Internal key slot in cylinder

casey_jensen

Not having much luck figuring this out. I need to make an internal slot in a cylinder. I thought maybe drawing lines on the wall and extruding the section, but I cant seem to draw on that surface. Maybe along the same vein, I was curious about an easier way to make external slots for snap rings other than drawing and extruding two circles. Any help would be appreciated

NeilCooke

Hi Casey - it depends on what the slot looks like (axial/radial). Have you tried revolving a profile around the axis of your cylinder? Revolving a rectangle around the axis is another way to make a snap ring groove.

daniel_chow

Hello Casey, I assume its a keyway in a shaft that you're after... here is what I would do:

Step 1: start a new sketch on the end of the shaft where you want the keyway. Click the "use" tool to use the end of the shaft as part of your new sketch.


Step 2: on that new sketch, draw a circle of the same diameter and concentric to the shaft.
 

Step 3: Sketch the keyway, add dimensions (which is what I didn't do)


Step 4: Extrude the keyway using the new sketch as a new part, reverse the direction so the new part interferes with the shaft.


Step 5: Use the boolean tool to subtract or remove the new part from the shaft and you're done. 


I should mention that I'm a beginner and this may not be the move time effective way of doing it. But it only takes about a minute. 

brucebartlett

@casy_jensen normally when creating a keyway slot you would extrude through from the end face with end on profile of the keyway. Make sure you have the Remove checked in the extrude dialogue to remove material rather than adding. For future reference you can only sketch planes or flat surfaces, this is the same for all MCAD programs.

Not sure if this what you are after, you could share a picture or even the URL of the public Onshape file (copy it out of your browser and paste here) to give us more detail. 

NeilCooke

Hi Casey - it depends on what the slot looks like (axial/radial). Have you tried revolving a profile around the axis of your cylinder? Revolving a rectangle around the axis is another way to make a snap ring groove.

casey_jensen

That makes sense for the snap rings. But yes, the slot would be lengthwise. How do i draw on the cylinder wall itself? Seems like the program doesn't see it as a plane that I can draw on. Extremely new to any type of computer drafting also

NeilCooke

If your cylinder axis goes through the origin then there are 2 orthogonal planes you can draw on and extrude a cut from there. The depth of the cut will be measured from that plane though. A sketch can only be drawn on a flat plane. 

daniel_chow

Hello Casey, I assume its a keyway in a shaft that you're after... here is what I would do:

Step 1: start a new sketch on the end of the shaft where you want the keyway. Click the "use" tool to use the end of the shaft as part of your new sketch.


Step 2: on that new sketch, draw a circle of the same diameter and concentric to the shaft.
 

Step 3: Sketch the keyway, add dimensions (which is what I didn't do)


Step 4: Extrude the keyway using the new sketch as a new part, reverse the direction so the new part interferes with the shaft.


Step 5: Use the boolean tool to subtract or remove the new part from the shaft and you're done. 


I should mention that I'm a beginner and this may not be the move time effective way of doing it. But it only takes about a minute. 

daniel_chow

Here is another way of doing this. As Neil mentioned, you cannot sketch on a curved surface. BUT you can start a new sketch on an OFFSET PANE that touches the curved surface. Here's how: 

Step 1: Find the diameter of your shaft, D/2 = radius which will be the distance of the offset pane.


Step 2: Create a new pane offset to the radius of the shaft. 


Step 3: Create a new sketch based on that new offset pane. You can now sketch on the "surface" of the curved shaft


Step 4: Sketch the length and width of your keyway


Step 5: Extrude the depth of your keyway as a new part, change its direction, you now have an interference which we will fix with the boolean tool. 


Step 6: Use the boolean tool to remove the new part from the shaft and correct the interference problem


I should mention that you will of course want to dimension and constrain your keyway, I didn't do that because I'm just showing how to do it. 

brucebartlett

@casy_jensen normally when creating a keyway slot you would extrude through from the end face with end on profile of the keyway. Make sure you have the Remove checked in the extrude dialogue to remove material rather than adding. For future reference you can only sketch planes or flat surfaces, this is the same for all MCAD programs.

Not sure if this what you are after, you could share a picture or even the URL of the public Onshape file (copy it out of your browser and paste here) to give us more detail. 

casey_jensen

Thanks everyone for the answers, I'm sure il be back with more questions. Really appreciate everyone taking the time to answer