Hand Planes -Why is the shaving smaller than the work piece?

[Ron Swanson Jr.]

Here's a dumb question they I've wondered about for a long time. 

 

If you take a full length shaving with a plane, and then stretch it out and compare it to the board it just came off of, it will have magically shrunk by about 20%. 

 

Does anyone know why that is?

 

Here's an example. I wrote on the work piece, took a full length shaving, and then stretched the shaving out. 

And like magic it's about 20% smaller than the work piece. 

 

My guess is that planing kind of scrunches up the fibers, but you can't stretch the shaving back to full length. 

Probably some obvious explanation that I'm missing... But i thought i would get some opinions. 

 

Thanks

 

(First pic is writing on the board. Second pic is after planing, i took the shaving and stretched it out on the board. The shaving was full length)

[Chet]

Here is a Q & A from Paul Sellers website on the subject.  It may answer your question or muddy it up.  It sounds like there are several things that can or do come in to play.

https://paulsellers.com/2015/12/plane-questions-answered/

 

[Ron Swanson Jr.]

On 10/24/2023 at 12:47 PM, Chet said:

Here is a Q & A from Paul Sellers website on the subject.  It may answer your question or muddy it up.  It sounds like there are several things that can or do come in to play.

https://paulsellers.com/2015/12/plane-questions-answered/

 

@Chet way to go! I *think* this is the answer right here:

 

"What is rarely mentioned today is that when a plane is pushed into the wood the woodgrain in the shaving itself is compressed and consolidated by the rise at the fore end or hump of the cap iron.".

 

Sounds like the compression and consolidation is what causes this to happen. 

 

Case closed! 

[wtnhighlander]

I'd be curious to see if this compression happens to the glued-up blocks that are used for Yosegi veneering? I suppose the plane used does not generally have a chip breaker set close to the edge, though.

[Von]

Thinking more about this, I suspect it's related to why the shavings curl - the compression isn't symmetric across the two sides.