Understanding Snug Fits: Uses & Benefits

[araanandv2]

What is a Snug Fit?
Where is it used?

I have come across slip fit, press fit...
But not snug fit.

Please explain.

Thanks
Ana

 

[FredGarvin]

"Snug" comes up under the locational clearance (LC) class of fits and limits.

As per Machinery's Handbook:

Locational clearance fits are intended for parts which are normally stationary, but that can be freely assembled or disassembled. They range from snug fits for parts requiring accuracy of location, through the medium clearance fits for parts such as spigots, to the looser fits where freedom of assembly is of prime importance.

"Snug" is a bit of a dangerous word to use because it can mean different things to different people. To me, "snug" means a clearance fit that is just slightly over line-to-line. I use this kind of fit for something like a guide pin that locates the cover of a gearbox. In the gearbox, the pin is pressed into the case, but has a very slight clearance fit to allow removal and installation of the cover while still keeping a pretty good control over the cover's location.

 

[Danger]

I had no idea that there were different classes of fits. Cool.
It seems that you use 'snug' pretty much as I do. To me, it's something that can be assembled or disassembled with moderate manual effort using no tools, such as the adjustment nut on a pair of pliers or the cover plate on a clockwork mechanism.

 

[mgb_phys]

Generally goes as:

Sliding fit = it can slide in out
Snug fit = you can push it in by hand
Interference fit = you can put it in with a press
Hammer fit = slightly optomistic Interference fit
<insert your company name> fit = doesn't fit at all.

 

[Danger]

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