Replies

1. 
   eddiefromAustralia | Jul 30, 2003 10:29pm | #1

   Make the maximum width of the pin/tail 3/4 of the thickness of the wood.

   Carcase dovetails 1:6, show dovetails 1:8

   Cheers, eddie

1. 
   AlanTurner | Jul 30, 2003 11:43pm | #2

   Eddie,

   I find your comment interesting.  I am not formally trained, but recall reading often that 1:6 was for softwoods, and 1:8 for hardwoods, without regard to 1/2 lap, through, or show.  Have I been labo[u]ring under a misimpression for years, or this this a subject of some debate?

   Alan

1. 
   eddiefromAustralia | Jul 31, 2003 12:01am | #3

   Hi S4S,

   Yes, a contentious issue to some extent.

   I'm off to work in 5 min so a really rushed answer.

   As softwoods are typically weaker, people generally suggest 1:6 for softwoods, which gives extra strength at the detriment of appearance.  The 1:8 ratio gives a less 'clunky' appearance to the joint.  For show joints, allow approx 3-4 times the width of the pin between each one.

   When I was training, I asked that same question and was told that if it's on show, stick to 1:8 and make sure it's accurate.

   Cheers, eddie

2. 
   DougF | Jul 31, 2003 04:20pm | #4

   Eddie,

   Gee I hate to sound stupid, but what does the ratio refer to?

   Doug

1. 
   Kevin | Jul 31, 2003 08:11pm | #5

   LOL if asking that makes you sound stupid then color me stupid too. I too have no idea what the ratio refers to and am curious to find out.

   Years ago while working as the finisher at a custom commercial fixture shop I asked our most experienced woodworker what I thought was a stupid woodworking question. His first response was to flatly state that the only stupid question is the one that is not asked. LOL I could tell by the look on his face that he was dead serious. I believe he was right about that, BTW.

   Regards,

   Kevin

2. 
   BG | Jul 31, 2003 09:01pm | #6

   Doug,

   The ratio refers to the slope of the doevtail.  This is where a picture is worth 1000 words...but i'll tey to explain how it is constructed. 

   A slope of 1 to 6 would equal 1/6th which is about 16 degrees and likewise a 1to 8 would equal about 12.5 degrees....therefore a ratio of 1 to 6 is stronger than 1 to 8.

   To position the bevel to the correct slope or ratio:

   draw a base line on a piece of paper and a perpendicular line in the center. (so you have an upside down 'T'.  Now measure to the left and right of the intersection the board thickness that you are working with and put a dot. ( in other words, to the left and right of the intersection there is a dot that is far enough away from the intersection that is equal to the thickness of the board)

   measure up the perpendicular line the equivalent of 6 or 8 times the board thickness and put dots at those respective locations.  Connect the dots on the base line and the perpendicular line...that is the slope=1to6 or 1to8 ratio. 

   last step: take your adjustable bevel square and place the blade on the base line and the blade on the slope line...tighten, now you are ready to mark out dovetail slopes on stock...whew!.....wish I had a picture.... 

1. 
   DougF | Jul 31, 2003 09:07pm | #7

   BG,

   Thanks.  That does make sense now.

   Doug

2. 
   DonaldCBrown | Jul 31, 2003 09:13pm | #8

   This is where a picture is worth 1000 words...

   Here's a picture.View Image

   In math terms, the ratio is the tangent of the angle.