Replies

1. 
   hotdogman | Jan 08, 2020 05:46pm | #1

   Make the lap joint good and snug. I have always had good success with glue on a tight lap joint. I guess you could use a couple of dowel pins as reinforcement and decoration but probably not necessary to keep it together if cut well.

2. 
   daverichards | Jan 08, 2020 06:42pm | #2

   What are you making and how will the joint be stressed? Probably as hotdogman suggests, glue will be plenty. Drilling holes for dowels may no add any strength.

3. 
   _mj_ | Jan 08, 2020 07:18pm | #3

   If it is a corner or a tee joint you have plenty of thickness in 2x2 material to make it a bridle joint which is far better structurally than a half lap. Pinning a bridle adds strength, pinning a half lap adds little.

4. 
   digitallimit | Jan 08, 2020 07:36pm | #4

   I am trying to make a semi-load bearing decorative shelve unit with 2x4 (correction) sanded super fine and has a high gloss clear stain.

   The end units will be in a frame configuration along the 4" surface, so the front profile is the 2" edge. (I think i have my: Surface, End and Edge - faces correct).

   I will then place dowel peg holes for adjustable shelves.

   The idea is to use cheap materials at this point to practice concepts and learn vocabulary.

   I didn't know if the lap joint would be strong enough to support the shelf ends. I got the idea from Ikea Gorm shelf unit, just turn the boards the opposite direction in the front face to get a lower profile in the view.

   Again it is for cheap shelf unit that I can practice lap joints and construction methods before I mean onto hardwoods. I understand hardwood will build differently, but I need the practice with tools and methods.

   I didn't know if the dowels would add strength to structure or just to keep the items together. I am unsure what I can build with just glue and pressure/clamping, since I am still learning.

   Thank you very much

5. 
   daverichards | Jan 08, 2020 07:47pm | #5

   So if you have nice smooth surfaces in the half lap joints that are properly glued, the glue joint will be stronger than the surround wood.

   And it's 2x4 instead of 2x2. So something like in this sketch.

   You can use your pegs for shelf pins like you suggest

   
6. 
   digitallimit | Jan 13, 2020 03:18pm | #6

   @DaveRichards
   Eh - that is 100% spot on - on what I want to do. I did not know the wood glue would be so strong.

7. 
   daverichards | Jan 13, 2020 11:11pm | #7

   "I did not know the wood glue would be so strong."

   Better living through chemistry. :)

8. 
   mikaol | Jul 17, 2020 10:53am | #8

   Hey Dave, Digital might be using 2x2s.
   Mikaol

9. 
   geedubbee | Jul 17, 2020 01:07pm | #9

   "I did not know the wood glue would be so strong."

   I love bridle joints and use them for door frames more than any other joint. However, in every joint torture test I have seen, the lap joint comes out on top. The one below is from FWW 2009.

   It is always important to remember that you are building something for a purpose. Even though a splined miter joint is stronger than a pinned mortise and tenon joint, BOTH may be more than strong ENOUGH for your purposes. Select the one that fits your design / aesthetic ;-)

   
10. 
    rob_ss | Jul 18, 2020 04:07am | #10

    Lap joints are plenty strong enough for this application.
    Just clamp them up well and make sure they are dead square.
    The key is making the surface very flat - the more ridges and bumps you have, the weaker the joint.
    It will be very good practice creating a nice surface for adhesion.
    If you screw up and the joint is a little gappy then use epoxy such as araldite, which is very forgiving of such errors, or Gorilla Glue, which is indestructible and good for the moderately badly done joint (wipe off drips with acetone or pare off with a chisel after 4 hours)
    TBH, since I discovered acetone, I use gorilla glue a lot...