question about fastening tops to decks?

[GodsReel]

Anyone ever heard of tapping the deck and using machine screws to fasten a t-top to deck, the guy who built my top and tower claims he has found this is better than wood screws. my deck was recently recored with nidacore and marine plywood (where console and tops would mount) I know that thru bolted would be ideal and i am looking into that. He tapped through the fiberglass and wood or nidacore and used either 1" or 1 1/4" stainless machine screws. I
need your thoughts.
thanks Paul

[strick]

Paul I have not heard of that before. All the ones I have seen use wood screws. That's not to say that machine screws wont work if the glass is thick enough then it probably will. I have seen machine screws used in other fiberglass applications that held together much smaller things then a t-top to a deck.

strick

[pelican]

Originally Posted by GodsReel

Anyone ever heard of tapping the deck and using machine screws to fasten a t-top to deck, the guy who built my top and tower claims he has found this is better than wood screws. my deck was recently recored with nidacore and marine plywood (where console and tops would mount) I know that thru bolted would be ideal and i am looking into that. He tapped through the fiberglass and wood or nidacore and used either 1" or 1 1/4" stainless machine screws. I
need your thoughts.
thanks Paul

nida core : basically made from recycled milk jugs,held with a light scrim bcking - this produt will NEVER hold a screw,or any othr kind of fastener - the fiberglass skin on both the top and the bottom will - however,i would never trust it...thru bolting and sleeving is the way to atach someting,when nidacore is used...

there's a trick when working with aluminum or solid fiberglass - if you're gonna use a 1/4 - 20 machine screw,just drill a 3/16 hole,insert the screw,and send it home,it will "tap" either aluminum of solid fiberglass - ocean yacht used this method alot...


no offense:
nida core is a product i treat like kryptonite...here's what it looks like...

i'm gonna guess the reason for the mix of core materials is due to what i stated concerning nidacore - not to second guess anyone,but,using a mix of cores - composite and wood is a little strange - normally,when using a composite,the core is removed in the area the fastener is going to be located,that area is filled with thickened epoxy,the epoxy will hold a screw...

[Islandtrader]

The method I have seen used by attaching screws to nida core is as follows.

Drill the hole over sized. Then chuck a allen wrench in to the drill ...the L part should then be inserted into the hole. Ream out the core and then fill with epoxy. Re drill and your done.

Now that being said every application has its limits.

[Old'sCool]

I thought of glassing 1/4 or 3/8 aluminum plate under my deck and doing the same but did not. I think that's the only good sub-structure for holding machine screws. SS or titanium too but the $$$$$

[GodsReel]

when i recored parts of the deck i used some nidacore and marine plywood where the console and tops and leaning posts would mount, there might be however some nidacore where the very back ladder legs attach to floor. but most everything is down into new marine ply and glass.

[wattaway2]

I like Islandtraders idea but might try something along with it I've used . Try using heli coil inserts in the epoxy that will give the screw something more substantial to work with and the helicoil "spring " would should bite into the epoxy a bit better that just a screw would

[gofastsandman]

Originally Posted by wattaway2

I like Islandtraders idea but might try something along with it I've used . Try using heli coil inserts in the epoxy that will give the screw something more substantial to work with and the helicoil "spring " would should bite into the epoxy a bit better that just a screw would

Honeycombs are designed to be somewhat stationary. Wood is not a 4 letter word. Iffn
used well.

Cher
the4

Or you could take IT`s idea and introduce an oversize dowel to hit. Separate and equal.

[pelican]

this is a repair i did a few months ago - the deck's cored with divinycell,the console was held in with silicone,and the t-top was atched to the deck with steel "toggle" style bolts...
the top pulled out,on all 4 points,the console was actually dislodged,and i was able to lift up on the whole assembly...


the boat was unrigged,t-top was removed,console removed - mounting points for the top were opened up and the core was removed to the inner skin,these areas were built to the original thickness,using alternating layers of 1808 and 3/4oz chop strand - built to approx 3/4" thickness.

upon reassembly,the top was mounted in the manner i described - the mounting holes were marked,and drilled 3/16",i used 1/4-20 oval head machine screws to atach the top to the deck - a shot of 3m 5200,was dropped where the mounting pads went,and in each screw hole - the screws were ran into the holes and tightened securley...

ocean yacht - viking yacht,these mfg's use this method of installing equipment.
there's no need to "tap" epoxy,or fiberglass,or lite thickness aluminum - all of these materials will accept a machine screw,when used in this manner - no helicoils needed.these screws will never back out,or pull...

as the pictures show: nida core is a honeycomb material - it has the worst screw holding capabilities,attempting to screw anything into that material,will result in a failed attempt...

[pelican]

looks pretty gresome,huh ?