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262292 Tony Blanks <dynnyrne@i...> 2017‑05‑18 I seek wisdom re toothing plane blades
Friends,

Wisdom would be wonderful, but I'm happy to settle for opinions and 
advice, so no need to hold back.

I have been tidying up my workshop, something I find myself forced to do 
once a decade or so by the ongoing growth in my accumulation of pieces 
of wood too small to use yet too good to throw away.  In doing so I have 
uncovered  a couple of toothing planes and several toothing blades, all 
old, all tapered.  Some blades are in good order, (no missing teeth), 
others are gapped.  The thing which puzzles me is that all seem to have 
been sharpened, as though for a common pitch (45 degree) smoothing 
plane.  This goes for the ones still in the plane as well as the loose 
ones, though its difficult to be sure of the original grinding angle as 
universally the bevels are well rounded suggesting that previous owners 
were careless, or saw no need for care.

I have never seen a toothing plane blade used in a common pitch plane, 
and the two bodies I have both pitch the blade at a little less than 90 
degrees.  The teeth tips are delicate: the gaps are in the run of teeth 
rather than at the corners where they might come from dropping the 
blade. So why were they all given a shallower bevel?

Since the "depth of cut" when used to scratch the surface of a piece 
with such a plane is effectively the depth of the vee between the teeth, 
it seems to me to make sense to grind these blades with a steeper bevel 
to better support the teeth.  A 60 or 70 degree bevel should still 
provide adequate clearance behind the teeth.  Or would it?

I have no intention of grinding the whole of the bevel to the steeper 
angle, that would cost too much of the toothed surface, and based on my 
toothing plane use to date I suspect that one re-grind of a couple of 
blades will well and truly see me out.

I'll be doing the grinding with a low speed wet wheel device so burning 
the tooth tips, which I would worry about if using a dry wheel, isn't an 
issue.

What say you all?

Thanks, and Regards,

Tony B
Hobart, Tasmania
262294 paul womack <pwomack@p...> 2017‑05‑18 Re: I seek wisdom re toothing plane blades
Tony Blanks wrote:
  > Since the "depth of cut" when used to scratch the surface of a piece with
such a plane is effectively the depth of the vee between the teeth, it seems to
me to make sense to grind these blades with a steeper bevel to better support
the teeth.

But the effective depth of the vee is a combination of the perpendicular depth
of the vee, AND THE BEVEL ANGLE.

It is obvious that grinding at 90 degrees would give no teeth at all, the rest
follows by extrapolation.

  BugBear
262311 Tony Blanks <dynnyrne@i...> 2017‑05‑18 Re: I seek wisdom re toothing plane blades
On 18/05/2017 6:58 PM, paul womack wrote:
> Tony Blanks wrote:
>  > Since the "depth of cut" when used to scratch the surface of a 
> piece with such a plane is effectively the depth of the vee between 
> the teeth, it seems to me to make sense to grind these blades with a 
> steeper bevel to better support the teeth.
>
> But the effective depth of the vee is a combination of the 
> perpendicular depth of the vee, AND THE BEVEL ANGLE.
>
> It is obvious that grinding at 90 degrees would give no teeth at all, 
> the rest follows by extrapolation.
>
>  BugBear


Oh that hurts, but thanks Bugbear.  Clearly I spent too much time being 
puzzled by this problem and insufficient time analysing, thinking about, 
or even giving passing consideration to how the 'teeth' are formed.  I 
was thinking in terms of the toothed edge of the blade, rather than that 
the teeth are the product of a ridged face and the bevel angle.  2 
lessons in one response is good value!

Regards,

Tony B
Hobart, Tass

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