ss

samson

18/03/2008 3:00 PM

Mouth of a Hand Plane

You can adjust the frog on some hand planes to make
the mouth smaller when you are making fine strokes. My
question: why does it make a difference whether the mouth
of a hand plane is larger or smaller? Does it make the
cut any smoother?

Thanks,

S.


This topic has 7 replies

JG

"Jeff Gorman"

in reply to samson on 18/03/2008 3:00 PM

19/03/2008 9:08 AM


"samson" <[email protected]> wrote in message
news:[email protected]...

> You can adjust the frog on some hand planes to make
> the mouth smaller when you are making fine strokes. My
> question: why does it make a difference whether the mouth
> of a hand plane is larger or smaller? Does it make the
> cut any smoother?

Yes. When working against the grain the tendency is for the edge to get
under the fibres. The backface lifts the fibres so they are rived instead of
being cleanly cut. The riving (splitting) and eventual breaking causes the
rough tearout.

A very closely set mouth acts so that its front lip presses down on the
fibres, preventing them from being raised and allows the edge to reach the
fibres and cut them.

Jeff
--
Jeff Gorman, West Yorkshire, UK
email : Username is amgron
ISP is clara.co.uk
www.amgron.clara.net

CF

Chris Friesen

in reply to samson on 18/03/2008 3:00 PM

18/03/2008 3:01 PM

samson wrote:
> You can adjust the frog on some hand planes to make
> the mouth smaller when you are making fine strokes. My
> question: why does it make a difference whether the mouth
> of a hand plane is larger or smaller? Does it make the
> cut any smoother?

It can help reduce tearout in some cases, but it's not strictly
necessary and it needs to be pretty small to be effective at this. See
this article by Chris Schwarz.

http://blog.lostartpress.com/default.aspx#a3f6a4a90-e2f4-4021-b0bb-a890659c6d1f

Chris F.

ss

samson

in reply to samson on 18/03/2008 3:00 PM

18/03/2008 4:23 PM

In article <[email protected]>, [email protected]
says...
> samson wrote:
> > You can adjust the frog on some hand planes to make
> > the mouth smaller when you are making fine strokes. My
> > question: why does it make a difference whether the mouth
> > of a hand plane is larger or smaller? Does it make the
> > cut any smoother?
>
> It can help reduce tearout in some cases, but it's not strictly
> necessary and it needs to be pretty small to be effective at this. See
> this article by Chris Schwarz.
>
> http://blog.lostartpress.com/default.aspx#a3f6a4a90-e2f4-4021-b0bb-a890659c6d1f
>
> Chris F.

Thanks for the good info, Chris (and the good blog site). Much
appreciated.

S.

ss

samson

in reply to samson on 18/03/2008 3:00 PM

18/03/2008 6:30 PM

In article <[email protected]>,
[email protected] says...
> On Tue, 18 Mar 2008 15:00:23 -0500, samson <[email protected]> wrote:
>
> >You can adjust the frog on some hand planes to make
> >the mouth smaller when you are making fine strokes. My
> >question: why does it make a difference whether the mouth
> >of a hand plane is larger or smaller? Does it make the
> >cut any smoother?
> >
> >Thanks,
> >
> >S.
>
>
> It makes a difference, the why is a bit complicated.
>
> Yes, a "tighter" mouth "can" produce finer shavings and a smoother
> cut.
>
> If you have the time take a look at
>
> http://www.amgron.clara.net/
>
> Jeff's Planing Notes will tell you more than youy want to know about
> the mechanics of the cutting action of a wood plane - it's a lot more
> complicated than most of us realize (or want to know).
>
> You can also read
>
> http://members.shaw.ca/petermichaux/workshop/BevelDownSharpening.html
>
> which is really about edge angles but can help one understand waht's
> going on when the plane blade shears (or breaks) wood.
>
> Regards.

Good information, Tom. Thanks.

S.

PH

Peter Huebner

in reply to samson on 18/03/2008 3:00 PM

19/03/2008 2:17 PM

In article <[email protected]>,
[email protected] says...
> You can adjust the frog on some hand planes to make
> the mouth smaller when you are making fine strokes. My
> question: why does it make a difference whether the mouth
> of a hand plane is larger or smaller? Does it make the
> cut any smoother?
>
> Thanks,
>
> S.
>

The idea is that it a smaller throat should reduce chatter (and tear-out?) when
going over knots and inter-locked grain.

In my experience holding the plane at an angle to the cut you're making and
setting to an even finer cut is a lot more effective at stopping chatter than
the most finely tuned throat. Maybe my technique is to blame...

-P.

--
=========================================
firstname dot lastname at gmail fullstop com

Ri

ROY!

in reply to samson on 18/03/2008 3:00 PM

18/03/2008 11:23 PM

On Tue, 18 Mar 2008 16:20:33 -0500, Tom B
<[email protected]> wrote:

>
>
>If you have the time take a look at
>
>http://www.amgron.clara.net/
>
>Jeff's Planing Notes will tell you more than youy want to know about
>the mechanics of the cutting action of a wood plane - it's a lot more
>complicated than most of us realize (or want to know).
>
>You can also read
>
>http://members.shaw.ca/petermichaux/workshop/BevelDownSharpening.html
>
>which is really about edge angles but can help one understand waht's
>going on when the plane blade shears (or breaks) wood.
>
>Regards.

If planing doesn't interest you have a look at these dovetails from
Jeff's site:
http://www.amgron.clara.net/dovetails/moorishdovetails/moorishindex.htm

TB

Tom B

in reply to samson on 18/03/2008 3:00 PM

18/03/2008 4:20 PM

On Tue, 18 Mar 2008 15:00:23 -0500, samson <[email protected]> wrote:

>You can adjust the frog on some hand planes to make
>the mouth smaller when you are making fine strokes. My
>question: why does it make a difference whether the mouth
>of a hand plane is larger or smaller? Does it make the
>cut any smoother?
>
>Thanks,
>
>S.


It makes a difference, the why is a bit complicated.

Yes, a "tighter" mouth "can" produce finer shavings and a smoother
cut.

If you have the time take a look at

http://www.amgron.clara.net/

Jeff's Planing Notes will tell you more than youy want to know about
the mechanics of the cutting action of a wood plane - it's a lot more
complicated than most of us realize (or want to know).

You can also read

http://members.shaw.ca/petermichaux/workshop/BevelDownSharpening.html

which is really about edge angles but can help one understand waht's
going on when the plane blade shears (or breaks) wood.

Regards.


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