How would you make this

[Don Baer]

I started out with the intent of just doing the submarine half hull but after a few suggested it i convinced my self that I wanted to make the whole hull so now I have the design complete I am ready to make some chips but I am running into a bit of a snag. If I make the two halves out of the same piece of stock by flipping it I am afraid won't be getting a perfect match up of the zero point and this will create to much misalignment form one side to the other since I don't have a rotary axis. I think the best solution is to make each piece from separate stock and then glue the two half together. This might be the cleanest solution at least until I can get a rotary axis.



The good news is I have reduced my machining time to under 90 minutes per half at 100 IPM...

 

[Bill Arnold]

Seems like you should be able to set it up as a 2-sided cut with carefully placed indexing pins.

Two sided Carve

 

[Wayne Eikenberry]

Could you make a holding fixture to take the place of the rotary axis? It seems like it could be fairly basic with a base and uprights on the ends that would allow the part to rotate and index. The parts to accurately index at 0 and 180 could be made on your cnc. Just a thought.

 

[Leo Voisine]

There are several ways to skin a cat as they say.

I think the two halves approach and the two side is about the same.

One issue you "might" have is on the tangent points. That is to say where the cutter is straight up and down as it is cutting the outermost extremities. If you are using a straight ball nose or a taper ball nose cutter the sides of the cutter will have a difficult time cutting the radius as it moves to the curve of the sub on those outer most radiuses of the sub.

So --- is it "really a problem? Maybe not.

OK - what about a FOUR sided setup. What about a little have filing and sanding?

I made a half hull model of a sailing hull once. No CNC. No power tools. Just a hand gouge and a LOT of sanding. It's not really all that hard to do.

Personally, I would do any one of the above mentioned methods. I don't really see is as a rotary job, though it could be done that way.