stripped threads on subal housing

I have an uwcs ball on top of my Subal ND20 for my focus light. Even though I was warned and thought I was careful I apparently over-tightened it and it will not come off, it just spins. I have tried having tension on it when I try and unscrew it, but no luck. Since I was forewarned I imagine this has happened to other folks. Any ideas?

Andy

You have a ball adapter like the one pictured in the attachment to this post?

It sounds like electrolysis (differing metals: stainless steel (the threaded stud) and aluminum (the housing and ball adapter) will create a weak electrical current when exposed to salt water). This can erode metal or basically weld them together.

The prevention:

-use silicone grease on the treads of the stud

-wrap the stud with a couple of wraps of teflon plumber's tape

-periodically, remove the ball adapter, clean the stud, and reapply the grease and tape

-add a sacrificial anode to both parts (back and main body) of your housing

The fix:

Once you remove the ball adapter, try using white vinegar to dissolve the corrosion (use modeling clay to build a little dam around the stud/ball adapter and fill it with vinegar; let is soak for a few days). You could also try the same trick with penetrating oil.

if the stud is fused to the housing:

-have a machinist remove (using Bridgeport machine, housing held in a jig, and end mill) the stud from the housing body

-replace the bad threads with a Helicoil insert

Take Care,

ChrisS

I have an uwcs ball on top of my Subal ND20 for my focus light. Even though I was warned and thought I was careful I apparently over-tightened it and it will not come off, it just spins. I have tried having tension on it when I try and unscrew it, but no luck. Since I was forewarned I imagine this has happened to other folks. Any ideas?

 

Andy

After you get it off.. You can replace the stock plastic adapter with a new upgraded all metal one and you won't have the problem anymore.

The plastic one is junk and the metal one is fully anodized aluminum.

Actually, it is not an electrolysis issue. Put it on too tight before a dive and would not come off after the dive, so it's just been on there for a year. Like the other reply stated it's just that the plastic mount that comes standard is junk (as I was told when warned "the plastic mount is junk, don't over tighten it or it will strip.").

I will replace it with a metal one. But first I need to get the other one off, preferably without having to use a hacksaw and ruining the ball.

Any ideas on how to get it off? I wrapped the housing in foam and a towel and put it in a vise and had someone pull as I unscrewed but no luck.

Andy

how does the mounting plate work?

(see attached picture)

(cap screw threaded into plate, plate screwed down to housing, ball adapter threaded onto exposed threads of cap screw?)

One way you could remove the ball adapter is:

-clamp the ball adapter in a vice (housing laying horizontal)

-use a jeweler's saw* to cut the stainless steel cap screw

-replace cap screw

_or_

(if the ball is loose enough to allow the jeweler's saw to slip between the ball and the mounting plate and make the 90 turn toward the housing)

-use the jeweler's saw to cut through the plastic mounting plate just inside the two mounting screws

_or_

-use the jeweler's saw to cut the the plate's mounting screws at about the mid-point of the plate's thickness

-carefully extract the cutoff mounting screws from your housing

-then replace the plate and the mounting screws

*very fine-toothed blade coping saw designed to cut metal

Take Care,

ChrisS

If you're uncomfortable with UW Nikon's suggestions, don't gp from bad to worse. Send it to Dan Blodget at Sub Aquatic Camera Repair and they'll fix it for you.

For others of you who may be reading this, the problem is that the stock plate is plastic and there is a metal insert (helicoil) in the plastic. The metal insert gets loose in the plastic. The ball adapter in the metal

insert will not come out of the metal insert because the metal insert just spins in the plastic plate.

I know of no other way then to hacksaw it off. The thread in the adapter is loc tited in and the only way to

get that out of the adapter is with hot water. Usually soaking it will loosen it. You could try pouring very

hot water over the adapter and see if you could loosen the stud from inside the adapter. If you can then

the adapter will come off leaving the stud in the plate. Then you can reach the small screws that hold

the plate to the housing and remove it.

Your adapter then can have a new 6mm stud installed into it.

Sorry for your problems. We try to warn everyone before they put an adapter in that plate to replace the plate with an all aluminum one.

Let me know how it turns out.

terry@ulcs.com

Terry

You could try just cutting the plastic away carefully with a Dremel tool or similar instead of doing surgery on the metal bits. The metal insert should come free relatively easy.

I had a similar problem with the standard Subal plastic plate with metal insert. In my case as I screwed the ULCS ball adapter into the plate the plastic part just split down the middle and the ball with metal insert came free. It was relatively simple to remove the metal insert from the ball using some pliers and a spanner. I replaced the Subal plastic plate with a solid aluminium ULCS BA-SP plate: