Door Trim? How do you...

[scoly]

get the mitres to fit? I'm in the process of replacing most of the trim in my house and have started with the doors. At this point I measure the angle of the casing with a cheap angle guage, divide by 2 and cut that angle. Most pieces seem to be off by very small amounts. Less than .5 degrees. Every door I've done so far has a space at the mitre. Have even tried cutting test pieces at 45,44.5, 45.5 and using them for the fit. Still having problems. Is this the norm? Have been able to make them look good by filling but am wondering if I'm just not getting it. What steps do all of you take? All suggestions appreciated.
Steve

[steve-norrell]

Sounds normal to me . . . I just did some trim around windows, doors and floor in our house. I do not believe that even one was perfectly square. You can check the "squareness" with a carpenter's square.

I usually attach the piece across the top first then start nailing at the top corners of each side, working down to the floor. The trim can usually be 'bent' to fit to the sides.

I also seem to use lots of filler -- dry wall compound if I am going to paint; wood filler if I am staining.

Good luck, Steve

[cabinetman]

You could first check the door jamb to see how square it really is. Since the casing (door trim) is usually set back from the edge of the jamb approximately 1/8", there is an allowance for a "fudge" factor.

At a line of about 1/8" above the top (header) edge of the door, I will put a small dot (in pencil) approximately 1/8" past both vertical jambs. I will cut the top trim with 45's on either end so the short dimension of the angles (bottom of the 45's) lines up on those two dots. Then on a scrap piece of trim I cut a 45 (opposites) on a piece about 3' - 4' long, so each end has a corresponding 45 for a match to the top piece. I will match up the top angles and see if the trim is a straight line down the edge of the jamb. If it isn't, I will adjust a skim cut to adjust the angle to get a tight fit. IMO it's real important to have the top piece as close to even in spacing to the header edge as it can be.

If the doorway is a lot out of square, adjustments to that angle can be "fudged" by slightly increasing the distance from the edges of the jamb.

[scoly]

Thanks for the input. Sounds like you both start at the top then sides. Just what I was looking for. I've been starting on one side and working around. Will give it a try.
Cabinetman,
Thanks for the primer. Will use your technique on the next door and would bet it goes much easier.
Steve

[scorrpio]

Always start with top. Getting two mitres to fit at once is near impossible. And don't play the 'degrees' game. I usually miter and attach the top piece, then use a bevel gauge - body along vertical jamb, blade along the miter - to get the exact angle, and set the saw to the gauge.

A more interesting question - how to keep the miter tight. Sometimes, the casing will warp slightly, causing the beautifully fitting miter to develop an ugly gap.
Action 1: store the casing in the room it will be installed in for a while so it can acclimate.

Action 2: After I cut the miter, I take the piece to a router table where I have a biscuit slot bit installed, and slot it for an H-9 biscuit. A miter glued and reinforced with a biscuit is not going to show gaps any soon.

A quicker solution is to fire a brad from above through top into the side piece. The thing is, you gotta be real careful. A badly angled shot will cause a very nasty-looking blowout through casing side or worse, face - which is why I prefer the biscuits+glue.

[eezlock]

door trim...

First, get a decent bevel gauge and set it to desired angle to make the correct angular cut. I saw an angular "shooting board" in one of the wood mags or diy books I have, that shows the best way for trimming the angular cut edge of the molding with a small hand plane. If you get it close to what you need it to be, but still isn't close enough, use the shooting board to hold the stock and lightly trim it till it fits just right. eezlock

[scoly]

Thanks again for the help. Weekend is almost here so will be trying out all the suggestions.
Scorpio brings up another problem. Keeping the mitre tight. I've tried shooting a brad through the top but experienced the blowout through the face. Decided to not do it again. His biscuit trick sounds good but I have trouble just nailing the joint where it's tight. Forget about warping. Holding it flush and shooting a nail sounds so simple but I feel like I need two more hands. Any suggestions on how to keep it tight while getting the nails in? I saw some sort of spring that was designed to hold a mitre together but can't remember where I saw it. Has to be a way.
Thanks again.
Steve

[cabinetman]

Are these the corner spring clamps you were referring to?

Find em at:http://www.constantines.com/index.as...ROD&ProdID=104

[sd]

Try these links:

Clam clamps
Spring miter clamps
Article on stitched miters

[backpacker85]

Another thing to check is to make sure the jamb is flush with the adjacent wall.
If it is slightly proud, fastening the casing tight to the wall tends to open the joint, and will drive you crazy chasing the miter, which may be fine. DAMHIKT

[scoly]

Links and lots of good suggestions.
Clampman
Yes, those are the ones. May have to get the set for doing picture frames some day but they seem a little pricey having to get the pliers and the spring clamp. Might be worthwhile if doing a lot at once. Thanks for the link.
sd
Your link to the clam clamps was worthwhile. Video for the clam was interesting. Looks like a good answer to the problem of holding the mitre. Site also has a lot of other info. Enjoyed it.
Thanks to all.
Steve

[JimD]

Sounds over but I cannot resist disagreeing a little. I like to put up one of the long sides first. I then cut a piece long enough for the top that the miter fits against this first piece but I do not nail it in place or cut the other miter yet. Then I do the other long piece and finally I cut the last miter on the top and nail it. I do not drive a lot of nails in the two sides until the top is in place. That way you can bend it a little to help the miter joint fit. One reason I do it this way is I hate to waste molding and if anything has to be redone it will be the smaller top piece. I purposely cut the last miter in the top about 1/8 long and check the fit. That typically gives you enough material to fix a bad fit without throwing th epiece away.

Jim