Friday, June 18, 2010

June 16th. Meeting: Finger Joints and More

       Before the meeting we needed to attend to some business, mainly collecting the dues of $20.00 for the year.  The dues are a way for Jamie to pay the MeetUp fees which are close to $150.00 for the year.  There haven't been too many takers but remember you can get those fees back if you want by doing a demonstration during a meeting.  I'm sure that many of you have a trick or two up your sleeve that we could all learn something from.  Just as an example, the router bit that Jamie showed to cut the slot in the drawer for the bottom was killer!  Matter of fact, I ordered one from Lee Valley this morning because the way I make me pistol cases that's a technique in their construction.  Here is the Lee Valley link so you can get your own.  Using the bit is much easier than running a blind dado and then chiseling out on the finger to allow the bottom to fit right in -- dynamite ; )
      Another item that came up was the Farmers Market (Fresh something or other) that will be in the Henderson area.  It would allow those of you who make items for sale a place to show and sell them.  Jamie mentioned that she believed that the Etsy Organization that she and others in our group belong to has something to do with this as well.  For those of you wanting to know more about them, here is a link to their website.  
      Okay, let's get on to the finger joints.  The advantage a finger joint has over just a simple nailed and glued butt joint is that you expose the long grain of the wood which gives the joint  strength.  Let me explain that concept for those of you new to this woodworking thing.  If you think of a piece of wood as a bunch of drinking straws laying side by side it'll help.  Imagine taking two bunches of those straws and putting the ends together with glue -- where would the glue go?  Yep, right down that hollow tube.  Now imagine putting the glue on the long sides (edges) of the straws and sticking it all together, they'll stick won't they?  Wood is essentially a bunch of microscopic tubes, the more edges of those tubes that you can use to join them, the stronger the joint will be.

The first step to the finger joint process is to cut a slot in the piece of wood you'll use for the jig.  In top  photo you see the dado head set slightly higher than the thickness of the wood being cut.  The blade is the two, outside cutters of a stacked dado head to obtain a 1/4" cut.  Jamie did a good job of explaining how the dado head works, it's a good investment to have.  On the left side there is a piece of wood next to the blade that is attached to the jig.  This is the exact width of the cut.  Basically here's the procedure:

  1. Cut a groove/slot in the piece you will use for the jig
  2. Move the jig over the exact width of the cut and screw it to the miter gauge.  The piece of wood that is the same width as the cut is then put into the slot you made in step #1 -- let's call that the guide pin
  3. You can see that Jamie then took her test board and held it upright against the guide pin to make a cut
  4. Each cut after that is made by placing the cut on top of the guide pin and working your way across the width of the board
  5. To cut the mating piece you put a spacer against the guide pin and align the mating piece with it.  This way you're cutting a notch out of the board -- after the first cut simply set the board over the guide pin and work your way across the board
    In the second photo, Jamie is doing a test fit.  Her secret weapon for adjusting the width of the cut was a hammer!  If the cut is too tight, gently tap the jig towards the right (looking at it from the operators position), too loose tap it towards the left.  Usually you'd make another test set of boards unless you lead a charmed and lucky life (like Jamie) and just go for it.

    In the third photo down, you can see that yes, the finger joints do indeed fit.  You'll notice too that they are quite proud of the surface but you can either plane or sand them flush.  When the drawer is finished this will leave a decorative element since the end grain will finish darker than the edge grain -- remember my straw example?

    Last but not least, the bottom photo shows how easily the slot cutting router bit I linked to earlier makes the dado for the bottom.  Like Jamie said, you can either radius the corner of the bottom piece or I would square off insides of the slot with a chisel.  I'd suggest cutting the bottom piece slightly undersize so that it will be able to float in the grooves.  Not too crucial if you're using a plywood, masonite, or MDF for the bottom but if you use solid material you need room for expansion and contraction of it.

    Hopefully we all learned something from the demonstration, I know that router bit was new to me and according to my shipping data I'll have one the middle of next week!  If you try this at home and have any questions you can contact me, I'll try to answer them.  I can't speak for Jamie but I'm guessing she'd help you out as well. 

1 comment:

  1. John,
    based on a conversation we had after Jamie's demo, I thought you might find this of interest:

    I stumbled upon it while checking out a favorite site of mine:

    Thought you might enjoy seeing that. Don't know if of any use or not.