Just got a hold of my new NP glide wind foil with the small wings and powerbox variant. I cant try it because I'm not sure if I make the power box hole in the board bigger, then it wouldn't fit the normal screw with a powerbox fin. Also I considered buying the deep tuttle box adaptor but I have doubts about the deep tuttle not fitting a normal tuttle box board as they are more common. Any opinions?

Use the provided tool to make your board hole the 2mm bigger m8. It will effect nothing and you can still use normal fins with m6 screws. Many slalom boards end up with ovals holes after using different fins and angling the screws to suit. The process is a lot less scary than you think. Also. The deep Tuttle head will not fit a normal Tuttle board.

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sambucabarnes said..
Use the provided tool to make your board hole the 2mm bigger m8. It will effect nothing and you can still use normal fins with m6 screws. Many slalom boards end up with ovals holes after using different fins and angling the screws to suit. The process is a lot less scary than you think. Also. The deep Tuttle head will not fit a normal Tuttle board.

Thanks a lot, I just wanted to make sure because screwing up a fin box is an annoying experience. Also do you got any advice for board/sail combinations for around 8-15 knots (65kg on small wings)

Good foiler around here on Tuttle NP Glide, blue one, uses 5.5 in those breezes at 70 kg and full wetsuit.

He also retapped his 2 M-6's to 3/8 bolts after the M-6's stripped the fin head threads after 20 days of use.

Up here in the Pacific NW we routinely tap the M6 inserts to 1/4-20 before we even start using the gear. This way we have much better availability of stainless bolts/screws from any ole hardware store (especially Ace).

Hope your 1/4 x 20 tapped aluminum finhead threads hold up.
My friend waited until one of the M6's started to show loosness, tapped to 1/4, used it 5 days, and noticed both showed looseness.
The walls seem thin for 3/8, so he plans on using brass fin receptors when his 3/8 show signs of stripping.

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segler said..
Up here in the Pacific NW we routinely tap the M6 inserts to 1/4-20 before we even start using the gear. This way we have much better availability of stainless bolts/screws from any ole hardware store (especially Ace).

Even the big box orange home improvement store has stainless M6 up to at least 90mm in many of their locations. Online is cheaper and much better variety. Spend about 10 bucks and buy a few in every size you might conceivably use. My understanding is that when you tap out M6 to 1/4, you are essentially elegantly cross threading the M6 because the difference in diameter (0.15mm) is so small, you end up with a weaker thread structure. It's fine with a fin but I would be uncomfortable hanging a $1000 foil from it. If the threads are compromised, a helicoil would be a better alternative.

https://www.boltdepot.com/Metric_machine_screws_Phillips_pan_head_Stainless_steel_18-8_(A-2)_6mm_x_1.0mm.aspx
www.stanleyengineeredfastening.com/fasteners/inserts/wire-threaded-inserts/helicoil-oversize--twinsert-screw-thread-inserts
www.iwindsurf.com/forums/viewtopic.php?p=242387

All good points. Yes, you are basically cross-threading. If the M6 material has any kind of formability (such as brass) this is no biggie.

For many years with fins we have tapped the M6 brass inserts to 1/4-20. Same for carbon foils that have M6 brass inserts. If it is aluminum, we leave it alone and live with M6. The exception is the M6 holes on the deep tuttle top of the Power Plate. I tapped those to 1/4-20. After dozens of sessions, they have not failed.

For the Slingshot M10 threaded holes, instead of getting the Slingshot M10-M6 adapter inserts (I think they are aluminum), I have gotten stainless steel adapter inserts online and tapped those to 1/4-20. After two years of use, those also have not shown any signs of wear or looseness.

So, if you go to a place like even Hood River, try to mount a fin or foil, and your screws/bolts are too long or too short, good luck finding a stainless M6, even with all the shops there. Ace Hardware up on the hill has a decent selection, but I use only hex-head bolts to avoid sticking a screw driver through the top of the board if it slips. A nut driver is safer. So, every shop and hardware has a big selection of 1/4-20 stainless in really long lengths. Two years ago, when I bought a brand new foil in Hood River, I could not foil the first day with it--in Hood River no less--because I could not find the correct length of M6 screw. My wife had to guard my gear at the Event Site while I ran all over town looking for the M6 screws, to no avail. (I foil with a Mike's Lab L6, which has a really thick tail and requires screws of 3" to 3.5".)

When you buy a foil from Sailworks, the first question they ask you is if you want them to tap the inserts to 1/4-20.

We yanks are still averse to metric.

Australian or European readers: ignore this message.

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segler said..
All good points. Yes, you are basically cross-threading. If the M6 material has any kind of formability (such as brass) this is no biggie.

For many years with fins we have tapped the M6 brass inserts to 1/4-20. Same for carbon foils that have M6 brass inserts. If it is aluminum, we leave it alone and live with M6. The exception is the M6 holes on the deep tuttle top of the Power Plate. I tapped those to 1/4-20. After dozens of sessions, they have not failed.

For the Slingshot M10 threaded holes, instead of getting the Slingshot M10-M6 adapter inserts (I think they are aluminum), I have gotten stainless steel adapter inserts online and tapped those to 1/4-20. After two years of use, those also have not shown any signs of wear or looseness.

So, if you go to a place like even Hood River, try to mount a fin or foil, and your screws/bolts are too long or too short, good luck finding a stainless M6, even with all the shops there. Ace Hardware up on the hill has a decent selection, but I use only hex-head bolts to avoid sticking a screw driver through the top of the board if it slips. A nut driver is safer. So, every shop and hardware has a big selection of 1/4-20 stainless in really long lengths. Two years ago, when I bought a brand new foil in Hood River, I could not foil the first day with it--in Hood River no less--because I could not find the correct length of M6 screw. My wife had to guard my gear at the Event Site while I ran all over town looking for the M6 screws, to no avail. (I foil with a Mike's Lab L6, which has a really thick tail and requires screws of 3" to 3.5".)

When you buy a foil from Sailworks, the first question they ask you is if you want them to tap the inserts to 1/4-20.

We yanks are still averse to metric.

Australian or European readers: ignore this message.

Not all Yanks. Chinook carries M6 to 100mm... next time...

Select to expand quote

segler said..
All good points. Yes, you are basically cross-threading. If the M6 material has any kind of formability (such as brass) this is no biggie.

For many years with fins we have tapped the M6 brass inserts to 1/4-20. Same for carbon foils that have M6 brass inserts. If it is aluminum, we leave it alone and live with M6. The exception is the M6 holes on the deep tuttle top of the Power Plate. I tapped those to 1/4-20. After dozens of sessions, they have not failed.

For the Slingshot M10 threaded holes, instead of getting the Slingshot M10-M6 adapter inserts (I think they are aluminum), I have gotten stainless steel adapter inserts online and tapped those to 1/4-20. After two years of use, those also have not shown any signs of wear or looseness.

So, if you go to a place like even Hood River, try to mount a fin or foil, and your screws/bolts are too long or too short, good luck finding a stainless M6, even with all the shops there. Ace Hardware up on the hill has a decent selection, but I use only hex-head bolts to avoid sticking a screw driver through the top of the board if it slips. A nut driver is safer. So, every shop and hardware has a big selection of 1/4-20 stainless in really long lengths. Two years ago, when I bought a brand new foil in Hood River, I could not foil the first day with it--in Hood River no less--because I could not find the correct length of M6 screw. My wife had to guard my gear at the Event Site while I ran all over town looking for the M6 screws, to no avail. (I foil with a Mike's Lab L6, which has a really thick tail and requires screws of 3" to 3.5".)

When you buy a foil from Sailworks, the first question they ask you is if you want them to tap the inserts to 1/4-20.

We yanks are still averse to metric.

Australian or European readers: ignore this message.

I'm glad you haven't suffered any failures. I've had proper brass inserts eventually fail on a foil before. For a guy who doesn't trust a screw driver, you trust brass more than I do. We all choose our battles, I guess.

I did the M6 to 1/4 conversions way back when - I think the tap is still in my toolbox somewhere. It doesn't make sense now when I can pop down to Home Depot or Ace locally and grab a screw. Or, as I suggested, just go online and order every size conceivable for about $0.30-0.50 a pop. I've even bought up to M6-100mm at HD locally - that's about 4 freedom units long. Maybe if Sailworks didn't enable everyone, someone in Hood River would carry more.

https://www.homedepot.com/p/Everbilt-6-mm-1-0-mm-x-100-mm-Stainless-Steel-Metric-Pan-Head-Phillips-Machine-Screw-860348/205115002