Force versus Pressure Explanation (with video)

[Rick Christopherson]

I wasn't going to post this here because I'm not sure whether the topic has come up a lot, but given the popularity of the topic at another forum I frequent, I thought some of the members here might like the information.

The topic of Clamping Force and subsequent Joint Pressure comes up a lot in woodworking. Unfortunately, there is much confusion about the difference between "Force" and "Pressure" as it relates to this topic. A couple of weeks ago there was a forum posting that highlighted the significance of this misunderstanding, which led me to an idea for a clearer example for explaining it. So I grabbed my camera and headed down to the shop for a quick video shoot.

I was unsure about even releasing the video this morning, so I was quite surprised by the rapid feedback it garnered in the first 12 hours. So here it is.

Force versus Pressure

 

[Sparktrician]

Great video!!!  The explanation was quite clear and instructional.  Thanks for putting it up.  As it opened, I started thinking that Mr. Rogers would mystically appear... 

[smile]

 

[waho6o9]

Awesome Rick, thanks for the info. 

 

[USPcompact]

Fantastic video! 

Nice cat, too!  [big grin]

 

[TJ Cornish]

May the Pressure be with you! (or was that the Force?)

 

[tiralie]

Rick:
Great job! Probably one of the best videos, with great examples I have seen.
Nice production and thought.
Now, can you do one on how various vacuum hose diameters affect the suction (fluid dynamics) when connected to, oh lets say a CT26?
Ya, ya  I know no good deed goes unpunished.
Thanks again for posting.
Tim

 

[joraft]

EXCELLENT work, Rick!

Oh how I wish that video would have been available a while back.  [smile]

 

[Jesse Cloud]

Great video Rick!  I'll bet you have done some teaching at some time in your life!

 

[flair woodworks]

As it opened, I started thinking that Mr. Rogers would mystically appear... 

[smile]

The opening reminded me of Roy Underhill.  Great video, Rick.

 

[joraft]

The opening reminded me of Roy Underhill ... 

Yes it does. But I'd like to know what all that white stuff is, and why he keeps his clamps under it.  [big grin]

 

[Michael Kellough]

Nice job Rick!

Next, I'd like to see an examination of the validity of the glue manufacturers 100psi recommendation.

PS  Inky is a beaut!

 

[joraft]

... PS  Inky is a beaut!

I thought he preferred to be called "Ninja Kitty".

 

[Rick Christopherson]

Nice job Rick!

Next, I'd like to see an examination of the validity of the glue manufacturers 100psi recommendation.

PS  Inky is a beaut!

Most woodworkers enter into that discussion thinking it is about strength. It's not about strength. It's about the visibility of the finished glue line. Many woodworkers I've talked with don't realize how visible their glue lines really are until they see how invisible they really can be.

 

[bruegf]

Nice job on the explanation, its surprising how many people don't understand this topic.

On a different note, any idea when you'll have the MFK700 supplemental manual available for download?

Thanks

Fred

 

[Rick Christopherson]

Oops. Actually I was just thinking about that manual last week. It got put on hold a long time ago, but has since been reactivated. Unfortunately, I never think about it when I have the time to work on it. It's almost entirely done except for applications. If anyone has any suggestions for applications for the router, I would love to hear them (via PM).

 

[Corwin]

Did I see a hole in your sock?    [blink]

 

[GPowers]

Great Video, You learn something new everyday.

 

[maxpower10]

Physics 101.  Good lesson!

 

[John Stevens]

Rick, thanks for sharing your video here--you're really gifted at that sort of thing.  I hope your video brought some clarity to the discussion over at the other forum.  That thread (I assume it's still one long thread) was a train wreck.

Regards,

John

 

[PaulMarcel]

Excellent video, Rick; especially liked the accessible way you present the differences with visuals that make it clear.

So... the socks were in the shot for Laurie's sake, right?