Router bit for dovetail joint

[MidTNtimbers]

Hey guys, it’s my first time posting here I was wondering if anyone had ever used the router bit and jig to lay out dovetail joints in a timber frame structure. I’m building a 16 x 24 timber framing and all my floor joists are dovetail into my silll plates. It’s a lot of work if I try to cut these up by hand and was really hoping someone that had experience in this and new trick to make this go faster.


 

[Jim_Rogers]

The solution to doing this faster is to not do it. With your sills being connected to a foundation there is no risk of the floor joists from pulling out. The industry has (in my opinion) moved away from dovetail joints as the dovetail timber shrinks and loosens up in the pockets.



 

The dovetail is going to shrink as shown with the red lines. To prevent pull out some have added wedges were the blue lines are shown. Crushing the dovetail somewhat with hopes that when it dries out it will not pull out because the wedges are there.

If you are concerned about sills spreading at mid span the joint to use is a tying joist with a simple mortise and tenon, like this:



 

 

 

 

If you have long sills, and are concerned about them spreading put two tying joists in. But the end cross sills should hold the ends and the tying joist should hold the middle.

Regular drop in floor joists can be used. Either secure with a screw, as it will be hidden by the flooring or a peg. But the peg will not be located correctly based on the distance from the peg hole to the end of the joist as the joist end is not long enough.



 
Drop in pockets shown beyond the tying joist on a long sill.

Good luck with your project.

Jim Rogers

[MidTNtimbers]

Thank you Jim .That looks like something more on my skill level. I’m starting with two small timber frame structures before we build our big house. The first one is the 16 x 24 and the second will be a 24 x 24 with blue prints. Purchased from Shelter institute. The idea is each time I build one to increase my skill level.  And of course everything gets better with practice.

If these tie joist are going between a sill plate and a mid span beam, how would I attach Both ends? I’m going to attach a picture of the framework already have done any advice or tips you could give would be greatly appreciated. I’ve watched several of your videos and we’ve spoken before via email. You guided me where I needed to go to buy the Big Al. Your help is always appreciated!

 

[Jim_Rogers]

You can do dovetails if you want, but it's really not needed.
The way it was done before is to use two skill saws.



 



 

one regular skill saw and one worm drive. One angles one way the other angles the other way. Then you just chisel it out:



 

If you can't take one or the other end cross sill apart to allow two tying joist ends to slide in from the side, then you can just do drop ins and secure them with screws.

Jim Rogers