FWIW, I put some scaffolding together with SPAX screws a while back. They worked fine and I highly recommend them. When I went to take it down things went as planned--other than a few buggered up heads they came right out. Then I went to knock some more together using the same screws and was surprised at how many of them broke going in--not one broke the first time but maybe 1 in 10 broke the second time.
On that basis I wouldn't bother trying to reuse screws.
So? Lots of people thing screwing is fun.
BINGO!
I couldn't agree more. I can't imagine taking a fence apart to save some old screws. I am tight, but not that tight.
Right on the spot as usual, Leon.
Robert
It is my understanding that, in the pioneering days, people would take apart whole houses when they moved to save the nails (for the next one)!
Bill
Back then each nail had to be hand forged. IIRC, they'd burn the old house down and sift through the ashes.
How many of us as kids had the job of straightening the bent nails to be re-used?
Dave in Houston
"Dave in Houston" wrote
My grandfather was a great junkman/recycler. I built a couple garages with him. Every nail was bent, recycled and in big buckets. We pullled the nail out, straightened it and drove it into the wood.
Dave in Houston wrote: ...
...
More to the point, how many still _have_ the job? :)
I reuse stuff routinely, including structural material and nails, screws, etc., as long as still sound.
For one thing, nails >20 years old are far better straightened than most new ones and old finish nails actually have a real dimple for the nail set and a neat, finished round head (instead of A sorry clipped chunk of soft wire w/ a blob mashed onto the end for a head... :( )
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Thought about that when I built my deck and only used screws that were = guaranteed not to rust, bust, or spring leaks.
Not even 10 years into it some boards needed replacing, cedar does not = last that long either, the screws were just about a rotted out as the = wood. That is why SS Screws in the fence.
BTB, all deck replacements are SS as well.
SWMBO, decreed that the gates in the fence needed to be lighter. I = backed out the screws, cut the wood in half, reinstalled the screws and = rehung lighter gates. SWMBO is ecstatic, I have a lot of new Brownie = Points and all it cost was some manual labour. Can't beat the cost.
P D Q
I typically use screws, but find nails better for molding. Nails can pop a little, but there are applications where that is not a concern. It is rare that I use a nail/screw for fine furniture, but they have their place too.
They are not a general purpose fastener, esp not for any kind of serious load. Drywall screws are hard & brittle....they pretty much suck but do work for drywall.
Drywall screws have ruined countless redwood or cedar fences. The fence might look ok when you drive away but a few months later the face boards will be streaked with rust.
I wonder how many kitchen cabinets installed in the last 15 years with drywall screws will come down in the next big SoCal earthquake.
Don't be hack; use drywall screws for drywall. And get some decent screws for general work.
cheers Bob
No. I mean it takes 16,000lbs to shear a nail.
Have you seen those tests they do with the giant machines that hold piece of whatever in one jaw while the other jaw pushes or pulls or tears the other end. This shear test has both jaws right next to each other, coplanar, while one jaw moves down, perpendicular to the length of the nail.
I'm guessing that has to do with how much weight is allowed, by code, to be held by a single nail. That has nothing to do with the shear strength limit of the nail. If the two were the same, then every house would collapse before finished.
You and I can exert much more than 150lbs with our bare hands.
A 16d nail has a nominal diameter of .162 inches. That gives an area of about 0.02 inches.
To get 16,000 pounds out of that area would require steel that could take a sheer stress of 800,000 psi. This is beyond the range of even exotic ultra high strength steels, let alone the the cheap junk that is typically used in modern nails. For a typical mild steel the shear strength woulde be around
60,000 psi, so multiply that by .02 and you have 1200 pounds.
I don't get what psi has to do with anything. You put half a nail in a clamp, the other half of the clamp moves down with the weight of 8 tons. That is well within many testing machines. They test steel beams and concrete sections way, way, beyond that weight.
IN ANY CASE, this irrelevant detail has nothing to do with my original point that a nail is many, many, many, many times stronger that a fu@&!ng screw! forest, trees? hello? anyone home?
Lighten up, Mike. You're talking about relative strengths, which inherently incorporates the differing material properties. It is not an irrelevant detail to correct an obvious error in shear strength, as this is what we are talking about, and shear strength is figured in PSI, which incorporates the area. It is not a question of whether a testing machine can exert such force, it is a question of whether the item being tested has the material properties to withstand that force.
Your point that a common nail is stronger in shear than a drywall screw is not coming under fire. It is the 16,000 lbs thing. Here's a little video for you to back up your point:
There are many reasons to use screws, but there are also reasons not to.
R
So... You're saying nails and screws shouldn't be used in forests or trees due to them being ... what?
Seriously though, I got your point about nails being stronger than screws. It has a lot to do with the fact there are grooves in a screw.
As a machine builder, I know all to well that the weakest point on a shaft or spindle is almost always where there is an undercut or snap ring groove, etc. You'd be amazed at how often something fails because a machined sharp angle or right angle is there on a steel or aluminum part instead of a machined curve of some sort.
Screws have lots of these stress points and thus break more easily. However, they do avoid coming loose with vibration, are more easily used to "suck" parts tight and all that jazz.
The strength of nails is way beyond what almost any home engineering job would need. If you don't believe me, drive some small finishing nails deep enough to be 50% in one piece of strong wood and 50% in the other... Maybe use two or three at most. Now try to "sheer" the nails by whatever manual method (toolless) you can think of. I bet they bend and come loose before you break any of them unless you bend them back and forth.
The screws will be even harder to break because you won't be able to work them loose by hand in most cases.
So... Depending on where you live, what you need the fastener for, etc. determines which to use. Personally, I like doing things the "right way" the first time which means the quality way even if there is some loss or waste.
Would I build a farm fence with screws? Probably not. Would I build a deck with nails? Probably not except for maybe the framework - but even then, I'd probably opt for screws here in NJ where we get hot, cold, wet, dry and generally a lot of traffic.
Just for grins... Let's assume your screw is similar to a 1/4-20 threaded bolt... That bolt, in the cheapest grade often used has a maximum weight bearing capacity of 2350 lbs. The suggested limit is lower because of vibration and other movement and is generally recognized to be around
200-300 lbs. That means a man my size can hang from a 1/4"-20 bolt all day long and pretty much move around all I want.A 1/2" bolt is approximately 450% stronger on average.
Now, let's presume the screw's shank is 1/8" diameter and similar in quality to the Grade 2 bolt... That means that it is probably capable of holding
500 lbs or so with a safety rating of around 40-50 lbs.Given the fact that screws are not machined out of quality materials, I'd divide those numbers by two for the average steel screw. The numbers will be slightly higher for a nail as there are no grooves.
This is all based on average quality bolts (Grade 2). Grage 5, Grade 8 and even higher grades for aircraft use, etc. are significantly stronger with a
1/4" bolt sometimes having a weight bearing capacity near 10,000 lbs.Bottom line? Unless you are using big fat "gutter nails" made of steel, you're not going to have a 16,000 lb. shear limit on the average nail.
What trees? What forest?
Regards, Joe Agro, Jr. (800) 871-5022
01.908.542.0244 Automatic / Pneumatic Drills:
I still swear I've seen that number and it surprised the crap out of me, too. I've been looking through some of my textbooks and publications, but don't have any more time to look.
-MIKE- wrote: ...
Then you don't understand what shear is all about...
consider the nail to be a small-diameter round beam.
I don't follow what you're trying to describe, anyway, and sounds like perhaps you're confusing tensile strength w/ shear...
How do you reach that astounding conclusion in general?
The relative strength of a nail and a screw will depend on their relative sizes and the material of which each is made and has little, if anything, to do w/ the difference between simply being a nail or screw...
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Drive a common 16d nail 2/3 into a 2x4. Do the same with a common screw of the same diameter shaft.
Take sledge hammer and swing it directly down on the nail. It will bend. Do the same to the screw. It will "shear" right off.
More to do with what's done to the steel during manufacture. The drywall screw is hardened and thus brittle.
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