From handtool chat - how to lay out a dovetail

Re: From handtool chat - how to lay out a dovetail

Ernie Miller


>What if you want/need more pins/tails would you just devide the board equaly by any number? The process looks slick I think I will give it a try this afternoon.

Re: From handtool chat - how to lay out a dovetail

George Makowski


>Ernie, This is an old drafting/geometry trick for dividing a line into nay given number of divisions by using proportions over direct measurements. It will work for any number of dovetails you want. Just divide the long angled line into the number of dividions you want to have on the straight base line, in this case the area to be dovetailed.

Another very useful application of this method is when working from plans. For example, if you have plans that show 1"=1' and you want an inch scale, use the long angled line method with twelve divisions and transfer those to a one inch base yielding a rule with divisions in 1/12". That is, you can divide any unit into almost any number of sub units to interpret scales or to make your own measuring devices standard or custom.

I have used this to lift plans where only the basic divisions are given and the drawing given is proportionally correct. Example a turning is said to be 8" long and a proportionally correct drawing with no other dimensions is supplied. Take the length of the turning from the drawing with dividers. Using the diagonal line method divide that length into eight units. Subdivide one of those units into fractions if you like. Then take any measurements you want from the drawing with dividers. Apply the dividers to your special scale and read how many inches the measurement is.

There is a variation on this often used on optical survey rods, the diagonal scale that allows you to generate divisons down to 1/100".

If you are interested, contact me offline and I can send you photocopies that explain how to generate scales and subdivisions.

Good dividing,

George in AL

Re: From handtool chat - how to lay out a dovetail *LINK*

Chris Scholz


>Reminds me a lot of the procedure that the "Federal Institute for Vocational Education and Training" (aka. BBiB http://www.bibb.de/en/index.htm) recommends (yes, the Europeans love to institutionalize things...) They also give a "dovetail formula" to calculate the number of pins based on width and thickness of the board(s) (unfortunately no English transation). http://www.schreiner-seiten.de/verbindungen/v_zinkung-offen.htm

Chris, Atlanta, GA


BiBB recommended procedure for dovetail joints

Re: From handtool chat - how to lay out a dovetail *LINK*

Andrew F in Australia


>Thanks Chris,

I was trained by European tradesmen and old-school English philosophies.

Yes, there's a formula in English as well when I was trained - I think that the space between pins was approx 1.5 times timber thickness, but I'm running on memory.

Here's a translated page of the German site that's nowhere near perfect.

CHeers,

Andrew


http://translate.google.com/translate?u=http%3A%2F%2Fwww.schreiner-seiten.de%2Fverbindungen%2Fv_zinkung-offen.htm&langpair=de%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools

Hi Ernie, how did it go

Andrew F in Australia


>I've actually dug out and dusted off my old trade notes and found the page I'm referring to.

Here's a potted summary of dovetail layout that took about 10 minutes to sketch up instead of the five I spent on the last one. The spacing for the tail sockets depends upon the width of the pins. (width at widest point is 3-4 times the width of the pin at it's widest pin.)

As well, I came across a drawing I did in tech college of a traditional drawer - this was a training drawing and shows a traditional drawer with a false front in veneered chipboard with a 5mm solid lip. (next post as I can only include one at a time.)

Shows clearly how the back of the drawer was cut in and details of the drawer slip. (the meaning of the blue ink is that it's an overlaid vertical view to be viewed separately to the pencil one.)

Cheers,

Andrew

Drawing - back and front dovetails

Andrew F in Australia


>see previous post for details