2d drafting mark meaning

[lululol]

I am reading 2d drafting to draw 3d model with Inventor. But I couldn't well understand meaning of this mark. 

There are some dimension (red circle) which make me confused.

 

 

I am drawing the blue part, and here what I draw so far.

 

 

 

I am still confusing the size of the thickness of the part and the hole on the surface.

 

Could you give me some idea?

 

Thank you. 

[SLW210]

Looks to be the sizes of the rectangular and square tubing.

 

The cutout is for the 100 x 100 x 8 Square Tubing 1.286 long and should be all the way through the 2 plates since it shows continuous lines. The 8 is the wall thickness of the tubing, just like the 20 is the plate thickness.

[lululol]

15 minutes ago, SLW210 said:

Looks to be the sizes of the rectangular and square tubing.

 

The cutout is for the 100 x 100 x 8 Square Tubing 1.286 long and should be all the way through the 2 plates since it shows continuous lines. The 8 is the wall thickness of the tubing, just like the 20 is the plate thickness.

 

then the Tubing is continuously enlarging from the size 100 x 80 to 100 x 100?

 

[SLW210]

Would seem to be 2 different tubes you are referring to.

 

Is that the only view you have?

 

Are you knowledgeable in steel shapes and dimensions?

[lululol]

23 hours ago, SLW210 said:

Would seem to be 2 different tubes you are referring to.

 

Is that the only view you have?

 

Are you knowledgeable in steel shapes and dimensions?

 

Now I am understand this draft! 

Two different Tubing is connecting with another Tubing!

Thank you so much. It was really helpful! 

 

[SLW210]

Come back if/when you have more questions.

 

If you can post different views, someone could give even more explanation.