What kind of bolt is this?

I've scoured the forums and internet and can't find any examples of these bolts. They're like a nail drive but backwards and with a threaded stud. The nail is driven into the wedge at the bottom of the hole so they're all bottomed out. I core drilled them out.

I've pulled short and long ones:

Close up of the "nail" end of the least rusted after cleaning it a bit:

I don't have a name, but its the same idea as Petzl Spit bolts, except a threaded stud instead of the threaded bolt hole of the Spits... Not a good idea at all considering there is no sleeve or mechanism to increase camming when pulling force is applied. The Spit is a very temporary or even one time use bolt, very short drill depth needed... All around very inferior in all respects to like a concrete screw or more modern expansion bolt mechanism. Benefit at the time was integrated drilling teeth, short length, light weight. Typically used with Petzl aluminum hangers, which obviously would not survive long in a humid cave environment.

 

Same idea as Kong Anchor Fix:  https://www.kong.it/en/product/anchor-fix/

Obviously your bolt doesn't have the integrated drill teeth and is longer.

Hammer drive pin or nail type (aka strike type) concrete expansion bolts, like the Petzl Long Life, or numerous others with threaded stud are perhaps the closest thing that is easy to find these days in a somewhat similar mechanism, and even those would be superior to what you have. Your style was a very short lived bolt that was quickly replaced with bolts without its same flaws, except for a few manufacturers of the aforementioned temp caving bolts.

Don't know the name (if there was any standard name for those), but you see them around now and then. The last one I found was quite rusted. When I tried to unscrew the nut, the whole bolt turned, and I turned it a few rotations and noticed that it crept out maybe 1mm. So then I just turned the nut back and forth and wiggled/pulled out on the hanger, and the whole thing (3.5" or so - pretty long) just came right on out with no problem!

Are these 3/8" or 10mm?

Austin Donisan wrote:

Are these 3/8" or 10mm?

3/8-16 thread

Austin Donisan wrote:

Are these 3/8" or 10mm?

Gregger Man wrote:

3/8-16 thread

Thanks for the replies everyone.

These bolts measured 10.5mm in diameter, an odd size. Though maybe my calipers are off. I'll check the thread size when I get back home in a couple days.

They were in desert sandstone (Red Rock Canyon) on routes put up in the '80s. All were still snug in the holes and required core drilling to get out. But the studs were sticking out of the wall over an inch, and bent and mushroomed ends 

Edge wrote:

BITD, you used to be able to find concrete anchors that worked in this way.

Not sure who invented this contraption, but I found it in the late 70’s in the talus at the base of the Prow on Cathedral Ledge. It was screwed together in one piece and missing the conical wedge, but the actual bolt was self-drilling and meant to be used in conjunction with the wedge after drilling.

That was the same set up used to use, horribly slow, but then again I didn't know any better.  I shudder at the crap I used to use that was acceptable back then.   

KrisG wrote:

Austin Donisan wrote:

Are these 3/8" or 10mm?

Thanks for the replies everyone.

These bolts measured 10.5mm in diameter, an odd size. Though maybe my calipers are off. I'll check the thread size when I get back home in a couple days.

They were in desert sandstone (Red Rock Canyon) on routes put up in the '80s. All were still snug in the holes and required core drilling to get out. But the studs were sticking out of the wall over an inch, and bent and mushroomed ends 

Gregger Man was correct, they're 3/8-16 (my calipers were off). Interesting that we don't have a name for them. I guess maybe they're not that common. For that reason I think I'll replace them as I come across them. And because many of them were put in like this:

The bent and mushroomed end means the nut won't back off all the way. I saw off the end of the bolt using the partially backed-off nut as a guide, and then remove the nut and hanger. Then core drill it out. Fortunately, I've been successful core drilling without water, or its accompanying mess, in the sandstone.

They are called "Spit" bolts (in some countries Redheads as the cone part was red) and made by Spit Paslode which is a construction fastener company owned by ITW Inc. 

Kris G

Those are Phillips redheads. Crap even back in the day. I tried to use 1/4" for ladders and they would snap on placement.

Edge

Self drives. Huge and shallow hole for little bolt. Again, with a set plug on base to anchor in. Some of these bolts had "wasp heads" that had to be snapped off and ideally ground flat for bolt hanger attachment. Lots of time to install and really not good. Hard rock were basically a show stopper in the drilling phase.

circa 1984 rawl split "drives" were ideal for 1/4" and 5/16" and 3/8" wedge style were best thing going until the 5 piece.

Don't get me started on USE diamond taper bolts....ugh

Thanks for the info everyone. 

I've replaced several of these Spit bolts now of varying lengths. I still haven't figured out how to tell them from a wedge bolt when I first see them in the rock. I pulled a couple that I thought would be them and they were wedges instead. But they all have SMC hangers so they're getting replaced regardless.

The "Spit" bolts are the european name for the self drive sleeve that folks indicated have a similar holding mechanism in the rock. 

I know those bolts you pulled as stud bolts. They are weaker than the more familiar wedge stud bolt because they have to be mild steel. Otherwise if they were hardened, they would crack when driven agains the expansion pin.

Kudos for making the effort to remove and replace!!