Thread: Cutting simple curves on a vertical mill

I think you could gear the rotary table to the X axis and cut a curve.
While gearing the X and RT for cutting spirals is done often, I dont recall seeing it used to cut a curve.

Stuart

here is an example of cutting curves for a cam by linking a dividing head to the x axis.
Cam Milling - YouTube

-Josh

Hi,
You can do it by free hand using the X and Y, but it will be slow. One tip would be to use the biggest cutter possible as it will help not seeing the steps like a small one would.

With the rotary table you position the work piece on the table (or a sub plate on the rotary table) so it lines up with the circle you want to cut.

Dave

A rotary table will allow you to cut radii centred on the R/T. For something the size of a Seig X2, I'd be guessing that a 4" rotary table (maybe a 6") would be about as big as you could go, so you are probably stuck with a 50mm radius as a maximum.
Anything other than a radius you would probably have to step things out in X & Y. Lots of X2s have been converted to CNC though.

Michael

Thinking about it a little more.... I'm wondering if it would still be " cutting curves that correspond to part of a circle's circumference"


Might have to draw it up.

Stuart

Draftsmen look away now.

This is what I think you would get if you fed a 100mm Dia circle with the center offset from the cutter by 20mm and the R/T geared to turn 360deg with 90mm of X movement.

Stuart

Stuart, I think you are assuming symmetry where there may not be any. One of the interesting things that can be done with a universal dividing head is turn it so that the axis of rotation is vertical (cf a rotary table) and gear it to the table as you were suggesting. The result is a spiral similar to a chuck scroll. I think what you have done with your diagram is assumed a reversal of table travel when 180 degrees is reached.

One day I'll have to try that. I don't know what I would use it for (it would be too soft for a chuck scroll) but there are somethings that you do just to say that you did them...

Michael

Hi Michael,
You're right there is something wrong with it not the least of which is 360deg, it should be "180 deg rotation with 90mm of X travel". But thats not all of it it should look more like half an ellipse than a cam. I'll have another go tomorrow.

Stuart

Well not being 100% happy with my second attempt at drawing it(and not wanting to put to much more time into it), I decided it would be easier just to make one.
Turns out my drawing was pretty right but it didnt have as many points.

Blue circle is 100mm.
The outer red line is 20mm Y offset from center with 10deg rotation and 5mm X feed. Yellow arrow is X feed , anti clockwise table rotation.
The inner red line is 10mm offset with the same feed.

Stuart

Thanks for your efforts, Stustoys. I actually understand what's happening

I don't have any specific project in mind, I was just curious never having used a mill before.