Drawing a part

Hi folks, its been quite a while since I have been on here. I started playing with sketchup again the other day and realized I am lost again. I am trying to draw this part as practice, but i got lost of the radius. I have never really learned how to draw parts in sketchup and was thinking about learning a cad program. But I want to give this a go and see how far i can get.

Drawing squares and circles is easy, but when it comes to looking at a drawing like this I am lost. From point 1-2 I can draw, but between 2-3 where you have the 5deg radius, how do you do that? And also go in the other direction after the radius to continue with the drawing?

Can someone explain or show me how this is done?


I wouldn’t necesarily try to draw this from scratch. Instead, I’d import the drawing you showed as an image. Scale it, using the tape measure tool, to make the drawing actual size. Then use the Line and 2-point arc tools to trace over the shape. For a radius, draw a circle with the appropriate radius and move it into position over the drawing. When you’ve finished that, make the part a component and use the Push/Pull tool to give it the correct thickness.

Draw the shape with sharp corners first. Then use the two point arc tool. Click on one side, then the move the mouse to the other until you get the magenta arc to show that its tangential to both lines, then click two more times without moving the mouse. I drew the arc bigger to make it easier to find the tangent points.
Select the arc and change the radius in Entity Info to e.g. 5mm
With the 2-point arc tool, double click near the other corners you want to have the same radius.

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You can get most of it from scratch without too much trouble but there’s an important missing dimension. You might be able to infer it from the drawing if you import it as David suggests.

I located the holes forst and the radius at the short end. The other one end isn’t dimensioned, though so it would be a guess.

I guessed/scaled the centre point of the hole to be about 10 from the end. Theres another circle at the bottom not dimensioned either.

Yes. That detail doesn’t appear to be called out. My guess is there’s another view of the part somewhere that we aren’t being shown.

Its actually a pdf file and I used the snipping tool to capture the image.

When the author posted the pdf file, that was actually all that he had in there. He had the length and the width of the part but no numbers, this is the actual pdf file of the drawing. There are many more pages in the drawing thats missing the dimensions but I am more concerned with trying to learn how to make this part.

McGordon, can you show how you drew the entire shape from scratch, just don’t go too fast.? DaveR normally makes videos like that and I always save them for reference.


If @McGordon doesn’t do it, I will.

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Did you try scalling and tracing over the PDF?

While we’re waiting for McGordon as he gets his beauty rest, here’s ONE way to draw it without tracing it.


You made this thing look so easy. The part that got me stuck was after the radius, I wasn’t sure how much of an angle i had to go into. When you mentioned 120deg and I saw how you used the guide lines to draw the shape, I never would have figured that one out.

I was originally drawing a huge square and then trying to get my shape. Thanks again for the video, I already downloaded it for future reference.

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Sorry. I should remember that and make things look harder. :crazy_face:

As I wrote, this is just one way to do it. There are probably 99 other ways to deal with this feline.

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Dave did a good job while I was sleeping, so I don’t know if there’s any point in doing a video now, but I’ll do one anyway. No microphone as my son borrowed it and didn’t bring it back.

I don’t remember exactly how I drew it the first time. I think I had two rectangles and rotated one then extended the lines until they intersected. I think I draw it slightly different every time. Here’s another way with lots of guide lines.

This is on YouTube so you can slow it down, pause it, rewind, etc. Click the ‘watch on Youtube’ link to see it larger or full screen.

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I just downloaded it, thanks again for the video guys. These are keepers for future reference if I forget.