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Question On Tapping 1/8" Aluminum

This works well for setting steel rivnuts, drill the hole to tightly fit the rivnut. I wouldnt want to do 100 this way but it is fine for a few
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Thank you. I've got 10 to do....on the ceiling. I'm tempted to buy a HF tool for $25. Also wondering if I should try and use self-tapping screws and hope that installing and removing won't destroy the threads. If that happened I could then do the nutserts. Ah, the never ending project. At this rate it will be Spring and warm weather will be here before I need this thing.
 
I'm not sure how many holes you have to work with, but if there are enough I think that sheet metal screws would work. I see two problems with the self-tapping one you tried. First, a #10 was probably too small. And second, a self-tapping screw can cut a new thread on it's second use. That leaves very little metal between the original thread and the second one.

A sheet metal screw would be the choice. It will form the thread instead of cutting it. So it should follow the original thread on the second and subsequent uses. Electronic enclosures have used sheet metal screws for a long time and, with due care, they can be removed and reused many times. I would think with the diameter holes you have a 1/4" sheet metal screw could be used.

A tip on reusing a sheet metal screw: Since the thread is already formed, you should insert the screw with moderate force only until it contacts the metal surface. Then, with that moderate force, turn it backwards until it "clicks". Stop immediately and turn it forward to tighten it. This ensures that it will find the original thread and not create a new one. Of course, do not over-tighten it.

And yes, whatever you choose, do use stainless.
I'm a little confused on the difference between a self tapping screw and a sheet metal screw. Does the sheet metal screw require that a tap be used to form the threads in the hole as the first step?
 
The sheet metal screws that look like a wood screw should be fine though drilling a hole will make the job easier, the self drilling type with a drill looking tip will remove the threads when they are removed
 
I'd use 10-32 screws and a form tap, formed threads are stronger. Drill new holes in the aluminum, push hard on the drill, and you'll probably get a big burr on the exit side, which will effectively give you more threads.

Minimum investment and not very much effort.
 
You can buy a cheap kit with multiple sizes of nuts plus a tool starting at $35. I searched for pop rivet rivnut. Interesting views and some nuance. SS better. SS may not grab in the hole and may spin.
I'd probably go with a plated steel or stainless insert anyway, and would drill the hole, apply some G-Flex (from West - it's an epoxy that has some flex built in) and would set the rivnut/nutsert/whatever-you-call-it.
 
You guys that are suggesting different screws are missing an important point; the OP said the existing holes are "3/16 or 11/64." 3/16 is .188, almost the major diameter of a #10 screw, while 11/64 is .172. Tap drill for 10-32 is .157, 10-24 is .150, no wonder they're stripping out. The only chance to use the existing holes is to go to a number 12 screw, tap drill size for 12-24 is .177, still iffy if the holes are actually 3/16. Drill them and use rivnuts.

Dennis
 
You guys that are suggesting different screws are missing an important point; the OP said the existing holes are "3/16 or 11/64." 3/16 is .188, almost the major diameter of a #10 screw, while 11/64 is .172. Tap drill for 10-32 is .157, 10-24 is .150, no wonder they're stripping out. The only chance to use the existing holes is to go to a number 12 screw, tap drill size for 12-24 is .177, still iffy if the holes are actually 3/16. Drill them and use rivnuts.

Dennis
Thank You. I was leaning toward the rivnuts. I wasn't sure how well tapping would go working overhead at the ceiling. I ordered some 1/4-20 aluminum rivnuts. Not the strongest option but my installation won't be very heavy and there'll be 10 connections. I have a jig for inserting thread inserts into wood so I'll give that a try. If that doesn't work I'll pick up the threaded insert rivet tool from Harbor Freight.....decent reviews so should work with aluminum.....wouldn't expect too much if using a harder metal.
 
Question re: Installing Rivnuts with shop made tools. I've watched a few rivnut installation videos using shop made tools. There seem to be 2 techniques. One technique holds the bolt head still while the nut that is at the top of the rivnut is turned. The other technique uses a lockwasher to secure the nut against the top of the rivnut and the bolt head is turned (usually with an electric drill/driver).
Thoughts...just curious.
 
Do the first, with a washer between the nut and rivnut with a bit of lube like the instruction sheet I posted earlier (post #20). Our products are installed all over the world every day with that method as many folks don't want to buy a special tool for one product, we provide the large flange steel inserts with our kits.
 
Do the first, with a washer between the nut and rivnut with a bit of lube like the instruction sheet I posted earlier (post #20). Our products are installed all over the world every day with that method as many folks don't want to buy a special tool for one product, we provide the large flange steel inserts with our kits.
Thank You.
Will do. I printed the instruction sheet.
What is in your kits?
 
Honestly, I don't see why a sheet metal screw won't work if you use the right size. Just make sure you drive it straight in. On reassembly, always turn counterclockwise until you catch the thread, and it should last indefinitely.
 
Honestly, I don't see why a sheet metal screw won't work if you use the right size. Just make sure you drive it straight in. On reassembly, always turn counterclockwise until you catch the thread, and it should last indefinitely.
I don't disagree and appreciate that you have taken the time to respond. Thank You. The rivnuts seem like a no-brainer and something new to try. I've already ordered some rivnuts online. I have at least one other application in mind for the rivnuts.
 
The frame came with 10 holes already drilled...although I could always drill more. From what I have read there are Cut taps and Forming taps. I just used regular sheet metal screws that do not have the cutting type point. Was this the wrong type? I can get some of the others that have the cutting point. If I use these initially what do I use going forward? The frame I will be attaching is 1 1/4" thick. Do these type of screws come in long lengths in oreder to match the thread pattern that has been cut?
If you had used the machine screws with cutting point all you need do is remove them and replace with regular stainless screws with the same thread.
 
I'm a little confused on the difference between a self tapping screw and a sheet metal screw. Does the sheet metal screw require that a tap be used to form the threads in the hole as the first step?
See my reply above. Most sheet metal screws form the thread which means the pilot hole needs to be larger. True self-tapping screws have a cutting point and can either be sheet metal screw type threads or actual machine screw threads. The latter type of self tapping are common on cars and I usually replace them with regular machine screws if I have to remove them.

With sheet metal screws the secret when reinstalling them is to turn them slowly backwards until you feel them move in slightly as they catch the root of the existing thread. Always then try to screw them in GENTLY and redo the backwards bit if they don't turn with very light force. Done right they can be removed and reinstalled many times - unless things get rusty.
 
See my reply above. Most sheet metal screws form the thread which means the pilot hole needs to be larger. True self-tapping screws have a cutting point and can either be sheet metal screw type threads or actual machine screw threads. The latter type of self tapping are common on cars and I usually replace them with regular machine screws if I have to remove them.

With sheet metal screws the secret when reinstalling them is to turn them slowly backwards until you feel them move in slightly as they catch the root of the existing thread. Always then try to screw them in GENTLY and redo the backwards bit if they don't turn with very light force. Done right they can be removed and reinstalled many times - unless things get rusty.
I agree in concept, but I think it goes out the window when holding something up against the ceiling.
 
I agree in concept, but I think it goes out the window when holding something up against the ceiling.
True, and even machine screws could be awkward while holding heavy panels up. In the case described in post # 1 I would rather see metal brackets that could be loosely mounted on 2 sides of the frame first and then the panel slid in and the screws tightened to snug everything up. I have a plywood panel that mounts in a frame in the ceiling under a tub and I used metal turnbuttons to secure it so there is no need to fumble with fasteners or tools. Everything is painted white so it's very unobtrusive.
 
Thank You. I was leaning toward the rivnuts. I wasn't sure how well tapping would go working overhead at the ceiling. I ordered some 1/4-20 aluminum rivnuts. Not the strongest option but my installation won't be very heavy and there'll be 10 connections. I have a jig for inserting thread inserts into wood so I'll give that a try. If that doesn't work I'll pick up the threaded insert rivet tool from Harbor Freight.....decent reviews so should work with aluminum.....wouldn't expect too much if using a harder metal.
Buy the correct tool. I've made jigs to install thread inserts into wood and the mechanism is completely different than setting rivnuts. The lever type tools have a better feel so you are less likely to overtighten it than with one where you turn a nut or bolt. Misused they can rip the threads out of an aluminum rivnut.
 
Buy the correct tool. I've made jigs to install thread inserts into wood and the mechanism is completely different than setting rivnuts. The lever type tools have a better feel so you are less likely to overtighten it than with one where you turn a nut or bolt. Misused they can rip the threads out of an aluminum rivnut.
I picked up the Harbor Freight tool today. I did a test using the rivnuts that came with the tool and surprise surprise they were not as flimsy as I've experienced with other HF hardware....I was expecting that they would be aluminum. It took 2 hands and a possible hernia....this is the $24.99 homeowner tool. I also received the aluminum rivnuts that I ordered on-line and tested one of those using the HF tool. Quite easy to do with one hand. Now I know what you folks have been talking about. If I ever need to use something stronger than aluminum I will defintely get a lever model. Now just need to get the recommended size drill bit. Boy, this project has taken on a life of its own.
 








 
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