Replies

1. 
   WillGeorge | Sep 27, 2009 04:03pm | #1

   Good morning to you also. I've been up since 3 AM.

   Do any of you guys make your dado slightly oversized?..

   Just my opinion but I would say do not oversize. Yes, many long boards (even short ones)  may change from perfectly flat to whatever they want to with temperature and humidity.

   I'd say it is what makes glue-up fun! It will help dry fitting all parts first. But I think this should be done prior to any final gluing.

   I do understand your asking the question though.  I have to admit that I usually use a router table to cut mine. I have bits for standard sizes and for the 'modern' .. to save money.. undersized plywood. My router table fence allows me to custom fit for what I am using/doing.

   As I use the router mostly, I had to think back of what I did when using a 'stacked' dado set for shims. Now... where did I put all those 8 inch floppy disks I had? I also remember something about oiled brown paper? Not sure. My old brain remembers MANY things. Just seems the memories get all mixed up these days!

   Sort of joking but sort of true also.

   I do not recall any 'cast-in-stone' fitting sizes to use for mating parts of any type of joint. 

   You say Dado for Casework.. I think Plywood.. Modern plywood stinks. I'll take the exterior/interior grade made in the USA and Canada from the 1960's any day!

   Canada made really good stuff if I could get it.

   No, I have not answered your question. Just food for thought.

   Do NOT rely on nominal sizes. Sometimes it takes hand fitting. Cut you Dado to what you think it should be AFTER averaging the width of it's mate..  Quick to do with dial caliper. Every 6 or is that 8 inches? Off to another subject...

   All In All .. I would say if you love woodworking.. You WILL get through this problem.

   Just have fun in the Swamp full of Quicksand...

    

    

    

2. 
   oldusty | Sep 27, 2009 04:30pm | #2

   Morning Ben ,

                  I build casework and cabinetry and do use dadoes , sounds like yours have been tight , is it plywood fitting into the dadoes ?

         In a perfect world 3/4" plywood should not be thicker , thinner seems to be fine but not thicker. My dado cuts exactly 3/4" most of the plywood is shy but fits every time .I place the part that fits the dado do it is tight to the inside of the case side of the dado .

           Now and then plywood will be thick , always dry fit , a quick sanding of the offending edge that will not show with the belt sander works every time and will not take much time.

        Have you made your dado set cut shy of 3/4" by restacking and shimming ?

             for many repeat cuts or a long run I will adjust the dado to fit better when needed,for special; or off size cuts.

                   regards             dusty,boxmaker

3. 
   knuts | Sep 27, 2009 04:31pm | #3

   All my dado troubles went away after I built a couple of these. My dado stack may even be rusty by now, but I won't bother to even look.

   http://www.ncwoodworker.net/pp/data/194/Dado_Jig.JPG

   
   

   ---

   Edited 9/27/2009 9:34 am ET by knuts

1. 
   jonnieboy | Oct 02, 2009 07:46am | #18

   Knut,

   I'd love to have a better look at this jig of yours. Do you have the plans for it, or can you direct me where to find them?

   -jonnieboy

1. 
   knuts | Oct 02, 2009 02:53pm | #19

   I got it from Shopnotes sometime ago, but I've found this link below. I made 3; 1/4" bit, 3/8" bit & 1/2" bit, just because I had the time, I suppose. The 1/2" is the one I use most. I use it for 1/2" to 1" cuts all the time. I also use it for sliding DTs on pieces that are too large for my Woodrat. Stopped dados; just clamp stop blocks to the jig. BTW, I screw the hardboard fences to the jig, instead of gluing them on. http://www.shopnotes.com/issues/076/videos/using-the-shop-built-dado-jig/

1. 
   jonnieboy | Oct 02, 2009 03:22pm | #20

    The video explains a number of my questions. Thanks a lot!

   --jonnieboy

4. 
   bones | Sep 27, 2009 04:50pm | #4

   First off, you are a lucky man being form VA!  Secondly, I'd not oversize your dado's That will lead to issues and by far more work shimming.  You don't exactly state what the glue up problem is.  Is it that the boards have a slight cup or bow that makes it hard or is it that you have to haul butt to get it together before the wood stars setting.  If its the boards, I have a dead blow hammer that works great and does not marr the wood.  If it's the glue, I use a slow set glue for this very purpose so I have time to make adjustments.   If either of these is not it, provide a bit more detail and i'm positive someone here has had the issue and a solution.  Unless you're a wahoo, go hokies, in that case go wahoos. 

   I was married by a judge - I should have asked for a jury.
   George Burns

1. 
   benphillips | Sep 27, 2009 04:57pm | #5

   Thanks for all of your suggestions. I am using MDF to make a raised bed for my mother-in-laws dog. it is basically a box that is 22x22x12. I added three sides to give it a little interest, and to hold the dogs bedding in place. The crap, i mean MDF measured 3/4. I setup my dado stack for 3/4. I knew it would be tight, but I had to really beat on it, and it didnt go together well at all.

1. 
   oldusty | Sep 28, 2009 02:22am | #7

   sometimes the mdf can be swollen as from RH factor , sometimes it varies on each sheet . I check each joint and quickly belt sand if needed from one side if it's tight .

1. 
   oldhand | Sep 28, 2009 03:09am | #9

   That's just what I was fixin' to say..

2. 
   SARGEgrinder47 | Sep 28, 2009 03:12am | #10

   If you are cutting the dado depth to say 3/8".. measure from the outside of the piece fitting inside to 3/8" from the tip toward center. In other words the piece that would fit inside the dado. Then use a square and pencil a line across. Blue tape on the line all the way around leaving the dado male piece bare. A few swipe on each side with a rasp to take it down siightly. Just test it as you go until you get the proper fit.

   Have fun...Sarge..

   Woodworkers' Guild of Georgia

1. 
   benphillips | Sep 28, 2009 03:47pm | #11

   Thanks Sarge..................I appreciate the tip.

1. 
   SARGEgrinder47 | Sep 28, 2009 05:00pm | #12

   Ben.. I might add that if you are using wood in this senario and the piece bows slightly after you final size it.. you can mesh the piece to the cut dado to see where it obstructs. If the good side is bowed up or down.. simply shade the obstruction with a pencil and take if off with a shoulder plane set for a very thin cut or you could use a rasp or fill or combination of the above.

   You may not have run into this yet but if you get heavy into using wood.. you probably will. It takes off what is needed to be taken off with out having to flatten the entire piece which compromises your intented final thickness.

   Have a good day...Sarge..

   Woodworkers' Guild of Georgia

2. 
   WillGeorge | Sep 27, 2009 07:10pm | #6

   I love it.. 

   I can remember when the air was clean and sex was dirty. George Burns!

3. 
   btberlin | Oct 04, 2009 04:57am | #21

   The quote at the end of your post comes from Groucho Marx, not George Burns.

1. 
   RalphBarker | Oct 04, 2009 06:18pm | #22

   There appear to be attributions of the quote to both Burns and Marx. Who said it first might be difficult to ascertain.

5. 
   nazard | Sep 28, 2009 02:59am | #8

   Good evening, Ben.  Just thought I would extend greetings from a fellow woodworker from Virginia that is also a dog lover!

   -Jerry

6. 
   hammer1 | Sep 28, 2009 05:00pm | #13

   You should always do a test fit with any joint cutting set up, not something small but something appropriate for a true test. When gluing up, the glue can make materials like MDF swell up. Putting glue on the "male" end can cause more problems than in the "female" slot. You need to work fairly quickly once the glue is on. If you have to pound on the work to get the joint home, something is wrong. You can either resize the dado or cut shoulders on the piece that fits in. The old timers used to say, you should be able to tap the joint together with your hat.

   Beat it to fit / Paint it to match

7. 
   JohnWW | Sep 28, 2009 11:58pm | #14

   Ben,

   You will almost always have to shim a dado set to get a good fit, the wood and the dado set main cutters are only nominally in even fractions of an inch. For a good fit you have to make test cuts and then adjust with either shims in the dado set or by planing off the piece that is going in the dado.

   John White
   Shop Manager for FWW Magazine, 1998 to 2007
8. 
   gofigure57 | Sep 29, 2009 02:36pm | #15

   Ben there are many simple ways to deal with this issue. I dislike messing with shims on dado sets, a waste of time for me. I have set my dado head up with shims , dadoed all my cab sides then upon assembly later in the afternoon had the plywood ends swell due to humidity changes and cause me fits, that was long ago.

   Now I set my dado head up slightly smaller than the thickness of the sheet stock I am using and to a depth of 3/8". 

   Upon assembly I will chuck up a 3/8 rabbet bit in a router or router table, run a few test pieces until fit is to my satisfaction  and go from there.

   
1. 
   bones | Sep 29, 2009 04:32pm | #16

   Good solution that's the method I use.  I was married by a judge - I should have asked for a jury.George Burns

9. 
   cowtown | Sep 30, 2009 07:27am | #17

   Ben-it's been a coupla decades since 3/4 or 5/8 anything actually matched the descriibed thichness.

    

   Absolutley think about shims, and even better yet, invest in a 40$ digital caliper to ascertain an acuurate thickness of material. Then shim yer stack to match, test and adjsust if req'd.

    

   Eric