# Help with Sliding Dovetails



## aaronmi07 (Oct 6, 2007)

Well, after being a member of this forum for almost a year now this will be my very first post. I finally bought my jointer (Jet 6" deluxe planer with 56" bed and quick change knives:thumbsup and planer (small 12" delta shopmaster...) this year and I am finally going to be building furniture not made out of plywood and 2x4's! WOO HOOO! Now it is time to build something my wife will let me bring in the house. So that leads me to this post.

I just got the preliminary plans approved by my wife for a knick knack shelf that I am going to build for her. I am going to join the brackets to the back and the top with sliding dovetails. The brackets at the ends though will be rabbeted and pegged since there isn't enough material. What is the best size dovetail for this job? I have 3/4" red oak for the material and I am thinking maybe making the dovetail 1/2" deep and 5/8" wide at the top of the male end. If that is good, which angle is best for this kind of joint 7 degrees or 14? I was thinking maybe the 7 degree since oak is so stringy and the pointier the tip of the top edge of the dovetail maybe the weaker it will be? The top dovetail of course will only be glued at the back for expansion and contraction so it has to be strong without glue. I hope my sketch came in OK if that helps. And now that it is in I just realized my peg layout is not going to work...:wallbash: I'll have to fix that 

Thank you,
Aaron


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## jerry (Nov 1, 2006)

As a general rule I never make the groove(female) deeper than half the thickness of the material. For a shelf like that I would use 1/2" dt bit about 3/8' deep.

Regards

Jerry


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## TexasTimbers (Oct 17, 2006)

aaronmi07 said:


> Well, after being a member of this forum for almost a year now this will be my very first post.


Well you got me positively flummoxed because I show your first post on Oct 7th, of last year. :huh: 

Only reason I looked was because you siad "... first post...." and I saw where you already had 27 so i wanted to see how you managed to make so many so quick! :laughing: 

What am I missing? :smile:


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## cabinetman (Jul 5, 2007)

You could do the joinery very simply by using blind splines. Unless you just like doing DT's.


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## bsharding1982 (Feb 25, 2008)

I began to do a project with Sliding Dovetails, but just couldn't get it right. They are definitely tricky. Maybe someone could suggest a good jig to help you out, something I have yet to find.

ps. tt, I think he means this is the first time he has started a thread.


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## aaronmi07 (Oct 6, 2007)

eh hmm... yeah, I ment to say thread. And I guess this would then technically be my second cause if I think about it I sort of started one when I introduced myself. Anyway....

Cabinetman, what would a blind spline look like exactly? I imagine a long rectangular spline with dado's in the brackets, top and back to accept the spline. If that is the case that wouldn't really hold the top of the shelf down. What I worry about, or imagine, is the top curling up, even just a tiny bit, leaving an unsightly gap between the top and the bracket.
I know there are easier ways to do this kind of thing, I mean I could just use screws, brads and glue and it would still look really nice but I love the challenge and the thought process. I really like bshardings idea of a jig of some kind. I have read before of using a tapered dovetail to make joining them easier when they are long, like for shelving, but these will only be about 5" long. I watched "The Wood Whisperer" put together his end table legs with sliding dovetails and he "made it look" really easy. I think I am just going to have to try several test pieces and see what happens. I would still though really like to know what you ment by blind splines cabinetman.


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## cabinetman (Jul 5, 2007)

aaronmi07 said:


> Cabinetman, what would a blind spline look like exactly? I would still though really like to know what you ment by blind splines cabinetman.



They are called "blind" cause you don't see 'em. Very simple to do. Basically you could use any wood or plywood 1/4" thick. It should be a smidgen shy of 1/4". You put a 1/4" dado (groove) into the top of the bracket, and the bottom of the shelf and stop it short from the front. You do this with a straight cutting router bit. If your groove is 1/2" or even 3/8" deep on both pieces, then your spline could be 15/16" x 1/4" for the 1/2" setup, or 11/16" x 1/4" for the 3/8" setup.

Since you glue them in, the shelf ain't goin' anywhere.


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## morgid (Apr 1, 2008)

jerry said:


> As a general rule I never make the groove(female) deeper than half the thickness of the material. For a shelf like that I would use 1/2" dt bit about 3/8' deep.
> 
> Regards


:thumbsup::thumbsup::thumbsup:


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## aaronmi07 (Oct 6, 2007)

Thanks guys! I really appreciate all your help. I am going to go with the sliding dovetails 3/8" deep. Thanks also for the blind spline suggestion cabinetman. If I have too much trouble with the dovetail grooves on the top I might just try those on the back. I'll post the finished product when it's completed.

Sincerely,
Aaron


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## Joe Lyddon (Mar 13, 2007)

aaronmi07 said:


> I just got the preliminary plans approved by my wife for a knick knack shelf that I am going to build for her. I am going to join the brackets to the back and the top with sliding dovetails. The brackets at the ends though will be rabbeted and pegged since there isn't enough material. What is the best size dovetail for this job? I have 3/4" red oak for the material and I am thinking maybe making the dovetail 1/2" deep and 5/8" wide at the top of the male end. If that is good, which angle is best for this kind of joint 7 degrees or 14? I was thinking maybe the 7 degree since oak is so stringy and the pointier the tip of the top edge of the dovetail maybe the weaker it will be? The top dovetail of course will only be glued at the back for expansion and contraction so it has to be strong without glue. I hope my sketch came in OK if that helps. And now that it is in I just realized my peg layout is not going to work...:wallbash: I'll have to fix that
> 
> Thank you,
> Aaron


Hi,

I'm not sure about answers to your questions... but, I made a similar shelf not too long ago... It may be able to help you...

http://www.ncwoodworker.net/pp/showgallery.php?cat=982

http://www.ncwoodworker.net/pp/showgallery.php?cat=500&ppuser=1389

I designed and built the shelf just so I could use The Sliding Dovetail... :yes: 

Hope it helps you...


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## aaronmi07 (Oct 6, 2007)

Thanks Joe, that is really neat! I never thought about leaving the ends of the dovetails exposed but I like that look, very nice.


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## Joe Lyddon (Mar 13, 2007)

To me, the only reason for doing the project, the way I did, was to SHOW those Sliding Dovetails... 

I think all DT's should be shown... would be a sin to hide'em! IMHO


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## allthunbs (May 14, 2008)

aaronmi07

I use the OakPark philosophy for a router table. I create the groove the same way you do, but the male slider is a bit different. I set the fence so that it almost completely covers the bit. I run both sides and test it. Too tight? tap the fence out a little bit and rerun the slider, both sides. Try the joint again. I use a block with a proper jointed face as a guide block to ensure tight contact with the fence. This is the only way to ensure controllable progress.

It is imperative that the bit depth remain the same while cutting the groove and the slider.

I hope this helps.


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## aaronmi07 (Oct 6, 2007)

Allthunbs... a little too late my friend. lol... But all is good. I know you replied over a week ago now but I actually cut my dovetails almost a month ago. I finally got to applying my stain to the project last night. I am really glad that I challenged myself to the extent that I did on this project. I have learned a LOT! Did you know that random orbit sanders will round the edges of your pieces? Well, that is probably pretty basic information for most people but it cost me quite a bit on this project. Did you know that without stops on your router table fence that stopped dados don't stop so well? LOL! If you have to glue up panels leave 5 or so extra inches to that you can run it back through your planer after you re-flatten a side. Especially when the guide leading to the platten on your dads old belt sander is all busted up and caused the sander to gouge the wood. Yikes did I make a lot of basic errors but they were really good ones. I decided when I started this job to allow myself 10 mistakes and then if I filled my quota I would allow myself ten more but whatever happened I was going to concentrate on correcting my mistake without throwing any pieces away if possible. I have succeeded! Soon I will post some pictures of the finished project and tell a little more of what happened. It isn't perfect but it will remind me every time I look at it to fail forward! My next project will reflect what I have learned this time around as well as continue to challenge me. I have a beside table for my sister that I am just itchin to get into. 

allthunbs, your process for cutting sliding dovetails is a good one. My mistake was not haveing a practice piece that I would have had had I not seriously oversanded my peices with my new ridgid random orbit sander prior to cutting my joints. Not one of my three korbels were the same thickness (and they were all rounded) so I had to work each piece in individually and the middle one I goofed bad. I know I just tapped that fence and I still don't know how it happened but it took a serious cut. I knew it when it started cutting wood that I had goofed. If they were going to be exposed I would have had to start over but since they weren't I figured that I could rip some thin strips and shim the joint. IT WORKED GREAT! I was jumpin for joy. Anyway, i'll have more to tell when I post my pics.

Cabinetman, I did decide to go with your blind spline for the middle korbel where it attached to the back. I hadn't thought it through well enough but my plan was to notch out the korbel to "hook" the back and then dovetail it but I reallized it was going to be more of a pain than necessary to try to cut a dovetail that far into the piece so I used your spline instead. It worked great!

Thanks everyone for your help!
Aaron


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## allthunbs (May 14, 2008)

aaronmi07: It just goes to show you that the fastest means of communications in history still requires lots of lead time.

"Did you know that random orbit sanders will round the edges of your pieces?"

Take a look at your sander. Take off the sand paper and look at the plate. It should be covered by some sort of material that has a bit of "give" to it. This is the part that actually does the "rounding over." I've done a few experiments without much success. My problem is that the base plate of the sander is made of stamped metal. This means that the surface is not flat and too many chances of cuts and divits in the target material. Ok, I've tried stretching a bicycle inner tube tightly over the baseplate and pad of the sander. The objective was to compress the factory made pad and make the surface a bit stiffer. It helped but not much. I've tried a thin piece of masonite but the masonite introduced four more cutting surfaces. The only real replacement is the old wooden block with a piece of sandpaper wrapped around it.

Just 10 mistakes huh? My first project was to cut a piece of wood 18" long, route four sides, seal, stain and cover -- OK, I cut a piece of wood to length, rounded the edges and stained it. This is several years later but thinking back, I'm around 40 mistakes and counting. You're doing well ;-)


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