How Do You Cut an Inside Corner 45 Angle?

[buckaroo01]

I have a problem that I hope someone can answer. How do you cut baseboard for an inside corner of 45 degrees? I understand the concept of coping an inside 90 degree corner but that doesn't work on an inside 45 degree corner. Most walls with a 45 degree wall leave an angle of 135 degrees so cutting 22 1/2 degrees will work. (I hope this makes sense)

I am using a 12" DeWalt Double Bevel Compound Sliding Miter Saw and the vertical clearance does not fit the 7 1/4" baseboard even though it only cuts 60 degree to the left and 55 degrees to the right. I'm thinking I need to cut miters at 67 1/2 degrees each, but not sure how to do it.

I appreciate any help.:confused:

[American and Proud]

Coping it won't work?

[Pipestone Kid]

buckaroo01: Think about it for a minute--if you want to mitre an inside corner of 90 degrees, you set the saw at 45 degrees for each cut. Thusly if the inside corner is 45 degrees you make each cut at 22 1/2 degrees. HTH
Jim

[ss_123]

I haven't actually tried this, but I would think you could make shims to rest on the bed of the saw to make the baseboard sit at an angle. The shim only has to allow the baseboard to rest at a 12.5 degree angle up from the bed (or 77.5 from the blade when vertical) , then cutting from either side of the saw blade, the head can be tilted to cut at 55 degrees to make up the remaining on your 67.5 degree cut.
To make this a little safer, you could hot glue the shim to the bed and put a layer of on top of the shim sand paper to help grip your baseboard.
I hope this makes sense...

[Woussko]

buckaroo

Is your problem that the saw won't rise up high enough above the table? Maybe you can rotate the baseboard 1/4 turn privided there are 2 flat sides.

While I doubt this very much, in my mind I picture something more like a RR tie being cut and only a huge radial arm saw would get that job done. I have heard of cases with very large crown molding and the need for a monster size CMS to cut it. How about a large manual compound miter box? Some of them take large work and they are safer for the user.

[Gofor]

Several other options:
1. Cope it as A & P said. Bevel the base board at 45 degrees (both pieces). But one up against the corner and slid the other one to it. With a pair of dividers, scribe the profile off the one that is flush to the corner onto the other one with the divider set at the same width as the boards are thick. Cut along the profile line with a coping saw to get a flush fit. If the top is square, you will have a butt joint instead of a miter, but it will be a tight fit. If the baseboard is painted, run a thin bead of caulk in the joint and smooth it out before painting.
It will be a little tight to get the dividers into such an acute angle, so you may have to tweak the cut with a rasp or sandpaper wrapped around a dowel to get a perfect fit (especially if the angle isn't exactly 45 or the walls aren't plumb, which is usually the case).
2. Cut it with a hand saw (the more teeth per inch the better) and tweak the fit with a sanding block. If cutting with a coarse saw, clamp a piece of scrap to the back of the cut (traditional push saw) or front (Japanese pull saw) to prevent tearout.
3. If you have a belt sander, clamp it upside down in a vise. Bevel to 45 and finish achieving the 67.5 angle with the sander.
Just other ways of getting a tight fitting joint.
Go

[tqcons]

If I were you, I would do these steps:

1- Check angle, divide it by two.
2- Clamp or screw one L shape fence 90 degree to the fence.
3- Set your saw exactly @ haft the inside corner plus haft degree.
4- Put your stock agaisnt your 90 degree fence and make your cut.

Pratice make perfect. Try it and you will love it. I even do crown with this way.

Good luck

TP

[buckaroo01]

I'm going to try some of the ideas that were posted tomorrow. I'll let you know how it works. Just measuring the angle, 45 degrees and dividing it in half gives 22 1/2 degrees. This does not work on an inside 45 degree angle, I tried it and believe me it is not even close.

[FSK]

I'm going to try some of the ideas that were posted tomorrow. I'll let you know how it works. Just measuring the angle, 45 degrees and dividing it in half gives 22 1/2 degrees. This does not work on an inside 45 degree angle, I tried it and believe me it is not even close.

Is it possible to post a picture on this?

[TOD]

Every one is thinking wrong here. Yes the cut is 22.5 degrees but that is from the fence. Which means you need to set the saw at 67.5 degrees which most saws cannot achive.

[Woussko]

Time for a hand saw and a protractor, I think :confused:

[billie_bob]

hello, I am new here; and would hardly consider myself an expert at installing crown molding. I found myself in a similar situation last weekend. This web site wast quite useful to me I hope it helps.

http://www.installcrown.com/

[buckaroo01]

I completed the inside 45 degree angle cut using the compound miter saw. I cut a 2x6 with a 45 degree angle and layed this flat on the bed of the saw. I then used a brad nailer to fasten the baseboard to this 2x6, then set the saw at a 22.5 degree bevel then made the cut.

The only problem was holding the baseboard in the air while the cut was made, but it worked.

Thanks for the many replies.:)

[Wood_Junkie]

The only options you really have here are a) use a tenoning jig on a tablesaw to hold your board vertical or b) a coping cut. However, you noted you're using a miter saw... soooo, you'll just have to cope (pun!).



Oop, just saw your posted solution. Good thinking!

[L Turner]

If I am reading this thread right your inside angle is not really 45, if it is it is avery sharp inside angle, I believe it would actually be 135 thus half would be 67.5 and what you have to figure out is how to cut the 67.5 angle

[tsbrewers]

I am going to bring up an ancient thread here, so I am quite sure the OP is done already, BUT, I wanted to try and explain the correct way to do it for the next time someone needs it done.

I will use baseboard as an example,

First piece that goes in to the corner cut at a long 45 so it goes all the way in to the corner. Second piece, cut a 22.5* angle on it (instead of the normal 45* on a cope) and then cut this out. Here is the tricky part, when you are cutting this cope, you have to back cut the piece at least 45*. On a normal cope you just back cut a little so the front hits, on this one you do the same, but you have to backcut the cope 45-46-47* degrees.

a little tricky the first time you do it, but once you do, it will make sense and fit great.

Brew

[tierraverde@comcast.net]

Tod is correct. You are working off the wrong 90 degree reference. Maybe you can clamp a board perpendicular to your back rail, and then set the saw to 22 1/2 degrees. Be careful that everything clears and the molding is secure.

[tsbrewers]

check out 2nd half of video. At about 3:00 I show how to cut this joint. Very simple, no need for extra boards, or tenoning jigs, or what ever else was suggested. Only difference is instead of cutting the cope at a 45* angle you cut it at a 22.5* (with piece up against fence, just like normal) and you have to back cut the cope at a 45* angle.

http://www.youtube.com/watch?v=tJrS4pZ4SoA

Brew

[Gizmoman]

If you have a dual slide compound miter saw, Why not lay the base board down flat on the miter saw table against the fence then use the compound saw settings. Thats what the saw was designed for.
If you were cutting crown molding for a True 45 deg reading the only way to cut it is with the miter and compound settings with the crown laying flat on the saw table. The only other option is to make a jig and bolt it to the saw fence. Most people say a compound saw wont cut the 45 deg angle for crown......there wrong....a dual sliding compound saw will do the job....

[tsbrewers]

it is easier and quicker to cut the base standing up, unless it is too tall for the fence. The makita's is pretty short, but I was only using 2-3/4" base. Plus, most compound saws will only lay down to 45 or 46*, sometimes that isn't enough for the outside corners. (without adjusting the stops)

The crown is the same way, if it is short enough for the fence, it is much easier cutting it standing up and not laying down. No need for a jig either.

I have never heard anyone say you can't cut a 45 on crown with a SCMS, heck that is what they are designed for.

Brew

[Gizmoman]

it is easier and quicker to cut the base standing up, unless it is too tall for the fence. The makita's is pretty short, but I was only using 2-3/4" base. Plus, most compound saws will only lay down to 45 or 46*, sometimes that isn't enough for the outside corners. (without adjusting the stops)

The crown is the same way, if it is short enough for the fence, it is much easier cutting it standing up and not laying down. No need for a jig either.

I have never heard anyone say you can't cut a 45 on crown with a SCMS, heck that is what they are designed for.

Brew

Brew, the only way to cut crown molding for True 45 deg is laying flat on the saw. A True 45 deg angle is 67.5 deg miter in the carpenters world.

[tsbrewers]

Brew, the only way to cut crown molding for True 45 deg is laying flat on the saw. A True 45 deg angle is 67.5 deg miter in the carpenters world.

wrong. as long as it is not extremely large crown it can be cut with a regular miter saw, doesn't even need to be a compound miter saw, and doesn't need to be flat on the table.

There are two ways, upside down with the bottom of the crown against the fence. at the correct spring angle, or with the crown sitting as it would be on the wall, so the bottom of the crown on the table of the saw, the back against the fence, sitting at the correct spring angle.

Brew

[tsbrewers]

Ok, here are a couple pics of how it is done, both are done without the trim flat on the table, and both can be done with a regular, non-compound miter saw. Only time these ways can not be used is if the crown is too large for the saw.

First, the most common method, the "upside down and backwards method" Second is with the crown sitting just as it would on the wall. the second pic shows a jig to hold the crown while cutting. As long as the crown isn't too big, it is just as easy to just hold it and cut it. and again, neither has the crown flat on the table or needs a 67.5 angle.

BTW, I know all about the carpenters world, since I have been a part of it for many years, with at least 10 just strictly trimming.

Brew

[TOD]

I don't know how this post got derailed and went to cutting crown. If you go back and look the OP is talking about cutting base molding.

[Gizmoman]

Ok, here are a couple pics of how it is done, both are done without the trim flat on the table, and both can be done with a regular, non-compound miter saw. Only time these ways can not be used is if the crown is too large for the saw.

First, the most common method, the "upside down and backwards method" Second is with the crown sitting just as it would on the wall. the second pic shows a jig to hold the crown while cutting. As long as the crown isn't too big, it is just as easy to just hold it and cut it. and again, neither has the crown flat on the table or needs a 67.5 angle.

BTW, I know all about the carpenters world, since I have been a part of it for many years, with at least 10 just strictly trimming.

Brew

Look at the attachments, this is a (True) 45 deg angle. Your demonstration is for a 135 degs. Look at a 0 to 360 angle finding protractor, set it at 45 degs. You will see how it will match the angle on the crown attachment below. If you were going to cut two flat pcs of wood for a 45 deg (true) angle the miter cuts would be 67.5 degs. How do you cut that on a miter saw when the deg settings on the saw dont go that far.
How would you cut the crown in the attachment, flat on the saw table or standing up against the fence ? If you can cut it standing up maybe you can teach me something. I'm always willing to learn......
Look at this link,it demonstrates a True 45 deg acute angle for crown.
http://www.garymkatz.com/Publications/OnSite/PDF%20Files/AcuteAngles.pdf
Maybe we should start a new thread so we dont steal this one

[Gizmoman]

Hey Brew, I tried your method out today cutting crown for a True 45 deg angle on crown molding. I dont see anyway it can happen with the crown standing up against the saw fence.
Maybe I'm doing something wrong or not understanding. The way I see it is the crown has to lay flat on the saw table using compound deg settings.

[tsbrewers]

Yes, if you want to cut that angle you are showing (true 45?) then you must use the jig gary shows in the pdf you linked to. But, as you can read in that article, he prefers to stand the crown up too, instead of laying it flat. In all my years of trimming, I probably have had that angle only once or twice, so I usually will make a quick jig like he did to cut it.

Brew