an issue with sticking bolts....

[Chuck Wintle]

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I have an issue when these bolts like the image are torqued to specification for a job where I work. The bolt is steel and the insert on the fixture is steel and the bolt tends to bind/stick as it is being torqued. I have tried anti-seize past to the underside of the bolt head, grease and oil yet the bolt will still stick to a certain extent. Its most noticeable when its needed to loosen and remove the bolts. Its with a very audible snap that the bolt releases. is there something out there that can be used to prevent this steel to steel sticking??

[Mac McQuinn]

Have you detected any corrosion in the threads whatsoever? Are you using a small machine washer under the head of the bolt? Would a stainless item give a smoother release? What level of torque are you at? Can you get to both sides to measure the bolt stretch to determine if the bolt is being over torqued for it's grade? Does it appear as if the insert is deforming at the applied torque?
Mac

[Scott Shepherd]

I've rebuilt a lot of precision machinery put together with socket head cap screws and they've always come out just like you describe, always. We used all the top of the line products when building machines and I've never heard or seen anything that caused them not to do that, nor have I ever heard of anyone saying they weren't supposed to do that. I suspect it's more the nature of the seating surface area vs. something like a Hex Head Bolt, that probably has a little more surface contact, but that's just a guess.

[Lee Schierer]

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Its most noticeable when its needed to loosen and remove the bolts. Its with a very audible snap that the bolt releases. is there something out there that can be used to prevent this steel to steel sticking??

That is pretty normal with socket head cap screws. Use a quality brand screw and a quality allen wrench and you shouldn't have any problems

[Ole Anderson]

You are more likely to have problems with stainless steel screws as they tend to gall and really get stuck permanently.

[Tom Stenzel]

Like Scott and Lee both have already said, I had the same experience with cap head bolts. Steel bolts, steel threads. If the material being bolted down was aluminum it seemed the 'snap' when the bolt was turned loose was noticeably louder.

It seemed the problem wasn't the bolt threads locking but the bolt and the material under the bolt head locking together. But that's a SWAG on my part.

-Tom