using a jigsaw for an angled interior cut (1 Viewer)

Woodworking question:

The flat roof of the birdhouse fits atop the angled sides (causing it to tilt down toward the front) and meets the straight back board (on the back).

The back board fits like a puzzle piece into a notch in cut in the roof. The notch looks like a bite taken out of the flat roof piece 4"x.75"

How do I make an interior angled cut in the notch cut into the roof to accept the back so that the roof piece fits (angled down) snug-ly against the straight back board?

If I cut the notch straight, the tilt-downward of the roof piece leaves a large gap between the straight back board and the roof, with only the bottom edge of the straight cut resting against the back board.

Interior cuts, anyone? Interior mitre with a jigsaw?

How? Help is appreciated.

Thanks!

MC

I doubt I'm understanding exactly what you're trying to do, but I think I do. I would use a small hand saw, specifically designed to make delicate, intricate cuts, to cut the sides of the .75" notch (also making a few cuts in the middle) and then use an appropriately sized chisel to remove the wood in the middle. It also sounds like you need to angle the top of the back board to match the angle of the notch in the roof.

This is either going to make sense or make me sound like a complete idiot!

No no, you're right on.

So, handsaw the notch in, let's say, inch-wide spaces into the .75" depth, and then chisel the angled "bite" across the 4" width of the notch?

Is there no, I dunno, jigsaw mitre block or something? One of my jigsaws has a moveable "base," which seems to double as a mitre angler, but it's nearly impossible to use in this situation since I'd be starting out at a right-angle to make my notch. (Gosh, you're right: without diagrams this is nearly impossible to actually describe.)

I wonder if I could find a tiny, mini band saw (maybe at Harbor Freight) that would let me make a tiny mitred band saw cut? (Harbor Freight has mini saws, like a mini-cut-off saw that's like a tiny circular saw for cutting molding and trim.)

Would a regular band saw allow this kind of angled cut?

You see how lazy I am: doing anything to get out of chiselling...

MC

Maybe I mean a "band saw"?

I wonder if this little thing does angled mitre cuts?

MC

That's a "chop" saw. It only goes straight up and down. A sliding compound miter saw might work but it would be tricky as you would have to make several passes to cut out 3/4". Do you have access to a table saw? How about angling a 3/4 inch dado blade? Or maybe a table mounted router?

Sorry, but I think my first idea is the best one .

WAIT! I have this! I have a table saw.

What's a "dado" blade?!

I will explore.

I like your first idea, too. But I want power, not chisels. So far. Chisels could be (and may be) my fall-back position.

MC

Dado's not the answer. Cool, tho. But I don't need a joined groove, I need a bite taken out of a flat piece, like a bite from a cookie.

So, I think, unless that little mini band saw at HF seems like it might help, I will end up either drilling a skil-saw blade hole (with a wide bit) and using the uncomfortable mitre base on the skil-saw to try to achieve my angled interior bite.

Or, yeah: chisels!

Anything I'm missing?

MC

Do it by hand. Coping saw. Specifically made for multi-angle/curve cuts that cannot be done with a standard mitered saw.



The Coping Saw

When do you bend the license plate and nail it on?

To me, "interior angled cut" means cutting a hole in the board (wood surrounds the entire hole) whereas "notch" means making a cut on the edge of the board (straight or curved). The coping saw, bandsaw, or jigsaw will all perform these cuts. Now, if you are trying to create a trench in a piece of wood (i.e. hole that doesn't go all the way through) then I'd suggest using either the chisel or a router (chisel to cleanup / square the corners).

Images below (from left to right) are mortise, notch, and hole. So which one are you trying to create?

BTW, this was done in seconds using Google sketchup. Check it out, it may help explain complex design issues more easily.

Hey, cool. Ok -- I'm trying to do the middle thing: A notch.

But, I need it to be squared, .75" deep by 4" wide, and I need the four inch cut to be angled toward the bottom (about 45-degrees, to match sloped side boards).

It's the "right angles" at the edges of the notch that are bamboozling me.

Two straight cuts in, .75" on each side. Easy. Then, I will need to cut the 4" length... but I don't know how to insert the drill bit for this. (I know I should drill a hole at the corners to fit the bit, right?)

I'm going to fiddle with Google Sketchup!

MC

So you are trying to do what's attached below?

Hee hee! Greg, that's totally cool. I have determined that when I next have time to fiddle with it, I will download the google sketch thing and play.

BUT YES, that [shown] is GENERALLY what I'm doing. Move the notch IN about .75", so it looks more like the second sketch in your previous post (a .75"-deep, then slanted-cut, notch) and you will see how the notch fits (in my design) like a Lincoln-Log onto the straight .75"-deep board that makes up the back of the birdhouse.

I'm a dork about being able to post images, otherwise I'd post an image here of my first birdhouse. I'm thinking actually of making this my new career.

MC

Gotcha. Here's two methods for making the cut. One would be ideal if the cut is exposed (i.e. needs to be visually perfect), the 2nd is if it just needs to be accurate for joining (to another board).

1) Build a jig to hold the workpiece at a 45&deg angle. Using a router table, move the workpiece and jig along the router table's fence. Move the fence to the next cutting position and make a similar cut. Slowly nibble at the cut (take 1/4" - 1/2" of wood off on each pass)... you'll need to raise the router's depth of cut a few times to complete this cut safely. By using the fence you can ensure that the notch sides are straight and square to the board face.
2) Use a jig saw, coping saw, or bandsaw and the jig mentioned above. Cut your edge cuts (notch sides) 1st. Then start in the middle and cut to one of the corners (try to saw along the line for the last little bit). You can now stick the blade in the part that was sawed to the line and make a straight cut along that line to finish cutting the notch.

Well... This is pretty much what I have been trying to do. I guess I get bunged up on the bit where you "start in the middle," etc. It's fine for joined pieces, as you say. It ain't professional woodworking. Who knew building a simple freaking birdhouse would this complex?!

I am trying to get better at using the mitre base of the old jigsaw I have to set the blade on an angle. And you say "Build a jig to hold..." as if I knew how to "build a jig." I'm just not this so-fist-ick-ated.

I appreciate your woodworking lessons, tho. I'm learning this stuff; I'll build a jig, I promise!

They're really getting to know me in Harbor Freight, tho.

MC

If you have a table saw (and apparently, you do ), you can do a variation of Greg's first method, but using a table saw instead of a router.

A dado blade is (essentially) just a wide, circular blade that hogs out a lot of wood in a single pass. But even if you don't have a dado blade, you can use a regular saw blade to nibble your way through the wood. Although there's more nibbling without a dado blade, you don't have to adjust the blade height and make multiple passes like you do (or should do) with a router bit, so in many respects, the table saw is a little safer.

Make a jig that holds the wood at a 45-degree angle and will register against the fence (just like you would for the router).

For the table saw: Make the end cuts first (don't do this on the router - see below), then gradually move the fence between each nibble pass so that a little more wood is nibbled off each time.

For the router: Be sure to move the piece from right to left against the fence, and hog out the wood closest to the fence first. (DON'T EVER pass wood between the router bit and the fence on a router table. Think about how spinning tires work to launch baseballs in a pitching machine, and you'll understand why.)

Be sure the jig is sufficiently long front to back so that it makes a lot of contact with the fence (for both the router and table saw). This will help keep things stable so that nothing racks and gets launched into the air.

Be careful, and keep us posted!

[Edit] There are exceptions to what I said about never passing wood between the router bit and the fence, like, obviously, when making grooves. But your situation doesn't meet those exceptions.