Aluminum wakeboard tower question

[Augoose]

Long story short, I have a new place to park my boat which is covered. In order for it to fit into the spot, the tower needs to fold. When I went to loosen the four 5/16" threaded bolts which hold the folded components together, all 4 heads broke. The tower has never been folded down that I know of and its likely its been frozen for years.

I tried PB buster, heat, etc to get them out but ultimately each broke. I then tied to use bolt extractors which ended up breaking one of my new carbide extractors, a pretty big one too. These SS bolts were in there and didn't seem to want to come out so I drilled each of them out.

Unfortunately I mucked up the threads inside the holes pretty good so that there is no way 4 new 5/16" bolts would ever thread in there an a manner which they'd easily come out when it was time to take the tower down.

So, my question is this - should I drill 4 clean new holes in the next larger diameter and then take it to someone to tap (because I don't trust myself to do it correctly), OR, could I drill clean new holes in the next larger diameter and then use a locking pin setup without threads? Would the stresses imposed from pulling a wakeboarder eventually oval out the pin holes in the aluminum? The fold location is about halfway up each vertical side of the tower and there are two 5/16" bolts per side.

The aluminum is about 2.5" - 3" in diameter, is tubular.

Thanks!

 

[Bondo]

Re: Aluminum wakeboard tower question

So, my question is this - should I drill 4 clean new holes in the next larger diameter and then take it to someone to tap (because I don't trust myself to do it correctly), OR, could I drill clean new holes in the next larger diameter and then use a locking pin setup without threads? Would the stresses imposed from pulling a wakeboarder eventually oval out the pin holes in the aluminum? The fold location is about halfway up each vertical side of the tower and there are two 5/16" bolts per side.

Ayuh,.... We need Pictures,....

You could;...
Tap the holes to 3/8"-16,....
Use crimpin' Nut-inserts in 5/16" threads, or 3/8"....
Or possibly go with the lockin' pins,...

But again, Pictures are almost Required...

 

[Augoose]

Re: Aluminum wakeboard tower question

Sorry- should have known better!

Photo 4 shows the tower in use with a red circle indicating the folding point. The black thing is what's left of the plastic hand screw which was previously used to release the bolt. When it broke on me last year that should have been a "clue".

Photos 1-3 show a close up of the section which comes apart in its current state. What's odd is that I didn't even drill out that top bolt (the bolt in the photo which looks nearly whole). Once I drilled out the bottom, the connection pulled right apart despite there being threads on the bolt AND in the hole....

Because I missed the edges of some of the bolts a bit I think I'd have to go up a couple of sizes, probably to 1/2", to get past all the rough stuff to get into some good metal with which to make new threads out of.

How do the crimping nuts work?

Do you need a close up pic of the condition of the holes?
Thanks!

 

[cyclops2]

Re: Aluminum wakeboard tower question

Why can't you C clamp the brackets together & drill all the way thru BOTH mated brackets & use FLAT HEADED SS bolts or round headed SS bolts with nuts in a drilled out recessed pocket for them ? You already have 1 set of pockets.

I would then select SS bolts that just slip fit into the drilled holes.

At least 2 C clamps are needed. 1 over a bolt hole & another along the mateing side seams.

ONLY drill 1 hole out at a time.........Put a bolt & snug nut in .....BEFORE drilling the second hole..........Rock solid hole line ups that way.

 

[Augoose]

Re: Aluminum wakeboard tower question

I like it as long as the consensus is that whatever bolts I put in don't need to be into threads in the aluminum. The original "nuts" where plastic anyway and were designed to be hand tightened.

 

[AviatorJim]

Re: Aluminum wakeboard tower question

I think to prevent any more damage, and prevent making the holes any bigger, a visit to a good machinist may be the way to go. That is assuming you can can find one who will make a repair.

But if you can't. . .

By stepping up the holes, and using a reduced head bolt you won't have to enlarge the pockets. Be sure you have new bolts with shanks that go all the way through, with the excess made up with washers under the nut. The threads will cut into the aluminum very easily. And then use nuts. Also stainless. Dissimilar metal corrosion is going to happen, but it can be reduced if you paint the area with a clearcoat. But then other appearance issues might come up. And a little antisieze can help too.

 

[Grandad]

Re: Aluminum wakeboard tower question

Unfortunately I mucked up the threads inside the holes pretty good so that there is no way 4 new 5/16" bolts would ever thread in there an a manner which they'd easily come out when it was time to take the tower down.
So, my question is this - should I drill 4 clean new holes in the next larger diameter and then take it to someone to tap (because I don't trust myself to do it correctly), OR, could I drill clean new holes in the next larger diameter and then use a locking pin setup without threads? Would the stresses imposed from pulling a wakeboarder eventually oval out the pin holes in the aluminum? The fold location is about halfway up each vertical side of the tower and there are two 5/16" bolts per side.

Once SS and aluminum "gall", there's not a chance you'll rescue the original threads as you have found. Tapping to a larger size will work as long as you don't still have some SS stuck in there where your tap is trying to cut aluminum. Your tap will wander to avoid the tough SS and you'll have an even bigger mess. If the tapped hole design failed you once, it may fail again with a larger tapped hole. I'd be inclined to drill a 3/8" clearance hole through both parts and countersink for an oval head bolt. The nut side could also be countersunk somewhat and have a SS nylock or acorn nut installed. Use an anti-sieze compound on all the threads including SS to SS. I have twist/sheared off stainless steel bolts that refused to loosen from SS nuts when both parts were brand new, apparently simply because they were dry. Using a through-bolt fastener will allow you to tighten the fitting together more securely than just pinning them together. You won't get any ovalling of the holes if the parts can't move. - Grandad

 

[cyclops2]

Re: Aluminum wakeboard tower question

Modern S S is OFTEN CRAP as Grandad & I have snapped many. Biggest problem is NEW thread SLIVERS STILL ON nut & bolt threads...
Wash nuts & bolts in a solvent. Blow dry. TEST RUN THE NUT & BOLT .........ALL THE WAY to see if it galls and jams tight in a VISE !!

When you have a good running set, put them in with a little Vasaline on the bolt threads.....A little.....Not enough to melt in the hot sun & run down something.

 

[Bondo]

Re: Aluminum wakeboard tower question

Sorry- should have known better!

Photo 4 shows the tower in use with a red circle indicating the folding point. The black thing is what's left of the plastic hand screw which was previously used to release the bolt. When it broke on me last year that should have been a "clue".

Photos 1-3 show a close up of the section which comes apart in its current state. What's odd is that I didn't even drill out that top bolt (the bolt in the photo which looks nearly whole). Once I drilled out the bottom, the connection pulled right apart despite there being threads on the bolt AND in the hole....

Because I missed the edges of some of the bolts a bit I think I'd have to go up a couple of sizes, probably to 1/2", to get past all the rough stuff to get into some good metal with which to make new threads out of.

How do the crimping nuts work?

Do you need a close up pic of the condition of the holes?
Thanks!

Ayuh,.... In pic #2,... The Holes should be Clearance holes....
The remainin' bolt pieces are in the Threaded holes....

Where/ what were you Drillin' on,..?? don't see any drill marks...

For the Fix,....
Do ya know anybody with Oxy/ Ac torches,..??
That's pretty Corroded,...
It's gonna take some extreme, Quick heatin', 'n quenchin' to get those stubs outa the threaded holes....

Are those holes all the way through, or blind holes,..??

 

[Augoose]

Re: Aluminum wakeboard tower question

Thanks all for the assistance. Exactly right - the drill wandered badly through the aluminum and SS bolt which made somewhat of a mess. I cleaned the holes by continually stepping up the drill bit size until all of the mess was gone. I'm off to the hardware store to get some new equipment to put it all back together. Hopefully I can find some large plastic hand nuts to make lowering and raising when it goes to the storage lot easier.

Thanks again!

 

[cyclops2]

Re: Aluminum wakeboard tower question

I would go with all metal parts for a tower.

The constant strain of beefy people & a jumper can generate some good shocks........Metal yes .Plastic no.

 

[Augoose]

Re: Aluminum wakeboard tower question

Where/ what were you Drillin' on,..?? don't see any drill marks...

It's gonna take some extreme, Quick heatin', 'n quenchin' to get those stubs outa the threaded holes....

Lol- I was drilling the bolts out! On a few I did a good job but one really wandered quite a bit!

Tried heat - didn't work. Ended up cutting the bolt off and then drilling it out. Not a single extractor in the kit I bought worked either.....

I ended up using 3/8" hardened allen head bolts going all the way through the aluminum with a large hand nut to tighten it down on the far side (that's what was there before). I then recessed the tube so the head of the allen head sits flush and doesn't protrude. I also lightly coated the threads of the bolts in marine axle grease. Takes about 30 seconds and all 4 bolts are out so the tower can collapse. Feels very solid.

Thanks again everyone for the assistance. This was a real bear drilling out five bolts......

 

[cyclops2]

Re: Aluminum wakeboard tower question

Extractors rarely work in corroded Alumimum..yours..Copper, bronze or brass. All really take hold of the threads.
They are great in hardned metals. Usually work easily then, because the threads are not stretched or jammed.

 

[Augoose]

Re: Aluminum wakeboard tower question

Extractors rarely work in corroded Alumimum..yours..Copper, bronze or brass. All really take hold of the threads.
They are great in hardned metals. Usually work easily then, because the threads are not stretched or jammed.

Makes sense. The threads really bite into that soft metal...