How do I make this cut?

[blackhorse]

I am attempting my first nutcracker and it required a 3/4" channel in the center of the torso about half way down, then a ramp to the bottom (for the lever to fit into). The torso turning is round and I'm having two problems:
a) How to cut the channel in the exact center of the turning and
b) How to cut the ramp at the same width.

The photo shows what I did on the B/S freehand, then with a chisel. It's not very pretty or accurate. Any ideas??

 

[john lucas]

That's one of the few turned items that I have never made. I looked up Bonnie Klein's article in American Woodturner vol12 no4 and she did it by laminating 3 sections. This way she was able to cut the middle section to shape using the table saw and then glueing them up with the proper gap.
Before I looked up the article I thought that you might be able to cut the slot on the table saw while the wood was still square. Use a flat cutting dado blade or if necessary repeat cuts with a 1/8" blade and then true up the bottom of the ramp with a chisel. Leave the piece a little long so you can fill in the slot with a scrap piece that is only glued on the very end. Then you could part and cut the end to length afterwords to remove the scrap piece.
Wish I had time to go out to the shop and try one but I have to go to the local park and demo today as part of Nature Fest.

 

[Clifton C]

My first thought would be to glue up your blank with a ¾ board in the middle and paper joints, turn, split apart and then glue in your ramp… If you cut ¾ out of the middle of the turning blank before you turned it, glued that piece back in with the paper joints, and used that piece for the ramp after turning, then the grain would match and you might have a fairly invisible joint.
cc

 

[Mark Warden]

Make yourself a tapered jig with a V groove that will sandwich the piece. Make sure both sides are the same thickness that wlil make the slot centered.Use a 1 inch strip of wood clamped to you table saw as a fence that way your clamps on the jig won't hit it.

 

[hockenbery]

We solved a similar problem, making a slot for a string puzzle we used in a youth turning class.

John mentioned gluing up first. that is what we did.

You would probably paint the nut cracker. Dealing with the flat wood you can match the parts before assembly.

In my opinion centering and aligning precut slots before turning is much easier than after.
And probably a bit safer for you and the wood.

The string puzzle below is a great project for kids of all ages. Kids are sure the gouge is going to get stuck in the slot. With sharp tools and fairly fast lathe speeds the kids have never had a problem turning a nice shape about the slot.

Happy turning,
Al

 

[MichaelMouse]

While square, mortise and make the slope with your "sharp chisel." ( Does anyone recommend a dull one?) Insert a place keeper piece of wood with a bit of hot glue to make sure your face is safe, and turn away. Knock it out when done. Centers are assured if you use a dedicated mortiser, because the center of the bit and fence distance serve as your end marks.

You can do somewhat the same trick for sliding dovetails on candlestands by routing while flat and easy to control, then turning to the diameter that leaves the flats as wide as the legs are thick.

 

[Steve Worcester]

Having never made one, my thought would be to make two at a time, end to end with a space between them. Then you could flip it and drive it with a spur drive between the two, like a propeller, and use a parting tool or such down the middle.

 

[hockenbery]

Steve,

sounds like a Square bowl solution 😉
I've seen you do those propellers quite nicely by the way.

I'm picturing the curve being convex as you described it.

I think you have to turn the slot from the middle and off set from center to get the curve correct.

You could turn 4 at once and bolt them onto some plywood so they would counter balance.
But we may be getting way off center for the solution needed.

Al

 

[blackhorse]

Steve's solution sounds pretty wild to me; or at least beyond my turning ability.

So far the idea of cutting the channels while rectangular, the filling the gap for turning appeals most to me.

Joe