it.
In the other case, the police woudn't tell me all the details, but it seems they figured out where he lived, staked out his place in the morning, followed him here and waited while he broke in through the back sliding glass door. Had a dog out front and a helicopter on alert if he got away, but they just arrested him when he was ready to leave. The homeowner was annoyed that they let him rummage through his house, but this way they had an iron-clad case with almost no need for anything other than police testimony.
I think they both went to jail, but it's been 20 years since one of them. He must be out by now.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes. I put more wood in the jamb and screws at least 3 inches, and a brass plates that wraps around the door by the locks to keep the door from cracking when kicked, and I finished installing the burglar alarm before I went to work again. It took a very long Monday (after the door was kicked in on Sunday.)
I had almost finished installing the window and door switches and the sirens for the burglar alarm, but I had to drill up from the basement to where the alarm control panel went next to the front door.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Of course the best way to install a 'secure' door is make it open _out_. That way the entire jamb has to give way vice some flimsy 'door stop' and striker plate area.
No people, there is no code that says doors have to open 'in'. Opening out saves an amazing amount of space inside. Can be a problem if youwant a storm door though.
Harry K
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/12/2010 7:57 AM Harry K spake thus:

No, there's no code requirement against outswing doors. But perhaps there oughta be.
The door I replaced that prompted this thread is an outswing door. Not being an expert on door replacements, but willing to tackle a new task, I checked with my contractor friend who's much more knowledgeable than I about such matters. When I described the situation (door falling apart, door frame rotting), he immediately told me that outswing exterior doors are just a bad idea all around.
This particular one wasn't helped by the fact that it was installed completely wrong and was destined to fail: the door jamb was installed flush with the edge of the exterior stucco, with absolutely no trim at all, so of course rain found its way in and started rotting things all around. (Luckily I only had to replace completely rotted-out framing at one place in a bottom corner.)
The new door is much better: I used stucco mold, so the door is at least recessed a little but from the outer wall, with flashing installed under the stucco. But it's still a problematic installation. Unfortunately there wasn't room for an inswing door because of a step that was too close.
Also used a steel door instead of the old solid-core one with hardboard panels. That sucker was so heavy I had to cut it into pieces to haul it away.
--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
David Nebenzahl wrote:

doesn't the fire dept like to see exterior inswing doors for ease of access in emergencies?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 12 Mar 2010 11:44:18 -0700, "chaniarts"

They are also supposed to be better in a wind storm.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@aol.com wrote:

And a blizzard.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.