topic Cutting a path into a cylinder. in AutoCAD Forum

Cutting a path into a cylinder.

Anonymous — Tue, 09 Aug 2016 15:55:35 GMT

I am trying to make a enclosure for a lead screw that will allow the nut (having an arm attached to it at a 90* angle form the lead screw) to be lead a specific path around the cylinder.

More simply, i need to find a way to cut a path into the side of a cylinder. I have tried creating a grid along the side and then using a spline to draw the path but this failed when i tried to presspull the area (which is closed), Which is probably an indication that i am trying to do the impossible but I thought i would ask the community before i try and think of an alternative.

I have attached a screenshot of where i am at the moment which should hopefully stop any confusion.

Any advise would be greatly appreciated. 🙂

Re: Cutting a path into a cylinder.

Kent1Cooper — Tue, 09 Aug 2016 17:12:51 GMT

Welcome to these Forums!

If your path will be regular in its curvature around the cylinder, you can use a HELIX as a path to SWEEP the cross-sectional shape of the groove along, and then SUBTRACT the result of the Sweep from the cylinder. Here I used a small Circle to Sweep along the Helix [left part], but you can use a different shape, and "dug" it out of the surface of the cylinder by Subtracting [right part]. Your proportions, Helix characteristics, groove cross section, etc., would be different, but the concept should be the same.

Re: Cutting a path into a cylinder.

Anonymous — Tue, 09 Aug 2016 19:27:28 GMT

Thank you for the quick reply!

I did look into using HELIX tool but unfortunately the path isn't regular. It needs to go vertically for X then curve gradually towards the top at an angle of around 45*.

I'm currently trying to create the desired path with a spline, use sweep to turn it into a cylinder and then subtract the path from the enclosure as you suggested with HILIX.

But i'm struggling to create a spline that increases in hight and also curves with the cylinder. Do you have any suggestions?

Re: Cutting a path into a cylinder.

Kent1Cooper — Tue, 09 Aug 2016 21:31:15 GMT

@Anonymous wrote:

.... unfortunately the path isn't regular. It needs to go vertically for X then curve gradually towards the top at an angle of around 45*.

....

But i'm struggling to create a spline that increases in hight and also curves with the cylinder. Do you have any suggestions?

I had what looks like some degree of success by making a grid of stacked Circles and vertical Lines, spaced so the grid spaces look close to square [you can refine the idea for any required degree of accuracy], and drawing a Spline Osnapping to intersections [left image]. In this case, I started at the bottom, went up 3 and over 1 twice, then up 2 and over 2, then repeatedly up 1 and over 1 to the top. I Extruded the next-to-bottom Circle to make a cylinder up to the next-to-top Circle level, so the Spline extends beyond the ends of the cylinder, and used SWEEP with [again] a small Circle along the Spline [middle image], and SUBTRACT to take the groove out of the cylinder surface [right image].

All the qualifications from before [shape of groove cross-section, etc.] apply here as well.

Re: Cutting a path into a cylinder.

Anonymous — Tue, 09 Aug 2016 21:56:22 GMT

Briliant! I wasn't too far off with my first attempt...

Thank you for your help!