Chisel marking knife for cutting really skinny dovetails.

[Derek Cohen (Perth Oz)]

Well, this is what happens when I get bored - I start inventing wierd tools.

This is (what I call) a "chisel marking knife". It is really a chisel-shaped marking knife for skinny dovetails. I decided that I needed a marking knife for very skinny dovetails - to be able to slide a blade between the kerf-wide gap at the top - as I could not use any of the the others that I have because they were just too thick. I have used a Stanley Knife blade to do this to date. I wanted something that could be punched downward on the inside face of the tail or, alternately, could be used as a standard double-sided marking knife. It would just have to be very thin, as thin as a Stanley Knife blade.

This one is made out of a steel plaster trowel (really tough steel - I wonder what it is?). Its final dimensions are 3/4" wide x 1" long and 1mm thick. It is bevelled at the front and sides (45 degree bevels). The picture here really needed a standard chisel alongside to better illustrate just how thin the blade is.

http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=11725

The plan is to do the saw cuts for the tails - but not cut out the waste - then place the tail piece over the pin piece and mark off the pin placement through the kerfs. Only then is the tail waste cut. This is demoed in the following post.

http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=11778

The pictorial sequence demos using the chisel marking knife cutting a really skinny dovetail.

Don't be too critical of the dovetails - they were cut and glued in well under 5 minutes. It took much longer to take the pictures.

The knife works really well (can't say the same for the accuracy of my sawing today!). Just push down and the edge makes a clean, thin line that is easily seen.

The knife can also be used along its side, as a traditional marking knife is used (all three sides are sharp).

As can be seen here, the blade just fits inside the kerf of my LN Independence dovetail saw. It is too thick for a Japanese saw.

The picture sequence is self-explanatory.

Regards from Perth

Derek

 

[Chris Knight]

Derek,
Unfortunately the site seems to be down at the mo.

 

[Gill]

It's back up now!

Gill

 

[Chris Knight]

Gill,
Thanks.

Derek - I see!

I was put to shame the other day by an old cabinetmaker (80 years plus) who cut skinny dovetails in an instant, He marked the pin board with his saw in the cuts he had made for the tails. Had all four corners (on a drawer three inches high) done in about as many minutes. I am trying his method but shan't be publishing my results for a while :wink:

 

[Pete W]

Well, this is what happens when I get bored - I start inventing wierd tools.

Doesn't look wierd to me - looks very good, actually

My only issue is the bit about marking the pins before you've actually cut the tails. Given that I haven't yet cut my first hand-cut dovetails you can take this with as large a pinch of salt as you like, but... I'd be a bit nervous about marking the second part before I've cut the first part. If you see what I mean.

Theoretically, it looks like a big commitment, and seems like it would remove a little room for error. I'd be interested to hear anyone's thoughts about this - I take it as a given that I could be missing something obvious!