Fin screws

I’ve stripped the head of a couple of my fin screws, what’s the best way to get them out without damaging the plugs, reverse drill? What speed? What type of bit?

a reverse drill might catch it…by reverse i mean a drill that cuts in the opposite direction than normal,so it would spin counter clock wise…that should work use it on a low speed…if this dosent work…well if you have a reverse drill bit , then you might also have some form of easy out with it i would guess,just use that in the hole you drilled…be shure the hole you drill is not going to hit any threads…thats it its just a screw in plastic i will come out easy…you relalise they dont need to be that damn tight that your stripping them.?

I only screw them tight enough to stabilise the fin, but the fins are old and have little indentations from constant use which might cause the problem, also I’ve found if they haven’t been taken out for a while they can be quite resistant…I’m hypothesising crystallised salt acting as glue!

sorry to be off topic but does anyone know what size exactly fin screws are? because i always seem to lose them and i want to go to the store and just buy a bunch so that i dont have to take out a fin screw in one board so that i can use a different board

The screw sizes vary with the nut plate. I’ve seen lots of different nut plates and likewise different screw threads. Measure the length of your present screw and take the plate to the hardware store to get the correct thread. Only get stainless steel screws. On removing stuck screws with stripped heads, use a drill bit the same size as the screw body and drill thru the head until it comes off. Remove the fin and put some “liquid wrench” on the screw stub and the nut plate. Let if soak in and turn it out with some needlenose pliers or visegrips. Don’t overtighten when you put the new screw back in.

Hey BB,

Is it a allen head (fcs, etc) or slot screw (Bahne, etc)? I looked through threads and I’m guessing it’s an allen head.

Before breaking out the power tools, search the archives for some easy fixes and try them first - I’d save drilling as a very last resort. Try a different key/wrench - yours could be stripped (they’re softer than the actual head of the screw), try a torx head screwdriver, and there’s even a soldering iron trick that might work.

You may have already exhausted these quick fixes but thought I’d throw it out there.



huh? are vise grips aplikable? hack saw? …ambrose…in touch with my neandrethal roots

Howzit blindboy, A little info please, what fin system is it or are you talking about the screw in a fin box. Aloha,Kokua

this is not different than any stripped/broken bolt problem on your car…

Soaking the threads overnight in penetrating oil (Liquid Wrench, Kroil, PB-Blaster are good) will help the threads.

Suggest next that if you have a dremel witha a cutting wheel, or a sharp hacksaw blade, that you cut a new straight slot across what’s left of the top of the screw and use a screwdriver.

AFter that, tools to remove the screw could be vice grip pliers, channel lock pliers, plain old utility pliers, sometimes nippers will get it (or cut off the remains of the screw head so you can remover fin and get at the screw better). Sometimes a 4-inch pipe wrench is useful. Use what you have/whatever it takes to grip what’s left of the screw head.

If the screw head is munged beyond grip or redemption, grind it off flush with the bottom and remove the fin. Then remove the sliding female threaded “washer” and hurl it into the weeds. Resolve to use some lubricant next time you screw it in. She’ll thank you.

Next, you

 Howzit Honolulu, I find a really small easy out works also. I like the idea of cutting the slot so you can use a screwdriver, that's a clever one. Aloha,Kokua

For what it’s worth, I have found that an appropriate Torx bit- #15 if I remember right ?? - will sometimes grip when a hex wrench won’t. Hot water or hot vinegar is good for dissolving the salts and such.

hope that’s of use


If your talking FCS, use the provided allen wrench, but put a drop of superglue on it first, stick it in, and wait 2 minutes. Works every time. You’ll need a new screw, and wrench however after that.

Lokbox, you’re a genius, I’m going out to buy the superglue right now, don’t you love low tech? There’s always a solution for us tool-less geeks if you think hard enough.

Go to this website and check out these trick tooless fin screws.

Here's my 2c, I just did this on a couple of old 70's boards that I am restoring for a customer.  You need to be really good with the disk grinder (2", no bigger) to get the head off without damaging the box or (God forbid!!) the board.  Drilling out the head is the way I prefer to go.   I center punch the screw in the middle of the slot to get a bite, then start off with a small bit that will not chatter or jump out of the slot.  I don't go verry deep with the first bit, just start out cutting the concave in the head of the screw.  Next, switch to a larger bit and do the same thing.  Go up in size until you are using a 1/4" or larger bit and the head will pop off.  You are trying to drill out the head, not the entire screw.  Once the head is popped off, take a 2x4 or similar piece of wood and a hammer and tap out the fin.  You will need to replace the tab by working it out of the box where the fin pin slot is.  I like to replace the stainless plate with the plastic plates & a brass screw.  The brass screws don't rust like cheap stainless does in salt, and the plastic can be removed without damaging the board or box when you bang a fin.  I go up to a 1/4" bit but you will figure out what works for you.  Just have a steady hand and you will be fine!  Just my 2C....

Thanks for the insights.  I think I’ll give it a try with the grinder, but the fin screw is pretty flush with the box, so if it looks like I can’t make any headway without damaging the board, I’ll just consider it a glass-on and keep trying to loosen it with WD-40/PB Blaster. 

I’m not going to replace the box or add FCS or anything awful like that, but just have some fun with some flexfins, bonzer fins, and the like…  I’m not really concerned about resale value (the boards are still my neighbor’s and he wants to take his kids surfing on them when they get older), I just love learning the history behind them (With the yellowed Hobie especially - you could just feel the history in the shape), and of course, surfing them- as close to originally designed, at least until my fin OCD takes hold and I start swapping out center fins every other session. I have a magic Greenough 4A that could really sparkle…

I’m up at Surfy Surfy periodically, maybe I’ll bring it in to JP next time I’m up there (I’m in Bay Park, SD).  I’ve had my eye on those Hank Warner Caster re-issues for a while, but to find an original just sitting around was amazing…

Being single fins, they probably have Bahne/Fins Unlimited s.f. boxes. You would be hard pressed to attempt drilling the screws out - especially if they’re in the rear end of the fin. Plus, the screw goes down 3/8" +/- to the plate - long way to drill down the center of a screw.

I would probably grind the head of the frozen screw off - you should then be able to pivot the fin off and out of the box and slide the screw shank and plate out easily.

The fin might be tight with salt/sand crud as well after so long in the rafters. A squirt of WD40 around everything and a tap with a rubber mallet or hammer and wood block would work…

You mention “putting new, modern fins in at some point”. I would recommend NOT removing the existing box and NOT adding more/other boxes - you’ll just be screwing the pooch as far as any value left - regardless of condition…Look around at True Ames, FibreGlas Fin , etc for some great alternative fins for that box.

Don’t know where you’re located but, if possible, you could take the Caster by Moonlight Glassing in Encinitas. I think they’re tight with the Caster family and could point you in the right direction in preserving the board - if that’s something you might want to do.

Would love to see the Hobie too.



Gonna go ahead and bump this thread.  

My neighbor has kept these amazing single fins “on his roof” for 20+ years (!).  They were under an eave and out of direct sunlight, and are actually in very good condition, aside from some nose/tail/bottom dings and some very slight twisting from sitting in one place for years.

The 5’10" Caster below in particular has me frothing, but there is a 6’3"x19" Hobie (which says "Hobie Power '76 on it) that is also very intriguing.  ID’ing these boards is probably best left for another time (Caster was bought OTR in PB in the early 80’s, he bought the Hobie off a friend sometime in the late 70’s).  Neither is signed or has any serial #'s, but I think both pre-date me, which I find amazingly cool.  The pics of the Hobie are terribly distorted for some reason, will try and get them up soon.

I’m in the process of restoring them both and getting them watertight (Caster deck is prinstine, but bottom is pretty torn up), and would love to put new, modern fins in them at some point.  Problem is, the fin screws are stuck as can be.  I soaked them in PB Blaster, no luck.

Drilling the screw out is probably the next step, correct? All dings are fixed, and I’m sanding them tonight, hopefully getting them in the water tomorrow. At some point I’d love to play with the fins, so any help is appreciated. 

Hopefully I didn’t completely screw the pooch with posting images…Here’s a teaser…