I was going to remove the side lights on our Rockwood 5th wheel to clean the metal ring of rust and repaint. However I quickly discovered these are not standard Torx head screws. A T20 is too large and a T15 is too small. Plus as shown in the attached photo, there are either 8 or 9, (I think it is 8) splines, where a Torx only has 6 splines. So far, the only tool I have that would remove them is an EZ Out but that will ruin the screw.Any ideas of what the correct fastern bit is called?

Can't answer your question but I sometimes I wonder if it's by malicious design that odd screwhead shapes are used in RVs. Would there be anything wrong with using standard shapes? I have replaced more than a few of mine. PS: I do have a drill bit that shape but not sure it's the same size.

My googling indicates that a Robertson bit will often do the trick on these 8-point screws. Same googling indicates that getting the correct bit can be costly and frustrating.Just google "screw head 8 point"

Google says:SCREW HEAD TYPEsI think it is a brother-in-law thing. The manufacturer picks the brand his brother-in-law sells...Roy Ken

I was thinking along the same way that Sue was.....that if it was a 8 point screw than a Robertson screwdriver might just work.

What kind of screw head | Good Sam Community

camperpaul
Explorer
Sep 29, 2013
workhardplayharder wrote:

i think I see a "chicken and egg" debate starting here.

The egg came first. ;)
workhardplayha1
Explorer
Sep 29, 2013
vic46 wrote:
Bob Landry wrote:
Rather than waste a lot of time angsting over a head type, I would remove all of them, go to a nut/bolt/screw supply house, buy a box of SS screws of the same thread size and with a head that you have a tool for, replace them and move on to the next project. A box of 100 will probably cost around $7, and with SS you won't have to deal with rust streaks.

HHHHHHHMMMMMMMMMMMMMMMMMMMMMMMMM, if you have a tool to remove them, why bother!

i think I see a "chicken and egg" debate starting here.
camperpaul
Explorer
Sep 29, 2013
ktmrfs wrote:
camperpaul wrote:
FWIW it is really a Bristol head screw, commonly used in aircraft.

bristol heads I've seen are a 6 point spline drive with a wedged taper so that it's virtually impossible to cam out. extremely good design, probably the most immune to damage of anything I've seen.

While this is an 8 point not really spline drive, certainly not the wedge taper.

Back in the '60s when I was in the avionics business, I had a complete set of "Hunter" Bristol wrenches.

The set included 4, 5, 6, 7 and 8 point wrenches.

----------- side bar ---------

Another area of confusion is "cross point" screw drivers.
A lot of people don't know the subtle difference between a
"Phillips" and a "Reed and Prince".
BurbMan
Explorer II
Sep 29, 2013
I have these on my Terry also...drive me nuts until I figured out that it was a 8-point head and that a square drive would fit. If you look at the philips head screws on the interior you will not the slots stop short of the center so they can accept a square bit also. Definitely an item to keep in your RV tool bag.

Still haven't figured out why the fasteners are 8-pt and not just square....
ktmrfs
Explorer II
Sep 29, 2013
Johno02 wrote:
The factory had something they thought were driver bits, so they had to design screw heads to fit. The surplus shops in Elkhart have a lot of this kind of stuff.

actually, this kind of square drive head is pretty common. I've seen it on lots of stuff other than RV's. Certainly not as common as a regualar 4 point square drive, but readily available.
ktmrfs
Explorer II
Sep 29, 2013
camperpaul wrote:
FWIW it is really a Bristol head screw, commonly used in aircraft.

bristol heads I've seen are a 6 point spline drive with a wedged taper so that it's virtually impossible to cam out. extremely good design, probably the most immune to damage of anything I've seen.

While this is an 8 point not really spline drive, certainly not the wedge taper.
Johno02
Explorer
Sep 29, 2013
The factory had something they thought were driver bits, so they had to design screw heads to fit. The surplus shops in Elkhart have a lot of this kind of stuff.
Big_Katuna
Explorer II
Sep 29, 2013
I learned the hard way. Had an enclosed trailer that had some and I needed to remove them. Took one out with a small pair of Vice grips and took it to our fastener place and they clued me in to the square bit answer.
camperpaul
Explorer
Sep 29, 2013
FWIW it is really a Bristol head screw, commonly used in aircraft.
joe_b_
Explorer II
Sep 29, 2013
Thanks to those of you that realized it was a square drive #2 Roberson bit. Fit just fine and I now have all 4 screws removed.

What a world of information that is available here on the forum.
thanks again

Forum Discussion

What kind of screw head

About Technical Issues

Related Content

wood screw tool

Stainless steel screws

Threaded screw inserts

Screwing into shower wall?

what kind of fifthwheel hitch?