Wood and Steel

On Feb 26, 11:02=A0am, julvr <[email protected]> wrote:
> I'm creating some custom hardware for a project I am doing --
> specifically a heavy duty hinge. =A0I'm thinking of using steel, as it
> is cheaper than aluminum, and stronger to boot. =A0Should I be worried
> about rust? =A0(this is for indoors only).
>
> Also, does anyone know how much wieght a .25" piece of steel can
> withstand before shearing?
>
> Thanks,
>
> John

A lot. It will depend on your plane of forces, and clearances, and a
bunch of other parameters, but the tensile strength of "typical" steel
is around 60kpsi.

If you are making a hinge for some sort of door, the steel is probably
not going to fail. It depends on how you plan to form the loops. Or
are you thinking an interleaved plate and pinning the whole thing? In
which case it will be the shear strength of the pin, not the plate.
Or...

If this is strictly indoors, and not a humid environment rust should
not be a big concern. But if you would be concerned about staining, a
simple blackening would be good. Or a clear coat if you like the
natural steel look.

JW

Tue, Feb 26, 2008, 9:02am (EST-3) [email protected] (julvr) doth posteth
thusly:
I'm creating <snip> Should I be worried about rust? (this is for indoors
only).
Also, does anyone know how much wieght a .25" piece of steel can
withstand before shearing?

How should I know if you should be worried about rust? Me, I'd
paint whatever and not worry about it.

A 25" piece of steel what? Tubing, flat sheet metal, your hinge?

I'd say do like you've been advised, go ask the metalworking guys.
But when you do, give them DETAILS, don't leave all the details out like
you did here. On the other hand maybe those guys read minds, I don't.



JOAT
10 Out Of 10 Terrorists Prefer Hillary For President - Bumper Sticker

I do not have a problem with a woman president - except for Hillary.

On Feb 26, 2:14=A0pm, julvr <[email protected]> wrote:
> Sorry, I guess I didn't mention the .25" steel was the intended
> diameter of the pin. =A0After some looking I worked it out that a .25"
> steel rod has a shear strength of about 350 lbs -- more than enough
> (especially as each hinge has two joints, and there are two hinges,
> which would mean that I have an effective shear strength of about 1400
> lbs. =A0I only need about 300lbs, which means I could concivably use
> Aluminum as well).
>
> As far as lacquer goes, I think the stress between the pin and the
> housing will remove any finish I attempt to put on, though thanks for
> the suggestion. =A0I may try to find a coated metal rod to use as the
> pin, though this still doesn't help me with the housing (which needs
> to be drilled). =A0I'm hoping that maybe a bit of grease will help here
> -- if not, I'll have to replace it down the road.
>
> John

Send it out an have it plated. You will pay a premium for a small
quantity of a couple pieces but if its a concern, which it seems to
be, a few bucks for plating wouldnt be out of line.

Mark

On Tue, 26 Feb 2008 09:02:51 -0800 (PST), julvr <[email protected]>
wrote:

>I'm creating some custom hardware for a project I am doing --
>specifically a heavy duty hinge. I'm thinking of using steel, as it
>is cheaper than aluminum, and stronger to boot. Should I be worried
>about rust? (this is for indoors only).
>

For most environments, no. But a quick coat of clear lacquer will
help prevent rust.

>Also, does anyone know how much wieght a .25" piece of steel can
>withstand before shearing?
>

Need more information. Google "Strength of Materials." Keep in mind
that not all steel has the same strength.

>Thanks,
>
>John

Sorry, I guess I didn't mention the .25" steel was the intended
diameter of the pin. After some looking I worked it out that a .25"
steel rod has a shear strength of about 350 lbs -- more than enough
(especially as each hinge has two joints, and there are two hinges,
which would mean that I have an effective shear strength of about 1400
lbs. I only need about 300lbs, which means I could concivably use
Aluminum as well).

As far as lacquer goes, I think the stress between the pin and the
housing will remove any finish I attempt to put on, though thanks for
the suggestion. I may try to find a coated metal rod to use as the
pin, though this still doesn't help me with the housing (which needs
to be drilled). I'm hoping that maybe a bit of grease will help here
-- if not, I'll have to replace it down the road.

John

"julvr" <[email protected]> wrote in message
news:723ac8d5-9cbd-4a87-bf7c-94e22576c878@s13g2000prd.googlegroups.com...
> I'm creating some custom hardware for a project I am doing --
> specifically a heavy duty hinge. I'm thinking of using steel, as it
> is cheaper than aluminum, and stronger to boot. Should I be worried
> about rust? (this is for indoors only).
>
> Also, does anyone know how much wieght a .25" piece of steel can
> withstand before shearing?

1. Use stainless if you are worried about rust... But don't try to drill it
until you check out the RPM rate calculations at
http://www.multi-drill.com/drill-speed-chart.htm. Stainless basically can
NOT be drilled without some sort of oil coolant on the bit... Unless you
have a machine that spins at 25 RPM. :)

2. Shearing? Lots... Maybe. Depends on how it will be taking the load.
All at once in a bust of energy or hanging weight, etc... If it shears,
aluminum wouldn't have worked for you nayhow unless it was 3X the size in
all dimensions (general rule of thumb comment, not set law...)

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

You can always blacken the steel and clear coat it to protect it.

Kate

"julvr" <[email protected]> wrote in message
news:723ac8d5-9cbd-4a87-bf7c-94e22576c878@s13g2000prd.googlegroups.com...
I'm creating some custom hardware for a project I am doing --
specifically a heavy duty hinge. I'm thinking of using steel, as it
is cheaper than aluminum, and stronger to boot. Should I be worried
about rust? (this is for indoors only).

Also, does anyone know how much wieght a .25" piece of steel can
withstand before shearing?

Thanks,

John

On Feb 27, 2:23=A0pm, [email protected] (Larry W) wrote:
> In article <[email protected]=
om>,
>
> julvr =A0<[email protected]> wrote:
> >Sorry, I guess I didn't mention the .25" steel was the intended
> >diameter of the pin. =A0After some looking I worked it out that a .25"
> >steel rod has a shear strength of about 350 lbs -- more than enough
> >John
>
> I think your calculation is a little off. As I recall a rough estimate
> of shear strengh of steel is 2/3 of tensile strength. Tensile strength
> of mild steel about 70,000 psi, someone correct me if I'm wrong,
> but I'm sure I'm in the ballpark for magnitude. Area of 1/4" circle
> is pi*0.25^2=3D about 0.19 sq in. 70000 * 2/3 * .19 =3D about 8800 lbs,
> That seems a little high perhaps, but 350 pounds is sure not going
> to shear a 1/4 bolt.
>
> --
> =A0 =A0There are no stupid questions, but there are lots of stupid answers=
.
>
> =A0 =A0 =A0Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar=
. org

You need to use the radius rather than the diameter, Larry, which
would drop it to about 2200 lbs, but it's still far more than adequate
for his purpose.

John Martin

On Feb 26, 12:02=A0pm, julvr <[email protected]> wrote:
> I'm creating some custom hardware for a project I am doing --
> specifically a heavy duty hinge. =A0I'm thinking of using steel, as it
> is cheaper than aluminum, and stronger to boot. =A0Should I be worried
> about rust? =A0(this is for indoors only).
>
> Also, does anyone know how much wieght a .25" piece of steel can
> withstand before shearing?
>
> Thanks,
>
> John

Before your question can be answered, its dimensions must be known as
well as the type of steel. If your concerned with corrosion on your
hinge, consider stainless or having the item plated.

Joe G

As it turns out, I was using half of the radius :). I was also using
a tensile yeild strength of 40000 psi (which is the pressure at which
mild steel deforms)...

Based on the updated calculations, Aluminum should work fine, and then
there are no rust issues -- A tad pricier, but I'll swallow the costs.

Of intersest, The shear strength of a size 8 steel screw should be
about 320 lbs. That's a lot stronger than I thought! (of course, if
you overtighten the screw, then it might be less, as then you have
introduced a tensile force... and of course, the shear strength would
be increased by the friction of the two materials being held
together... Hmmm.. not that useful of a number after all... :) )

John

At the risk of sounding like a smartass...
if you put a wee bit of oil or white grease on the hinge, it will not only
swing smoother but it will resist corrosion.

Another nice finish on steel is an oil finish. Pretty common too.

Kate

"julvr" <[email protected]> wrote in message
news:[email protected]...
Sorry, I guess I didn't mention the .25" steel was the intended
diameter of the pin. After some looking I worked it out that a .25"
steel rod has a shear strength of about 350 lbs -- more than enough
(especially as each hinge has two joints, and there are two hinges,
which would mean that I have an effective shear strength of about 1400
lbs. I only need about 300lbs, which means I could concivably use
Aluminum as well).

As far as lacquer goes, I think the stress between the pin and the
housing will remove any finish I attempt to put on, though thanks for
the suggestion. I may try to find a coated metal rod to use as the
pin, though this still doesn't help me with the housing (which needs
to be drilled). I'm hoping that maybe a bit of grease will help here
-- if not, I'll have to replace it down the road.

John

"julvr" <[email protected]> wrote in message
news:723ac8d5-9cbd-4a87-bf7c-94e22576c878@s13g2000prd.googlegroups.com...
> I'm creating some custom hardware for a project I am doing --
> specifically a heavy duty hinge. I'm thinking of using steel, as it
> is cheaper than aluminum, and stronger to boot. Should I be worried
> about rust? (this is for indoors only).
>
> Also, does anyone know how much wieght a .25" piece of steel can
> withstand before shearing?
>
> Thanks,
>
> John

try rec.crafts.metalworking

In article <[email protected]>,
julvr <[email protected]> wrote:
>Sorry, I guess I didn't mention the .25" steel was the intended
>diameter of the pin. After some looking I worked it out that a .25"
>steel rod has a shear strength of about 350 lbs -- more than enough
>John


I think your calculation is a little off. As I recall a rough estimate
of shear strengh of steel is 2/3 of tensile strength. Tensile strength
of mild steel about 70,000 psi, someone correct me if I'm wrong,
but I'm sure I'm in the ballpark for magnitude. Area of 1/4" circle
is pi*0.25^2= about 0.19 sq in. 70000 * 2/3 * .19 = about 8800 lbs,
That seems a little high perhaps, but 350 pounds is sure not going
to shear a 1/4 bolt.


--
There are no stupid questions, but there are lots of stupid answers.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

In article <93050ce1-104a-4e77-aeaa-3e27ec1f37e3@o77g2000hsf.googlegroups.com>,
John Martin <[email protected]> wrote:
>On Feb 27, 2:23 pm, [email protected] (Larry W) wrote:
<...snipped...>
>> but I'm sure I'm in the ballpark for magnitude. Area of 1/4" circle
>> is pi*0.25^2= about 0.19 sq in. 70000 * 2/3 * .19 = about 8800 lbs,
>> That seems a little high perhaps, but 350 pounds is sure not going
>> to shear a 1/4 bolt.
>>
>> --
>
>You need to use the radius rather than the diameter, Larry, which
>would drop it to about 2200 lbs, but it's still far more than adequate
>for his purpose.
>
>John Martin

Oops! Good thing I'm not an engineer!


--
When the game is over, the pawn and the king are returned to the same box.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org

"julvr" <[email protected]> wrote in message
news:723ac8d5-9cbd-4a87-bf7c-94e22576c878@s13g2000prd.googlegroups.com...
> I'm creating some custom hardware for a project I am doing --
> specifically a heavy duty hinge. I'm thinking of using steel, as it
> is cheaper than aluminum, and stronger to boot. Should I be worried
> about rust? (this is for indoors only).
>
> Also, does anyone know how much wieght a .25" piece of steel can
> withstand before shearing?
>
> Thanks,
>
> John
Of course I could determine that if I only knew the rest of the dimensions.
You left out a few things to say the least.
However, as I am retired, I don't do that sort of thing anymore.

Jim