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Options for cutting slots for door panels?

6K views 19 replies 11 participants last post by  splintergroup 
#1 · (Edited by Moderator)
I have to build 16 cabinet doors… which is quite a bit. They are simple stile and rail doors, joined with loose tenons.

Now I am wondering what would be the most efficient way to cut the grooves for the panels? I have done this before with a 1/4" upcut spiral bit on a router table. But I am wondering if a slotting cutter wouldn't be better for this job.

I have seen a video where someone used a slotting cutter with a hand-held router. The door was dry assembled with clamps, popped up, and then the slot was simply cut by "riding the inside edge", so to speak. The only problem would be, that the width of the slot would have to exactly match the panel thickness… There are adjustable slotting cutters, but quite expensive.

The other option would be a router table, and route the slots into the individual pieces, using a stop block or markings on the workpiece to make the stopped cuts on the stiles.

I'd love to hear your technique, let's make my life easier :)
 
#3 ·
One problem you may have, depending on the width of stiles and rails, and the width of the cutter, is stopping the cut accurately . Of course if they are mitered then it doesn't matter.

- SMP
I would use stop blocks, but I also had the idea of dry-assembling the door frame, and then routing the slot by simply following the inside edge… this could be done on a router table as well.
 
#5 ·
Previously I always did this type of operation with a straight bit in a router table, mark the fence for entry and exit points and do the stopped grooves that way.
But I recently bought a box-slotting bit (https://www.leevalley.com/en-ca/shop/tools/power-tool-accessories/router-bits/47818-box-slotting-bits) because it was the only way I could figure for cutting the slot for a drawer bottom in a curved front drawer. Works amazingly well, and will be the way I do slots in any frame-and-panel construction where the groove can't go all the way to the end, including drawers. Not sure I'd feel comfortable using one of these bits in a router table (for what it's worth, the manufacturer says not to).
 
#6 ·
Previously I always did this type of operation with a straight bit in a router table, mark the fence for entry and exit points and do the stopped grooves that way.
But I recently bought a box-slotting bit (https://www.leevalley.com/en-ca/shop/tools/power-tool-accessories/router-bits/47818-box-slotting-bits) because it was the only way I could figure for cutting the slot for a drawer bottom in a curved front drawer. Works amazingly well, and will be the way I do slots in any frame-and-panel construction where the groove can t go all the way to the end, including drawers. Not sure I d feel comfortable using one of these bits in a router table (for what it s worth, the manufacturer says not to).

- jdh122
That sounds great. What I want to do is pretty much the same thing, just for cutting a slot for a panel instead of a bottom. I am considering this bit, which would also allow me to vary the width of the slot:
https://www.amanatool.com/53600-quadraset-1-7-8-dia-x-1-8-23-32-x-1-2-inch-shank.html

It's not quite clear what depth can be cut with that slotting cutter though (if using the pilot bearing as a guide). The bearing could be replaced for different depth, or a router table could be set to any depth. I still think, with the right setup, it should be possible to use a hand-held router and cut all four slots in one go. It might require a custom router base plate to make things safer, but I think it would be well worth it.
 
#7 · (Edited by Moderator)
I think that the fastest and most efficient way is to cut the grooves on a table saw. You can use either your regular blade or a dado blade. I start by cutting all of my rails and styles to a bit more than final length and make sure I cut the rails long enough to include the tenons. I adjust the saw fence so that when I make two passes, rotating the work piece end for end for each pass, the resulting groove is the width I want. This also assures that the groove is centered in the work piece. If the resulting groove is wider than 2 X the blade width, I may have to make a third pass to cut out the remaining "fin" in the center. I then cut the tenons on the rail ends to fit the groove. If I don't think the groove is deep enough I may use a router bit at the router table to deepen it.

Of course, this method leaves the mortise and tenon exposed at the top and bottom of the doors. If you don't like this, use the same method at the router table and start/stop the cut before you reach the end of the styles. Then after the grooves are cut, come back and deepen the groove for the mortise if you need to.

If you are also putting a profile on the panel side of the rails and styles, you can get something like this that will do it all in one pass. Then use the complementary set to cut the tenons to fit the profile and groove.
 
#8 · (Edited by Moderator)
This is the bit I use. WHITESIDE RABBETING, BISCUIT JOINING & SLOTTING ROUTER BIT 1-1/4" LARGE DIAMETER 3/8" CUTTING DIAMETER 1/4" CUT LENGTH 1/2"
SHANK 2 FLUTE

I find 1/4" has a ton of applications, so it serves many duties, actually more drawer bottoms than most. It cuts to 3/8" deep which is almost too deep for some, but projection through the fence controls that easily enough. Plus it comes as a 1/2" shank. So many of the "slot cutters" only come in 1/4" shank, and I hate 1/4" in a table for anything. Plus with Whiteside, maybe all?? You can change the diameter of the bearing if needed, and make it many other sizes, just off the bearing. Versatile cutter.

https://www.holbren.com/Whiteside_Machine_1914

Font Metal Fashion accessory Titanium Auto part
 

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#9 ·
I think that the fastest and most efficient way is to cut the grooves on a table saw. You can use either your regular blade or a dado blade. I start by cutting all of my rails and styles to a bit more than final length and make sure I cut the rails long enough to include the tenons. I adjust the saw fence so that when I make two passes, flipping the work piece end for end for each pass, the resulting groove is the width I want. This also assures that the groove is centered in the work piece. If the resulting groove is wider than 2 X the blade width, I may have to make a third pass to cut out the remaining "fin" in the center. I then cut the tenons on the rail ends to fit the groove. If I don t think the groove is deep enough I may use a router bit at the router table to deepen it.

Of course, this method leaves the mortise and tenon exposed at the top and bottom of the doors. If you don t like this, use the same method at the router table and start/stop the cut before you reach the end of the styles. Then after the grooves are cut, come back and deepen the groove for the mortise if you need to.

- bilyo
IF you are using a .250 wide saw blade, then your set up is faster, but time to cut is much longer because of tenon cutting. All that zoom zoom zoom takes time. Getting a LOT longer of you only have a 1/8" blade. With the router set up is a few minutes longer, but you are done with all of your cuts so much faster, even if you take nibbling cuts for depth of cut through the work.

Actual cut .250 kerf, FTG blade. Almost always out of stock, because they sell so many of them. Again, that do many jobs .250, 1/4" to the decimal point challenged. Slickest absolute flat bottomed saw blade I own. Now this is drawer bottoms, at least for me. Dado Rabbet joints, uhhh huh…
 
#11 · (Edited by Moderator)
The table saw method is not an option for me, since I don't want exposed tenons (or exposed slots).

One of the biggest problems when using plywood panels is, that they are never really ¼" in thickness. They say they are… but most of the time are not. Since I ordered panels from two different places, I now have one panel that is pretty much ¼", and another that is just over 3/16". That's why I opted for one of those adjustable slotting cutters… we'll see how good that works.

By the way, how deep do you cut these grooves? Previously I always cut ¼" deep, and found that to be sufficient. The cutter I ordered cuts ½" deep, but this can be changed by using a different pilot bearing.
 
#12 ·
One problem you may have, depending on the width of stiles and rails, and the width of the cutter, is stopping the cut accurately . Of course if they are mitered then it doesn't matter.

- SMP

I would use stop blocks, but I also had the idea of dry-assembling the door frame, and then routing the slot by simply following the inside edge… this could be done on a router table as well.

- DrTebi
As long as your stiles and rails aren't too narrow, should be fine. If you do a 1×2 stile and rail for example you might get an exposed slot, or just totally mess up your loose tenon idea.

I have done what you proposed, just know you have to round off the corners of your panels. I used a arc cutting template, mark and then jig saw and sneak up to line on disc sander. Works fine once you get the hang of it.
 
#13 ·
One problem you may have, depending on the width of stiles and rails, and the width of the cutter, is stopping the cut accurately . Of course if they are mitered then it doesn't matter.

- SMP

I would use stop blocks, but I also had the idea of dry-assembling the door frame, and then routing the slot by simply following the inside edge… this could be done on a router table as well.

- DrTebi

As long as your stiles and rails aren't too narrow, should be fine. If you do a 1×2 stile and rail for example you might get an exposed slot, or just totally mess up your loose tenon idea.

I have done what you proposed, just know you have to round off the corners of your panels. I used a arc cutting template, mark and then jig saw and sneak up to line on disc sander. Works fine once you get the hang of it.

- SMP
Rails and stiles are all ¾" thick, and between 3 and 5 inches wide.

Regarding rounding off the corners of the panel… I hadn't thought about that. I was going to square off the round ends of the cuts in the rails! Maybe I am just thinking too square :)
 
#14 · (Edited by Moderator)
my kitchen was remodeled before I went into woodworking.
The Ikea doors were obviously done with this kind of bit:
https://www.rockler.com/freud-99-764-bevel-rail-and-stile-bit-set
It is more than 20 years ago and it didn't move.

One bit makes the grooves and male molding
and the other one makes the tenon and a female molding ensuring perfect fit in the corner.
 
#15 ·
Well…..
With a simple straight rail and style door panel. I'd imagine it's not a raised panel right? Maybe a 1/4" plywood panel is going in the slot?

The simplest, cheapest, and not that hard method is to cut the slot on a table saw. A set the fence to cut a groove and do the same to all the pieces. Then slide it over a bit and make a second cut to all of them at once. A block to keep the wood against the fence will ensure it doesn't get away from you. You can cut the slot any thickness you want to match the plywood insert.

Then Use the table saw to cut a 1/4" long tenon on the top and bottom pieces. You don't need loose tenons. And all doors have slots that are cut through end to end top to bottom.

It looks good but is usually not noticeable unless you twist your neck to look, and is simple. If you've got a router table to cut the tenons on the ends of the top/bottom pieces it can be easier but you can get by with the table saw.

Hand Wood Human Gesture Finger
 

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#16 ·
Thanks for your comments…

I am aware of these "joinery router bits", but my experience is different… in my kitchen two doors, made with these joints, broke. Not surprisingly maybe, since a pull-out drawer behind it blocks the door at times, the door hits the drawer, stresses the joint… and then "crack"... That's an end-user error, I admit, but still, I prefer to use 2" long loose tenons. I have a setup to cut the mortises already, so this shouldn't be too much trouble.
 
#17 · (Edited by Moderator)
I figured I should post a little follow-up, since I now have that Amana router slot cutter set and made slots for the first couple of doors.

The slot cutters are really quite nice. They come in a foam package with lots of spacers, instructions for setting different groove widths etc. I also bought two more ball bearings, which allow me to make the ¼" deep cut that I need for my panels.

While the foam insert is nice, it only came with a plastic sleeve. A Montechristo cigar box fits almost exactly, after shaving off a tiny bit of foam:
Rectangle Wood Material property Font Electric blue


Here is the shaft mounted with the ¼" wide cutter:
Musical instrument Electronic instrument Audio equipment Rim Gas


I initially routed the slots as I had planned, by clamping the door together (with loose tenons in place). This actually works quite well, only that you end up with rounded ends everywhere. This is easily fixed for the rails, by taking the clamps off and running the pieces through individually.

But then why not just run all pieces through the bit on their own? I just needed to make a pencil mark to indicate when to stop routing the slot of the stile. The math is quite simple, it's the radius of the cutter. This got me a bit too close to my mortises than I liked, so I stopped a bit earlier. This means just a little bit of rounding over the corners of the panels, no big deal:
Brown Rectangle Wood Communication Device Wood stain


Here you can see the pieces together:
Brown Wood Rectangle Wood stain Hardwood


It really works great! Love this bit. Later, when I need to fit the thinner panels, I will try odd sizes by combining cutters.

The only drawback with slot cutters is, that it makes a whole lot' a mess. It's hard to capture the shavings the cutter leaves behind. But I find this a lot easier to use than an up-cut spiral bit, or using the table saw. Here you don't have to put the pieces on edge anymore, which makes it really safe and easy. Also, in comparison to an up-cut router bit, the slot cutter here cuts with the grain, so it's a much easier job for the cutter as well.

Got these four done in no time:
Table Rectangle Wood Flooring Floor
 

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#18 ·
If your mortises are deeper than your groove, why not just run the groove into the mortise?

With the mortise being deeper, you aren't losing the alignment. I don't think you're giving up anything more than a minuscule bit of strength, if any.

I would think the time savings would well offset the strength loss…
 
#19 ·
If your mortises are deeper than your groove, why not just run the groove into the mortise?

With the mortise being deeper, you aren t losing the alignment. I don t think you re giving up anything more than a minuscule bit of strength, if any.

I would think the time savings would well offset the strength loss…

- Axis39
You are right, it probably doesn't make much of a difference. But then again…
It really doesn't take much effort to route a stopped groove. It's the same as running it through, just stopping a bit earlier.

I can see that the rounding off of the panel corners takes a bit of extra time. I will know once I cut some panels. I think if the panels are just slightly under-sized, the rounded grooves may actually fit as they are.
 
#20 ·
Are all your doors the same dimensions?

First off, a slot cutter would be much cleaner and more efficient than a straight bit, assuming you have a router table 8^) The slot width issue would be easy enough to solve by using a thinner-than-panel cutter and just raising the bit for a perfect fit (or go with a single pass and make your panels the same thickness).

If your doors are all the same. you could dry-fit them together and make a jig to hold it while routing.
Basically a solid frame maybe made with half lapped corners, just like your doors except the width of the rails/stiles would be extra wide for steps of stock around the perimeter to hold the door in position.

You them simply rout with the slot cutter around the inside perimeter (cutters guide bearing rides on the door or you jig). The rounded corners of the slot really don't matter as long as the slot completely extends to allow a full panel to be inserted. You would simply radius the corners for fitting.
 
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