Delta Slotted Screws - What's their story?

[drbelleville]

I am looking to find out what the history behind the non-typical Delta only "Concave" Slotted screws is. Were they available in certain grades, etc...

Thanks,
-Maurice

[a01butal]

They were originally used in aircraft construction and are called High-Torque fasteners. There is a special driver used to install them and it is a very secure connection between the screw and the driver bit. These fasteners are not very easily found anymore but sometimes show up.

[templeofspeed]

I'd love to find that driver...I wonder if it's that military-only 9/32" drive? I have some Snap-on tools that are that format...was supposed to limit theft.

[drbelleville]

Brown Tool makes them.

[drbelleville]

They were originally used in aircraft construction and are called High-Torque fasteners. There is a special driver used to install them and it is a very secure connection between the screw and the driver bit. These fasteners are not very easily found anymore but sometimes show up.

Thanks, that helps a bunch, and I guess if they are good enough for aircraft, then they are sure good enough for some awesome R/C Cars.

-Maurice

[Lonestar]

I learnt something today thanks to you guys... most awesome board on the planet

Cheers
Paul

[V12]

My Delta Super Phaser also is using the High-Torque screws but I have no tool for working with those. I think just the 8-32 screws were High-Torque.

[Coelacanth]

Speaking of screws, I wonder why the Robertson headed screws never became more popular & widespread? It's a Canadian design that has advantages over other more popular heads. You can more easily torque a Robertson screw one-handed, the head will even retain a screwdriver if you let go; having only 4 points (square), it's less likely to strip than the more commonplace hex-headed screws, and there's almost zero chance of a Robertson screwdriver slipping while torquing the screw, which happens all the time with slotted and Phillips-headed screws. Phillips-headed screws are the most likely to strip out, yet they're the most widespread. Go figure...

[kaiser]

wow, an actual usefull slotted screw. i didn't know those existed.

on the square drive screws, we used to use them for decking and the trouble was cheap bits. if you weren't 100% vertical the bits would wear fast and then strip heads. i know some belt fed screw guns use them, but they have very hard tips.

[Coelacanth]

wow, an actual usefull slotted screw. i didn't know those existed.

on the square drive screws, we used to use them for decking and the trouble was cheap bits. if you weren't 100% vertical the bits would wear fast and then strip heads. i know some belt fed screw guns use them, but they have very hard tips.

True, it's like any other screw I guess, no different from using Allen keys or low-quality hex drivers with hex-heads. But all else being equal, Phillips & hex heads will strip out easier than Robertson heads because Phillips heads don't grip the driver and hex heads are already closer to being round from the get-go.

[V12]

Are you talking about screws like this? I know someone who bought a car with these screws and is not able removing the motor because of the missing tool. We always wondered what sort of screws this is.

I think you´re right on what you´re saying on that Robertson head but maybe the TORX screw is even better. I have worked with screws like this for some time and never was stripping any screw. Corally is/was using those screws and including a TORX screwdriver with their kits. But also I have little problems with hex-headed screws as I´m using just very good good hardened tools. The cheap angled allen keys what are included with some of the kits should been thrown away right from the beginning.

Yes Phillips-headed screws really could be a pain but I´m using these just for few vintage projects, sometimes even replacing with hex-headed screws. Regarding the old green 8-32 Phillips-headed screws from Associated I actually like them for their look and never had a problem but again this is by using the right screwdriver.

[jwscab]

yes, philips are not the greatest, however, there is a little background on philips which may also benefit some of you guys using metric phillips heads.

there are three different kinds of philips that you might run across.

dirt cheap crap, both screws and drivers, either poorly hardened or generally crappy construction. not much you can do about them overall except replace with better hardware.

'standard' philips, which you might see in drywall screws. most good bits/drivers will have some serration to aid in gripping, and the driver and screw are matching and manufactured to have a good fit and tolerance.

JIS japanese standard. These guys will give you a headache if you try and use 'standard' screwdrivers on them. They are the standard for most metric hardware that is supplied through asian manufacturers, ie, pretty much everything you run across these days. They have slightly different specs in flute angle and width, and really need the right driver for the job. I was having a heck of a time with some clone heli screws(very small metric hardware), and I found a nice set from mcmaster-carr that work really well. part number 53325A21 I use them on all the kids toys these days and they are the correct drivers for most metric hardware.

sorry if this is derailing the thread too much, just an interesting thing I found that really helped all those frustrated rounded screws.

[V12]

That´s another area where you have to be careful with cross-type screws. Screws and tools just using that cross are Philips. Cross-type screws with additional serrations are Pozidrive. This is also cross-type but very different than Philips. Mixing up Philips screws with Pozidrive tool or backwards will strip the head of the screws very easy.

[kaiser]

this is a cool discussion, personally i prefer torx over everything else.
i'm into 1:1 vw's and all the newer cars have torx all over the place and they are so easy to work with, even when "stuck".

the tamiya phillips with the slot are those the pozidrive? they don't seem to be true phillips (too shallow), i have an old phillips that works well with them but if it's super tight i use a slotted that just barely fits.

[V12]

Don´t know exactly at the moment how Tamiya screws are looking like but if the head of a cross-type screw has an additional smaller cross turned at an angle of 45° degrees, than it´s not Philips but Pozidrive. This smaller cross looks similar to serrations as mentioned before. Comparing both screw typs side to side you will see the difference much better.

Regarding screwdrivers it´s even easier as you can see the second smaller cross "blades" of a Pozidrive screwdriver very good. Philips tools also have a quite sharp tip where Pozidrive use a rounded tip. This means using the sharp and therefore slightly longer tip of a Philips tool prevents this from digging into a Pozidrive the full amount. So when fastening a screw it´s not possible transferring all of the torque into the screw head and the screwdriver will slip at a certain point and strip the screw.

Yes TORX is very good for transferring high torque and should have least amount of wear when using the same screw over and over again. I think VW was one of the first using TORX for 1:1 cars.