Cincinnati Tracer Milling A Turbine

A bit of cool pre CNC machining.

https://i.pinimg.com/originals/44/b3/f1/44b3f12b786fc0c9cb2e14eb663d9c93.jpg

Very nice sir.

I used to have "machinery Magazine" bound copies, and they had one where a tracer was mounted on a tracer.

IIRC it was a large VBM/VTL and the round parts were not exactly round.
So, somehow the first tracer used the part as a template, it's actuator moved the second tracer's template
(the shape to be cut), to keep the second template in reference to the part as it revolved.

Is that a Bridgeport M head doing the cutting?

cranium said:

Is that a Bridgeport M head doing the cutting?

Click to expand...

I think ???? it's one of Cinci's own, lots of Contourmaster info here Page Title

A wonderful photo; thanks for posting it. I will add it to my collection of fascinating old photos.

I stand in awe of the people who worked-out these complex setups.

There is a similar photo here;

https://www.practicalmachinist.com/...d-way-304104/?highlight=supercharger+impeller

The same, or a similar, machine perhaps.

Notice how the pattern they are using is made. The old time draftsman at work used to do jet turbine blades and vanes. He explained the process went roughly as follows. Engineering would define the math formula for a blade. Then he would then calculate a series of points and plot them all out on a huge sheet of paper done at a very large scale maybe 1 point every 1/4". Then he would tells me how they would then play connect the dots between the points. Next step was to use an optical tracer to cut the thing into a sheet of maybe 12ga steel. Locating holes got drilled through the sheets and MDF board was sandwiched in alternating layers between the steel plates. Then someone came by with a sander and blended the whole thing together.

After that they had the master pattern for a hydraulic reducing tracer mill to carve one out of metal. He tells me he had a lot of fun doing this sort of work back in the day. I guess it isn't much different from how a modern 3d printer works one layer at a time but a lot slower now.

A Rolls Royce jet engine designer related that when he began, they would calculate the base, midpoint, and tip of a turbine blade and fair the rest in between, then test it to see how they had done. Now they compute so many stations that it is effectively continuous and they calculate a blade, make it, and it matches the design. He said he was still amazed that the performance was just what they calculated.

Bill

I have had the below pic hanging in my cubicle for the last couple of years. Doing 5 axis stuff for a while, it seemed appropriate. They both seem to be the exact same machine. Note the date in the lower right corner.

Paul