Trouble getting self tapping screws to bite.

[Hobby_Man22]

I've never had any luck with self tapping screws threading into metal. Am I doing something wrong? I always had to drill a small pilot hole to keep it from wandering off and usually you use a punch to prevent this, but with a self tapping screw you shouldn't have to.

 

[Doug Arthurs]

I use mostly self drilling screws so no need for pilot holes. The only time I would use self tappers would be in thin aluminum and then usually just press hard to form a dimple then drive it in.

 

[chinboys]

What type of metal and how thick (most self tappers are 10-20 RC in hardness)? What sort of cutting head is on the screw (blade versus taper cutter)?

There isn't any shame to drill a small pilot hole or a tap size hole to tap except for the speed and steps involved (number of fasteners required).

 

[BillK]

HM.
Are you using self "tapping" or self "drilling" screws ? Self tapping are made to work with a pilot hole. Self drilling have a drill point on them and drill their own hole. I have never had an issue with the self drilling ones.

 

[finn]

Try a different brand. I have found a wide variance in how easy self tappers bite, depending largely on who made them.

 

[larry_g]

What type of metal and how thick (most self tappers are 10-20 RC in hardness)? What sort of cutting head is on the screw (blade versus taper cutter)?

There isn't any shame to drill a small pilot hole or a tap size hole to tap except for the speed and steps involved (number of fasteners required).

HM.
Are you using self "tapping" or self "drilling" screws ? Self tapping are made to work with a pilot hole. Self drilling have a drill point on them and drill their own hole. I have never had an issue with the self drilling ones.

X2 on the above. I also find that setting the drill/driver to hammer mode works things a bit better.

lg
no neat sig line

 

[Mr_fixit]

There's many different self tapping or self drilling bits, thread forming bits, with different threads, heads, wings, drill point , depending on what you're screwing into. Coarse threads into something very thin isn't going to work. Whether you're screwing into metal or wood, or combination of both, requires specific screws. some info here. https://uk.rs-online.com/web/generalDisplay.html?id=solutions/self-tapping-screws-guide

 

[allinon72]

Varies widely depending on what material you are screwing into and the quality of the self tappers. Cheap ones are basically worthless on anything but the thinnest of material.

 

[JRC3]

Sometimes you have to put some *** behind it. I've used them to replace the plywood deck on my utility trailer, that's pretty thick and I didn't pre drill. Last week I used some to do an impeller mod on my snow blower, also pretty darn thick.

 

[BFBOB]

Self Piercing screws are the best, strongest for what I use them for - attaching wiring devices to steel studs. Since they don't remove any metal, there's a lot more for the threads to grip. Not as easy to find as the self drilling screws, but they're out there.

 

[NUTTSGT]

I'll second what many said above. I'll also suggest to start the screw slowing depending on the material. You have to get it started before you go wide *** open, it's not a drywall screw going into sheetrock/stud.

 

[Marctrees]

Be aware the drill length portion of the self drill screw MUST be at least as long as the thickness of the material you will be going through, otherwise it will stall and not progress.

Marc

 

[nadogail]

Self Piercing screws are the best, strongest for what I use them for - attaching wiring devices to steel studs. Since they don't remove any metal, there's a lot more for the threads to grip. Not as easy to find as the self drilling screws, but they're out there.

IMHO. I would go to the place where meta studs are sold to find the self piercing screws.

 

[Dadillac]

Most people drill at a much too high speed when drilling metal. Slow the drill down and watch those screws plow right through

Don

 

[Daniel Dudley]

They sometimes call self piercing screws needle point screws.

 

[Dustball]

I've never had any luck with self tapping screws threading into metal. Am I doing something wrong? I always had to drill a small pilot hole to keep it from wandering off and usually you use a punch to prevent this, but with a self tapping screw you shouldn't have to.

Self-tapping (needs a pilot hole, cuts its own threads)

Self-drilling (drills its own hole and cuts its own threads)

Self-piercing (pierces its own holes in sheet metal)

Which one are you trying to do?

 

[Marctrees]

In my experience Malco makes quality screws and tools for the sheet metal trade.

I have used their self drill and self pierce many times.

Marc

 

[Hobby_Man22]

Self-tapping (needs a pilot hole, cuts its own threads)

Self-drilling (drills its own hole and cuts its own threads)

Self-piercing (pierces its own holes in sheet metal)

Which one are you trying to do?

The middle picture

 

[rburke65]

Drill/ driver setting torque too high....ripping out threads?

 

[Dustball]

The middle picture

Ok, self-drilling screws it is. All you should need is a center punch to mark your hole location.

As for material thickness, I go by the thickness being no more than the length of the drill section of the screw. Any more than 1/8", I drill and tap for regular screws.

Some good tips-
https://www.fastenermart.com/self-drilling-screws.html

• To avoid point breakage, the drill point must completely penetrate the material before thread pick-up occurs because the screw advances faster when tapping than drilling.
• Recommended driving speed for most efficient drilling is also different for the different sizes. For example, one manufacturer indicates the drill capacity of a #8 screw with a #2 point is 0.035 - 0.100" and recommends a drill speed of 2500 RPM. A #12 screw with a #5 point is rated for 0.125 - 0.500" material thickness at 1500 RPM. For best results, always follow the screw manufacturer's guidelines but, in general, 2000 to 3000 RPM and end pressures between 25 and 65 pounds should produce satisfactory results for most applications.

 

[Hobby_Man22]

Dustball thanks fornthe help. It looks like I just wasn't giving the drill enough rpm. Plus I went out and bought a magnetic drill bit.