Sheet metal screw help

[musigenesis]

I have a piece of plywood that I'm trying to attach to the inside of my rear exit door. I bought self-tapping screws for this and they work as far as attaching the wood to the sheet metal is concerned, but I want to be able to remove and reattach the panel from time to time. When I try to back these self-tapping screws out it appears that the threads made in the hole get stripped out and then the screw just starts spinning.

Do I need to buy a tapper and pre-thread the holes in order to be able to remove and reapply the screws?

 

[BlackJohn]

I have a piece of plywood that I'm trying to attach to the inside of my rear exit door. I bought self-tapping screws for this and they work as far as attaching the wood to the sheet metal is concerned, but I want to be able to remove and reattach the panel from time to time. When I try to back these self-tapping screws out it appears that the threads made in the hole get stripped out and then the screw just starts spinning.

Do I need to buy a tapper and pre-thread the holes in order to be able to remove and reapply the screws?

Have you applied pressure behind the wood and screw as you back it out?
Keep the wood and screwhead in contact and they should back out easily.
Tapping such thin metal likely won't do a lot, not enough meat if you get my drift.


John

 

[CMORGANSKOOL]

I bought self tapping screws from home depot that I can remove and reinstall. They're called self tapping zinc coated metal joist screws I think They come in a black box. I'll take a pic thursday when i'm on the bus. I've used them all over the bus. I think these are the screws. https://www.homedepot.com/p/Everbil...tal-Screw-100-Piece-per-Pack-801042/204275119

Another alternative is to use the screw clip or anchor https://www.webstaurantstore.com/ja...M7VIC6AUDlSg4tHq_QMtuRi1p-icUBjxoCQ6cQAvD_BwE

 

[Danjo-SKO]

What you could do is drill all the way through the door with a 1/4” bit then install bolts that are long enough to go through the door and plywood. Put a nut on the bolt, then the plywood and another nut.

 

[musigenesis]

I bought self tapping screws from home depot that I can remove and reinstall. They're called self tapping zinc coated metal joist screws I think They come in a black box. I'll take a pic thursday when i'm on the bus. I've used them all over the bus. I think these are the screws. https://www.homedepot.com/p/Everbil...tal-Screw-100-Piece-per-Pack-801042/204275119

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Yeah, that's the kind I'm using (only with a gasket washer as well) but they don't seem to be coming out. Maybe that gasket is hosing things?

 

[o1marc]

They strip when you put them in too far. Cinch them snug, everyone hits them till they seat and one more turn strips the threads you made.

 

[peteg59]

Self tappers aren't designed to be installed and removed with any regularity.
The parent metal is too thin to capture any real thread profile so it'll basically wear itself out in one or two on~off cycles.
Something like this could work without drilling through the outer sheetmetal of the door:
https://www.amazon.com/30PCs-Stainl...s=gateway&sprefix=screw+incert,aps,184&sr=8-4

But then you'll have to buy or borrow the insertion tool:
https://www.amazon.com/rivet-thread...=B00RCPVLKE&psc=1&refRID=XHV4T4AAEHH0Q5RAE7TW

Looks like the tool comes with a variety of nuts so depending on how many you need, maybe just the tool "kit" would get you by...?

 

[musigenesis]

I bought self tapping screws from home depot that I can remove and reinstall. They're called self tapping zinc coated metal joist screws I think They come in a black box. I'll take a pic thursday when i'm on the bus. I've used them all over the bus. I think these are the screws. https://www.homedepot.com/p/Everbil...tal-Screw-100-Piece-per-Pack-801042/204275119

Another alternative is to use the screw clip or anchor https://www.webstaurantstore.com/ja...M7VIC6AUDlSg4tHq_QMtuRi1p-icUBjxoCQ6cQAvD_BwE

Huh, I just bought the brand you linked at Home Depot (Everbilt) and these are actually working (thanks!). I'm using #10 (instead of #12, maybe that thread is too coarse for the sheet metal) and I'm also just using the screw to drill through the wood and the metal at once (before I was pre-drilling a larger diameter hole through just the wood).

 

[musigenesis]

Self tappers aren't designed to be installed and removed with any regularity.

Yeah, I think I'm going to change my plan and pre-paint the thing and just attach it once.

 

[TheHubbardBus]

Self tappers aren't designed to be installed and removed with any regularity.
The parent metal is too thin to capture any real thread profile so it'll basically wear itself out in one or two on~off cycles.

Good advice here (as usual).

There are apparently a large variety of female fasteners designed for this type of application. It looks like many won't require the use of special tools. The following link is just an example of the kinds of products available. I haven't used any of these, nor know where to source them, so no endorsement. But this is the kind of solution you want, musigenesis.


http://www.psminternational.com/en/product/product.aspx?typeid=3

 

[CMORGANSKOOL]

If you need a panel just add a hinge and latch. Access panels are always good.

 

[musigenesis]

If you need a panel just add a hinge and latch. Access panels are always good.

This is actually the inside portion of a sandwich (sheet metal outside plywood inside) that covers where the bottom window on my rear exit door used to be, so I don't need regular access to it (hopefully I will never need it).

 

[somewhereinusa]

Self tappers aren't designed to be installed and removed with any regularity.
The parent metal is too thin to capture any real thread profile so it'll basically wear itself out in one or two on~off cycles.
Something like this could work without drilling through the outer sheetmetal of the door:
https://www.amazon.com/30PCs-Stainl...s=gateway&sprefix=screw+incert,aps,184&sr=8-4

But then you'll have to buy or borrow the insertion tool:
https://www.amazon.com/rivet-thread...=B00RCPVLKE&psc=1&refRID=XHV4T4AAEHH0Q5RAE7TW

Looks like the tool comes with a variety of nuts so depending on how many you need, maybe just the tool "kit" would get you by...?

You don't need a special too to install nutserts, it can be done quite easily with a bolt, a nut and a flat piece of steel with a hole in it. I use them quite a bit.

For the OP with the question about removing self tapping sheet metal screws. The ones that have a tip that looks like a drill bit often hard to get all the way out. After it stops coming out the tip seems to get stuck, just pry it out the rest of the way. As others have said though, they aren't really suitable to be taken out and replaced.

At just a quick glance I didn't really see anything on this page that looked like it didn't need some sort of special tool to swedge it into a hole.
http://www.psminternational.com/en/p....aspx?typeid=3

 

[o1marc]

You don't need a special too to install nutserts, it can be done quite easily with a bolt, a nut and a flat piece of steel with a hole in it. I use them quite a bit.

That will work, but I find the inserts are hard metal. This method would be time consuming. Worth getting the tool, I have the same one as below, eBay, $33.

https://www.ebay.com/itm/Rivet-Gun-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

The kit that comes with inserts have a selection of mostly small sizes we would not normally use. I had to purchase a separate 5/16" mandrel.

 

[musigenesis]

For the OP with the question about removing self tapping sheet metal screws. The ones that have a tip that looks like a drill bit often hard to get all the way out. After it stops coming out the tip seems to get stuck, just pry it out the rest of the way. As others have said though, they aren't really suitable to be taken out and replaced.

Yeah, that wasn't the problem - the screw was getting stuck all the way in, with the threads stripping as soon as I tried to back it out.

I think my problem was pre-drilling a hole all the way through the wood. When I then put the self-tapper in, it took forever to get through the sheet metal and then wouldn't come back out. When I instead just use the self-tapper to go through the wood and then the sheet metal, the screw goes straight in and locks. On my test piece I was able to screw them and take them back out three or four times with no problems. I'm not going to push this, though - hopefully I won't ever have to take them out again.

 

[peteg59]

You don't need a special too to install nutserts, it can be done quite easily with a bolt, a nut and a flat piece of steel with a hole in it. I use them quite a bit.[/URL]

You might do that on a flat panel and get away without using the correct tool, maybe, but in the OP's situation he's looking to screw into the rear E exit door. A 2 wall panel...

 

[musigenesis]

You might do that on a flat panel and get away without using the correct tool, maybe, but in the OP's situation he's looking to screw into the rear E exit door. A 2 wall panel...

I don't follow you - my rear exit door (the part I'm attaching to, at least) is flat.

 

[Iceni John]

Rivnuts and Jacknuts may work just fine for you - if you use aluminum Rivnuts you can use the cheapo Harbor Fright tool, and for Jacknuts the cheap Marson tool works fine. If you want to use SS Rivnuts you'll definitely need the better tools. And if you really want something to stay in place, use the Bollhof PlusNut threaded anchors - they're serious!

John

 

[peteg59]

I don't follow you - my rear exit door (the part I'm attaching to, at least) is flat.

Your rear door is made up of 2 panels. The original yellow painted outer skin, and the tan, blue, or green painted inner skin, making a sandwich of air in between.

If you were to drill a hole through your inner door, you'd hit a second metal barrier you'd have to drill through to go all the way through the door.

Make sense?

 

[musigenesis]

Your rear door is made up of 2 panels. The original yellow painted outer skin, and the tan, blue, or green painted inner skin, making a sandwich of air in between.

If you were to drill a hole through your inner door, you'd hit a second metal barrier you'd have to drill through to go all the way through the door.

Make sense?

Well, of course I know how my door is constructed - the reason I'm using self-tappers to attach my plywood panel is because I can't go all the way through the outer skin. I think your point was relevant to the rivnuts discussion (which I haven't been following because I got the self-tapping screws to work properly).

I am interested in learning how those work, but fortunately I don't need them for this particular bit.