Helical slot in stainless steel tube - anyone have the equipment for this?

[evildrome]

Hang on.... if I'm seeing this correctly the 'lift' component is just a function of the way you've decided to deal with the rotation.
If all thats *actually* required is the rotation (about 270 degrees?) then why not just mount the shaft in a bearing and rotate it with a small servo? Either geared or direct drive.

 

[Fergie 307]

Hang on.... if I'm seeing this correctly the 'lift' component is just a function of the way you've decided to deal with the rotation.
If all thats *actually* required is the rotation (about 270 degrees?) then why not just mount the shaft in a bearing and rotate it with a small servo? Either geared or direct drive.

Does seem a case of engineering overkill, not sure exactly why this design has been chosen. But hey the original question was how to cut a helical slot in a tube, and some interesting ideas have come out of it.

 

[ChaiLatte]

It's the sort of thing that would have been done years ago with a driven dividing head, lots of calculation and half a day or so of setup on a manual machine...

Minimal calculation. Assume 5tpi leadscrew and 40:1 dividing head. 38:59 gearing between leadscrew and dividing head input is near enough. Setup is quick as unlike a helical gear, you do not need to angle the table.

Working out below:

He wants 80mm over 220 degrees, so 131mm or 5.154" lead (7200/1397 exactly). A 1:1 ratio between screw and DH will give 8" lead. We thus need to gear down 5.154/8 (0.6442 or 900/1397 exactly). Using a continued fractions calculator, 38/59 (0.6441) is close enough.

 

[Fergie 307]

Have to say having looked at your videos and read the description i feel i must be missing something. Surely this could be accomplished at a fraction of the cost and complication by just using a suitably geared turntable?

 

[Jonm]

Would a metal cutting chop saw do it with a series of cuts. Bit of care needed to line it up when the tube is rotated. Obviously two cuts would be required. Drill a holes at the ends before cutting the slots.

I was thinking of something like this

https://www.screwfix.com/p/titan-tt...zBkjk7xTXRE48Fo2P5AaAhcMEALw_wcB&gclsrc=aw.ds
Set it to the angle of the helix, clamp tube in place, cut making sure disc does not cut other side of tube. Rotate tube, move it a bit and cut again. Seems fairly simple. Am I missing something?