Re: Problem attaching RAPAS ADAPTER - Stuck screws on AP-1200

Harley Davidson

I have had this same problem with a non-astronomical item before on aluminum with a SS setscrew. I actually twisted a bondhus  wrench [never broke it] and the damn setscrew did not budge! Out came the drill bit to take care of that problem.


On 10/13/2014 9:08 PM, Don Anderson jockey_ca@... [ap-gto] wrote:
Hi Joe
When I read your post about the "white paint" you saw when you got the one screw out, that got me thinking that I believe I know what may have caused the screws to get stuck. Basically what I think has happened is that "white paint" looking stuff you saw is corrosion products (aluminum oxide) that have built up between the SS screw and aluminum threads in the mount housing. You can get this corrosion when two dissimilar metals are in contact with each other (the battery effect) in the presence of moisture. Maybe the mount in a previous life, was allowed to accumulate moisture repeatedly. This problem is quite common in the boating world when using SS fasteners in aluminum. It can also be a problem with car engines where spark plugs seize in aluminum heads. Aluminum oxide aka Alundum is a very hard very abrasive material. It is the stuff used to make grinding wheels and sand paper! Joe, the upshot is that if corrosion product buildup is the problem, you may not get the the other screws out in one piece and may have to drill them out completely. I have personally run into this stuck screw corrosion problem with aluminum and SS several times in the past. Should you get them out or end up drilling and re-tapping the holes, I suggest you use a good quality anti seize compound such as "Anti-Seize" by Master Corp part no. M133 or equivalent on the screws during re-assembly.
Good luck with the remaining screws.
Don Anderson  

On Monday, October 13, 2014 5:17 PM, "JunkMailGoesHere@... [ap-gto]" wrote:

Don't drill the heads out yet! Buy a Torx screwdriver set that can be used with a socket wrench. Find the smallest Torx bit which will NOT fit as it is just slightly too large to fit in the stripped hex hole. Hammer it in until it is FULLY seated then use a socket wrench to turn it.

---In ap-gto@..., wrote :

    After oiling the screws with “rust breaker”, and trying the L-wrench again, I managed to get just one screw removed.
It finally came loose with a “SNAP” sound.
The stainless steel screw end threads were coated to just over 1/8”  in “white paint”. I assume that is the powder coat that got into the screw holes in the paint shop. It was either thick enough after drying to pack the threads tight, or it was still wet when the backplate was screwed on. Anyway, it behaved  just like Loctite.
    I heated the other two screw heads with a soldering iron, hoping it would burn the paint on their threads, but the heat was likely absorbed by the axle. So, the other two screws are too damaged by the L-wrench and bits, and now have to be drilled out, at least upto the top of their threads. Hopefully, tomorrow, with the backplate removed,  Vice Grips might remove the “screw stems”  left behind ... unless the paint still grips them too hard.
    Perhaps the assembler of the new mounts, should back off such screws,  just to clear the threads of paint or aluminum filings, before re-tightening them.
    Geeez, when I started out, it was  to be such a simple task of quickly attaching the RAPAS adapter  :-)
Joe (“Jonah” ?) Z.
Sent: Monday, October 13, 2014 3:01 PM
Subject: Re: [ap-gto] Re: Problem attaching RAPAS ADAPTER - Stuck screws on AP-1200
We always use stainless hardware, never used anything else. Some stainless is softer than others. 303 is softer than 304.

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