Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Default Sheet metal screws vs sheet rock screws....

Awl --

In metal, 16 ga. Related to my doorbuck Q, figgered I'd narrow it down a
little

How do the two compare, both fine and coarse thread? Loads would be mostly
in shear, but there could be some pullout forces.

I've never seen fine/coarse thread sheet metal screws, just in sheet rock
screws. Do they exist?

I'm assuming doorbucks are 16 ga.

--
EA


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Default Sheet metal screws vs sheet rock screws....

"Existential Angst" wrote:

I've never seen fine/coarse thread sheet metal screws, just in sheet rock
screws. Do they exist?


Fine pitch sheet rock screws are for metal studs. What was the question again?

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
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Default Sheet metal screws vs sheet rock screws....

You haven't said what the application is. Roger may feel like he wasted his
time responding, if you're asking about mounting the chin-up bars you've
been talking about lately, but his post is informative.

You've been around enough, and it should be apparent to you that you need to
mention what it is, you're asking about.
There isn't much point in responding to questions when the person asking is
being vague, IMO.. many times it takes a couple of days before the details
are eventually presented.

If this is the same question asked again, about mounting the chin-up bar..
what're ya gonna do, keep asking until someone says it's a good idea to use
DW screws?

I don't like using DW screws for much of anything other than drywall. Ever
notice that sharp "snap" when they're overtightened?
The common DW screws are hard and brittle, and will break suddenly under
certain circumstances.
I definitely wouldn't use them in metal, but that's me.

You should be examining real screws.. self-tapping or other style for
mounting a chin-up bar.
Generally, the most secure method will be to get as many threads as possible
into the thickness of the material that the part is being attached to, which
means a fine-thread, self-tapping type screw, most likely (or nut-sert type
products that were mentioned previously).
If the fasteners that you recommend fail, the user could sustain a
laceration, or possibly brain trauma. Good luck fending off the lawyers.

If you're trying to come up with a simple solution for the end user to mount
a product that you intend to sell, safety should be the primary factor. If
some doofus can't install the product, then they'll return it to the seller,
or improvise a solution (not your problem).

--
WB
..........



"Existential Angst" wrote in message
...
Awl --

In metal, 16 ga. Related to my doorbuck Q, figgered I'd narrow it down a
little

How do the two compare, both fine and coarse thread? Loads would be
mostly in shear, but there could be some pullout forces.

I've never seen fine/coarse thread sheet metal screws, just in sheet rock
screws. Do they exist?

I'm assuming doorbucks are 16 ga.

--
EA



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Default Sheet metal screws vs sheet rock screws....

"Wild_Bill" wrote in message
...
You haven't said what the application is. Roger may feel like he wasted
his time responding, if you're asking about mounting the chin-up bars
you've been talking about lately, but his post is informative.

You've been around enough, and it should be apparent to you that you need
to mention what it is, you're asking about.
There isn't much point in responding to questions when the person asking
is being vague, IMO.. many times it takes a couple of days before the
details are eventually presented.

If this is the same question asked again, about mounting the chin-up bar..
what're ya gonna do, keep asking until someone says it's a good idea to
use DW screws?

I don't like using DW screws for much of anything other than drywall. Ever
notice that sharp "snap" when they're overtightened?
The common DW screws are hard and brittle, and will break suddenly under
certain circumstances.
I definitely wouldn't use them in metal, but that's me.

You should be examining real screws.. self-tapping or other style for
mounting a chin-up bar.
Generally, the most secure method will be to get as many threads as
possible into the thickness of the material that the part is being
attached to, which means a fine-thread, self-tapping type screw, most
likely (or nut-sert type products that were mentioned previously).
If the fasteners that you recommend fail, the user could sustain a
laceration, or possibly brain trauma. Good luck fending off the lawyers.

If you're trying to come up with a simple solution for the end user to
mount a product that you intend to sell, safety should be the primary
factor. If some doofus can't install the product, then they'll return it
to the seller, or improvise a solution (not your problem).


Well, the real Q is along the lines you've mentioned.
"Real" sheetmetal screws, such as hvac ductwork, really can't put ANY
threads in the material itself, ductwork is just too thin. I always thought
the tek-type screws were the wrong thread design for this application.

Even 16 ga is sort of thin, but chassis screws seemed to have been developed
for this purpose, which is why I mentioned them in the earlier thread, but
no one picked up on this. Roger touched on these, which I'll continue in a
response to him.

Chassis screws seem to be a discontinued item, so I wonder how practical,
under load conditions (not really found on radio chassis) threads in thin
material is.

Which is why I'm asking about threading vs. *binding* of thin material
together, via a larger ratio of major to minor diameters.

I keep mentioning SR screws, because the coarse thread screws really seem to
have a much better major/minor diam ratio, and I believe I've seen
specialty-type screws that used this strategy.

If the answer is, STFU and buy a box of self-drilling sheet metal screws,
then I'll do it, but this never really seemed to be the "right" solution, on
basic geometrical/mechanical grounds, for the above threading reasons.
--
EA


--
WB
.........



"Existential Angst" wrote in message
...
Awl --

In metal, 16 ga. Related to my doorbuck Q, figgered I'd narrow it down a
little

How do the two compare, both fine and coarse thread? Loads would be
mostly in shear, but there could be some pullout forces.

I've never seen fine/coarse thread sheet metal screws, just in sheet rock
screws. Do they exist?

I'm assuming doorbucks are 16 ga.

--
EA





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Default Sheet metal screws vs sheet rock screws....

It occurred to me that the users' weight shouldn't be supported by screws
(shear), but instead, by welded pins on the device's brackets that protrude
thru holes drilled in the door frame.. with the screws providing secure
attachment to the frame.

As for DW screw's binding, that's appropriate in wood or softer materials..
essentially a result of surface area contact and displaced material. Steel
doesn't compress.

As for the ductwork comment, those screws aren't intended to support loads,
only to keep the joint from separating. Ducts are generally suspended by
various types of straps and brackets.
Basically, all that sheetmetal screws need to do is pierce a hole and then
be driven in. The steel is soft and thin so very little cutting action is
taking place.
In thicker steel, even with a drilled pilot hole, most common screws (DW or
SM) will not cut threads or displace the metal enough to attach something
securely.
I know this from experience.. nearly all common screws will break before
they cut or displace thicker steel.

When I mentioned fine threads, I was thinking 32 TPI, not the difference
between sheetmetal screws and DW screws (or fine-coarse versions of each),
but forgot to mention that.

I suspect that 4 welded 1/4" pins (each side) would probably be more than
adequate for supporting most folks' weight. This would most likely require a
template for the installer, and fairly accurately positioned holes for the
pins and screws.
I think the nut-sert fastening system would probably be best, but probably
too complicated for many folks to install. They don't absolutely require a
special installation tool.. they can be installed with a stud and washer,
nut and wrench.

Aside from the methods of fastening a device to a door frame, many folks
probably wouldn't like the idea of not being able to close a door because
this thing's installed.
If they have a door with a steel frame, it's likely for security.

--
WB
..........


"Existential Angst" wrote in message
...

You should be examining real screws.. self-tapping or other style for
mounting a chin-up bar.
Generally, the most secure method will be to get as many threads as
possible into the thickness of the material that the part is being
attached to, which means a fine-thread, self-tapping type screw, most
likely (or nut-sert type products that were mentioned previously).
If the fasteners that you recommend fail, the user could sustain a
laceration, or possibly brain trauma. Good luck fending off the lawyers.


Well, the real Q is along the lines you've mentioned.
"Real" sheetmetal screws, such as hvac ductwork, really can't put ANY
threads in the material itself, ductwork is just too thin. I always
thought the tek-type screws were the wrong thread design for this
application.

Even 16 ga is sort of thin, but chassis screws seemed to have been
developed for this purpose, which is why I mentioned them in the earlier
thread, but no one picked up on this. Roger touched on these, which I'll
continue in a response to him.

Chassis screws seem to be a discontinued item, so I wonder how practical,
under load conditions (not really found on radio chassis) threads in thin
material is.

Which is why I'm asking about threading vs. *binding* of thin material
together, via a larger ratio of major to minor diameters.

I keep mentioning SR screws, because the coarse thread screws really seem
to have a much better major/minor diam ratio, and I believe I've seen
specialty-type screws that used this strategy.

If the answer is, STFU and buy a box of self-drilling sheet metal screws,
then I'll do it, but this never really seemed to be the "right" solution,
on basic geometrical/mechanical grounds, for the above threading reasons.
--
EA





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Default Sheet metal screws vs sheet rock screws....

"Existential Angst" wrote:

OK, my app has nothing to do with doors or frame installation, but rather
mounting something (a chinup type bar) TO a door frame.



Must be a tall door, a short EA, or bent knees.

Why not just make a pull up bar out of pipe and cement it in outside?

Two pressure treated posts, drill a cross hole for the pipe to fit through both and two
bags of premixed concrete to fix it in the holes. Takes up no space IN your home.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
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Posts: 387
Default Sheet metal screws vs sheet rock screws....


"Existential Angst" wrote in message
...
"Wild_Bill" wrote in message
...
You haven't said what the application is. Roger may feel like he wasted
his time responding, if you're asking about mounting the chin-up bars
you've been talking about lately, but his post is informative.

You've been around enough, and it should be apparent to you that you need
to mention what it is, you're asking about.
There isn't much point in responding to questions when the person asking
is being vague, IMO.. many times it takes a couple of days before the
details are eventually presented.

If this is the same question asked again, about mounting the chin-up
bar.. what're ya gonna do, keep asking until someone says it's a good
idea to use DW screws?

I don't like using DW screws for much of anything other than drywall.
Ever notice that sharp "snap" when they're overtightened?
The common DW screws are hard and brittle, and will break suddenly under
certain circumstances.
I definitely wouldn't use them in metal, but that's me.

You should be examining real screws.. self-tapping or other style for
mounting a chin-up bar.
Generally, the most secure method will be to get as many threads as
possible into the thickness of the material that the part is being
attached to, which means a fine-thread, self-tapping type screw, most
likely (or nut-sert type products that were mentioned previously).
If the fasteners that you recommend fail, the user could sustain a
laceration, or possibly brain trauma. Good luck fending off the lawyers.

If you're trying to come up with a simple solution for the end user to
mount a product that you intend to sell, safety should be the primary
factor. If some doofus can't install the product, then they'll return it
to the seller, or improvise a solution (not your problem).


Well, the real Q is along the lines you've mentioned.
"Real" sheetmetal screws, such as hvac ductwork, really can't put ANY
threads in the material itself, ductwork is just too thin. I always
thought the tek-type screws were the wrong thread design for this
application.

Even 16 ga is sort of thin, but chassis screws seemed to have been
developed for this purpose, which is why I mentioned them in the earlier
thread, but no one picked up on this. Roger touched on these, which I'll
continue in a response to him.

Chassis screws seem to be a discontinued item, so I wonder how practical,
under load conditions (not really found on radio chassis) threads in thin
material is.

Which is why I'm asking about threading vs. *binding* of thin material
together, via a larger ratio of major to minor diameters.

I keep mentioning SR screws, because the coarse thread screws really seem
to have a much better major/minor diam ratio, and I believe I've seen
specialty-type screws that used this strategy.

If the answer is, STFU and buy a box of self-drilling sheet metal screws,
then I'll do it, but this never really seemed to be the "right" solution,
on basic geometrical/mechanical grounds, for the above threading reasons.
--
EA

A good threadsert that will accept a machine screw will be much stronger
than sheet metal screws.


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Default Sheet metal screws vs sheet rock screws....


"Existential Angst" wrote in message
...

OK, my app has nothing to do with doors or frame installation, but rather
mounting something (a chinup type bar) TO a door frame.


Here is how I would install a chin up bar in a steel door frame.

Weld plates to the end of the bar so the over all length is the same as the
space between the frame.

The plates need only be as wide as the door stop section of the frame.

The plates should have 4 1/8 inch holes in each.

Position the bar, drill one hole on one side and pop rivet.

Level the bar and drill one hole in the other side, rivet.

Drill three more holes in each side and rivet.

The project is now done. With 8 rivets in sheer it will not go anywhere.

--

__
Roger Shoaf

Important factors in selecting a mate:
1] Depth of gene pool
2] Position on the food chain.





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Posts: 539
Default Sheet metal screws vs sheet rock screws....

"Wild_Bill" wrote in message
...
It occurred to me that the users' weight shouldn't be supported by screws
(shear), but instead, by welded pins on the device's brackets that
protrude thru holes drilled in the door frame.. with the screws providing
secure attachment to the frame.

As for DW screw's binding, that's appropriate in wood or softer
materials.. essentially a result of surface area contact and displaced
material. Steel doesn't compress.

As for the ductwork comment, those screws aren't intended to support
loads, only to keep the joint from separating. Ducts are generally
suspended by various types of straps and brackets.


An excellent insight.
In fact, it's not the screw itself that can't support the load per se, it's
that in sheet metal, the screw is *improperly cantilevered* to take a lot of
shear, so twisting will occur. visavis screws in wood.

The shear, tho, is actually addressed somewhat along the lines of the
pinning suggestions, so really all's I need is pullout resistance.
Toward that end, I think the answer lies in "deep thread" screws, which I'll
query in a separate thread.
--
EA




Basically, all that sheetmetal screws need to do is pierce a hole and then
be driven in. The steel is soft and thin so very little cutting action is
taking place.
In thicker steel, even with a drilled pilot hole, most common screws (DW
or SM) will not cut threads or displace the metal enough to attach
something securely.
I know this from experience.. nearly all common screws will break before
they cut or displace thicker steel.

When I mentioned fine threads, I was thinking 32 TPI, not the difference
between sheetmetal screws and DW screws (or fine-coarse versions of each),
but forgot to mention that.

I suspect that 4 welded 1/4" pins (each side) would probably be more than
adequate for supporting most folks' weight. This would most likely require
a template for the installer, and fairly accurately positioned holes for
the pins and screws.
I think the nut-sert fastening system would probably be best, but probably
too complicated for many folks to install. They don't absolutely require a
special installation tool.. they can be installed with a stud and washer,
nut and wrench.

Aside from the methods of fastening a device to a door frame, many folks
probably wouldn't like the idea of not being able to close a door because
this thing's installed.
If they have a door with a steel frame, it's likely for security.

--
WB
.........


"Existential Angst" wrote in message
...

You should be examining real screws.. self-tapping or other style for
mounting a chin-up bar.
Generally, the most secure method will be to get as many threads as
possible into the thickness of the material that the part is being
attached to, which means a fine-thread, self-tapping type screw, most
likely (or nut-sert type products that were mentioned previously).
If the fasteners that you recommend fail, the user could sustain a
laceration, or possibly brain trauma. Good luck fending off the lawyers.


Well, the real Q is along the lines you've mentioned.
"Real" sheetmetal screws, such as hvac ductwork, really can't put ANY
threads in the material itself, ductwork is just too thin. I always
thought the tek-type screws were the wrong thread design for this
application.

Even 16 ga is sort of thin, but chassis screws seemed to have been
developed for this purpose, which is why I mentioned them in the earlier
thread, but no one picked up on this. Roger touched on these, which I'll
continue in a response to him.

Chassis screws seem to be a discontinued item, so I wonder how practical,
under load conditions (not really found on radio chassis) threads in thin
material is.

Which is why I'm asking about threading vs. *binding* of thin material
together, via a larger ratio of major to minor diameters.

I keep mentioning SR screws, because the coarse thread screws really seem
to have a much better major/minor diam ratio, and I believe I've seen
specialty-type screws that used this strategy.

If the answer is, STFU and buy a box of self-drilling sheet metal screws,
then I'll do it, but this never really seemed to be the "right" solution,
on basic geometrical/mechanical grounds, for the above threading reasons.
--
EA





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