# Frame & Panel Door Corner Joints



## Stevedore (Dec 28, 2011)

As I mentioned in another thread somewhere here, I'm planning to make replacement cabinet doors for our kitchen. Simple frame & panel "Shaker" design, as seen in the jpg I attached.

Question: Is 3/8" a sufficient depth for the panel groove in the rails & stiles, and for the tenon length on the ends of the rails? 1/2" just "seems" better to me for strength purposes. I only ask because in our previous home, I had installed Kraftmaid cabinets with similar doors, and one of the corner glue joints had cracked due to opening against the adjacent door edge. Sort of a levering effect, I guess. Those doors were grooved about 3/8" deep, & possibly less.

An added advantage with my new doors will be that the panels (MDF) will be fully glued into the rails & stiles, which will add some degree of strength, I suppose.

Any thoughts/comments appreciated, as always.


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## 35015 (Nov 24, 2012)

Stevedore said:


> ...Simple frame & panel "Shaker" design... Question: Is 3/8" a sufficient depth for the panel groove in the rails & stiles, and for the tenon length on the ends of the rails? 1/2" just "seems" better to me for strength purposes...


Personally, I could never build something this far out of context from the original methods...Those tenon should be stepped down and go all the way through the Style...whether they are draw born tight...or...glued and clamped. 1/2" is no where long enough in my view of it...

Many modern assemblies are manufactured just the way you have described...I personally don't see that as a good practice in design, application of durability...but that just me...

Just my 2¢ on it...Good Luck with your build!!

j


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## Steve Neul (Sep 2, 2011)

Actually on my cabinet doors the panel groove is closer to 7/32". I sized it that size in order to use common 1/4" plywood which is a metric size which is closer to 7/32". Using plywood you can glue the panels in which makes them real solid and also helps the overall strength of the door. The solid wood panels should float loose because of wood movement.


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## 35015 (Nov 24, 2012)

Steve Neul said:


> Actually ...in order to use common 1/4" plywood which is a metric size...


I agree about getting to glue in the MDF...that is possible with this materials and it takes a lot less skill or effort to create a panel door "look-a-like" that can then be painted to hind the MDF. A very common practice in mass production and DIYer projects for sure...

I think my last remark was about the tenon assembly interaction for the styles and rails. On that account I still personally like solid wood joinery with longer tenons...which are stronger. Are shorter tenons "strong enough"...probably...but then again...??...floating MDF panels and longer tenons glued in are probably strong enough too, or they seem to be in my experience with them...

I'm confused about the 1/4" being metric? 1/4" plywood (or MDF) is 1/4"...and isn't a "metric size" at all...but an empirical size...that equals 6.35 millimeters. This is larger than 6mm MDF which is the standard thickness in the metric range for this material... True 1/4" plywood (or MDF) would never fit in a 7/32" (~5.56mm) groove...

Did I miss something?

j


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## Steve Neul (Sep 2, 2011)

Jay C. White Cloud said:


> I agree about getting to glue in the MDF...that is possible with this materials and it takes a lot less skill or effort to create a panel door "look-a-like" that can then be painted to hind the MDF. A very common practice in mass production and DIYer projects for sure...
> 
> I think my last remark was about the tenon assembly interaction for the styles and rails. On that account I still personally like solid wood joinery with longer tenons...which are stronger. Are shorter tenons "strong enough"...probably...but then again...??...floating MDF panels and longer tenons glued in are probably strong enough too, or they seem to be in my experience with them...
> 
> ...


I had a bad day today and missed the part about the MDF. I was thinking plywood. We went today to clean my wife's nephew's apartment and found it a complete pig pin. My son and I hauled out enough trash to fill two dumpsters and didn't get it all and it was only a one bedroom apartment.


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## 35015 (Nov 24, 2012)

Steve Neul said:


> I had a bad day today and missed the part about the MDF. I was thinking plywood. We went today to clean my wife's nephew's apartment and found it a complete pig pin. My son and I hauled out enough trash to fill two dumpsters and didn't get it all and it was only a one bedroom apartment.


Happens to us all Steve...No worries!

I thought I was the one that missed something? 

Sorry about the day...Some folks can be really messy to say the least. Hopefully he will straiten out his act for you families sake and his own...

j


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## ORBlackFZ1 (Dec 25, 2013)

Stevedore said:


> As I mentioned in another thread somewhere here, I'm planning to make replacement cabinet doors for our kitchen. Simple frame & panel "Shaker" design, as seen in the jpg I attached.
> 
> Question: Is 3/8" a sufficient depth for the panel groove in the rails & stiles, and for the tenon length on the ends of the rails? 1/2" just "seems" better to me for strength purposes. I only ask because in our previous home, I had installed Kraftmaid cabinets with similar doors, and one of the corner glue joints had cracked due to opening against the adjacent door edge. Sort of a levering effect, I guess. Those doors were grooved about 3/8" deep, & possibly less.
> 
> ...


Since you are gluing MDF panels between the stiles and rails, you really don't have to worry about a 3/8" or 1/2" depth. Either one is going to work and the difference will be insignificant. The glued MDF panels will add a significant amount of strength in the XY plane. In other words, if downward force is applied to the cabinet door handle, the hinges will probably be damaged before the door is damaged. 

The Z plane is another story. If the force applied to the door is in the direction of the door opening or closing, then the amount of strength the 1/2" adds over the 3/8" is more, but not that much more. The glued MDF panel will also add some strength.

You will also need to think about the longevity of your cabinet doors. Your glued 3/8" deep joints are dependent on the glue holding up over the years of use. A properly designed, cut and assembled mechanical joint will hold up longer than a joint that has simply been glued.

When I am after very strong joints on two (2) pieces of wood being joined at an angle, I use a bridle joint. Some people don't like the end grain look, but with the correct wood, sanding and finishing, the joint can be very attractive.

The bridle joint can be made even stronger by adding a "mechanical" hold. By drilling a couple of 1/4" holes through the bridle joint and gluing in some 1/4" dowel, the bridle joint becomes even stronger. Make sure the dowels fit very tight and you won't even need glue.

The bridle joint can be made with a hand saw, a band saw, a table saw or even a router table. 

The photo below shows a handle for a dust collector cart, that has multiple bridle joints. The wood is white southern pine. 

Eric


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## TimPa (Jan 27, 2010)

of course you can choose whatever joinery techniques that suit you. but 3/8 is very common on stile and rail depth. I have made cabinet doors for many years that way now, and have not had a single joint failure yet.


however, the joint fit must be good. the tenon should not bottom out in the bottom of the groove, leave a few thousands for glue. the tenon shoulders should sit flush and tight. I seldom go less that 1 3/4" wide on the stile and rail. 2 to 2 1/4" wide is better.


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## Steve Neul (Sep 2, 2011)

Keep in mind MDF is heavy and the thicker you go the more hinges you will need on the doors to support the weight. 1/4" MDF would work fine and most tongue and groove router bit sets are made with a 1/4" cutter. 

Also keep in mind that MDF often is thick with formaldehyde at the surface and sometimes it interferes with the finish you use. It would be good if you would thoroughly sand the door panel with 180 grit paper before inserted in the door.


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## Stevedore (Dec 28, 2011)

Steve Neul said:


> Keep in mind MDF is heavy and the thicker you go the more hinges you will need on the doors to support the weight. 1/4" MDF would work fine and most tongue and groove router bit sets are made with a 1/4" cutter.
> 
> Also keep in mind that MDF often is thick with formaldehyde at the surface and sometimes it interferes with the finish you use. *It would be good if you would thoroughly sand the door panel with 180 grit paper before inserted in the door*.


 I hadn't thought about sanding the MDF; seems like a good idea. We're doing a painted finish on the cabinets & doors, so sanding would probably help with paint adhesion. Couldn't hurt, and easy enough to do.


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## Steve Neul (Sep 2, 2011)

Stevedore said:


> I hadn't thought about sanding the MDF; seems like a good idea. We're doing a painted finish on the cabinets & doors, so sanding would probably help with paint adhesion. Couldn't hurt, and easy enough to do.


I don't know how much the formaldehyde affects other finishes but it can't be good. My experience is with lacquer. I've seen lacquer take a week to dry on MDF where on anything else would dry in ten minutes in warm weather. Sanding the same piece of MDF and it will dry in ten minutes too. MDF is formed in a press so it would make sense most of the chemicals come to the surface. It seems that minor sanding removes this excess layer of chemicals on the surface.


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## bargoon (Apr 20, 2016)

I am making similar shaker style doors using solid maple for the stiles & rails and 1/4" maple plywood for the panels.

I set my table saw to cut the grooves to match the thickness of the plywood which we all know is thinner than 1/4".

I used a dado set to cut the tongues on the rails. Kept raising the dado blade and trimmed both sides of the tongue until it fit the grooves.

Cheers


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## 35015 (Nov 24, 2012)

Steve Neul said:


> I don't know how much the formaldehyde affects other finishes but it can't be good. My experience is with lacquer. I've seen lacquer take a week to dry on MDF where on anything else would dry in ten minutes in warm weather. Sanding the same piece of MDF and it will dry in ten minutes too. MDF is formed in a press so it would make sense most of the chemicals come to the surface. It seems that minor sanding removes this excess layer of chemicals on the surface.


There are fans of MDF and the "modern methods" of building these style doors...and...there are those of us that don't care for it. It's a perspective, when you boil it all down, as basically a T&G set up for these doors (panel, style, rail) al well glued and clamped are going to more than hold up to what most folks will use them for in their life time. In other works, it good enough and looks good. 

For me, my background and the way I was raised...looks and adequate (aka good enough) never met with approval by anyone I worked with, or hung around. So over time that affects the way your outlook develops, at least it did with me...I only share this as explanation for my perspectives. On that note, I will only use MDF if forced to by project spec's. It's just nasty stuff, full of fillers, toxins in most of the least expensive brands (formaldehyde as just one example) and isn't coming out of the most environmentally sustainable industries.

Note: there are some up and coming companies with good standing on the environmental end of making MDF type sheet good...

Just food for thought...

j


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## Steve Neul (Sep 2, 2011)

Jay C. White Cloud said:


> There are fans of MDF and the "modern methods" of building these style doors...and...there are those of us that don't care for it. It's a perspective, when you boil it all down, as basically a T&G set up for these doors (panel, style, rail) al well glued and clamped are going to more than hold up to what most folks will use them for in their life time. In other works, it good enough and looks good.
> 
> For me, my background and the way I was raised...looks and adequate (aka good enough) never met with approval by anyone I worked with, or hung around. So over time that affects the way your outlook develops, at least it did with me...I only share this as explanation for my perspectives. On that note, I will only use MDF if forced to by project spec's. It's just nasty stuff, full of fillers, toxins in most of the least expensive brands (formaldehyde as just one example) and isn't coming out of the most environmentally sustainable industries.
> 
> ...


In my career most MDF was used in mostly in commercial fixtures. It usually was covered with formica and if you could get over moving cabinets heavier than lead worked very well. It was stable and formica adhered to it well. In any case commercial fixtures usually had a duty life less than ten years and discarded for a new design. Then we started seeing more and more veneer covered MDF which we refereed to as concrete core plywood. It got to where you were seeing it used a lot in residential cabinets where there was a high risk of water exposure. People can't seem to understand that MDF is literally a sheet of paper and to get it wet is the same as getting a sheet of paper wet.


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## 35015 (Nov 24, 2012)

Steve Neul said:


> ...People can't seem to understand that MDF is literally a sheet of paper and to get it wet is the same as getting a sheet of paper wet...


Big yes...!!!

It may have had (does have?) its place, but it just is not a quality product or material in my experience. Its always been a "down and dirty" material, when good work wasn't wanted, needed or could be afforded...and only got worse from there...in my experience. The negatives its been connected to (i.e. indoor air pollution, industry environmental impact, inconsistent quality, mold issues, out-gassing, finish failures... etc) made me avoid it like the plague after a very short time...

I would, if wanting a sheet good, go with a good plywood product over MDF everytime. Thick paper...LOL...is not something I want in my woodworking project...

j


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## mmwood_1 (Oct 24, 2007)

My 2 cents on this: On my cabinet doors, my standard joint is a bridle joint, as pictured on Eric's post (also called slip joint, through mortise and tenon). It is probably as strong a joint as can be made on these doors. I sometimes put a peg in them, too, as he suggested. For the most part, the 3/8" industry standard which you get when you use frame and panel router bits will work. I have had to repair a number of them for people, but in a kitchen with 15 doors, there would usually be one door that the wood cracked due to the torque on those short tenons. The rest held. So, while it is not the IDEAL joint, it mostly works.


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