# Could someone help identify this joint?



## thatfatninja (Oct 19, 2015)

Greetings everyone - first time poster.

In my thirst for knowledge, sometime I can't leave something well enough alone until it consumes me. As a younger guy, I've only ever seen/worked with standard/easy joinery techniques (dowel, finger joints, biscuit, etc...) and I know there are quite a few variants out there but I've come across one I have never seen before and not sure what it's called or why it was chosen.

I've attached a picture of the joint to this post - it's from a drawer in what we think is an antique dresser (actually all the drawers in the dresser are joined the same). Seems like creating this joint would be lot of effort to me for something that is only seen when the drawer is open.

Any help is appreciated - it's driving me nuts for no other reason then I don't know what it's called.

Scientia potentia est!


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## woodnthings (Jan 24, 2009)

*no picture*

You must enlarge the attachments window and "upload" the attachment for it to be included in the post....?

OR if you are looking at a online photo, "copy" and "paste" into the text of the post.


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## shoot summ (Feb 21, 2014)

I googled "circle and pin dovetail", first hit shows that same joint.

The internet is a wonderful tool when you learn how to use it!!

http://www.harpgallery.com/library/dovetails.htm

I also googled images for "unusual antique dovetail joints" and found hits for it as well.

Technically though they are called "pin and cove", or Knapp joint, they are(obviously) machine made.


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## Alchymist (Jan 2, 2011)

Also known as "pinned dovetail", though not technically a "dovetail".


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## thatfatninja (Oct 19, 2015)

Ah! It was a google fail on my part it seems! I think I went every which way with my search terms other than what was blindingly simple. Doh.

Thanks for the responses, it places the piece in the timeframe I thought so I think I'm going to have it appraised.


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## antkay1 (Dec 2, 2015)

you learn something new everyday


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## 4DThinker (Mar 13, 2013)

Fairly easy to cut using a CNC with vertical clamping capability. Looks like it could also be done with a plug cutter bit (to leave the pins), a drill for the holes and a band saw to round around them. Jig to ease regulated spacing between holes/pins.


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## FrankC (Aug 24, 2012)

4DThinker said:


> Fairly easy to cut using a CNC with vertical clamping capability. Looks like it could also be done with a plug cutter bit (to leave the pins), a drill for the holes and a band saw to round around them. Jig to ease regulated spacing between holes/pins.


Not that complicated, the pins are actually dowels.
http://johnmarkpower.blogspot.ca/2010/05/knapp-joint.html


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## mmwood_1 (Oct 24, 2007)

Thanks for that link, Frank. Interesting reading.

I'm not sure why it would be referred to as any sort of dovetail joint, though. There are no dovetail shapes in it, and that is what the dovetail joint is named for. Nor is there a wedge principle at work, as in the dt. Seems to me that whoever coined that "pinned dt" or "circle and pin dt" phrase had no understanding of woodworking joinery.


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## 4DThinker (Mar 13, 2013)

I'd call it a pinned rabbet. You could get the same strength from a simpler rabbet that just had a row of dowels (pins) through it into the end grain of the drawer front. Even better if the pins weren't dowels but simply made from the end grain of the front. The arcs don't add much but a little more glue surface area for the considerably harder effort to create them. 

4D


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## FrankC (Aug 24, 2012)

4DThinker said:


> I'd call it a pinned rabbet. You could get the same strength from a simpler rabbet that just had a row of dowels (pins) through it into the end grain of the drawer front. Even better if the pins weren't dowels but simply made from the end grain of the front. The arcs don't add much but a little more glue surface area for the considerably harder effort to create them.
> 
> 4D


4D, you may be on to something, this is taken from the patent document for the machine that Knapp patented to make the joints;


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## 4DThinker (Mar 13, 2013)

Good thing only the machine is patented. Here is a version I cut out using my CNC. Fresh out of some pine scraps. Not yet glued. 

4D


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## FrankC (Aug 24, 2012)

That looks great, certainly unique.


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## spud (May 17, 2017)

pin and crescent joint


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