I tried to model this 2D drawing
Here’s what I got
kisat_prat.3dm (488.5 KB)
Can you tell me what mistakes I did ? What should I do?
Here’s what I got
kisat_prat.3dm (488.5 KB)
Can you tell me what mistakes I did ? What should I do?
I’m not sure why you say that you made a mistake. It’s not done and perhaps a bit messy at the internal surfaces but it looks to be going in the right direction.
If you explode all you have and join what you need, you can proceed from there.
That is basically one straight line that you revolve. The curvy part that you see is just the result of cutting the horizontal bore with the vertical one.
This part of is bottom or side? If it’s side why it doesn’t seem in right of 2-nd drawing? If it’s bottom why it doesn’t appeqar in 3-rd drawing?
Because that view is a top view, and the feature is obscured.
I did it this way… An outer solid body with the inner part subtracted (machined out) from it. That’s how the thing is actually made.
- Cut up the image into 3 pieces and set up picture frames for top, front and side views, scale appropriately
- Use the images as a guide, but enter real numbers at the keyboard.
- Set the center at 0,0,0 !
- Model the outer main body parts - an extruded chamfered square for the upper part, cylinder for the lower.
- Model the side tubes and flanges - cylinders and a box. Punch the 4 bolt holes in the box (can do this later as well)
- BooleanUnion all the outer body parts, turn layer off.
- In Front view, draw the two profiles - the horizontal and vertical bores. (the angle for the taper is 1:7 included)
- Revolve the profiles around their axes and cap to make solids.
- BooleanUnion the two revolved parts.
- BooleanDifference the result of the above (core) from the main body.
- Add fillets and chamfers with FilletEdge, ChamferEdge.
- Done.
- I did NOT model the specified threads…
–Mitch
Valve.3dm (1.6 MB)
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How do you find UnionInner vertical diameters? What is mean 1:7 ?
It’s a taper specification of 1 part in 7 - but that includes both sides (visually according to the drawing), so it’s actually 1 in 14 from the centerline. I drew a line 14 units vertical and 1 unit horizontal and that gave me the angle - 4.09°
The diameter at the top of the taper is given at 56mm. The length and the angle of the taper itself determines the bottom diameter. As far as the uppermost bore, as it’s an M76 thread, didn’t look up what the root diameter was when I drew it, so I just estimated that one from the drawing… But it looks like it should be 73mm diameter bore for an M76 x3 thread.
–Mitch
Doesn’t matter what grid properties are? I changed Minor grid lines every to 5.0mm and Major grid lines every to 10, snap spacing 1.0. For 1 horizontal unit I must change snap spacing to 5.0 mm, right?
As long as your Document Properties > Grid > Grid snap > Snap spacing is set to 1.0 mm as you say you have set it to, you will be able to snap to (x,y) = (1,14). If you change the snap spacing to 5.0 mm you will not be able to grid-snap to (1,14).
You can draw the (0,0) > (1,14) line by entering the following on the command line:
line
0
1,14
That is, you don’t need to use the grid at all. Personally, I never ever use it.
I’ve modeled the taper.mitch.3dm (221.4 KB)
How can I model the uppermost bore (I don’t understand how you done it with that thread)?
Same procedure as the rest:
Revolve the green curve around the center and cap. (the 36.5 mm dimension is from Mitch’s 73 mm diameter for the M76).
About the threads, what is the purpose of this model? Typically, threads are not modelled but indicated on the drawing. Note that you also have threads at the right-hand outlet.
Yep. me neither. The grid is a recipe for disaster, you never know what you’re actually snapping to. Very few things in this world can be broken down into nice, even units. It might be helpful at some point if your task is to lay out some parts based on a specific grid, but other than that, it has little real-world usefulness and can easily induce mistakes. Better to get in the habit of specifying your own dimensions at the command line with keyboard input than relying on grid snapping.
–Mitch
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Ok. I’ve finally done it.
lriv.3dm (489.6 KB)
However, I wonder how model that taper with Taper comand (Transform>Taper)?
You could, starting with a 56mm diameter cylinder… but that’s doing it the hard way IMO… You would still need to draw the line that represents the taper first, as you need to derive the bottom diameter from the top diameter and the taper angle. So it’s still easier to revolve. Alternatively, if you knew the angle then you could also use Extrude>Tapered; if you knew the bottom diameter you could make either a truncated cone or loft between two circles… Many ways to do the same thing in Rhino.
–Mitch
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I guess the one difficulty was the reading a 2d drawing. Not all symbols I know.
Yes. The little “V” symbols indicate surface finish (roughness) - not needed for the Rhino model, only for the fabrication of the part. The Ø symbol means “diameter”. Anything with an M__x__ designation is a metric thread (diameter x pitch). There are a couple of places where it’s noted in Russian something like “4 places” (holes, chamfers)… I can’t read Russian, but I can infer that’s what it says from the context.
Here’s a page with some of the common GD&T symbols…
–Mitch
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Thanks, Mitch!!! You’re a smart and kind guy!
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