If I had to do an inlay like that, I would use a chisel to outline it, then a chisel or a gouge to remove the bulk of the waste, then clean up the bottom with a router plane.

Depending on how big the cross needs to be, I agree with Dave: knife, chisel, and router plane. 

Barb

for inlay like that I use double sided tape (on the cross) then outline with a razor knife, (you can outline with a chisel too)  then use a small router with straight bit to hog out close to the line.  Then finish with sharp chisel, use the razor outline to set your chisel.  Pretty easy

 

Thanks for those recommendations.  Guess it's a good think I finally bought a knife last spring and the WorkSharp to get my chisels in shape.  I'm not very confident with hand tools, buy I guess that means I have room for improvement.  Time to get out some practice boards!

Take small cuts, keep the blade square and upright. 👍🏼

So, tried some knife-chisel-router plane.  Not good.

When I try to go "north" I get tearout, but if I flip the board to smooth the top part, I cannot get the router plane to track (hangs up on the blade).  Plus I think the grain direction is a factor. I'm obviously doing something wrong.

So, my next question, if using a "real" router, I assume it has to have the plunge base?

Better on second attempt, but still having trouble getting depth here (arrow)

The first one looks pretty good. I would have done a lot more with the chisel before switching tools. The route plane only comes out once you have defined edges to contain its blade.

Rather than using the chisel flat, try to angle it to do the edges first like steps 2 and 3 in this crude drawing. By taking small bites, the grain direction will matter a lot less, and you can nibble your way to a good middle without boogering up the edges.

And then flatten the chisel out and make the trenches wider. Only at the last step do you break out the router plane to level the bottom of the trench. But you want small bites.

Also, I would be looking at 1/4 inch inlay or thicker to start. Thinner stuff will be harder to work with.

Thank you Dave.  I have a lot to learn with hand tools.  Definitely needed to get the sides deeper/defined better.  I like your terminology - I sure did a good job boogering up the edges.  I attempted to edge them (about 45 degrees) to make it look intentional and that was a total disaster.  🙄  

Yeah, Barb. One of the tough things when starting is figuring out when to switch from one tool to the next. Do it wrong enough times (as I have) and you start to get a better feel for when it’s time to switch. Had some of that today on my current build. Haven’t been taking pictures, but I should’ve. It would’ve made an instructive build blog.

I'm with Dave on using that method.
Score quality lines with the knife, then rest a wide chisel in the lines depression, hold upright, and give a light tap.
Best if the chisel is the full width of the line, as with the ends of the cross.
Then cone in at a shallow angle and flake off a small amount that will intersect with the bottom of the cuts from the chisel taps.
The bevel on the chisel will eventually force it away from the center of your inlay area the deeper you go, that is why you take light bites when starting.

Process is repeated until you are down a bit (maybe 1/16").
After that you have a clean border established and can get more aggressive.

The router plane is susceptible to grain tearout, but for the edges, the bottom of the chisel cut should be equal to or greater that the router planes depth (i.e all surfacing cuts should intersect a pre-cut line of severed grains).

For the bottom of the "pit", a router plane will get you close, but as you've discovered, tearout is an issue. 
The router bit in the inlay kit will alleviate this problem since it cuts with a rotating bit versus the router plane.

Of course if you plan to fill the area with alternate woods/material, any tearout will be hidden and just your clean edges will matter. 

I have ordered a plunge base and a inlay router kit so hopefully, with practice, that will help.  I do plan to try the knife/chisel/plane again as it just seems like a skill I should have.  I greatly appreciate all the tips and steps to follow.

If you’re using knife/chisel/router plane, don’t be afraid to go back with the knife to cut through the grain so your chisel is less likely to tear things out. And if you get some small tear-out, you can always glue the bit back in place, wait for the glue to dry (I generally wait overnight, because at that point I need a mental break, even if I’m still ok physically), and come back later for a second try.

A LOT of my shop furniture will have small repairs like that, because I find it’s the most effective way of teaching myself to do things correctly, and I mostly practice new techniques on shop furniture.

Barb, along with what others have said, make sure your tools are SHARP sharp. Re-hone your chisels while you work. Nothing wrong with over-honing. Bashing a thin edge into wood dulls it quicker than you’d think. Sharp tools make all this much easier.