Reattaching Stanchion with no Access to Thru-Bolt

[Silverman]

I was able to remove the bolts holding one of the stanchions on my stern pulpit, but there is absolutely NO WAY to reach the nut to thru bolt when replacing. The other 2 are easily reached. What is the best way to reattach considering thru bolting this one stanchion is impossible? Should I fill the hole with 5200 or epoxy and lag screw this one stanchion or do you have suggestions for a better way. I will use butyl tape to seal and hopefully will never have to remove again. (busted weld this time). thanks

[tkeithlu]

Welcome to the forum, Silverman.

With no access, yes, a lag bolt will have to do. Assuming the hole is clean, start by determining it's diameter. Without a proper caliper for that job, insert drill bits of increasing size from your 1/64" set. Then, you want a screw that has a body (not including the threads) that is tight in that hole. At this point investment in a vernier caliper is wise. It should be long enough to grip without quite bottoming out. Yes, I think that I would bed it in some 5200 in the process.

Good luck with it.

[BigBeakie]

As an alternative, fill an oversize hole with toughened epoxy, ie Cabosil and fibers, then drill and tap for a stainless helical insert like Helicoil or Recoil. Then you have stainless to stainless thread strength from your stainless screw to the stainless insert. Get the longest inserts for the available hole depth, which is usually 3 times hole diameter. Some of them you can stack on top of one another if the hole is deep, to get maximum thread contact.

[tkeithlu]

That's a good idea for gaining more strength, BigBeakie. I'll remember that for the next time I'm in that situation.

The core of the problem is that the original bolts supplied more strength than a lag screw can. Whether the lag screw will be adequate none of us can answer for sure.

[GordMay]

Greetings and welcome aboard the CF, Silverman.

Toggle Bolts [wing or snap] might be another alternative to lag screws, or inserts.

[Jammer]

There are a variety of threaded inserts available that can help with these situations. For high strength applications you would want to bed them in epoxy with silica filler or something.


https://www.mcmaster.com/threaded-in...ainless-steel/


You may be able to fish an epoxy-coated nut or nut and washer in place with wire or thread in an area that has some access but not enough to allow a hand or tool.

[notiesbob]

What did Catalina recommend???

[j.g.evans]

When faced with your problem I was able to slide in a 1/4" AL plate and then was able to tap threaded holes to fasten into. Sometime I use automotive Gorilla Hair to hold it in place while drilling and to fill voids.

[geoff3nebel]

Does the stanchion have one big threaded bolt to secure it? Is it alu or stainless?
If it’s stainless with one big bolt, take it to your local stainless welder and get him/her to cut off the original and weld on a longer one

[chasmains]

Look at rivet nuts too. https://www.mcmaster.com/#97467A728 is a SS 3/8” rivet nut. Max installed length is 0.47”. So a backing plate can be accommodated. An installation tool is needed and McMaster sells them too. I have used them to install a rigid boom vang. No problems so far.

[Hudson Force]

I'm wondering if there is an application using the type of butterfly wing nuts that are used when installing grab bars to tiled shower stalls. The folding wing nut is inserted through the drilled hole and then the threads are tightened to anchor the fixture. If stainless fasteners are made of this type and the bore is epoxy filled afterwards, it could work well.

[Cheechako]

Hmmmm.... seems if you can reach two nuts what...3-4" away from the problem one there is a way to reach the problem nut. ?
Tape a nut to a reacher of some sort? A socket extension with a universal joint? A heavy flexible wire?
Could you push a bolt up through from the inside and put the nut outside?
There's always a way!
Someone assembled it in the beginning....

[Sailing August]

Fill the hole with fiberglass powder & epoxy.
Drill and tap a new hole.
Install a threaded insert with epoxy for extra hold.

[Cheechako]

How thick is the glass? I have drilled and tapped fiberglass and used a bolt several times.

[Hudson Force]

Originally Posted by Cheechako

...........................
Someone assembled it in the beginning....

'but often assembled during a stage before other large pieces of the vessel were assembled and covering the access.