What does this thing do?

[Rik ShawParticipant @rikshaw]

I have had this for so long I've forgotten what its purpose is. Any one……..?

Rik

Its 2" x 1.5"

Edited By Rik Shaw on 09/03/2021 17:16:50

[Rik ShawParticipant @rikshaw]

…..gauge?

[Tony Pratt 1Participant @tonypratt1]

Don't know it's purpose but judging by the scribed lines a hand made 'thing' ?

Tony

[bernard towersParticipant @bernardtowers37738]

Looks like a woodworkers dovetail jig

[Michael GilliganParticipant @michaelgilligan61133]

Posted by bernard towers on 09/03/2021 17:21:52:

Looks like a woodworkers dovetail jig

[Robert ButlerParticipant @robertbutler92161]

If it is a dovetail jig it can only be used for marking out, who would risk fine dovetail saws or chisels using it as a guide for cutting the joint?

Robert Butler

[JasonBModerator @jasonb]

That's why they are usually called dovetail marking gauges rather than jigs.

[MichaelRParticipant @michaelr]

 

 

I don't think it is anything to do with marking out dovetails, in the days before machine cut dovetails a joiner would use a template for marking out

made from a piece of thin metal as above drawing or use a sliding bevel to mark out, and what is the vee notch for?

Michael

Edited By MichaelR on 09/03/2021 20:30:49

Edited By MichaelR on 09/03/2021 20:31:58

[JasonBModerator @jasonb]

You can get ones that you mark on the inside of as well as ones like you show that use the outside edge

Vee notch is for when you mark out the ctr spacings so just line up notch with mark and you get your DT placed equally either side.

Edited By JasonB on 09/03/2021 20:39:49

[MichaelRParticipant @michaelr]

Jason, I stand to be corrected, not seen that type before.

Michael.

[Michael GilliganParticipant @michaelgilligan61133]

This brought back an ancient memory … I engraved the dovetail angles for hard and soft woods onto my plastic 60° set-square, to save me some drawing time in the ‘O Level’ Woodwork exam.

MichaelG.

[Robert ButlerParticipant @robertbutler92161]

It must also be noted the joints were marked out with a "marking knife" – never pencil although the marked lines could be highlighted with pencil and the waste also marked with pencil.

Robert Butler

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robert Butler on 09/03/2021 21:27:47:

.

It must also be noted the joints were marked out with a "marking knife" –

.

… and of course, Rik’s device might require the use of both left and right hand ‘marking knives’ to allow each cut to start in in the corner. 

MichaelG.

Edited By Michael Gilligan on 09/03/2021 22:05:43

[Robert ButlerParticipant @robertbutler92161]

Or reverse the the direction of application of the knife which is only sharpened on one edge.

Robert Butler

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robert Butler on 09/03/2021 22:08:40:

Or reverse the the direction of application of the knife which is only sharpened on one edge.

Robert Butler

.

That was my point, Robert … reversing the direction would risk damaging the knife by contact with the internal corner.

MichaelG.

[JasonBModerator @jasonb]

Or use a spear/vee point marking knife which has a double edge.

Myself it's a scapel for fine work and Stanly knife for more run of the mill work just tilting the blade one way or the other to get the bevel close to the edge, hardly ever use my Japanese marking knives.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 10/03/2021 07:03:50:

Or use a spear/vee point marking knife which has a double edge.

Myself it's a scapel for fine work and Stanly knife for more run of the mill work just tilting the blade one way or the other to get the bevel close to the edge, hardly ever use my Japanese marking knives.

 

.

… That would be even more at risk of being damaged

… and I had already presumed that Robert was a purist; so would be using a traditional one-sided marking knife. [which he subsequently confirmed]

MichaelG.

.

Edit: something in this style 

https://www.axminstertools.com/crown-112-marking-knife-ax21839

Edited By Michael Gilligan on 10/03/2021 08:39:55

[Rik ShawParticipant @rikshaw]

So its a dovetail marking jig. Thanks for all the replies. Not surprised I was clueless – "brown" stuff does not float my boat!

Rik

[Robert ButlerParticipant @robertbutler92161]

Gentlemen to shatter a possible illusion, I remember well my woodworking lessons over 50 years ago now. Regrettably not much time for woodwork now. Dovetail squares (now there's a contradiction in terms) permit striking out using a proper marking knife with the unsharpend edge of the blade resting against the square thereby preventing wavy lines.

Robert Butler

[Michael GilliganParticipant @michaelgilligan61133]

Robert,

So far as I can tell, my only illusion was that I thought you must be currently an enthusiast woodworker.

Your description, of the proper knife and its use, is exemplary.

My comment about needing two knives related specifically to their proper use in Rik’s device.

MichaelG.

[DalboyParticipant @dalboy]

My marking out knife is a similar design to the one Jason shows which means one knife can do both sides. I have yet not had any damage to it when marking out dovetails or any other work.(Except when I dropped it on the floor and blade hit first as it always does).

Also worth noting is that the gauges that Jason shows have different angles either end so care is needed to use the same end for both left and right marking out. The one where there is an internal dovetail is also different angle to the outer angle

[Author]

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