KiwiProp thread strpiped

[tawhiri]

I have a two blade SDC from Kiwiprop and one of the 6mm stainless locking grub screws has stripped the thread of the fibreglass in the hub. Could I tap it out to 8mm and put a helicoil in to accomade the 6mm grub screw?
My main concern is, will the grub screw become corroded into the helicoil and then I can not remove it next season?
Thanks in advance

 

[rob2]

It does sound like your best option and they are available in stainless, too. It won't be corrosion that might bind the screw in, but galling. Stainless threads can grab and lock to each other just as the smaller dinghy bottlescrews do. Best to use some waterproof grease or coppaslip on the threads to prevent it.

Rob.

 

[danielefua]

I have a two blade SDC from Kiwiprop and one of the 6mm stainless locking grub screws has stripped the thread of the fibreglass in the hub. Could I tap it out to 8mm and put a helicoil in to accomade the 6mm grub screw?
My main concern is, will the grub screw become corroded into the helicoil and then I can not remove it next season?
Thanks in advance

Just a question for the experts: is it true that to prepare the hole for a 6 mm helicoil you can use a standard 8 mm tap? I thought that special taps were needed.
For sure you must be careful about the pitch: I don't think that the hole for a 6x1 helicoil can be prepared with a 8x1.25 tap.

Daniel

 

[TNT]

Daniel, that is correct, helicoils are pitched so its not poss for them to screw out when screwing in the parent thread.

tawhiri, there are some good products on the market that would allow you to fill the hole completely and re-dril/tap the original size, take a look at the Loctite range. you may find that you have to open the hole up a bit and prep the edges but I am certain that it can be repaired to original spec.

 

[tawhiri]

Daniel
You are correct that the standard 8mm pitch is 1.25, but I have an 8mm tap with 1mm pitch because I had to repair the stanchion base which by chance is also 6mm.

 

[savageseadog]

What fibreglass in the hub?

 

[tawhiri]

plastic hub

This is all plastic, see photo below

 

[FullCircle]

Is it not Nylon66 or Zytel (proprietary name?

Give Alan Pollard a ring at Vecta Marine, he will advise probably for free, may even offer a repair. 01672 564456.

 

[colhel]

I have a two blade SDC from Kiwiprop and one of the 6mm stainless locking grub screws has stripped the thread of the fibreglass in the hub. Could I tap it out to 8mm and put a helicoil in to accomade the 6mm grub screw?

Fraid not. Helicoils require a special tap. The correct drill sze is 6.3mm.