Noob - Cut too much off miter cut for base trim - options?

I have been collecting woodworking equipment for various projects but the current mission style double bay bookcase is my first real woodworking project from scratch. I took some Wood mag plans and modified them to make a double bookcase as the wife needs more book storage. Things had been going along swimmingly, until yesterday.
I was cutting the bottom base trim for the bookcase, the trim covers both of the double bay bookcase fronts and wraps, with the 45 deg mitre cuts to join side base trim. It has 2" legs cut on the ends, and one in the middle. I had one end done, then cut the other and it was about 1/8" too long. Ok, So I measured and used a square to draw a line, double checked, and then cut. Well, now its about 3/32 too darn short! &$%(&@! Now, I've thought to ways to solve this and wanted to ask for sage advice.
1. remake the part (obvious answer) 2. trim a little off of the side overhangs of the front vertical trim, which would recess the base trim a bit to fit correctly 3. (the one I'm currently favoring) Cut the center leg portion out of the trim with vertical cuts, then replace with a slightly bigger peice to make the total trim part fit correctly. Use biscuits to join the wood. 4. Cut in part of the leg as above, but only insert a small 3/32 slice held in place by biscuit(s) 5. Use wood putty to fill the gap at the miter joint (LOL)
As the finished part will show so totally,I figured replacing all the leg portion of the center would make it appear as if it was designed that way. I could orient the grain vertically to give some contrast.
Any advice?
other misc questions:
A buddy who has built much furniture recommended I finish parts before assembly, but this seems like a PITA. What is recommended by the majority?
Currenly the carcass for the bookcase rests on the floor, but I was considering making the base trim be the only support as it was in the plans from Wood although I modified them somewhat. Is is preferable to have less contact with the floor, or would having the plywood frame also hitting add strength? We'll have this baby loaded with books, need strength. FYI, Trim is 3/4" QS oak.
Thanks, S
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
scott wrote:

I'll take what's behind door number 3. If you can fix a mistake in such a manner that it looks like you meant it to be that way, you're the only one who will ever know. By the way, whenever I make a mistake like that, I always turn off the lights and go do something else for a while. You need to get over the frustration of making the mistake and give yourself a little time for a solution to gel - just like you did here.
Personally, I would let the plywood come all the way to the floor to carry the load. I'm sure the trim would hold it, but why not get some help?
DonkeyHody "Never wrestle with a pig. You'll both get muddy, but the pig likes it."
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I'm not sure if I'm following but if this is a trim piece with a flat back, can you take some material off the back side of all of the pieces and then re-install? You will lose a little thickness but might be able to gain enough in length between your already cut miters.
Mike O.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ok, now admittedly I have not learned much about miter joints, so this is all pretty new to me. I made a hardwood floor trim transition for around my fireplace floor tile and that had miters on it, but I ended up making one leg of it where it goes back to the hearth area 1/4" short, and I had to add a short section of cut wood to fill it in. No one notices but me, but miters have not been something I'm very comfortable with yet.
On this project, its just a board laying on edge acting as trim for a bookcase, meeting two other trim peices the same size for the sides. Its all 3/4" oak.
If I use the planer to reduce the thickness of the front trim, it won't fit with the side trim right, correct? trimming off the back side of the trim on the planer isnt' going to make the 45deg trim anylonger, would it?
I'm not sure planing is a good idea, as it has two arches cut into it where the two bookcase carcasses are behind the trim.
I have done a good job of getting my wife to let me have tools, but feel silly having made this mistake on my Dewalt 12" sliding compound miter saw (LOL). I probably would have been better off with a back saw and a miter box!
Scott
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If you trim the backs off the sides, the outer corners of the eventual joint will be closer together when installed, as well as all coresponding points along the mitre, making the front span shorter.
Sounds like you need to make both sides and front 3/64" "thinner" (~.047").
-
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
scott wrote:

Correct. But ask yourself what happens if you take the same amount off the back of the pieces it is supposed to mate to.
Look at what happens to the length of the top line in this drawing if you take material off that surface. (Assume that the bottom line is the exposed face)
--------------------------- \ \ \ \ _______________________________\
------------------------------ \ _______________________________\
At issue, and not something we can know because (IIRC) you didn't tell us: how thick the pieces are or how much of an error you made or if there is any reason why the pieces MUST be a certain thickness and CANNOT be planed below that point. You'll have to make that call.
If your error is only a 1/16th or an 1/8th, AND the trim is sufficiently think to start with, quite possibly you can gain enough length from planing the back to close the gap. Remember that you have to plane the matching pieces, too ... and (assuming a 45 deg. miter) they will account for 1/2 of the needed growth.
Otherwise, look for a different answer. Actually, I like the idea of cutting out a nice big hunk from the middle and inserting a contrasting piece of wood or just making a narrow cut to get the length you need and applying some sort of escutcheon over the cut (if the design style will permit this). IIRC, the design style you are using calls for mostly straight lines so you MAY need to simply bite the bullet and use the trim piece on the matching table you were planning on making all along. ;-)
Bill
--

I not only use all the brains that I have, but all that I can borrow.

Woodrow Wilson (1856 - 1924)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Correct. You would need to take that piece off and run all three pieces. The front and both sides.
If you take off just enough (off all the pieces) to make the front piece work, you will need to cut the side pieces a little shorter since they will be a little long now.

It won't make the trim any longer but will make the distance between your miters longer. Imagine a 2x4 laying flat with one end cut at a 45 across the 2x4. Let's say that the board measures 10" from the square end to the short side of the 45. Now imagine ripping 1/2" off of the short edge of the 2x4. Your 2x4 isn't any longer (it is narrower) but now the distance from the square end to the short side of the 45 is 10 1/4". Same idea with your trim pieces as long as you remove the material from the back side.
If the pieces are too fragile to saw or plane to reduce the thickness then this won't help anyway. Besides, you might not like the look of the thinner piece although as bent said, you don't need to remove very much..
Mike O.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.