Is there any reason to not use a SHC screw for securing mast to the board (via deep tuttle box)? Is there a danger of applying too much torque? I have a torque wrench I could use although I have no idea what torque spec to use and I don't really want to use a torque wrench in a corrosive environment.

no problem to use those
you can tighten by feel

I have used them since the start as I'm not a fan of hex heads, no problems at all, as above just torque by feel. The only thing I'd say is just be careful what washers you use, due to the typically smaller head diameter on a SHCS they can bend washers pretty easily.

I'm not a fan of hex heads. <= but why?

we used them for a decade in slalomsurfing in the DT boxes for all long fins?
and now I'm using them for Racefoils.

Select to expand quote

t36 said..
I'm not a fan of hex heads. <= but why?

we used them for a decade in slalomsurfing in the DT boxes for all long fins?
and now I'm using them for Racefoils.

Just personal preference, while theoretically a hex head can tolerate greater drive torque no one should ever be encountering those issues on a windsurfer fin/foil box so that's a moot point. What you can't argue with is that a SHCS has better positive engagement with the drive tool, which I personally find much nicer, you can also pull the fasteners out with the tool too which is a bonus. S/S hex head fasteners, at least in Australia, typically have very slim heads so are not very tolerant to incorrect tool engagement angle....which leads to them being quite easy to round/general pain so I personally prefer the SHCS. Each to their own.

Me too, I've been using SHCS on my fins for a decade and using on my foil mast - board connection now. I like them for the same reasons as CJW plus I can use the same key that comes with my sails (on fins at least). I save hex heads for my lawn mower

I use Torx 30, the same as every other bolt on the foil.

I use hex heads, external hex. With Phillips, if you slip, the sharp tip on the screwdriver makes nice deep holes in the board. Yuck.

Torx is good, too, for footstraps. Square drive, too.

Do NOT use a torque wrench, or any kind wrench, or power driver. Just use hand pressure. It's enough, and it's safe.

Hex heads are fine. Gentle hand/finger tight is all you need (depending on screw driver or t-handle).

Thing with tuttle heads is you need the head secure in the box so the taper of the head is engaging with the ends of the box. You can do that by pulling the head in with the screws, or by gently and progressively levering the mast against the screws so that it seats down.

If you choose to pull the mast in with screw tension then you'll be screwing in with a lot more than finger tight. I'm guessing around 5-6nm. That's plenty to chew out your hex heads with repeated use. You should still check the seating by levering the mast and re-tightening the screws.

Levering the mast is more gentle on the screws and is quite a gentle action. Don't overdo that. You can split the ends of your tuttle box.

I moved to 316 torx head screws. I haven't worn out a screw head since I switched about a year ago.

I am still using the philips screws on my wingding foils. The foils came with them and the screws sit down deep inside holds in my boards. There's no chance of scratching or damaging the deck.

I've also had a bit of retail therapy and bought Wera stainless steel tools. They are a beautiful thing to use. They can be bought at Bunnings, Amazon or RS-Components.

Select to expand quote

segler said..

Do NOT use a torque wrench.

"Do NOT use a torque wrench" The local tyre jockey might think that but he certainly wouldn't say it out loud.

But if you're not going to use a torque wrench a bit more leverage than you get with a screw driver handle is better. When I was a boy a turner and fitter told me you could get the correct tension by feel. Go into Zen mode and feel the elasticity of the metal, the vibrations as the nut judders onto the thread. I later acquired a torque wrench and saw that the method has merit. You can get an M6 to full tension with a bare screw driver handle but when using full strength your feel goes out the window.
Allen key sets with a comfy handle that goes to right angles lets you tighten them up without too much effort.

I do also use outer hex screws for fins and foils and tighten only with hand wrench. Works great and the screws are everywhere available. And massive washer wich do not bend

Gorgo wrote: "Thing with tuttle heads is you need the head secure in the box so the taper of the head is engaging with the ends of the box. You can do that by pulling the head in with the screws, or by gently and progressively levering the mast against the screws so that it seats down."

This is exactly what Sailworks advises when you buy a Moses foil from them. You keep levering and tightening until it does no lever any more. That ensures full seating of the foil into the rounded tapered ends of the box. This is critical for carrying the cantilevered loads of the front wing against the board.

The reason I am adamantly against using a power tool is that I once saw a formula racer pull his fin completely through his board with a power driver.

Select to expand quote

Grantmac said..
I use Torx 30, the same as every other bolt on the foil.

Have you found a good supplier for uncommon fasteners? I've used Pacific Fasteners in Vancouver for a lot of things but even they don't carry certain things such as M8 small OD washers. Fastenal has a great selection but they won't do retail. There's a few places in the US that have want I want but then there is shipping...

www.accu.co.uk/en/

Select to expand quote

shmish said..

Grantmac said..
I use Torx 30, the same as every other bolt on the foil.

Have you found a good supplier for uncommon fasteners? I've used Pacific Fasteners in Vancouver for a lot of things but even they don't carry certain things such as M8 small OD washers. Fastenal has a great selection but they won't do retail. There's a few places in the US that have want I want but then there is shipping...

I am guessing you are talking about Fastenal Canada? on this side of the border you can buy retail (I bought m6x120 mm hex socket for my foil from them).

Select to expand quote

WillyWind said..

shmish said..

Grantmac said..
I use Torx 30, the same as every other bolt on the foil.

Have you found a good supplier for uncommon fasteners? I've used Pacific Fasteners in Vancouver for a lot of things but even they don't carry certain things such as M8 small OD washers. Fastenal has a great selection but they won't do retail. There's a few places in the US that have want I want but then there is shipping...

I am guessing you are talking about Fastenal Canada? on this side of the border you can buy retail (I bought m6x120 mm hex socket for my foil from them).

Yes, Canada. They tell you to go to Grainger Canada and guess what Grainger says. If you want a part that we don't normally stock, you can only buy it if you're a business customer. It's infuriating. The sales person actually told me it's for liability reasons. He said they couldn't put warning labels on custom orders so they don't want the liability. Such BS. I just want to buy a few screws and washers. You'd think I was asking for enriched uranium.

Select to expand quote

Gorgo said..
I've also had a bit of retail therapy and bought Wera stainless steel tools. They are a beautiful thing to use. They can be bought at Bunnings, Amazon or RS-Components.

Thanks for that Gorgo! I have been looking all over and not found a stainless torq driver. The steel ones only last a couple of months in my salty life.