Question about sketches and constraints

[rob]

I'm still struggling on with my slot together kangaroo mechanism. I'm determined to get it working! 

I have traced out the shape of the body side onto a sketch. There are two axle holes which I assume need to be constrained into position. (yes?) 

I've added dimensions between the two holes but cant work out how I can fix them in position. 

I'm guess I need to add a horizontal and vertical construction line that touch the body then add dimensions from those. Is that the best way of doing it and if so how do I make these construction lines so they touch the body?

Sneaky second question. I need to create a plane that runs at 45 degrees through the circular hole below. I'm guessing I need to make a construction line across the circle ? If so, how do I do that!? Or if not, how do I best make the plane? 

Thanks in advance! I really do appreciate the help I have been receiving on this forum as I have been struggling up the nursery slopes of F360. Thanks everyone! 

I've attached the roo file below.

[TheCADWhisperer · Accepted solution]

Why not use the Origin as a logical datum?

Do you really want these angled lines to the quadrants - or do you really want to the Tangents?

[etfrench · Accepted solution]

You need to add at least one dimension relative to the Origin in order to fully constrain a sketch.  Splines are not easy to constrain, so I usually use the Fix/Unfix command on them.  See attached file for one way of constraining that sketch.

[TheCADWhisperer · Accepted solution]

Add some spacers as needed.

[davebYYPCU]

Constrain as you go, your circle/s should be black for expected result, draw a construction line at 45 degrees

then make it coincident to the centre of the circle.

then use Construct > Plane on angle.

Might help....

[jhackney1972]

No one answered your "sneaky second question".  I used @etfrench supplied fully constrained sketch to create the 45 degree work plane through the center of the hole in my Screencast.  I have the Plane at Angle command on my toolbar but if needed you can find it in the drop down Construct menu.

[rob]

Good point! thanks!

[rob]

Thanks! I'll give that a try

[rob]

That's brilliant! Thanks! 

One question, as i drive the wheel anti clockwise the geometry of the roo get more and more tangled. Any idea what is going on there? Thanks again!

[rob]

Brilliant! Thanks very much!

[TheCADWhisperer · Accepted solution]

@rob 

Check this one.

[rob]

Thanks! Looks like the problem was my initial design, the four bar linkage in the lower leg is unnecessary. Gonna try it again with a single full leg piece. Thanks again!

[TheCADWhisperer · Accepted solution]

I kind of like the aesthetics of the two legs slightly offset.

[rob]

Agreed! Though, as a learning project I might be better off trying to keep things relatively simple!

I really feel that spending a day with someone fluent in F360 would be really useful - failing that, these forums have been an awesome help! Thanks! Just about to post my next question as I'm stuck again!

[TheCADWhisperer]

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@rob wrote:

I really feel that spending a day with someone fluent in F360 would be really useful ...

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Don't take my example as the way it should be done - I was just trying to throw something together without spending a lot of time.

I would probably do this differently from the start.