self drilling screws??

[Heavyfire14]

how strong are they? i only have one holding up my muffler hanger and was wandering if its stong enough to leave there or what kinda bolt/nut should i use?

and also the hanger is bolted to the body on like a crossmember type thing. i go offroading and need it to stay bolted on and not come off (and i dont have a welder)

 

[alwaysFlOoReD]

It would depend on how big the shank of the screw is. If it's close to 1/4" o.d. I'd guess o.k.
As far as offroading keep a repair kit on hand; mechanics wire and pliers.

Richard

 

[BRUTUS_T_HOG]

they are strong, however with age and rust they get extremely brittle and snap from sudden jarring

 

[Ozwynn]

they are strong, however with age and rust they get extremely brittle and snap from sudden jarring

yep. we just break them off when replacing the nailer strips on a flatbed ..... not that difficult.

 

[Heavyfire14]

i think ill put one or two more on just to be sure it holds, and i always carry tools in my truck

 

[Will]

The interior of my bus/camper is attached with them. All RVs are held down to their frames with them. They are brilliant.

 

[RatDog8o8]

Look at it this way -
If you do need to "upgrade" to a bolt/nut arrangement, there will already be a hole pre-drilled. Just enlarge it suitably for the new fastener.

 

[Heavyfire14]

^^ yea true haha

 

[straycat]

There called Self Tapping screws, Bro. You can get them in several types of coatings like Zinc (a good choice). I have used them on a lot of my trucks and dirt bikes over the years and never had any issues with them. Check out this website and get some info about them.



http://www.mcfeelys.com/self-tapping-screws

 

[RatDog8o8]

There called Self Tapping screws, Bro. You can get them in several types of coatings like Zinc (a good choice). I have used them on a lot of my trucks and dirt bikes over the years and never had any issues with them. Check out this website and get some info about them.



http://www.mcfeelys.com/self-tapping-screws

Variations of this type of screw have a small "drill point" on the end; therefore the name "self-drilling" does actually apply. It has to "self-drill" a hole before it can "self-tap" it.

This is a typical "self-drilling" sheetmetal screw:

This one has a notch at the point, that acts like a tap for cutting threads:

Here's a "self-tapping" bolt. The notches/grooves allow it to "self-tap" to a certain degree:

Either term works.

 

[straycat]

I see what you are saying but...all my self tapping screws just drill into place, I don't need a drill hole to start it. I just place it where it is going and it goes right on in. I have used them for years on everything around the house and cars, bikes and trucks. Love them.

 

[kunar]

I see what you are saying but...all my self tapping screws just drill into place, I don't need a drill hole to start it. I just place it where it is going and it goes right on in. I have used them for years on everything around the house and cars, bikes and trucks. Love them.

Then all of your self tapping screws are really self drilling. Just a way of being more specific about what exactly you're talking about I suppose. Self drillers have a special point to drill a starter hole, self tappers do not.

Back on topic, I would use 2 screws just so the strap can't pivot. As long as the metal you're drilling into is solid you should be fine

 

[straycat]

Then all of your self tapping screws are really self drilling. Just a way of being more specific about what exactly you're talking about I suppose. Self drillers have a special point to drill a starter hole, self tappers do not.

Back on topic, I would use 2 screws just so the strap can't pivot. As long as the metal you're drilling into is solid you should be fine

That is confusing. I just buy and always have bought Self Tapping screws. That is what is on the box of screws I always buy. I thought that is what all of them were called.

 

[RatDog8o8]

I think it's just the "industry's" way of bandying semantics. Some say self-drilling, others say self-tapping. SD-type have a small "drill-bit" tip; ST-type have the grooves. Maybe there's a third sub-category....."self-starting".....with an extremely sharp point that doesn't technically "drill" a starter-hole.

Oh well.....to the OP....
I'd do as has been mentioned and "double up" on whatever fasteners you're currently running. You can always "upgrade" later to a bolt & nut arrangement should the current method prove too weak or become loose.

 

[Heavyfire14]

i think im either gonna have to go to a bolt and nut or mount the hanger in a differnt location because the screws keep getting loose (i put a seconed one on today and it still got loose). i think its cause their screwed inti some thin cab metal and not the frame