Raise Panel Doors gap questions

[Craig D Peltier]

Hi, Im getting pretty close to making raised panel doors for my kitchen. Im going to use eastern maple.
My questions are

1) Im going to use tongue and groove for the door joints, whats the allowance measurement that the panel is suppose to be thinner where it fits into the groove so it can expand thickness wise? 1/32nd? On the router cutter bits are they already tapered near the end of tongue cut so I dont have to worry about it?
2) Same type question, How much deeper should the dadoe be to allow for movement , top, bottom and sides? 1/16th on each side, so 1/8 for vert and 1/8 for horizontal.
I tried space balls once.Im not a fan of them and I have heard there not really needed. If I was to use them how much of a deeper dadoe do you have to allow for a space ball , say if tongue is 3/8.

Thanks

[Peter Quinn]

Craig, most cabinet door panel raisers are designed to cut a 3/8" tongue (some people call it a 'flat') on the edges of the panel to slip into the groove. You don't need to make your "groove" in your styles and rails deeper than 3/8".

As far as panel "thickness", the panel is not going to change thickness significantly and neither are the rails and styles if the stock is dried and acclimated to your environment. In the door shop where I worked we typically allowed .005"-.007" difference in thickness between the tongue on the door panel and the groove it slid into. A difference of 1/32" is equal to .0325" which will cause the panels to rattle badly and slide out of alignment. For comparison a typical sheet of printer paper is .004". What I'm saying is you want a friction fit between the panel and the groove that allows the panels to swell and move but not rattle and slide around freely.

Almost all of the movement in your panels will be across the panels width. Typically you leave 1/16"-3/32" gap between the panel and the bottom of the groove on each side and on the top/bottom, so yes 1/8"-3/16 is safe. The actual movement depends on the species, your local climate, and what season you are assembling the doors. It takes a lot of experience to get it perfected, but these ranges are safe.

There is not typically a "taper" on router tongue and groove cutters, and panel raisers don't produce a tapered tongue either. The tongue and grove joints that hold the door frame together need to fit snugly to make a good glue joint. I recommend rounding over the outer edges of your panels slightly with sand paper to reduce friction and ease assembly.

Space balls are a PIA big time. If you use them try gluing them into your rails and styles before assembly. Use very little glue and allow it to dry completely before assembly. They make little square foam sponges which are much easier to use because they don't role out on you during assemble and they compress easier. Check Rockler and Woodworkers Warehouse for the sponges. They both cut down on the possibility of panel rattle during the dryer months in temperate climates where humidity varies widely.

If you use the sponges or spaceballs I think the 3/32" gap on each side is preferred. They make different sponges with different compression factors, so check the manufactures recommendations on that one.

[Craig D Peltier]

Craig, most cabinet door panel raisers are designed to cut a 3/8" tongue (some people call it a 'flat') on the edges of the panel to slip into the groove. You don't need to make your "groove" in your styles and rails deeper than 3/8".

As far as panel "thickness", the panel is not going to change thickness significantly and neither are the rails and styles if the stock is dried and acclimated to your environment. In the door shop where I worked we typically allowed .005"-.007" difference in thickness between the tongue on the door panel and the groove it slid into. A difference of 1/32" is equal to .0325" which will cause the panels to rattle badly and slide out of alignment. For comparison a typical sheet of printer paper is .004". What I'm saying is you want a friction fit between the panel and the groove that allows the panels to swell and move but not rattle and slide around freely.

Almost all of the movement in your panels will be across the panels width. Typically you leave 1/16"-3/32" gap between the panel and the bottom of the groove on each side and on the top/bottom, so yes 1/8"-3/16 is safe. The actual movement depends on the species, your local climate, and what season you are assembling the doors. It takes a lot of experience to get it perfected, but these ranges are safe.

There is not typically a "taper" on router tongue and groove cutters, and panel raisers don't produce a tapered tongue either. The tongue and grove joints that hold the door frame together need to fit snugly to make a good glue joint. I recommend rounding over the outer edges of your panels slightly with sand paper to reduce friction and ease assembly.

Space balls are a PIA big time. If you use them try gluing them into your rails and styles before assembly. Use very little glue and allow it to dry completely before assembly. They make little square foam sponges which are much easier to use because they don't role out on you during assemble and they compress easier. Check Rockler and Woodworkers Warehouse for the sponges. They both cut down on the possibility of panel rattle during the dryer months in temperate climates where humidity varies widely.

If you use the sponges or spaceballs I think the 3/32" gap on each side is preferred. They make different sponges with different compression factors, so check the manufactures recommendations on that one.

Thanks Peter for taking the time to explain this.Its a great help, hopefully to others as well.

[Greg Cole]

Craig,
Not much to pile on Peter's comments.....
The new version of space balls are space barrels, not sure of the exact sizes, but the look like they might stay put in the rabbet a bit better. I've gotten by with silcone caulk in a pinch too.
Prefinishing parts is a must for RPD's too, I'm sure you've heard it before but worthy of repeating I guess.

G'luck on your kitchen, as posted elsewhere today, I dragged out installing some of mine for a wee bit (ok, 2 years) & LOML makes sure to remind me of that quite often. Guess she likes opening the upper cabinet doors to see what's inside, I didn't mind the see through doors...LOL

Cheers.
Greg

[David DeCristoforo]

"...you want a friction fit between the panel and the groove that allows the panels to swell and move but not rattle and slide..."

I would only like to add that this "friction fit" should not be so tight that you cannot easily insert the panel into the groove "by hand". If it is "too tight", assembly will be a "nightmare".

YM

[Kevin Newman]

I'm fairly new to the sawmill, but thought I would throw in my 2 cents worth on space balls.

I've been making raise panel doors and teaching others to make raise panel doors for a number of years. I personally would recommend using space balls(or barrels) over any other product. The expansion/contraction capability and density of the space ball in my opinion is far better than the foam type products and is much more durable over time. The foam products have more of a tendancy to breakdown over time. The space balls are made from a neoprene rubber that even left in landfills for hundreds of years wont break down.

I have had not problems with space balls moving around. The space balls are designed to be used in a 1/4" groove(or dado) cut by the stile and rail profile bit. The space balls are .26" wide. Most stile and rail router bits cut 1/4" wide groove. A shaper bit on the other hand might be different, as I am not an expert on shapers. If the groove is cut properly, there should not be a problem with the space balls rolling around. They should stay in place.

I would highly recommend not putting any glue in or around the groove where the panel is or where the space ball is. The panel needs to float in the style and rail frame. Dried glue eliminates the ability for the space ball to do it's job, which is to allow the panel to expand and contract and float. It will only get in the way. Over time the door will eventually split at the joints because it will not have the room it needs to expand and contract.

Just my opinion from experience.
Kevin

[Greg Heppeard]

I've been working in cabinet shops on and off for over 10 years (mostly in the door department) and agree with Kevin. I've always pinned the back of the panels at an angle to keep them tight against the front profile of the groove. It works great even if the panel is a little thin...it happens. I've never worried about the space balls rolling around a bit during construction, usually the panel is snug enough to keep them in place once the door is assembled.

[Steve Clardy]

I'm fairly new to the sawmill, but thought I would throw in my 2 cents worth on space balls.

I've been making raise panel doors and teaching others to make raise panel doors for a number of years. I personally would recommend using space balls(or barrels) over any other product. The expansion/contraction capability and density of the space ball in my opinion is far better than the foam type products and is much more durable over time. The foam products have more of a tendancy to breakdown over time. The space balls are made from a neoprene rubber that even left in landfills for hundreds of years wont break down.

I have had not problems with space balls moving around. The space balls are designed to be used in a 1/4" groove(or dado) cut by the stile and rail profile bit. The space balls are .26" wide. Most stile and rail router bits cut 1/4" wide groove. A shaper bit on the other hand might be different, as I am not an expert on shapers. If the groove is cut properly, there should not be a problem with the space balls rolling around. They should stay in place.

I would highly recommend not putting any glue in or around the groove where the panel is or where the space ball is. The panel needs to float in the style and rail frame. Dried glue eliminates the ability for the space ball to do it's job, which is to allow the panel to expand and contract and float. It will only get in the way. Over time the door will eventually split at the joints because it will not have the room it needs to expand and contract.

Just my opinion from experience.
Kevin

I've been working in cabinet shops on and off for over 10 years (mostly in the door department) and agree with Kevin. I've always pinned the back of the panels at an angle to keep them tight against the front profile of the groove. It works great even if the panel is a little thin...it happens. I've never worried about the space balls rolling around a bit during construction, usually the panel is snug enough to keep them in place once the door is assembled.

Ditto the spaceballs.
Very seldom have I had one fall out.

[Peter Quinn]

Never had a problem gluing in the space balls, keep in mind I'm talking a VERY small drop of glue applied with precision to the ball which is then place with tweezers and left untill dry. I wouldn't go spreading glue in your panel grooves, that will cause big problems.

Space balls do resist compression better than the sponges which depending on your application may be a good thing or a bad thing. As for the lifespan of an open celled polyurathane foam vrs rubber, I'm guessing we'll all be dead long before either fails. They also make 'barrels' of rubber as a third alternative. If you use any of these make sure to adjust your panel gap to the manufactures reccommendations for the product you choose.

As an alternative to either, I have seen some veteran woodworkers (ie old timers) apply a dab of glue at the center of the top and bottom rails in the groove to keep the panel from moving but allow seasonal movement. It requires quick and careful panel centering during assembly. IMHO its a much more elegant solution to door making than driving nails into the back of the door (even very small ones).

[Joe Chritz]

Listen to Peter.

Although, I buy .26 spaceballs and have never had one move once stuck in the grove. When I had a brand that was oval shaped it was actually .25 thick and I had to glue them in place.

If you had bad luck with spaceballs try a slightly fatter version before giving up completely. It is all I will use now. I used foam, silicone cut into pieces and two or three types of "spaceball" before settling on the round .26 ones I have now.

I think mine came from WW supply and are the spaceball brand.

Joe

[Peter Quinn]

Good tip Joe..entirely possibly I have developed a compensating technique and loathing for some cheap knock off product my boss was buying. Gonna give a sample of the .26" actual space balls a try. The ones I've used were not round exactly and measured all over the place.