Stainless Hardware Lesson

nope, they are probably 'galled'. a condition that happens when you put together two unlubricated stainless steel parts. essentially the pressure of rubbing has spot welded the pieces together. this condition does not respond to penetrating oils and other normal methods since the parts are not rusted or dirty.

Unfortunately I would also say this is what has happened - I had the same experience with new replacement stainless bolts on my bike - great, I thought, fit and forget, except when I was halfway through installing the first bolt I had to take it out and it seemed unusually stiff. I HAD to get it out so slow extreme force was eventually applied even if it stripped things, but it came out - a call to the supplier confirmed it must always be used with copperslip grease or similar to stop this very problem occurring.

I think the only solution may be force but very slowly to minimise heat causing more spot welds, else it will be a spark eroder or similar drastic action

Nick

Fred McKenzie hath wroth:

Congratulations and welcome to galling. What you've done is inadvertently scrape off the protective oxide coatings from both pieces and welded them together. Next time, try some anti-seize goop in the threads. Incidentally, you can have the same galling problem with aluminum and titanium.

You're correct that oil won't do anything useful. However, freezing should work. Clean off as much oil as you can remove with some solvent. Find someone that has liquid nitrogen. If that's difficult, some dry ice. Freeze only the bolt, not the ball mount. A bolt that size will take some time to shrink, so you may need to freeze it for some time. My guess(tm) is about 2 hours. You could also warm up the ball mount end, but it's probably not necessary. When the bolt is nice and cold, do the brute force trick again. Don't beat on it with a hammer or impact wrench as you're likely to shatter the bolt.

Another way is simple brute force. Build some custom vice jaws and lock the ball mount in place. Flatten the sides of the bolt and attack it with a big wrench and "torque amplifier" (steel pipe over wrench handle). Beat on it with a hammer if necessary.

Another alternative is to just leave it as is. It's now a permanent part of the ball mount. If it's sticking out too far, cut it back to a usable length or install a threaded sleeve between the ball mount and QD2 disconnect.

This is a relatively common problem with stainless. It will 'friction weld' itself easily, and once that happens nothing seems to get it apart. I've some interesting stainless bolts and nuts that this has happened to, and have seen the effectiveness of the welding being higher than the failure point of the bolt!

What is worse, it is difficult to predict when this will happen, but it is important to use a stainless compatible anti-sieze compound on stainless hardware.

I doubt you'll get it apart... If you want I can give you a picture of a bolt end with a non-cross threaded nut--the bolt snapped rather than the nut coming off (and it took a lot of work to break that bolt!)

You may have better success drilling it out, if that's an option.

Fred McKenzie wrote in news:fmmck-055CC2.15500821102007 @nntp.aioe.org:

When dealing with frozen parts, I use a torch to heat the parts up (if they and their nearby parts will stand the abuse. Get 'em good and hot - a red glow is not too hot - and back the screw out.

The obvious disclaimers as to the dangers of this method, such as red hot metal burning things, and "Don't try this at home, kids!" apply.

- 73 de Mike KB3EIA -

Joe & All-

Thanks for the information and suggestions. I understand stainless is a poor conductor of heat. I might try a combination of freezing the parts and then using a torch on the outer piece to increase the temperature differential.

The female threads may have been tapped prior to crimping that piece to the top shell of the ball, and the crimping process could have distorted the threads near the crimp. If I had known about the likelihood of "galling", I might have tried re-tapping the threads prior to installing the QD.

Fred K4DII

Hi, Fred. Retapping won't help, unless you have an oversized tap. What will help is using an adjustable die on the male part and squeezing the die down quite a bit before using it. This will give you a less than 50% thread engagement, but will still be enough for your antenna. Antisieze compound is the real answer. Also, if you ever need to drill and tap stainless, use the next larger size drill bit for the tap you are going to use. Otherwise you will surely break the tap. I have scars to testify to learning that!

Good luck, Paul KD7HB

Paul-

I understand there is also a "thread chaser" tap, which might be slightly oversized. I was thinking about the distorted threads being cleaned up by re-tapping. Perhaps one of the local hardware stores will have a 3/8-24 tap, as well as some anti-seize compound.

I contacted New-tronics by E-Mail. They also suggested heating the female threaded part with a torch. They apparently have encountered the problem before, but their instruction sheets never mentioned it or the need for an anti-seize compound.

Also, New-tronics does not sell parts, only complete assemblies!

Fred K4DII