I've got a 2003 chevy express 3500 microbird. I'm finding it difficult to get screws to screw into the metal. I've tried pre drilling and it just doesn't seem to work. What am I doing wrong? Obviously people are able to do this, but how? Are my self tapping screws wrong? Am I using the wrong bit to predrill? BTW, This is on the interior.. Thank you all!
fo4imtippin
Senior Member
Sharper drill bit if predrilling. I use my cheap harbor freights for wood and my milwaukee ones for metal.
Some self tappers suck as well. They might look the same, but some are like driving a nail into steel.
Sometimes i struggle with predrilling a hole so i grab a proven self tapper and throw it in since it gets a fresh tip every hole.
If you are going wood to metal, these are the screws to use. The same looking ones from lowes dont work.. they have two lengths. One for plywood (3/4 wood) and one for 2x thickness.
https://www.homedepot.com/p/Teks-12...-Self-Drilling-Screws-40-Pack-21384/100145370
I have found the same on some metal to metal self tappers as well. Could be the hardness of the metal or something.
Some self tappers suck as well. They might look the same, but some are like driving a nail into steel.
Sometimes i struggle with predrilling a hole so i grab a proven self tapper and throw it in since it gets a fresh tip every hole.
If you are going wood to metal, these are the screws to use. The same looking ones from lowes dont work.. they have two lengths. One for plywood (3/4 wood) and one for 2x thickness.
https://www.homedepot.com/p/Teks-12...-Self-Drilling-Screws-40-Pack-21384/100145370
I have found the same on some metal to metal self tappers as well. Could be the hardness of the metal or something.
HamSkoolie
Senior Member
The quality of fasteners varies wildly. From the quality of the material they're made from to the method of manufacture and the surface finish, if any.
Then there's the pitch of the threads and their relationship to the diameter of the fastener.
The thickness of the metal you're screwing into and it's hardness also play a large role.
Generally, the thicker the metal you're fastening, the larger (as a percentage of the fastener diameter) your predrilled hole will need to be. Of course there are the self drilling fasteners which do a fine job (if you buy quality fasteners) which drill the perfect sized hole.
If you're having issues try experimenting with the same metal in a place you don't need the fastener and see if a different sized hole fixes the problem or whether you need better fasteners.
I will second the use of TEK brand fasteners and I also recommend the "star" drive (torx) heads as they are far less likely to slip and strip.
Personally, I like torx head and larger threads but that's just me.
Then there's the pitch of the threads and their relationship to the diameter of the fastener.
The thickness of the metal you're screwing into and it's hardness also play a large role.
Generally, the thicker the metal you're fastening, the larger (as a percentage of the fastener diameter) your predrilled hole will need to be. Of course there are the self drilling fasteners which do a fine job (if you buy quality fasteners) which drill the perfect sized hole.
If you're having issues try experimenting with the same metal in a place you don't need the fastener and see if a different sized hole fixes the problem or whether you need better fasteners.
I will second the use of TEK brand fasteners and I also recommend the "star" drive (torx) heads as they are far less likely to slip and strip.
Personally, I like torx head and larger threads but that's just me.
- Joined
- Oct 4, 2017
- Posts
- 188
Echoing the Teks chant
I'm gonna echo the Teks screw chant.
What can be problematic is places where the steel is multi-layer thick, or there's a flange or hidden angle piece in there, especially if the layers aren't tight together. Broke quite a few @#%&* drill bits... I used them everywhere I put wood to metal, and I found that it was best to not rely on the screw's own drill point to make the hole. What worked best for me was to drill a slightly smaller hole with a HSS twist drill, and use the screw's own drill point to properly size the hole for the threading. I found that once in a while the little "ears" didn't break off when entering the steel, and hogged out the hole so the threads wouldn't form. That was rare, though.
I found a good source for Teks at Jake Sales. Sizes and lengths not available at the big box stores, and good prices for quantities. REALLY good service and fast shipping, too. I used a heckuva lot of them, so 500 quantity bags weren't a problem.
jakesales.com
I'm gonna echo the Teks screw chant.
What can be problematic is places where the steel is multi-layer thick, or there's a flange or hidden angle piece in there, especially if the layers aren't tight together. Broke quite a few @#%&* drill bits... I used them everywhere I put wood to metal, and I found that it was best to not rely on the screw's own drill point to make the hole. What worked best for me was to drill a slightly smaller hole with a HSS twist drill, and use the screw's own drill point to properly size the hole for the threading. I found that once in a while the little "ears" didn't break off when entering the steel, and hogged out the hole so the threads wouldn't form. That was rare, though.
I found a good source for Teks at Jake Sales. Sizes and lengths not available at the big box stores, and good prices for quantities. REALLY good service and fast shipping, too. I used a heckuva lot of them, so 500 quantity bags weren't a problem.
jakesales.com
Iceni John
Senior Member
If the steel is fairly thick, you could tap threads for machine screws / bolts in it, then you'll have a very secure attachment. For thinner steel that still requires high-strength fasteners I use Böllhoff PlusNuts that are a beefed-up version of Jack Nuts, but installing them is very tricky: I ended up making my own installer tool using a coupling nut and a proper thrust bearing with needle bearings, and this works so much better than the "correct" tools. Otherwise, for lighter loads good ol' RivNuts usually work quite well, but expect a high attrition rate when installing them! Jack Nuts are hopeless: don't waste your time with them. I prefer all these methods over self-tapping screws because they produce reliable machine-screw threads that won't ever distort or pull through.
I checked into using Dzus quarter-turn fasteners for things that may need to be removed from time to time, but they're very spendy, so I'll stick with the three methods I mentioned!
John
I checked into using Dzus quarter-turn fasteners for things that may need to be removed from time to time, but they're very spendy, so I'll stick with the three methods I mentioned!
John
Last edited:
mmoore6856
Senior Member
yea i used tek screws been 6 years now and they are still holding great.
nikitis
1994 International 3800 - Thomas, T444E 165HP
You mean Older American Made Steel is way harder than todays Chinese made soft metal screws?
Who would of thought?
Things were made better back then they are today. That's the sad reality of things. My bus which is 30 years old had virtually zero rust on the floor, but I'm finding on here people buying 15 year old buses with rusted through floors all the time.
My advice is to get a tap and die, and tap all of the holes you drill. Drill bits today are all too soft, even for the highest quality bits. Reason being is because modern steel is softer to save money on resources, and all steel sourced today isn't as hard as it used to be. The industry knows this.
To Harden steel it takes heating it up to cherry red, then instantly cooling it down several times. The faster you cool metal when it is that hot, the harder it becomes.
Samurai Sword makers understood that steel molecules, are like round balls, and only connect from round edge to round edge leaving space between the molecules which also in turn makes the metal softer and weaker. When Steel is heated to cherry red, those molecules warp into blocks which are square, and the edges fit better like a perfect tetris game with no spaces. Thus more contact to each other, and more solid. Less space in between the molecules. This is how a samurai sword is made. They heat, fold the blade 200 times, instant cool to harden it again, and each time it pushes more and more of those spaces out of the metal.
When cooling metal when cherry red, then pouring water on the metal, locks those molecules in the square shape, but if you let it cool slowly, it will round out again and actually become weaker.
(Also a pro-tip for welders, if you are welding something that is load bearing, pour water on it asap after welding to harden your welds)
This is an extra step that takes a lot of energy to make. The manufacturer process doesn't do this well anymore on modern steel to save money and we've been getting softer steel today within the last 15 years, and the bits sold today are also softer and can drill through the metal easier, but when you apply these bits to some older hardened steel, the bit is going to dull before you cut through that steel in many cases.
The king pin keys I had to drill out for my king pin job where extremely hard. It took 15 drill bits to get all the way through it. (They were welded in in my case)
Solution is to tap each hole on the hardened steel. The tap will be made extremely hard, and should be strong enough to cut threads through your holes even on the good steel, then use machine screws. The thinner the metal the thinner the threads you'll want anyway.
Who would of thought?
Things were made better back then they are today. That's the sad reality of things. My bus which is 30 years old had virtually zero rust on the floor, but I'm finding on here people buying 15 year old buses with rusted through floors all the time.
My advice is to get a tap and die, and tap all of the holes you drill. Drill bits today are all too soft, even for the highest quality bits. Reason being is because modern steel is softer to save money on resources, and all steel sourced today isn't as hard as it used to be. The industry knows this.
To Harden steel it takes heating it up to cherry red, then instantly cooling it down several times. The faster you cool metal when it is that hot, the harder it becomes.
Samurai Sword makers understood that steel molecules, are like round balls, and only connect from round edge to round edge leaving space between the molecules which also in turn makes the metal softer and weaker. When Steel is heated to cherry red, those molecules warp into blocks which are square, and the edges fit better like a perfect tetris game with no spaces. Thus more contact to each other, and more solid. Less space in between the molecules. This is how a samurai sword is made. They heat, fold the blade 200 times, instant cool to harden it again, and each time it pushes more and more of those spaces out of the metal.
When cooling metal when cherry red, then pouring water on the metal, locks those molecules in the square shape, but if you let it cool slowly, it will round out again and actually become weaker.
(Also a pro-tip for welders, if you are welding something that is load bearing, pour water on it asap after welding to harden your welds)
This is an extra step that takes a lot of energy to make. The manufacturer process doesn't do this well anymore on modern steel to save money and we've been getting softer steel today within the last 15 years, and the bits sold today are also softer and can drill through the metal easier, but when you apply these bits to some older hardened steel, the bit is going to dull before you cut through that steel in many cases.
The king pin keys I had to drill out for my king pin job where extremely hard. It took 15 drill bits to get all the way through it. (They were welded in in my case)
Solution is to tap each hole on the hardened steel. The tap will be made extremely hard, and should be strong enough to cut threads through your holes even on the good steel, then use machine screws. The thinner the metal the thinner the threads you'll want anyway.
Last edited:
mmoore6856
Senior Member
Drill bits today are all too soft, even for the highest quality bits. [/QUOTE] I drilled 1,000 holes when I raised my roof. So I could use hard carriage bolts to look like the original rivets. I used only 3 (three) 3/16 cobalt bits to do all them holes. Good bits and the proper knowledge of cutting speed can make any drilling job easier. I also have cheap drills when there is a risk of breakage and they cut good with proper speed and oil
mmoore6856
Senior Member
Reason it took 3 was I broke a couple
fo4imtippin
Senior Member
I have broken a lot of m35 cobalt bits. They are pricey. My 2 DeWalt drills have broken clutches so I have to brace my arm and send it. For the cost of broken bits, I couldve bought 2 new drills with new clutches.
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