A while ago: http://nika.frontier.iarc.uaf.edu/~cswingle/archive/get.ph-
tml?message_id=103919#message (holy passage of time, Batman - it was
over a year ago!)

I made a cutting gauge. But it's got a problem. The wedge doesn't hold.
I've fancied up the fit and finish, but the blade still slips out in
use. I'm starting to think the angle's too steep.

Does anyone have a cutting gauge, with a brass retaining wedge that
holds nicely, and could measure the engle for me?

Then I'll fix up my gauge.#

I'll square up the mortise (currently tapered), fit a patch piece, and
then cut a new mortise at the new angle. Meanwhile, the old brass wedge
will be filed down.

Yeah, I could make a new one (marking gauges for conversion are cheap),
but I can't bear trashing a salvageable tool.

       BugBear

(who also made a cutting gauge with a machine screw blade holder, which
works, but is less pretty than a brass wedge)

Hi Paul,

> Does anyone have a cutting gauge, with a brass
> retaining wedge that holds nicely, and could
> measure the engle for me?

I've got a recent Marples cutting gauge. 

The original wedge was poor, with a massive casting line down the middle
of the wedge, making the wedge shape more semicircular than flat.  Obvious
casting flaw, so I drawfiled the wedge smooth and square, maintaining
original angle as close as possible

Thickness at toe of wedge = 5.0mm
Thickness at top of wedge = 6.65mm
Length of wedge landing =  25.4mmm (that's 1" Jeff, oddly enough, some
conventions never change)

Angle = 3.7 degrees

Wedge holds firm, too firm on some occasions.

As an aside, I notice that the blade is slightly tapered in width from the
heel to the cutting edge (narrower at the cutting end of the blade).  Not
a substantial amount, maybe 1mm difference over 50mm length.

Cheers,

Andrew

Andrew Fairbank wrote:
> Hi Paul,

<>

> Angle = 3.7 degrees
> 
> Wedge holds firm, too firm on some occasions.

Thanks - there's clearly some variation, since another galoot
(in an email) gave a measured angle of 11 degrees.

Any more people want to vote/opine on this?

      BugBear

I use 10 degrees. I don't know if it is the best but it works with my
methods. But something to think about the wood the wedge and plane are
made out of is a key. The harder the woods the more the wedge sticks and
the harder to adjust. 
 That's why I like oak and beech and such for wedges over purpleheart or
ebony or cocobolo or such.

> FWW had an article recently about wedging tenons, both tusks and the
> simple
> split tenon type. The author suggested that the key to all wedging was
to
> make the wedge 5 degrees or less.

Oops I was thinking planes. I had missed the first post (G)

Andrew Fairbank wrote:
> Hi Paul,

> 
> Angle = 3.7 degrees
> 
> Wedge holds firm, too firm on some occasions.

Sounds like I need to drop my angle, which is what
I suspected. Mine is at 11 degrees, and slips.

Thanks to all (both!) who replied.

    BugBear

FWW had an article recently about wedging tenons, both tusks and the simple
split tenon type. The author suggested that the key to all wedging was to
make the wedge 5 degrees or less.

Take it for what it's worth.

Matthew Groves
Kearney, Nebraska

on 5/12/03 10:39 AM, steve knight at stevek@k... wrote:

> I use 10 degrees. I don't know if it is the best but it works with my
> methods. But something to think about the wood the wedge and plane are
> made out of is a key. The harder the woods the more the wedge sticks and
> the harder to adjust.
> That's why I like oak and beech and such for wedges over purpleheart or
> ebony or cocobolo or such.

bugbear wrote:

> 
> Sounds like I need to drop my angle, which is what
> I suspected. Mine is at 11 degrees, and slips.

OK - last night I filed my brass wedge down,
chisled the (old, too large for the new wedge)
hole in the stem clean and square, worked up
a patch piece of mahogany, and glued it.

This morning I planed off the excess
(thank you, LV, for making an excellent
low angle block plane), and tested.

Yep - the wedge now holds just fine. For anyone else
that's interested, my wedge ended up
at 5.5 degrees.

A wedge angle this low does mean you have to be
very accurate when paring the tapered mortise.

5.5 degrees is a one in 9 slope,
which means that if you pare 1/32" of an inch from
your mortise, your wedge will move forward by 9/32"
or around 1/4"

Because of the way I patched my old mortice,
I actually did my fitting by sandpapering the patch piece
before glueing. If I were working on a fresh gauge,
I'd probably get the mortice "close" and then file the
wedge for the final fit. I can file metal a lot
more accurately than I can pare tiny mortises.

     BugBear

bugbear wrote:
> For anyone else
> that's interested, my wedge ended up
> at 5.5 degrees.

Dang. Transcription error.

should be invtan(2.5/22) ~= 6.5 degrees.

Apologies to all.

       BugBear