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Author Topic: Sheet metal screws  (Read 190 times)

Roadturn

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Sheet metal screws
« on: September 23, 2018, 09:47:11 PM »
I don't understand how it works.

On my 71 Tramper Camper the screws holding down the panels are #10 one-inch long. Some anchor in fairly solid. Other feel like all the bite they are getting is the other panel of tin they're overlapping.

I want to replace the (zinc) screws with stainless steel. Do I really need all of them to be an inch long?
1971 Tramper Camper
working on it

dufferDave

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Re: Sheet metal screws
« Reply #1 on: September 23, 2018, 10:09:03 PM »
An inch long?

Sure, if you like to waste 3/4 inch of grip length.

You would almost certainly be just fine to use 3/8 or 1/2 inch smscrews if you are only going through two sheets. If the fasteners seem to fit loosely then you may want to step up one or two screw sizes.

The only reason I can think of for using 1 inch screws would be if you were driving into a wood frame behind the layers of sheet metal, and even then using a smscrew would be the wrong type of threaded fastener to drive into wood.

Gary RV_Wizard

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Re: Sheet metal screws
« Reply #2 on: September 24, 2018, 11:36:33 AM »
The factory probably just used all the same screw lengths on it, for simplicity on the assembly line. You can use whatever suits best. 

Sheet metal screws have the attributes of being self-tapping and fully threaded, so they are typically used to attach metal to wood as well as metal to metal, but there are a zillion variations in screw types. Some of them intended for very specific circumstances.
« Last Edit: September 24, 2018, 11:44:24 AM by Gary RV_Wizard »
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

wackymac

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Re: Sheet metal screws
« Reply #3 on: September 24, 2018, 12:14:51 PM »
I would use the same length that came out.  I NEVER use wood screws for anything.  Either sheet metal screws or drywall/deck screws.
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Utclmjmpr

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Re: Sheet metal screws
« Reply #4 on: September 24, 2018, 01:20:11 PM »
  You can bet the factory screws were placed with an air gun,, and so many will be "spun"  so not holding much because the threads have been compromised.. # 10 screws are VERY large for this application,, most are # 6 or # 8..>>>Dan
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dufferDave

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You are right!
« Reply #5 on: September 24, 2018, 09:46:30 PM »
.... # 10 screws are VERY large for this application,, most are # 6 or # 8.....

But ya gotta do what ya gotta do. If the hole is stripped out from an over-torqued #8, then #10 is the next biggest commonly available that will restore a tight joint.

Or you could use a pop rivet in a dollop of sealant. Simple now for getting a repair completed, but a PITA if you ever have to do further repairs in the future.

Roadturn

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Re: Sheet metal screws
« Reply #6 on: September 25, 2018, 01:34:45 PM »
Thanks, folks. Very helpful advice.
1971 Tramper Camper
working on it

Gary RV_Wizard

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Re: Sheet metal screws
« Reply #7 on: September 25, 2018, 04:08:08 PM »
Heck, I have an old house with aluminum siding and an aluminum framed and paneled screened patio where I've had to go as large as #14 to get a grip in an old screw hole. The originals were #6 or #8, but that was 40 years ago!
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL