Dovetail marking gauge

[bugbear]

Anyway, having been indoctrinated into 7:1 and 8:1 by constant repetition, I couldn't understand the 5:1 by a master cabinetmaker. However, when you make the drawer, you realize that, since there is but a single whole pin, the use of 5:1 solved some problems that 8:1 would not have. The use of 5:1 created enough mass in the pin to give it strength, and give it the appearance of strength so it looks right, yet still have a fine pin entry. The lesson for me was that this master maker saw deeply into what he was doing, and adapted the details to suit the situation. He used shallower dovetail ratios elsewhere in his constructions, for example in the case joinery.

Kirby's dovetail book (which is a tad slow in pace, but VERY good) claims that in most uses a dovetail joint is so over-kill-strong that your choice of spacing, size and angle can be principally guided by aesthetic considerations. He says that he normally uses "angles" in the range 1:5 though 1:7, a statement eventually reflected in my two (meep, meep) Dalziel made templates.

BugBear

 

[Derek Cohen (Perth Oz)]

Wiley wrote:

The use of 5:1 created enough mass in the pin to give it strength, and give it the appearance of strength so it looks right, yet still have a fine pin entry.

BB replied

Kirby's dovetail book (which is a tad slow in pace, but VERY good) claims that in most uses a dovetail joint is so over-kill-strong that your choice of spacing, size and angle can be principally guided by aesthetic considerations. He says that he normally uses "angles" in the range 1:5 though 1:7

(He also noted

a statement eventually reflected in my two (meep, meep) Dalziel made templates.

, to which all I can add is "You rotten swine you!". :lol:

The dovetailed pine boards in my above pictures were completed at 1:5 (or 5:1 if you insist :lol: ). My general preference for drawers is 1:7 (as 1:8 is too skinny). However I used 1:5 in this workshop cabinet carcass as I needed to strengthen the pins as much as possible.

I think that one tends to forget (not visualise) what the cut pins look like and, instead, concentrate on the cut tails, especially if you cut tails first. The pins of a 1:7 or 1:8 board with skinny tails would be so fragile that they would not lend any strength, indeed any credibility to Kirby's contention.

This was clear to me later - too late - that such widths are better suited to hardwood pins, not softwood. (having said this, the cabinet in question is very rigid as it is reinforced by sliding dovetails).

Here are the cut pins. Note that the board is 3/4" thick:

I imagine that Kirby is not referring to such slender pins, but something more substantial, say 1/4"-1/2" wide at the apex.

Regards from Perth

Derek

 

[bugbear]

I think that one tends to forget (not visualise) what the cut pins look like and, instead, concentrate on the cut tails, especially if you cut tails first. The pins of a 1:7 or 1:8 board with skinny tails would be so fragile that they would not lend any strength, indeed any credibility to Kirby's contention.

Well, yes; if you push things to extreme extremes (!), even a dovetail isn't strong enough.

But Kirby's point remains; a dovetail joint is so strong as to allow a substantial (but not unlimited, as you say) envelope of aesthetic choice.

BugBear

 

[Wiley Horne]

Well, 1:5 is a typical recommendation for softwood, so Derek is in the mainstream, particularly with the tiny entries. And more particularly for use in a carcase.

Where Ian Kirby says to "let aesthetics govern", surely he is talking about dovetails one can see--like drawer dovetails, as opposed to carcase dovetails that are generally concealed behind moldings*. For drawers, I think his contention stands as stated, because the dovetail joint is 'overkill strong' for a drawer**. In the case I was mentioning (Seymour's lady's tables), it happens that 5:1 is more aesthetically pleasing than a skinnier pin or skinnier two pins, and I suspect that's why it was used by Seymour, even though joining hardwood components.

So most likely everybody is right (<.

Wiley
_____________

*Or secretly mitered, like those ones Rob hid from us in his last F&CM foray.

**So long as the drawer is working as designed--if it gets stuck in wet weather and the owner decides to yank it the heck out of there anyway, cause he needs those car keys, who knows what happens then.

 

[bugbear]

An entirely reasonable, thoughtful and well expressed post.

You're very new to internet forums, aren't you

BugBear

 

[Anonymous]

I have to remark on Derek's pencil holder.

You've dating yourself, amigo. :lol:

 

[Derek Cohen (Perth Oz)]

Roger, I sometimes look up old posts on the BP CD and see the familiar names there. Then there are some that just seem to have disappeared, never to be heard of again, and I wonder where they are?

Regards from Perth

Derek

 

[woodbloke]

Thanks, Wiley, that's very interesting.

Rob Stoakley is also rather a dab hand at knife making. I have one of his and it's superb. Maybe he'll post a few pics for you :-k :wink:

Cheers :wink:

Paul

...as requested:

Chisel will be collecting his at West Dean tomorrow - Rob

 

[paulm]

Chisel will be collecting his at West Dean tomorrow - Rob[/quote]

Yep, sure will, can't wait, thanks Rob !

Cheers, Paul

 

[Wiley Horne]

Those knives that Rob made are just killer. Lucky folks to be receiving them. Everything he does shows high professionalism and taste.

Wiley

 

[Paul Chapman]

And I was lucky enough to get one that Rob made earlier. A little smaller but perfectly formed

Cheers :wink:

Paul

 

[Wiley Horne]

Beautiful, Paul!

Wiley

 

[Harbo]

And here's one I made from African Blackwood - blade from a Stanley knife.

Rod

 

[paulm]

Nice one Rod

Cheers, Paul

 

[frugal]

And here's one I made from African Blackwood - blade from a Stanley knife.

There was an article in British Woodworking issue 5 by Alan Wood about making some very scary looking dovetail marking blades from stanley knives.

 

[PaulO]

...as requested:

Chisel will be collecting his at West Dean tomorrow - Rob

Fantastic.
Are you making the ferrules yourself, if so, how? Do you have any photos of their construction?

I have a range of marking knives I use, from a swann-morton through, Chester Toolworks, Blue Spruce and a Hock marking blade (as yet without a handle fitted).

Most of them have their time and use, but I have yet to find one that I could call a favourite.

 

[woodbloke]

PaulO wrote:

Are you making the ferrules yourself, if so, how? Do you have any photos of their construction?

The ferules are commercially available...I bought a pocket full of 12mm from the Ashley Isles stall at Yandles a while back. The final polish on the knife is achieved on the leather wheel of the Tormek after finishing on the lathe with some worn 320g. I'm just about to start another couple in ebony and got the blanks roughed out last night...one will have a grip rather similar to a traditional barrel shaped fountain pen - Rob