Facts, myths and opinions about fasteners

[LittleSister]

I stumbled upon the webpage, '10 tricks engineers need to know about fasteners' (link below) that I thought might be of interest/controversy to some on here. Example - 'spring washers don't work'.

I was surprised, for instance, by the claim that any more than 6 thread turns' depth doesn't add any strength to a fastener (assuming same materials).

The debates/quibbles below the line are interesting, too.

There's also much to engage and distract the mechanically minded, creative and just plain curious on his home page (including various ruminations on how to avoid getting distracted!).

https://engineerdog.com/2015/01/11/10-tricks-engineers-need-to-know-about-fasteners/

 

[vyv_cox]

I was quite surprised to read the part about DTI Smartbolts. From around 1984 I worked closely with a UK company called Rotabolt, who I am pretty confident invented the principle. https://www.rotabolt.co.uk/ Is DTI making them under licence or have they just nicked the idea. I think the colour indicator may be theirs though, Rotabolt use a rotating cap.

Quite an interesting page though. I worked a lot with bolting and agree most of what is said, although ISTR that the proportion of load on the first thread of the nut was a lot higher than 34%.

 

[thinwater]

I was quite surprised to read the part about DTI Smartbolts. From around 1984 I worked closely with a UK company called Rotabolt, who I am pretty confident invented the principle. https://www.rotabolt.co.uk/ Is DTI making them under licence or have they just nicked the idea. I think the colour indicator may be theirs though, Rotabolt use a rotating cap.

Quite an interesting page though. I worked a lot with bolting and agree most of what is said, although ISTR that the proportion of load on the first thread of the nut was a lot higher than 34%.

There was an article in Good Old Boat magazine last month that ran through some of this in the process of discussing galling.

The tid bit I like to remind people of is just how SLOWLY you need to turn SS bolts that are highly loaded. Think about how a nut can get hot, and then remember that the heat is concentrated at the surface. The last few turns should take minutes, not a few seconds. Same with rigging screws, although they are bronze. And don't spare the lube.

 

[rotrax]

There was an article in Good Old Boat magazine last month that ran through some of this in the process of discussing galling.

The tid bit I like to remind people of is just how SLOWLY you need to turn SS bolts that are highly loaded. Think about how a nut can get hot, and then remember that the heat is concentrated at the surface. The last few turns should take minutes, not a few seconds. Same with rigging screws, although they are bronze. And don't spare the lube.

Interesting-thank you.