pilot holes?

[George]

Watching 'This Old House', they are forever driving various wood screws without drilling pilot holes. Recently, they did this with some decent-sized lag screws, to pull a couple of 2x8's together.

How does this work? ISTM that the threads would lock into each piece of wood, and the screw could not possibly draw the two pieces up - that the only way this could happen would be for the screw to strip in the 'top' piece'. It's hard to picture a lag screw doing this.

Obviously, though, it does work. What am I missing?

Thanks, George

[jamesgangnc]

Usually there is some blank shoulder on longer screws. Enough so that there is not many threads in the top piece of wood.

[willshak]

George wrote the following:

Dis you see the lag screws? Some have no threads a distance from the head end.

[Erik]

I've seen more than a few things on those home improvement shows that deviate from 'real world'.

Beyond a shadow of a doubt, everything shown is staged, rehearsed and edited to hype the episodes featured product/s and materials, and to motivate viewers up off the couch and into big box stores... or calling the contractor.

They're just thinly veiled infomercials...

Erik

[George]

I remember seeing an interview of the woman who was a member of the his & her team on one of those shows. Every show would start out as if they were a couple and it was Saturday morning and they would decide to do something. First it was a plant stand or something trivial then a 60' multi level deck then a complete basement renovation including relocation of numerous service lines to accommodate the "environmental chamber" they picked out. All done in a weekend of course.

She explained how she had little idea of what she was doing and how everything was carefully choreographed by the manufacturers rep so she could walk in and set the last tile or drive the last screw.

[George]

Proper technique is to drill a pilot hole. This does two things, it minimizes splitting and lowers stress on the fastener when it is torqued in. A lot of things in construction can be either "see it works" or done properly for longevity.

[hrhofmann]

The principle sounds great, if they really are that easy/less expensive to manufacture, why don't you go into business?

[DerbyDad03]

re: "I know how screws are manufactured..."

I'm not justifying the full cost, but the process of manufacturing a "medical device" is just a bit more expensive than manufacturing a drywall screw.

Aside from the added cost of producing, packing, storing and shipping a sterile product and all of the research and regulatory costs that have to be recouped, there's the tracking systems that must be in place so they can find all the people that have the rusting screws in their leg 20 years later, the insurance costs so they can compensate all the people that have the rusting screws in their leg 20 years later and pay the doctors to replace the screws in all the people that have the rusting screws in their leg 20 years later, etc.

Yes, $1800 is pretty steep, but the "real" number is still going to be magnitudes of order higher than anything you'll find on the shelf at Lowes.

[Han]

Smitty Two wrote in news: [e-mail]:

Must have been really specialscrews. My leg broke - both tibia and fibula, about 2" above the ankle. It happened while on vacation in Holland. About 4 hours after it broke, I was back from the OR and resting in my hospital room. 12 screws in the 2 plates to get both bones to heal. The Xrays aren't clear enough to see the threads on the screws. I got billed ~?7,100 together for both ambulance (?685) and all the surgeon's and hospital costs (3 nights - ?6,450). Exchange rate was ~US$1.30/? at the time, so US$9,230. There was an additional $150 for medications to get me home. So, if you need to break a leg, go to Harderwijk, Holland to the St.Jansdal Hospital .

[willshak]

And even more expensive than "medical devices" are "military devices".

[Vic Smith]

Probably the one I used to tell my wife was phoney as hell. The doll was maybe 10-15 years younger than the guy. Just as you say, they talked but never worked. And never produced a bead of sweat, or got a speck of dirt on their "work" clothes. There was one gal whose show I could watch. Big gal. She rolled up her sleeves and did some work. Can't remember her name.

--Vic

[jamesgangnc]

[e-mail]:

The screws they use for plates are not as complex.

[Han]

jamesgangnc wrote in news:9b7ad8bd-4af6-4640-82cc- [e-mail]:

I was thinking of that, but then, it seemed that the plates were more to align the bones,and the screws to make the pieces of bone become one bone again.

[N8N]

Having set up thread rolling equipment personally a long time ago in a land far far away, I can say that for a screw as you describe, you really want an artiste setting up those roll dies. Having fought with some difficult ones for a simple single pitch fastener, I can easily imagine the time it would take to properly set that up. Or perhaps they were run through two different machines in two steps?

Additionally, I doubt those screws are made of simple carbon steel, rolled and then heat treated. Might be titanium, and I don't know if you can even roll those, might have to be cut on a lathe?

nate

[N8N]

that too; I have an appointment set up to have a plumber come over and do some really basic work on Saturday. A friend of mine asked why (knowing I was handy and had all the tools) my response: "the house is over 60 years old. I'm not paying for his material and expertise; I'm paying for his insurance and truck stock if something goes wrong." Yeah, I can *probably* repack a 63 year old spigot myself, but if something busts, I don't want to be making six runs to the store to fix it.

nate

[Shaun Eli]

Medical screws are probably titanium- they're non-magnetic so they don't screw up an MRI (or, more properly, don't screw you up in an MRI). At least the ones in my elbow are titanium.

[mm]

But how many could you make in a row after you set up the roll dies?

Maybe. That would cost plenty of money.

[Ed Pawlowski]

"N8N" wrote

Good thinking. When my FIL passed away, we'd visit my MIL at the house they lived in for decades. They are 275 miles from us. I'd see things that needed fixing, but would not touch them. I can just see myself on a Sunday morning trying to get the city to come out and turn the water off at the street because nothing else would fully stop the flow. Eventually she sold the house "as is" and moved in with us.

[mm]

See. You should have fixed it, even if you had to stay till Monday.

[Han]

mm wrote in news: [e-mail]:

Hey, mm, Ed is a good guy!! No implied bad-mouthing,please!!

LOL