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Case miters with a router

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Forum topic by AGolden posted 09-19-2020 09:04 PM 312 views 0 times favorited 7 replies Add to Favorites Watch
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AGolden

77 posts in 217 days


09-19-2020 09:04 PM

Hello all,

I am wondering if anyone has ever had any luck making case miters/box miters with a router. I am thinking of something like using a large chamfer bit with a guide bearing and either taping or pinning a straightedge to the edge of a board so that you can cut the miter along the entire board thickness and have the pilot bearing ride along the straightedge. has anyone done this? is there a practical limit to how thick a board you can do this with? should you do it in multiple passes or can you cut the whole miter in one pass? does it depend on the thickness of the board? Let me know your experiences. Thank you!

Edit

It seems like I could be a little more clear here so here are some more details.

I am thinking of using a router table for making these case miters in a similar setup to this mockup below (only illustrative, not actually planning on doing it like this exactly)

The plywood rides along the guide bearing and the 45 degree angle would be cut into the end of the wood that is attached to the plywood.

I know this method can work but I am asking more about what the best way to execute it is. I imagine with larger bits and thicker wood it would be a lot of material to chew through in one pass so it might be better to do it in multiple passes.


7 replies so far

View LittleBlackDuck's profile

LittleBlackDuck

5797 posts in 1704 days


#1 posted 09-19-2020 09:07 PM

Why not use a router table?... Don’t have one?... Great project to undertake.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View therealSteveN's profile

therealSteveN

6454 posts in 1457 days


#2 posted 09-20-2020 08:43 PM

Duck isn’t wrong, sounds like he prefers to do them on a router table. I really like to do them hand held.

I see it as, the breakdown of work as bring tool to the work, or work to the tool is the first decision. Can you show a pic if what you will be doing, or better describe the actual job in terms of size, weight. More info will help you do this safely, and accurately. Type of router, does it have an edge guide? Size of project, and is it just straight lines, or is it curved?

Fact is: You can rout the edge of a board with the bit, and just running it flat, and FLUSH to the table top. It is possible you will find the router “tippy” meaning it wants to roll off the edge, and this will mar your cut, and could be a safety concern. For hand held use, most folks use an edge guide when hand held routing is how they are going to do it. The guide will work wonderfully on flat, straight edges, going around curves could prove to be a bit of a challenge. Especially on a first attempt.

I really like the Porter Cable edge guide, but know, if you don’t have a PC router, it may not fit everything out there, so at that point, you have to see what that brand of router offers.

https://www.amazon.com/PORTER-CABLE-42690-Guide-Models-Routers/dp/B0000222V9

-- Think safe, be safe

View northwoodsman's profile

northwoodsman

388 posts in 4629 days


#3 posted 09-20-2020 09:05 PM

Rockler sells a 45° corner miter lock bit for doing what you are talking about. I have one but have not yet used it.

-- NorthWoodsMan

View AlaskaGuy's profile

AlaskaGuy

6112 posts in 3192 days


#4 posted 09-20-2020 10:57 PM


Hello all,

I am wondering if anyone has ever had any luck making case miters/box miters with a router. I am thinking of something like using a large chamfer bit with a guide bearing and either taping or pinning a straightedge to the edge of a board so that you can cut the miter along the entire board thickness and have the pilot bearing ride along the straightedge. has anyone done this? is there a practical limit to how thick a board you can do this with? should you do it in multiple passes or can you cut the whole miter in one pass? does it depend on the thickness of the board? Let me know your experiences. Thank you!

Edit

It seems like I could be a little more clear here so here are some more details.

I am thinking of using a router table for making these case miters in a similar setup to this mockup below (only illustrative, not actually planning on doing it like this exactly)

The plywood rides along the guide bearing and the 45 degree angle would be cut into the end of the wood that is attached to the plywood.

I know this method can work but I am asking more about what the best way to execute it is. I imagine with larger bits and thicker wood it would be a lot of material to chew through in one pass so it might be better to do it in multiple passes.

- AGolden


I’d use the router fence and not mess with have to put a template for the bearing to run against. I’d also table saw off most of the material first.

BTW on how long of miters are you making and how many?

-- Alaskan's for Global warming!

View LittleBlackDuck's profile

LittleBlackDuck

5797 posts in 1704 days


#5 posted 09-21-2020 12:14 AM

With the added picture it’s obvious you have the table.
You need a fence… even if it’s just a board clamped to the tabletop (if the fence is for whatever reason impossible/impractical).
As Ala’G suggested, hog out some of the mitre on the tablesaw to make life easier… Alternatively sneak up on it on the router “fence” in 1/8” (or so) increments for cleaner results… just endure you feed all the pieces through before advancing the fence…
Make sure you use a backing board for endgrain passes.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View Robert's profile

Robert

4051 posts in 2364 days


#6 posted 09-21-2020 10:48 AM

How about a fence and coping sled?

Or, its easy to make push block that rides along fence. You also have a backer to eliminate tear out. Be sure it’s perfect 90°.

I buy the cheap padded plastic ones and screw them to the wood.

-- Everything is a prototype thats why its one of a kind!!

View Axis39's profile

Axis39

357 posts in 480 days


#7 posted 09-21-2020 02:11 PM

I built three tables recently and skinned them with 1/4” QS oak plywood, so they had the waterfall edges and the grain all lined up nicely.

I tired several methods to figure out how to get the corners nice and crisp and the thing that worked the best was using the fence to keep that very fine corner nice and straight and crisp.

My bit is like the one in your picture, with a bearing. I had the bearing buried in the fence to make sure that the plywood edge riding up a hair here and there wouldn’t have an effect.

It worked better than I expected. But, it’ll be a long month of Sundays before I undertake that on purpose again!

-- John F. SoCal transplant, chewer uppper of good wood

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