The #140 trick is dead ...

[Derek Cohen]

.. long live the blue tape trick!


I've been marking and cutting dovetails where the pin- and tail boards are not square to one another. Holding the boards together to transfer tails to pins has been difficult. 

I considered the "140 trick", which I first encountered about 15 years ago when Rob Cosman demonstrated it in one of his videos. This consists of a shallow rebate ("rabbet" for you who do not speak Australian or British English) on the edge of the tail board, and it is used to register the tails against the pins.

This method has since been taken up by many, and here is demonstrated by Chris Schwarz (off his blog) ...





It's called the "#140 trick as Rob used a LN #140 skew block plane to plane the shallow rebate (actually shallower than that completed by Chris, above).

During the course of a video I put together recently (the worst video in the world, so don't ask), I have the following idea and actually created it on the spot. I loved the result, and so I have written it up below. 

This is an alternative to the #140 trick. A rebate is unnecessary. 

This is the tail board, along with cutting gauge and pin board marked with blue tape ..



Set the cutting gauge to the depth of the tail. This may be done when marking, or later ...



Now stretch three layers of blue tape across the base line. It really does not matter how exact you are (I'm rather casual here). All that matters is that the tape is over the line ...



Trim off the excess ...



Now use the cutting gauge to trim the tape to the baseline ...



This is create a fine fence exactly at the baseline ...



The fence acts in the same way as the "#140 trick", except that it may be peeled away afterwards and there is no altering of the dimensions to the board ...



The blue tape on the pin board acts as a non-slip, and the fence is additive in stabilising the two together.

To aid in aligning the boards, I use a simple square made from wood ...



This is placed against the back of the pin board, and the tail board is square off ...



I have removed the square here, but it is not necessary to set it aside ...



The blue tape trick is great when marking dark woods ...



Regards from Perth

Derek

[Mike Brady]

I agree that the 140 rebate is probably an unnecessary step.  It does clean up the inside corner of the joint if that is an issue for the maker.  I can imagine cases where it might be worth the effort; such as the interior of a jewelry box, but less so for an inside corner of a drawer.  The tape layers is a good substitute for the rebate.

I also am finding the blue tape is a good reference for guiding the saw in those first critical strokes.  It does not necessarily help keep the saw plumb and square.  That is a sawing skill that the maker has to develop through practice and the use of a small square and a keen chisel to tune up any margins that did not come off the saw quite true.  Tape helps transfer a profile accurately but it transfers the profile from the inside of the joint.  An out-of-square sawing line will still result in problems on the assembled joint (particularly tail-board gaps).

My explanation may not be clear.  Let me know if I need to expand on it.

[Aram]

Thanks, Derek. The best ideas are the simplest!

I tried the #140 trick for the first time yesterday, but with a skew rabbet plane. It worked a treat. (Is that how you say it?) But it does take some fiddling to set the fence exactly.

I like your blue tape technique. I'll try it on my next project.

[theoldfart]

Guess I'll put my 140 in a less accessible spot in my tool chest! I like the process Derek, thanks for the post.

[Martin S.]

Derek, I always enjoy your posts, and this one is no exception.

You have a tremendous amount of knowledge, and I appreciate your willingness to share.

[Hank Knight]

Derek,

Quit beating yourself up over your video. I watched there whole thing and enjoyed it for a number of reasons. It clarified some points you made in your written descriptions of angled dovetails. It was easy to follow, and it was nice to see you in action and hear your voice after all these years of following you in print on these boards. True, you're not Albert Finney, but you made a nice video. I like the tape trick and I like your method of using tape to highlight the dovetail scribe lines. I plan to try both on a project I have underway. I've used the 140 rebate trick in the past. It works, but I find the extra step unnecessary and a little fiddly. You tape trick looks like an easy way to accomplish the same thing.

Hank

[Skip J.]

Derek,

Quit beating yourself up over your video. I watched there whole thing and enjoyed it for a number of reasons. It clarified some points you made in your written descriptions of angled dovetails. It was easy to follow, and it was nice to see you in action and hear your voice after all these years of following you in print on these boards. True, you're not Albert Finney, but you made a nice video. I like the tape trick and I like your method of using tape to highlight the dovetail scribe lines. I plan to try both on a project I have underway. I've used the 140 rebate trick in the past. It works, but I find the extra step unnecessary and a little fiddly. You tape trick looks like an easy way to accomplish the same thing.

Hank

Hi Derek; nice video, we can just fast forward every now and then, no problem at all, keep'em coming...

[Jim Waldron]

Derek:

About that video: Self deprecation is sometimes charming, but in this case, it's inappropriate. Your video is great. I'm 75 yo, and a lot of woodworking vids put me right to sleep. Your's didn't. It was engaging, clear, informative, complete and, while not particularly concise, it would have been less effective with jump cuts to shorten it. I vote for more.

[Derek Cohen]

Thank you all for your supportive comments. I must admit to feeling quite tongue-tied in front of a camera. It is different when there is a live audience from whom you can gauge a response. My hat is off to all those that do this regularly.

Regards from Perth

Derek

[DCM]

that's a great idea Derek & as usual, a great step by step tutorial
I look forward to giving it a go
Thanks for sharin
David