Cabinet doors newbie question

[dave1119]

1st project with the bt3000. Cut rails and stiles for new shaker cabinet doors.
Using a 6" dado stack to groove 1/4" for plywood panels. My question is when I setup dado stack for 1/4" cut there seems to be a little to much gap where panel goes into groove. When I remove one of the cutters it makes a 1/8" groove which is too small and requires a couple more passes through the saw. (the gappage is between 1/16 and 1/8)

Do I want the extra gap between plywood panel and groove slot? and use space balls? or do I want a more snug fit? If I go back to just using one blade and make more passes then it kind of defeats the purpose of buying the dado stack for a 1/4" groove. Although when I go to make tenons on the rails I'm sure they will go much quicker with dado stack so I will probably keep the set.

Working with Oak purchased from local cabinet shop which he ripped into 2.75 widths and ran through the jointer for me. (nice guy)

Oh, and no router (in-laws was only 1/4" collet and wasn't doing the job.

[Black wallnut]

Dave it sounds like you have undersized plywood which is normal. Space balls would help. You could also just run a rabbeting bit around the inside of the door and then use applied moulding to hold the panel in like one would for glass panels. This adds to the work but your panels would not rattle.

[dave1119]

Also worth mentioning is that on a test run my oak plywood had only 1 side finished (big box store) and the plywood that I will be using from my local cabinet shop will be finished on both sides. Should I expect a little thicker piece on the 2 finished sides?

[Black wallnut]

Not necessarily! Most plywood is undersized these days. It is best to check each sheet as all is not uniform in size. One of my currnet projects is a dresser where I'm sing two sheets of 3/4" birch ply from different mills. There is a very noticable difference in thickness between the two and it is creating some issues.

[drumpriest]

Here a trick, you can cut your dado with just 1 cutter, and here's how. Set the fence so that instead of cutting down the middle of the board, it is offset slightly, then cut a groove, rotate the board 180 and cut again. This will make the groove wider, by moving the fence slightly you can dial in the width you need and it will be perfectly centered. This works well for things up to 1/4", and ply is typically under 1/4".

So, for instance, you have a 3/4 board, you want a 1/4" groove, you would set the fence to 1/4" cut-rotate-cut. Now if you want slightly less than 1/4" just nudge the fence out slightly, which moves the 2 cuts closer to the center of the board, and makes the groove smaller.

Space balls are great, btw, they really help with the rattle.

[dave1119]

In my dado set there were 2 cutters, 2 6" blades, shims, spacers. Since the cutters are thicker and 2 together being a 1/4" is a little wide, how about 1 cutter and 1 blade?

[drumpriest]

You will get a lot of chip out if I get your meaning. The 2 blades go on the outside to score the dado boundaries. A chipper at the edge would mutilate your wood. When I said "one cutter" I didn't mean 1 chipper, I meant that you can make that cut with your regular TS blade.

Sorry for any confusion.

[dave1119]

thanks, I meant to say one cutter and a 1/16" chipper but the instructions call for chippers to be inside 2 outside cutters. What I really need is another dado cutter that is 1/16" instead of 1/8".... does that make any sense...

I guess my goal was to do all of these in one pass instead of 2 or 3

[Tom Miller]

Something's not adding up here. If undersized ply is the culprit, the gap should only be ~1/32". To top it off, at least some dado sets are usually a little undersized themselves to account for this.

To OP: what dado set to you have? And pardon this question, but just to be clear -- were you using the two outer blades, as opposed to the chippers, to make the cut?

BTW -- welcome to the forum!

Regards,
Tom

[dave1119]

Craftsman 6" dado steel set. I started on a test piece running just the 2 cutters which would give me a 1/4" groove. With plywood undersized the gap seemed excessive (and i need to measure the gap again) but with 1 cutter on one pass not big enough.

I have not used the chippers yet which led me to think why couldn't I add the 1/16" chipper to 1 cutter but instructions call for a cutter on each side when a chipper is used.

Again, I'm not whining just curious if and how I can get a 3/16" cut in one pass.

[billwmeyer]

Dave,

I heard you had a little wind out your way Monday. I hope you had no damage. I'm glad to see another Kansas flag on the forum.

Bill

[Black wallnut]

"just curious if and how I can get a 3/16" cut in one pass."

The simple answer is no you can not in one pass get this.

[poolhound]

As others have said ply is rarely exactly the size advertised hence the reason for undersized router bits.

I bought a sheet of 1/4" for some drawer bottoms this weekend and it was actually sized in mm (5.2). Its also worth noting that many dadoe blades are also not necessarily exact and usually come with a variety of different sized shims so you can setup exact widths at least thats how mine is.

To cut the grooves for my drawer bottoms I cut them in two passes not to much extra work.

If your ply is the regular undersized variety then yyou could use and undersized router bit in your router table and that will do the trick.

[Tom Miller]

Hmmm, so I guess the conclusion is your ply is just really undersized. In which case your dado set is not going to cut it, so to speak, as you initially feared. (BTW, I don't think dado blades are intended to be run separately, but mostly as a quality of cut issue.) And, it sounds like an undersized plywood router bit is also going to be too big, if the ply is that undersized.

I've heard of folks stacking circular saw blades to make dado cuts -- not necessarily recommending it. I'd be most inclined to do two passes on a regular blade myself.

Sorry I couldn't be of more help.

Regards,
Tom

[just started]

I guess you could try using 2 thin kerf blades with a shim between them to get the width you need. I never tried this, just what my over-tired brain came up with early this morning.