Slingshot 10mm Bolt conversion

Foiling related talk in here
Post Reply
Posts: 258
Joined: Mon Nov 19, 2018 8:44 pm
Location: Hayling, Avon, Poole or QM
Has liked: 70 times
Been liked: 73 times

Slingshot 10mm Bolt conversion

Post by Smidge » Thu Aug 08, 2019 12:49 pm

Slingshot foils come with 10mm fin box bolts. They say they have tested normal 6mm bolts and concluded they are just not strong enough for foiling (despite supplying a M10 to M6 conversion thread as an option that I currently use). They recommend to replace 6mm bolts very frequently if you do use them.

This link goes through how to drill out your fin box to take M10s (scary!!) - as obviously the holes in your fin box wont be wide enough (unless its a Slingshot board).

If Slingshot have had this experience its difficult to imagine that other big foils arent susceptible to the same issue - so maybe replace bolts regularly. Hard to imagine they are making it up as its a commercial disadvantage for them to be shipping non industry standard bolts and encouraging people to drill out their boards if they buy a Slingshot. It reminds me of the Neil Pryde pink one non standard foil fin box bolts with the wide imperial thread - that was to increase the strength of the thread connection in relatively soft aluminium, but they didnt tell anyone that, so it just irritated and some mistakenly got their masts rethreaded to standard narrower metric)

Not sure if Im going to do the frightening drill thing or replace bolts regularly..... ... -hardware/

Posts: 264
Joined: Fri Nov 23, 2018 4:59 pm
Has liked: 4 times
Been liked: 91 times

Re: Slingshot 10mm Bolt conversion

Post by Sailrepair » Thu Aug 08, 2019 3:47 pm


I have been foiling a few years and never bent a M6 bolt. Bending a bolt would suggest the foil head can rotate in the tuttle box, I wouldn't have thought it could, maybe I'm wrong.

The Pryde powerbox foil heads come with a 8mm drill bit with its own handle so it looks like a "T" shaped cork screw so that you can drill out your board.

Posts: 82
Joined: Tue Jul 09, 2019 3:26 pm
Location: Highlands
Has liked: 65 times
Been liked: 27 times

Re: Slingshot 10mm Bolt conversion

Post by Farnorthsurfer » Thu Aug 08, 2019 11:35 pm

So I am also using Slingshot gear and bought a Tuttle head for the mast brand new on offer from eBay. I was pretty surprised to find it had 10mm threads for the ‘fin’ bolts. It also proved impossible to buy the 10mm to 6mm adapters here in the UK and despite writing to Slingshot UK who weren’t any help I had to order from the USA.
I don’t think it’s the best plan to have the 6mm adapters in the first place as they are sure to corrode into the Tuttle head sooner or later.
BUT, I have noticed on the Slingshot web site that the adapters are in short supply and on offer, are sure sign of old stock. And that the Tuttle head adapters now appear to have smaller 6mm holes in place of the 10mm originals.
If anyone can confirm this that would be good?
I was going to write to Slingshot but it’s on the list and I haven’t got round to it yet.
Can’t say I will spend more cash on a new head at least not until the old one corrodes out.
As for strength, the 6mm bolts are primarily in tension surely and to bend them the mast would have to move in the box.
More likely with the Slingshot drilled holes rather than barrels like a fin which would allow a slight misalignment and stop the screws bending perhaps?

Posts: 62
Joined: Wed Jun 19, 2019 9:34 pm
Has liked: 19 times
Been liked: 21 times

Re: Slingshot 10mm Bolt conversion

Post by nimo » Fri Aug 09, 2019 7:30 am

Personally I think the 6mm bolts will be strong enough providing that :
1) the head is FULLY into the box . make sure it is clean before assembly. a small spray of silicon spray will help here.
2) the bolts are in good condition and fully tightened up.

Any movment in the head to box joint will break bolts, but there should be none if it is all assembled correctly.

Post Reply