sorry if this has been covered, tried a search w/no success.
I’m about to start trimming the inside of a home, window & door trim will be painted poplar. It will be a three piece casing detail, beginning with a flat, beaded 1×4, a backband applied around the outside and a sort of picture molding applied over the 1×4 and against the outside backband. Pretty standard look. My question is how would you join the legs and head of the beaded 1×4. I’ve done this before and I’ve mitered that joint, working under the assumption that since the molding and backband will be mitered, those joints will be less likely to open if the 1×4 is mitered also (all wood moving the same direction). But after a few years, I’ve noticed some joints separating ever so slightly ( short ends of the 1×4), really no big thing and if it were stain grade, probably not noticeable. In fact the HO’s don”t notice it at all. I’m wondering if I would be better served by running the head piece long and haunching the pieces, pocket srewing them. I’m kinda making that word up, but I’m referring to when you run the head casing long and really just miter the bead, legs cut square and head bead sawn back to the 45. I do that all the time when its just beaded casing w/nothing applied. This might be a 6 of one or half dozen thing, just wondering how you pro’s do it. I can biscuit and/or pocket screw if it matters. Whats the concensus on what holds up best over time?
Thanks
Replies
It's called a jack miter. If you're applying a separate back band, it's definitely the way to go. I would use a miter saw and a tablesaw to make the joint. Undercutting a little with the tablesaw is ok. You won't be able to get a biscuit joiner in there because of the "haunch", but pocket screws would be a good idea.
thanks woodguy,
jackmiter is the term. I'm ok with cutting those, usually do it with a table saw and miter saw or japanese saw and chisel. Question is if this would move less over time with the other mouldings applied? Maybe this is why so many are using mdf?
I've seen it a million times (ok, maybe dozens) on Victorian-era and early 20th century homes where this was a common design. Eventually you'll see the joint telegraph through but it won't open up like a miter will. You might get a tiny gap at the bead but not like you would if a miter opened up. The backband disguises any movement on that side.
I recall it as being called a "Mason's Miter" I believe it originated in stone work. I am unaware of that term "Jack Miter"...might you have a reference that I could peruse, so that I can be correct?
I have quite the appetite for Etymology and origins of slang..but for the life of me, I have never heard that term in 20 plus years of woodworking. Is it maybe a local venacular?Parolee # 40835
Oh..sorry. A haunched tennon is best described as a tennon that has a step in its large dimension , normally that haunch, will fit in the same groove as a panel, bewhilst the tongue of the tennon will mate fairly in it's matching mortise. That extra "beef" on the shoulder provides both resistance to twisting of the frame work, and closes the end of the panel groove, when one runs the dado in straight stock, and then proceeds to lop off lengths.Parolee # 40835
Sphere,
In my understanding, a "mason's miter" is when an inside corner is formed entirely within one of the two pieces making up a corner. This is slightly different than the joint being discussed in this thread.
If I can find a picture to clarify, I will.
FWIW, I haven't heard the term "jack miter", either. I'm not saying it's incorrect -- just that I haven't heard it before.
Regards,
Ragnar
Yep, I think yer correct. I was envisioning something else.Parolee # 40835
Sphere, I don't remember where I learned the term, but it was probably 8 or 10 years ago when I was working on a crew restoring a victorian house in Cambridge, MA. So maybe it is regional, but here's a couple other references to it:
http://www.windsorone.com/moldings/howto/section.asp?qsHowTo=Jack+Miters
http://www.garymkatz.com/TrimTechniques/jack_miter_jig.html
Yeah, without sawing it ( get the pun), i'd have to agree that I am thinking of a different miter.Parolee # 40835
I too have always heard of it called a jack miter, just couldn't draw up the term with original post. Yes, I've always glued miters even throw biscuits in when possible. I also have the exact same detail in my own home which is 100+ yrs. old, just seems that old growth stuff is a lot more stable (must be the lead in the paint) and when you replicate with new it moves a lot more. Think I'll do it though.
thanks
That'd work. You could get real snazzy and overlap the joints. I saw that done once on a very high end joint. But who'd want to pay for the labor?
(Basically the head piece ran full length, but the front half was mitered, the back ran to the end and was screwed into the mitered leg, backed up with hide glue, then backbanded)
Real trucks dont have sparkplugs
>> But after a few years, I've noticed some joints separating ever so slightly ( short ends of the 1x4), really no big thing and if it were stain grade, probably not noticeable. In fact the HO's don"t notice it at all. <<
How do you know? Did you ask them? :-)
Seriously though, would it be to obvious (obnoxious) if I asked if you glued the miters?