Recently I made a face frame for a tall bulilt in cabinet. About 6′ by 2′. Used poplar wood well dried 3″X3/4. The cross pieces for the drawers were made of the same wood 1’X3/4. I clamped them in place after drilling the pocket holes to ensure they were flush with the face etc. After tightening the screws, no glue, I finished sanding everything and set it aside. Ater a week I pick it up to attach and everyone of the cross pieces has “lifted” above the face the same amout, about a quater thickness of a fingernail. just enoughr to catch and to be noticeable when painted. I am clueless as to why this is happening. Can anyone give an explantion? Thanks
Replies
It's hard to say for sure, but I would guess that your frame picked up a bit of moisture while it sat around for a week. Poplar is softer and more fiberous than other hardwoods and more susceptible to moisture (humidity) levels.
I use pocket joinery on all of my faceframes, but get them attached to the carcass within a few hours at most. My stain/finish/painting "process" includes a last minute inspection just before beginning the finish. On the few occasions when I've seen this situation, a quick touch-up with the finish sander fixed the problem.
Hello bak,
I used poplar and pocket holes (no glue) to make the face frame for my shop cabinets and did not experienced this problem. Perhaps the edges of the rails were not perpendicular to the faces, which caused the stiles to slowly but surely slide out of the face plane a little? Wondering if the type of screw (Kreg sells 3 types) may also be an issue here?
Regards,
Senomozi
A couple of possibilities:
1) The initial moisture content in the two pieces was different, and so as they equilibrated, they moved by different amounts. This you can fix by resanding.
2) The grain orientation in the pieces is different, and so as they absorb or give off moisture, they will continue to change thickness by different amounts. This you have to live with (short of remaking the frame).
I don't have enough experience with pocket-screw joinery to know whether or not this is a reasonable possibility, but it seems to me that the differential thermal expansion between the steel in the screws and the wood could also lead to a situation where the screw forces the two wood pieces to move slightly with respect to each other.
-Steve
Hi bak ,
I have been using pocket screws for my face frames for 25 years and always use glue , unless the frame member is meant to be removable like in front of a built in washing machine or water heater or such .
When you say you clamped the parts in place , did you clamp them down or side to side like if they were doweled ?You should be clamping them down to your work surface .
Even under the best circumstances after screwing the joints together they often will move usually in the direction the screw goes . If the face will be fastened to a cabinet I sand after attaching and after they are glued to the box no movement will occur as a rule .
Why aren't you using glue ?
Granted there is end grain to edge grain in most if not all the face joints but a frame and panel door has the same orientation as well and we would never think of assembling doors or other F&P frames without glue .
My advice is to use glue it won't cost much or take much time but it will prevent the parts from moving .
give it a try
regards dusty
Are you using a Kreg jig? They don't allow the hole to penetrate all the way through the first piece of wood for fear of damaging the jig. When you drive the screw through, it blows out the remaining piece of wood, and that's usually enough to put the alignment off a fraction. You can avoid this by using a drill bit to finish the hole once the piece is clamped up. Doesn't hurt to penetrate the second piece of wood a fraction, so there's even less chance of a sliver of wood between the pieces. This problem is usually noticeable before you sand the fitted pieces, though.
Jim
Wood moves when it gains and loses moisture and joints made with Kreg screws don't lock adjoining pieces of wood together tight enough to prevent that movement. Also, wood shrinkage can loosen the screws. One or both of the frame members cupped, twisted, or shrank and created the offset you now have.
Using wood that is quarter sawn for the frame and making sure it is acclimated to the shop before starting work will reduce the chances of this happening in the future.
John White
Yestermorrow School, Waitsfield, Vermont
I agree ( again ) with dusty. There's no reason not to use glue. that's what I do for all my face frames.
Plus, I quit using poplar for paint grade several years ago because I've found it to be too unstable ( it might be better in other parts of the country, but I can't find it here ). I now use maple.
Paul
Edited 11/8/2007 4:23 pm ET by colebearanimals
Sounds like you are using a kreg pocket hole jig.Since you are not using glue , the angle at which the screws are drilled causes the shift in the joint. I would suggest using glue or us a different pockethole jig that drills straighter.
Thank you for your input.! Humidity and moisture differences I do not believe are and issue here. And from now on I will use a bit of glue. The other possibility is that in moving the face frame around it weaked the frame enough to cause some mvnt. It just surprised me how uniform it was for all four cross members. Anyway it is fixable and I'll follow th advice given next time.
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