I managed to hit something with the centre fin on a thruster setup. The box is slot a box. There was no (minimal) damage to box itself, but all the plastic around the front screw is pretty much useless. I can't just push a bigger screw through it as anything screw grips onto basically just comes out in shreds. It does look like it is just plastic and I have not damaged the box. Are the screw holes part of the box meaning the whole box needs to be replaced or is there any easier way to fix this? Can I just put a new plug in the hole?
That particular slot box uses
(1) a screw that is near on impossible to find
(2) a self tapping thread thru the plastic. Nowhere near as good as the ones with the brass threaded insert. Unfortunately manufacturers choose to use different ones
If you still have the screw, a major rough up, then fill with molten plastic, re-drill and re-tap may work.
Or if you still have the screw I can replace the box with one the same (I have some)
Alternative is a threaded furniture insert like this: http://www.ebay.com.au/itm/281090532936?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
if you can find it in stainless and M4 or M5 (the M6 abouve may work but will encroach outside the box and need further fill work. Overall it is 13mm dia so its not easy)
Downside to the latter is you then have one screw different to all the others. But if it is to salvage a good board for the sake of$20 insert and a difficult but do-able install then why not
Last option, rebox in US, different slot boxes, or MT
Mark,
I still have the screw. If you replace box I assume that is major surgery - ie you have to cut the old one out of the board to replace? I never had any work done on a fin box before.
I assume it is much more time consuming then repairing a dings, noses, etc.
The board is one of the 5 box boards I am going to try the quad before doing any major surgery, but being 95KG I suspect I will need\prefer the grunt of thruster setup.
The furniture screw idea is a good idea as well.
Thanks for all your help
^^ Yes it is a cheap fix - I am using them in M6 for other things but it has to be stainless and smaller. Dunno if they are even available...
Let me know if u find them
I'd use one of these:
www.alibaba.com/product-detail/Heat-set-brass-knurling-insert-nut_60266766303.html
Finding the right one might be difficult though.
there is a topic on the Starboard site "Repair of damaged footstrap screw thread or vent screw threads"
You maybe able to apply the same methodology to repair your fin screw.
http://www.star-board-windsurfing.com/2016/products/repair_guide/
good luck
I find none of those knurled inserts work for very long when not actually moulded in.
I have used everything you can think of for putting a bolt into plastics and epoxying in the coarse thread furniture type is the only way to avoid it pulling.
Search helicoil and keysert - this would be the engineering approach to fixing a stripped thread.
The recoils need you to be able to thread a thread that is still quite close in size to the thread you have stripped so will depend on how much material is left in the hole.
The keyserts are a solid insert so are quite a bit larger in size so may be too big. The good thing about them is that you just have to buy the insert and use regular sized taps where as the recoil system requires a special tap and can get expensive if you need to buy the kit. Although a lot of engineering shops should have one.
Another option is to get some threaded rod or the thread off a bolt and drill and tap it, then drill and tap the board to take the new insert. Advantage is he insert can be made big to get into fresh material
