Proper fit for dado's and rabbits?

[bluchz]

I am making some kitchen cabinet. The upper cabinet assemblies are making me crazy! I took the time to cut all the pieces. The cabinets are assembled with dados, rabbits, glue, and brads to hold it all together while the blue dries. I took the time to set up my dado cutter on the table saw and make sure that i could put the 1/2" ply into the 1/2" groove with just firm hand pressure. Now that i am putting everything together with glue it all needs hammered together! Is this common? Should i have allowed more space in my dados? I sure hope this assembly will last. I would hate to be redoing this in a few years. Any suggestions would be appreciated, i have another set of upper cabinets to make for my house.

 

[Joe Scharle]

Apparently, there has been some swelling. I know....duh. If you can get them in with a light persuader, you should be OK. Too much of course, can crack the case. Humidity is such a factor this time of year, that I try to plan assembly the same day as I cut. Maybe if you can get the pieces in the house, they'll go together better tomorrow.

 

[Mike Davis]

2 thoughts:

Are all your pieces of plywood the same thickness?

Can you sand the edge a little so it will fit in the dado?

Not too much or it will be slack after it shrinks and taper it just a bit so it fits tighter as it goes into the dado.

 

[Bas]

I think you'll be alright. It's considerably warmer and more humid today than it was last Friday, so anything cut then will be a tighter fit today, plus the glue will also cause light swelling. Unless you have a fully air conditioned basement shop, most likely your shop is more humid than your kitchen. That means that if you can fit it together with some gentle persuasion, things will only get looser from here on out. I concur with Joe's idea of moving the pieces inside before assembly to acclimate, that will help.

 

[Canuck]

I too agree with fitting and assembly the same day if possible.

I have had the experience of setting up the dado and found that the fit can sometimes change even from the same piece of plywood. A very light sanding and gentle persuasion usually works ok.

Here is another example of humidity effects.....

I am smack in the middle of assembling a small desk for one of my daughters. I like to use beechwood dowels for my joinery. I drilled all of the dowel holes and inserted the dowels for a dry fit on Friday. Today, I am taking the leg/apron assembly apart for glueup. Well....guess what. I needed a pair of pliers in order to free up and remove the dowels.:wmad: In just a couple of days, the dowels swelled enough to almost lock the joint together. A common issue with wood and humidity.

I am sure that things will work out for ya. Better too tight of a fit than loosy-goosy!:gar-Bi

Wayne

 

[bluchz]

Well i finally got it all together. I don;t know if i would call it gentle persuasion though. I guess time will tell. It was annoying. I cut the dados today and assembled in the same day. but the parts were cut a few days ago. Some of the pieces were warped, i guess this happens with single side finished ply. It was annoying but now i am dine with that and am on to building face frames and doors, Maybe i can get some pics to show off! lol Until thenccasion1

 

[Jeff]

I am making some kitchen cabinet. The upper cabinet assemblies are making me crazy! I took the time to cut all the pieces. The cabinets are assembled with dados, rabbits, glue, and brads to hold it all together while the blue dries. I took the time to set up my dado cutter on the table saw and make sure that i could put the 1/2" ply into the 1/2" groove with just firm hand pressure. Now that i am putting everything together with glue it all needs hammered together! Is this common? Should i have allowed more space in my dados? I sure hope this assembly will last. I would hate to be redoing this in a few years. Any suggestions would be appreciated, i have another set of upper cabinets to make for my house.

Help, I'm confused here! Are the sides solid wood with vertical grain or 3/4" t ply with a 1/2" wide dado to fit the 1/2" t ply shelves? :dontknow: I just want to learn/understand for future reference.

I thought that ply was dimensionally stable even with our high NC humidity and that the expansion/contraction of solid wood is usually negligible along its length (i.e., vertical for cabinet sides). So the matching dados should still fit as planned even though they weren't milled and assembled on the same day.

If that's correct it seems that the ply sheets used for the shelving are not uniformly 1/2" t or that the shelves have warped after they were milled to size. :help:

 

[bluchz]

I am making or was making upper kitchen cabinets boxes. I made the boxes from 1/2" plywood which had 1 side finished. I took the time to set up a stacked dado cutter in my table saw, tested it with a scrap until the fit needed firm pressure to make it work. when i went to make the final assembly i needed a hammer and a block of wood to get some of the pieces together. It was frustrating after making such an effort and taking the time with the dado and table saw. The good thing is that it is over now and i am on to face frames and doors. This experience might lead to make the dado's a little looser fitting and hope that the glue can make up the difference next time? not sure what i will do lol The materials were all 1/2" ply.

 

[ehpoole]

I'd like to throw out one more possiblity...

Usually, when we do a test fit with a scrap piece of wood, we tend to use a relatively small scrap for the test (why waste good wood?!). If your scrap was 4" wide and required 5lbs of force to insert, then all other things remaining the same, a 32" dado will require 8-times as much insertion force (40lbs) assuming no other variations in thickness or warping/cupping of the wood to be inserted -- or any irregularites in the dado cut itself.

Just my $0.02...