Fake Sliding Dovetail

[rhull]

From my folder of "interesting things" I've collected from various places in the 'net. I've no idea where I grabbed this pic, or who produced it, but I found it intriguing.

[TDHofstetter]

That IS an interesting joint. Saves a world of fitting grief when it comes to assembly time, yet still retains as much of the strength of the full sliding dovetail joint as one really needs.

[Joe Lyddon]

That's not a fake DT...

It's a short Sliding DT...

I've seen it a lot in chests of drawers... mounting dust shelves, etc.

I haven't seen it being used like your picture... it would be easier to just glue the pieces together... for the panel!

[fredbelknap]

That's an unusual joint. Looks like it might work on in a cross grain situation for expansion unglued or just one end glued.

[sawduster]

An interesting application of that joint, but I'd have to be leery of it considering the grain direction. I'd be concerned about blowing out the sockets, especially if they were to be glued using PVA glue since the wood would be absorbing moisture from the glue and expanding.

As Joe mentioned, similar joints have been used for attaching shelves to uprights and they lend some structural improvements to help reduce racking and to keep the sides held together. Most times those are stopped joints or the case has a face frame so you don't see the end of the dovetail.

It would be a good exercise in joint making, but I don't know that it would be any stronger than just gluing the jointed edges together or using a normal tongue and groove joint.

[dcarter636]

That is intriguing; it looks a lot like work but it is a non-ferrous replacement for Norm's "... brads to hold it together while the glue dries."

Actually I suppose it is an effective dry joint if it remains unstressed and the boards are constrained from sliding apart.

[hescores]

Ok, as someone who has never cut a dovetail before, hopefully y'all can enlighten me.

As I look at that picture it appears the dovetail is proud of the rail. So, how do you cut the rail and still leave enough for the dovetail?

Actually now that I type this I'm thinking using a router with a stop, then having to clean it up with a chisel. Am I right?

Then again, maybe it's just the picture playing tricks on my eyes.

[lexrex]

Dec 1, 2009 10:24:59 GMT -6 hescores said:

Ok, as someone who has never cut a dovetail before, hopefully y'all can enlighten me.

As I look at that picture it appears the dovetail is proud of the rail. So, how do you cut the rail and still leave enough for the dovetail?

Actually now that I type this I'm thinking using a router with a stop, then having to clean it up with a chisel. Am I right?

Then again, maybe it's just the picture playing tricks on my eyes.

You would first cut the groove with whatever method you chose and then, you are right, most likely run it through a router with a stop to get the short dovetail.

[TDHofstetter]

I think he's looking at the tail part, Chris - at the ends of the tongue.

Hey! I spelled "tongue" with a 'g' instead of a 'q' that time!

A router would be my means of choice for making that straight tonque, with a stop. After cutting the dovetailed end, it'd take some cleanup work with a chisel unless the pinned (grooved) part was cut long enough to handle the rounded-over excess.

[sawduster]

For say 3/4" material, you would likely run a groove the full length of the edge using a 1/4" bit in the router or with a dado head on the TS or comparable untailed tool method. This makes your groove and wastes out the center of the DT making it less work for the DT bit to do. Then you use the DT bit to finish up, centered on the groove and set to the same depth as the bottom of the groove. Then you add that widened area at back of the front end using chisels. Since the areas where the DT ends at the groove will not be seen, no need to square off the rounding left by the DT bit. That's for the socket edge of the board.

For the tail edge, you would run the DT first over the full length of the edge, then use a rabbeting bit or fence and a straight bit to make the tongue, starting and stopping the cut at the ends of the DT tails.

[fredbelknap]

Probably just as easy to make a full sliding dovetail.

[rhull]

I wasn't really posting this as necessarily a great use, as shown. More a conversation piece.

However, the idea definitely has merits. You really only need to make the outside 1/4" as the dovetail, which makes this totally do-able by hand. It's certainly easier to cut a matching tongue and groove than a sliding dovetail.

This "trickery" joint reminds me of a M&T that was featured in one of the WW mags a while back (I want to say Fine Woodworking) made by that guy who makes his through-tenons look like they're carved like shapes or letters. In reality, it's just a small part of the joint. It's kind of trickery, like this joint.

[Joe Lyddon]

Dec 1, 2009 20:44:44 GMT -6 fredbelknap said:

Probably just as easy to make a full sliding dovetail.

Might be just as easy to cut... BUT, not as easy to fit and install... the longer, everything (all thicknesses) must be perfect... If the wood expands in one place & not another, BIG problem!

The longest I've made have been about 7" ... they weren't hard to slide into place.

[hescores]

Well, I'm glad to see that I was at least on the right track with my thinking.