min thickness for the back profile on cabinet door?

[andy photenas]

Hello all. I am trying to setup my shaper with a panel cutter bit that runs with a back cutter. The style of bit is a flat angel but im not sure if its 18 or 15 degrees. So the issue im having is this, when i set the bit flush with the rail and stile face. while leaving the small 90 degree edge that brings that slope on the raised panel cutter to the top of the panel leaving a small 90 degree edge around the middle of the panel. it leaves such a narrow piece of wood on the back of the rail and stile that im not sure if its too small and i have the wrong bit? I would buy the proper one in a min but im not sure if this is wrong or not. Can anyone tell me the min. thickness for that back part of the profile cut on the rail and stiles ? or any other info to help me figure this out.
also i should state that im using a frued cutter that came with a shaper i bought and i just had it sharpened. im using this with a MLCS back cutter.

thanks for any help guys.

[Wayne Lomman]

Can you do a pencil sketch of your profile with some dimensions? It will help with sorting the problem. Cheers

[Martin Wasner]

I'm left with a bit over an 1/8" holding the panel in on the backside with a 3/4" thick door. We run the same dimensions on all profiles.

[Bill Dufour]

On the shaper sets I have the tongue is a hair less depth then the groove it mates into. This is also a hair under the depth of the cut as seem from the front face.
Bill D.

[J.R. Rutter]

Sounds like the cutter set is made for thicker rail/stile stock. Or more likely, you are combining a mission / shaker style cope / stick set with a raised panel when it is designed to run the groove closer to center combined with a flat panel.

1/8" would be the absolute minimum that is typically left on the back side of the groove. I like to finish at 5/32" or more.

[Warren Lake]

if you are worried its weak then machine your material thicker if you can. That said there was a time it was easier, 4/4 was a certain thickness at times up to 1 3/16" rough so to make your rail and style to 7/8" say you could do that. I think the door makers are at 13/16" for the most part so that alone would give you a bit more meat. What you are experiencing is one the draw backs of cope and stick cutters. By their nature they have to place the tongue to the back of the profile, its a given right off the bat, no way around it so if you want more meat you need thicker material. Its one of the reasons I dont use those cutters. That statement will change for me when I get a full size heads that make a tennon not a tongue and using material thickness that allows you to center it.

[J.R. Rutter]

What you are experiencing is one the draw backs of cope and stick cutters. By their nature they have to place the tongue to the back of the profile, its a given right off the bat, no way around it so if you want more meat you need thicker material.

This is the type of cope and stick that I thought OP was talking about. You can put the T&G anywhere you want. But if you try to use a raised panel, then you are stuck with a thin back. I leave it to the customer to tell me where to put it - centered for best strength, or offset towards the back like this sample.

https://i.imgur.com/9udolUih.jpg

[Warren Lake]

all the cope and stick put the tongue to where it has to be based on the profile. you are right with that style you can drop it to what you want, other styles with a step you wont have a choice if you want the step or how much that step is. You determine how far you want to drop it for the look you want. if you do a raised panel the old guys made the panels lower than the rails and styles.

[Martin Wasner]

Not really related, but I hate that profile that JR posted so much. The glue line never seems to disappear the way it does when the rail goes into a shoulder.

[Warren Lake]

its related and good point, ill go one further the reason that big door companies dont stand behind lines telegraphing back through at the rail and style joint is because of cope and stick. It simply doesnt have the stability of a tennon and mortise door joint.

[J.R. Rutter]

Not really related, but I hate that profile that JR posted so much. The glue line never seems to disappear the way it does when the rail goes into a shoulder.

I have not had that issue. One of my customers just used this for paint grade doors. I made sure that there was a tiny bit of glue along the knife edge of the rails and let them dry over the weekend. They turned out great. Maybe the devil is in the details on this profile. Great Lakes made these inserts for me and they seem to be ground so that the joint line is *very* tight at the face. No visible glue line.

[J.R. Rutter]

its related and good point, ill go one further the reason that big door companies dont stand behind lines telegraphing back through at the rail and style joint is because of cope and stick. It simply doesnt have the stability of a tennon and mortise door joint.

What kind of lines? Raised "glue creep", or a shrunken line at the joint, or a "crack" type line?

[Warren Lake]

I wasnt talking that profile just general glue line telegraphing back through, not my issue but I see it often and have read in the past, at one point emailed a few major door makers. Friend got a vanity and kitchen and its disgusting the vanity came with most of the glue lines showing through.

[J.R. Rutter]

Yeah, I see what you mean. A lot of big produces take doors out of the clamp right to the sander, then the glue line gets telegraphed through the finish.

[Martin Wasner]

I have not had that issue. One of my customers just used this for paint grade doors. I made sure that there was a tiny bit of glue along the knife edge of the rails and let them dry over the weekend. They turned out great. Maybe the devil is in the details on this profile. Great Lakes made these inserts for me and they seem to be ground so that the joint line is *very* tight at the face. No visible glue line.

Could've been a multitude of things at play causing the ones I made to have so many problems. It was a long time ago at a another shop I was working at. They got painted as well, but I remember the glue lines when being sanded being obnoxiously large.

I swore off that profile because of my experience with it.

[Kevin Jenness]

The issue the OP points out is driven by keeping the raised panel face at or below the rails and stiles. This is required only if the completed doors need to be run through a panel sander. I like to have at least 3/16" at the back shoulder. I have seen plenty of production doors with 1/8", and I even made some recently at the client's insistence on using a specific thickness and profile, but it seems weak to me.

I like to run the stock through a wide belt prior to assembly. Accurate setup minimizes levelling the joints and I don't have to sand out cross-grain scratches, plus I can put the panel where I want it.

The profile JR shows reminds me of the time a customer asked the shop I was in to make a set of doors with a thumbnail bead omitting the quirk, so the cope and stick profiles met at the door face in a horizontal plane. Finish sanding was a nightmare as any deviation from flat produced a visually out of square joint. JR's example is close to vertical so it would take some sloppy sanding to be problematic in that way.

[David Kumm]

I've done what others have said. Rails and stiles at 7/8-1 1/16 depending on my profiles. Avoids all the problems, makes me happy when I open a door and separates me from the herd. I even like them on inset doors. Dave

[Robert Engel]

Andy,

Is the panel bit part of a matched set of the rail/stile you're using? If not, that's probably the issue.

The minimum would be about 1/8" on 3/4 - 13/16" stock.

Kevin brings up a good point. If you're hand sanding there is not absolute need to for a flush panel. Its really impossible to visually tell if a panel is 1/16 - /8 proud of the frame. That said, when drilling for euro hinges, its nice to have a flush panel but you can also drill prior to glue up.

[Martin Wasner]

and I don't have to sand out cross-grain scratches,


I see this frequently. And don't understand it.

How does sanding cross grain scratch differ from with the grain other than it's harder to see the scratch when it's with the grain?

I kick everything I can through the widebelt at an angle to make the scratch as obvious as possible.