Replies

1. 
   saschafer | May 22, 2009 04:22pm | #1

   Can you tell us a little bit more about how this is going to be used? "Strongest possible" would probably involve buried steel rods and such; I'm assuming that's overkill for what you intend to do. So the real question is, "What is 'strong enough'"?

   -Steve

    

1. 
   GarnerT | May 22, 2009 04:30pm | #2

   Hello Steve,

   Looking to sell some of these creations and as such, would want to produce a low coffee table that could easily withstand a reasonable amount of weight if someone were to lean or even sit on it.

   Thanks for your reply..

   Garner

1. 
   saschafer | May 22, 2009 05:00pm | #4

   I need some help in picturing the joint. I've sketched out some basic mitered coffee table ideas:

   View Image

   Are any of these like what you're thinking of?

   -Steve

    

    

   
1. 
   GarnerT | May 22, 2009 05:28pm | #5

   Hello Steve, 

   The version to the rear of the three options is an accurate representation.  Stability end to end is obviously my priority.  I do envision some 'rail' type of additions to be used but really like the clean look of the two folded 45 degree joints with no rail or shelf underneath.

   Thanks!  Let me know what your thoughts are.

   Garner

1. 
   saschafer | May 22, 2009 06:38pm | #6

   I would first ensure that the miter is clean and smooth, and that the two halves of each joint mate well, without gaps.

   I would next drill a couple of small (1/4", say), shallow dowel holes in the face of each miter. These will be used with very short (about 1/2" long) dowels to ensure alignment during glue up. Drill the holes in one half of the joint, use dowel centers to transfer the hole positions to the other half, then drill the mating holes.

   Next, I would drill a series of overlapping 1/4" holes in two places in each half of the joint. The idea here is to create a couple of slots to house a pair of heavy-duty steel angles such as these (Simpson Strong-Tie HL33, available from Home Depot for about $5 each):

   View Image

   If necessary, I'd clean up the slots with a chisel. A tight fit is not necessary, as we're going to be using epoxy to hold everything together. Just make sure that the angle goes all the way into the slot without binding.

   Finally, I would glue 45° clamping blocks to the faces of the boards on either side of the joint (probably three pairs of blocks for something the width of a typical coffee table). These will be cut off after glue up.

   Now, it's glue up time. After doing a dry run to verify that everything goes together properly, I would first use some masking tape to mask off the faces of the boards in the vicinity of the joint, so that they don't get any epoxy on them. Then I would mix up some West System #105/#205 epoxy, adding some #403 microfibers for thickening (all available from Lee Valley). I would then take a deep breath, liberally apply epoxy to the slots and miter faces, insert the angles, and clamp everything together.

   -Steve

    

   
2. 
   YesMaam27577 | May 23, 2009 01:15am | #7

   In addition to the advice you've got regarding the joinery, you'll need to be very aware of the moisture content of the slabs that you'll be working with.If the slabs are not sufficiently dry when you do the joinery, the resulting movement might open those miters up.

   Politics is the antithesis of problem solving.

3. 
   Napie | May 23, 2009 02:31am | #8

   Get Tage Frid's book on joints and look up the "full blind spline miter".  Very strong and easy to cut with power tools, (only a tablesaw and router needed) and perfect for this application.  He also shows how to cut it on his video.

2. 
   WillGeorge | May 23, 2009 03:33pm | #9

   Can you tell us a little bit more about how this is going to be used? "Strongest possible" would probably involve buried steel rods and such; I'm assuming that's overkill for what you intend to do. So the real question is, "What is 'strong enough'"?

   -Steve

   I hear you ALOT! In my opinion a perfect answer! My 'good Son-In-Law' is a Professor? OK. not sure.. He Teaches Teachers..

   He has more books than anyplace except for our USA National library!

   Some time back I made him a VERY LONG and DEEP book shelf.. Two 1/2 by 1/2 90 degree Cold Rolled steel angle iron (had plated in Zinc) for each shelf routed underneath and out of view!

   He thought the shelves were a bit heavy.. I told him I thought he was a bit Heavy liking Hard Rock. I thing we left it at that!

2. 
   oldusty | May 22, 2009 04:55pm | #3

    Garner , 

               Cutting the miter cleanly will be more difficult then creating the spline joint imo .

          One way :

       Once the 45° angle is cut , clamp the pieces to be splined together face to face with the long points of the miter equal then use a router with the desired slot cutter bit .The router base rides on the cut miter of one while routing the other .

              You can stop the slot before the ends to stay blind or hidden.

        Hope that helps

            regards    dusty

1. 
   GarnerT | Sep 20, 2009 08:43pm | #10

   Good afternoon,

   Went back to a post from the late spring.  What would your advice be on getting an accurate 45 degree mitre that would allow for a 'folded' edge joint?  I know I should be thinking of a crosscut sled but haven't yet built one....

   Thanks..

   Todd

1. 
   oldusty | Sep 21, 2009 12:16am | #11

     Hi Todd ,

          I guess you are working on the same project as earlier talked about , for cutting the 45s I would run my blade into an auxiliary fence on the correct angle and snip off the 45° waste leaving a knife edge on the mating parts .

                tell me more if I have missed the answer

            regards from Oregon         dusty

1. 
   GarnerT | Sep 21, 2009 01:24am | #12

   Dusty,

   Sincerely appreciate your time and earlier responses.  I have not yet executed on this folded joint as I have leaned toward metal legs.  My concern is aligning the second mated part that would run down from the horizontal table top.  Once I cut the 45 on the longer piece, I would need to flip the shorter end cut.  Question is alignment of that piece if I am working with 'live edge' slabs that are not dressed and have uneven edges.

   Greetings from Toronto. 

   Your advice is greatly appreciated.

   Todd

1. 
   oldusty | Sep 21, 2009 03:15am | #13

     Todd,

   I think I have an idea what you want now , with a rough live edge a sled on the TS or perhaps a new sharp carbide blade on the skillsaw cranked to a 45° angle guided along a straight edge .

        Cutting the short piece will be the harder imo , how about cutting the shorter end cut first , you will have more surface for your saw and straight edge and clamps .Then go back and 45 the long piece if you use a skillsaw.

        If you run it through the TS on a sled , still cut the small end first perhaps.

             either way you should be able to only lose an 1/8" so the grain will wrap pretty well I would think . Not sure about  folded corners , sorry ?

        Just gluing with tape and light clamping should hold this corner fine .

                   regards         dusty

2. 
   Shoemaker1 | Sep 23, 2009 05:26am | #14

   I think I understand what you are doing. You want to take out a V and leave the top grain as undisturbed a possible. Make a ply wood guide. cut from the back side with skill saw, set for the thickest part - one nose hair. Make qpposing 45% degree cuts, fold and glue edge.Think I have hear this as a "Waterfall Joint" may be try google.Show use when done