Through Mortise before or after turning?

[Justin Florentine]

Hi everyone, I'm not a turner, don't have a lathe, and haven't even used one since the 80's. However, I'm trying to make a toy Corsair plane for my son for his 3rd birthday. I'm planning on getting some time on a lathe at the local Hackerspace, and I have my blank all laid out. The part that really needs to be turned is the fuselage (douglas fir).

Now, after reviewing my design, I have deemed it non Toddler-Proof. I think the best way to attach the wings (black walnut) to the fuselage, would be to cut a mortise all the way through the fuselage, and have the wings meet in the center with dowel pins. I think that would give maximum leverage to the wings on drops.

So my question to the forum: were I to cut this mortise prior to turning, will I get unacceptable (i.e. would not pass for "battle damage") tearout around that through mortise when I turn the fir blank? Am I better off turning it first, and then building a jig to hold it steady and cut the mortise with a forstner bit on the drill press?

Thanks!

[Bob Hamilton]

Hi, Justin:
It is almost always better to cut mortises while the stock is still square or rectangular. I would not expect too much chipping out if your tools are sharp but if it is a problem you could cut a filler piece and put it in the mortise until the turning is complete.

Good Luck!
Bob

[Prashun Patel]

Doing it before is easier, but you risk being off center if you do not line your blank up properly between centers when subsequently turning.

i dont believe tearout will be an issue. In fact, i think you risk blowout from drilling more than tearout from turning.

heres what I do:

Line up the blank in the lathe and turn it partially, leaving most of he ends square, but turning the mortise point about 75 pct so there is just a bit of flat left. Then take it to your drill press. The square parts on the end will allow the blank to sit flat, and the teeny flat at the point of drilling will tell you where dead center is. Drill your mortise.

last, complete the turning, which will remove any minor blowout from the drilling.

[Brian Kent]

I would also drill before turning. The Corsair's wings are not straight across at midpoint, so I think it would be much easier to get those odd angles correct on a square blank. The wings are also thick where they join, so if you are using dowels, the base of the wing could cover any chip-out. I assume the walnut is straight grain. Complex walnut grain is chippier in my experiences with making boxes.

[Robert Henrickson]

Line up the blank in the lathe and turn it partially, leaving most of he ends square, but turning the mortise point about 75 pct so there is just a bit of flat left. Then take it to your drill press. The square parts on the end will allow the blank to sit flat, and the teeny flat at the point of drilling will tell you where dead center is. Drill your mortise.


Exactly the approach I've used in orienting spindles for drilling. It works very well.

[Fred Belknap]

IIRC the Corsiar had fold up wings and the wings were attached to the bottom of the plane fuselage. Where the wings folded was at a different angel. Might be easier to mount the wings on a flat place on the bottom of the fuselage with a dowel and glue.