Trimming Interior Slab Doors

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  #1  
Old 11-18-11, 11:18 AM
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Trimming Interior Slab Doors

We are replacing all of the beat-up old interior doors in our house (11 of them, total) with six-panel hollow-core doors. One thing to note: We are new homeowners, so we have very few power tools. We'll need to purchase/borrow pretty much everything needed for this project, so we're trying to figure out the best way to do this, but in doing so, hope to buy tools that are versatile and can be used for various future tasks.

To help with the hinge mortise situation (and this is obviously a single-use gadget, but whatever), we purchased this hinge template from HD/Ryobi, so we can use a router to cut the mortises.

When we got the new and old doors out the other night to begin figuring out our process (and determining what tools we might need), we discovered that we're going to have to trim all of the doors. We knew we'd need to trim the length/height of each door, but we didn't realize that we'd need to do the width of them, too. For instance, we have a 24" brand new door--and discovered that it's SLIGHTLY too tight in the designated opening. Upon measuring, we found that the old door is 23 7/8" instead of 24"--so we need to trim the new door a measley 1/8".

What is the best way to go about this? I've read and have been told so many different things at this point, I don't know which way is up. I've been told to use a table saw, but then was told that a table saw would be difficult because it would be hard to keep the door completely level/straight when running it through. I was told to use the router with a bit for straight cuts, but then I talked to someone else and he seemed to think that was crazy. I saw something about using a power planer, but I'm not sure about that, either. Seems like it would perhaps be easiest to use a circular saw and a straight edge? But 1/8" seems tough no matter which way you slice it. (Like how I did that there? Slice? Get it? )

Also, after we make the cut... what is the best way to help slightly bevel the edges/smooth things out? Power sander? Easy enough to sand by hand, or is that ridiculous?
 
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  #2  
Old 11-18-11, 12:16 PM
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I would use a circular saw and a straight edge but before trimming the slab I think I would be looking closer at the jamb. Are the side jambs straight (23 7/8" top to bottom) or bowed?

A power plane will also do the job as will a good hand plane. If you decide to plane the door make sure you mark the width line first.

If you opt to trim the slab with a saw, cover the cut line with masking tape first to help control splintering and use a quality fine tooth (80T) blade. If there is a show side to the door place that side down.

If you don't have a lot of experience doing this sort of work be sure to practice on some scrap wood - especially the hinge mortising.
 
  #3  
Old 11-18-11, 12:40 PM
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Thanks. We'll take a look at the jambs--hopefully they're not bowed!

Also, I figured we'd practice a time or two with the hinge mortising on one of the old doors.
 
  #4  
Old 11-18-11, 01:01 PM
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"I would use a circular saw and a straight edge"

To elaborate, take a straight edge [a 1x or 2x is fine] and clamp it to the door. That makes the straight edge a fence and will help you keep the saw going straight. Usually the set back on the base plate of the saw is 1.5" so you'd need to clamp the straight edge that amount away from what you intend to cut off.
 
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Old 11-18-11, 01:49 PM
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As a person who sold those....I never understood the reasoning of the companies that made them. The pre-hung doors are undersized, but the slabs are full width. I mean really? If you are replacing a damaged door..then there should be no need to trim width. If you are replacing frame and all...then you use pre-hung. If you are building a frame, then it would be easy to size it...cause it would be the NOMINAL width anyway.

If you were replacing a really old door where the frame was matched to a full width door (not so many of those around anymore), then I could understand....but shouldn't the minority pay the additional cost? Just like those folks who just have to have that grand 84" tall entryway and then balk at the cost of a special order storm door?

Rant over.....
 
  #6  
Old 11-18-11, 05:06 PM
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Hi Tools you may need Skill saw, router, 5/8 Round router bit, Drill Motor, packageof drill spades, 21/8 holesaw Plane.



On your new door decide what is the top of the door. Example on a six panel door the small panels go to the top. On a slab door the top may be marked if it isn’t then it will make no difference.
I have hung about 100 doors as a repair not construction. I will try to help you as best as I can.
With your old door in place check the fit. Most fits are OK. Fit is the reveal on the top bottom and sides of the door. With the old door still in place mark it top and back. The back is the side with the hinge pins. Mark the new door top and back this is for your reference it is very easy to get turned around doing this. Pull the pins on the old door and remove all the hardware including the hinge leafs. Do not remove hinge leafs on the door jamb. Measure the old door and cut the new one to that length be careful not to splinter the new door, score the door or clamp a piece of scrap wood on the side where the saw blade leaves the wood.
Set the old door on the side with the hinge mortise up. Line up the new door at the top of the old one. The back of one should be against the front of the other. With a combo square scribe the mortise of the old door to the new door. Now take one of the hinge leafs and trace the hinge between the mortise lines you just drew remember the pins on the hinge go to the back of the door. The hinge leaf is probably marked on the back side from paint or varnish, use this line to guide you when tracing the hinge. An interior door is 1 3/8”The hinge will set about 1 1/4” across the door. Use a router to cut out the mortise if you use a chisel be careful cut only across the grain of the door style or you will split it.
Install the leafs on the new door with only one screw on each leaf make sure to drill a pilot hole for the screw or you WILL SPLIT the door. If the door has 3 hinges , leave the middle one off until you fit the door.
Place the new door in the jamb put the top pin in first then the bottom pin, you may have to adjust the bottom leaf a little tap it up or down to make it fit. That’s why I use only one screw at first. With both pins installed, drill your pilot holes and put in the rest of screws in the top and bottom hinges.
Put a screw on the front of the door where the knob will go, you need the screw to pull the door closed so you can mark the door where it hits the jamb. Remove the strike plate off the door jamb. With a pencil mark the door where it hits the jamb. Remove the door and plane down to the line, take your time. You may have to mark the door 2 or 3 times to get the fit.
With a pencil, mark on the back side door casing, the center of the hole located on the door jamb used for the door lock Close the door and transfer the mark to the door. With a combo square use that mark to scribe a line on both sides of door about 3” long and across the style.
Now find the back set of the lock you are using. A new lock will tell you, if you use the old lock, measure the old door from the edge to the center of the hole. 2 3/8” and 2 3/4 are common sizes. Measure also the size of the hole you will need 2 1/8’’is common.
If the back set is 2 3/8. On the line you drew on the door make a mark 2 3/8 on each side of the door. If the hole is 2 1/8, use a 2 1/8 hole saw, cut half way through the door and finish the cut from the other side do not plunge straight through you will splinter the door. Mark the center of style and drill a hole to fit the door latch use a small as possible hole to fit the latch you don’t have much room to spare. Some latches need to be mortised to fit if this is the case put the latch in the hole and trace the face of it then remove the needed amount of wood and install it. Remember to drill pilot holes. Install the lockset and the third hinge if needed. Now wasn’t that easy?
Good Luck, Woodbutcher



[SIZE=2][/SIZE]
 
  #7  
Old 11-18-11, 05:29 PM
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Thanks so much for all of the help so far. Woodbutcher--thanks for taking the time to type all of that out!

OK, so... two more things. First of all, the slab doors we bought already have the knob and latch holes/mortise carved into it. Whether that's a good or bad thing (making it easier or harder on us), I'm not sure. I know it will require more measuring and lining up, and might require that we trim both the top and bottom of the door, but aside from that, I think it'll be OK.

Secondly... I was measuring a bit and looking very closely at our first door tonight, and I noticed that the space between the door and the jamb is not even all the way down the sides. However, the door itself is the same width from top to bottom--so obviously the door is square/plumb, but the jamb is not. I'm not sure if this is a concern, since the door closes correctly and all (it's just ugly and beat up!). We're not looking for perfection here--we just want nice-looking new doors that close. It seems to me that if we use this old door as a template, we'll still get that, even if the spacing is a little off. Am I wrong?

P.S. Gunguy--I totally agree. It's ridiculous! These things should all be of standard size.
 
  #8  
Old 11-18-11, 05:40 PM
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Hi,
Just a word of caution. If you have to plane or cut the width of the door. Do it on the hinge side. If you do it on the lockset side you will change the backset ot the door and possibly ruin it.
Good Luck Woodbutcher
 
  #9  
Old 11-18-11, 05:54 PM
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I'd recommend you go buy yourself a 78" level which is the best thing to use to determine if your jambs are straight or if they are bowed. You'd also want a framing square to check the top hinge side corner to determine if the head is square or not. You'll also want to measure carefully the distance between the jambs at the top, middle and bottom. Don't assume that they are parallel. I often will clamp the 78" level to the door and use it as the straightedge to make my cuts. I also use a fine finish blade in my skilsaw. It tends to make less tearout, and it leaves less saw marks that I have to sand out.

Not sure if anyone mentioned it, but if the door is not bored for your handle and you cut the latch side of the door, I'd recommend you put a slight 3° bevel on the leading edge of the door. If it's already prebored, check the latch side to determine if it already has a bevel, and remember that is the side of the door that the hinge pins will be on. (mentioning this so that you don't happen to get the door backwards due to the direction of the bevel)
 
  #10  
Old 11-18-11, 06:26 PM
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Woodbutcher--Thanks, we will make sure to take off any width on the hinge sides. We figured as much, but a reminder is always good.

XSleeper--What do we do differently if it turns out that the jambs are bowed? I ask because, like I said, the doors do open/shut correctly as they are, so the slight differences in spacing from top to bottom does not seem like a big concern. Or is there something I am missing?
 
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Old 11-18-11, 06:45 PM
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If the jamb sides are bowed, I'd probably try to straighten them out. I guess if you aren't worried about it, neither am i. ;-) I prefer to see a perfect reveal around a door when it is closed... not a 1/8" on the side at the top and 1/4" near bottom. If the hinge side is bowed and you don't straighten it out, I would scribe to the bow, so that all your hinge mortises will be the same depth. But whatever. Depends how picky you want to be I guess.
 
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Old 11-18-11, 06:52 PM
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Judging by the posts that I've seen and the supposed difficulty of this project, I *think* we will be happy if we can just get the door up successfully and it opens and closes. LOL.

However, the perfectionist in me has to ask--how would we go about straightening out the jambs? I assume this would require removing the trim, doing something within the wall, etc.? And if that's the case... that would completely cancel out the reason we are trying to do slabs in the first place!
 
  #13  
Old 11-18-11, 07:07 PM
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Depends which way they are bowed and where. Also depends on how well they shimmed the doors when they were installed. In some places they don't shim very much if at all, which can lead to some pretty shabby jamb installations that don't stay straight over time. Popping the casing off is usually pretty easy... you cut the painted edge with a knife and carefully remove it. Pull/cut all the nails so that you can reuse it again. And if you have a brad nailer or finish gun you will have it made.

If the jamb needs to come out, you will hold up the 78" level and add some shims. If it is bowed out and there are no shims, you would probably want to shim it straight and nail it back to the studs. If it's bowed out and they OVER shimmed it, you might have to cut out the shims and reshim. Starting with a straight jamb helps, IMO.
 
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