Questions and concerns for the AUTOCAD 2020 book assignment "10-5 Scooter Assembly". - PLEASE HELP - cannot draw right?

[antonio_traverso885]

I am currently studying at NYIAD to get my CAD certification, and so I reached out to my school with the following concerns for the AUTOCAD 2020 book assignment "10-5 Scooter Assembly". The lady that I was on the phone with was no help and did not have much knowledge of technical issues with mechanical engineering, unc standards, or complex shapes. And they only give me 15 minutes over the phone of help from their "success center".

Can someone lookover my three main concerns listed below and get back to me ASAP?

I have attached my drawings and screenshots of my book references, PLEASE HELP.

1. My first issue I am running into is on the scooter assembly assignment 10-5 --> part number 5-kickstand! (Pg. 483)

I am so confused on how to properly draw this part, as I redrew it more than ten times and have had no luck on matching the original assignment drawing from the book.

Can someone create this part so I can see what I am doing wrong? I left 11 different iterations of the drawing to see if I was misinterpreting where the extension lines are defining the dimensions, but any way I do it just did not match the book's drawing. (Just follow my notes on the drawing to look over the different solutions I tried starting from the bottom). I am going crazy trying to get it right and understand why I cannot draw this properly. PLEASE HELP. 

2. My second issue I am running into is on the scooter assembly assignement 10-5 --> on the left side of Part 2-handle bar, where the two radii meet and the thickness changes from 1" thick to 0.12" thick. I couldn't understand how mathematically the two radii of 0.75" and 0.25" would connect and still leave 0.12" of thickness (vertically), so I placed a 0.75" radius circle via the bottom quadrant to the bottom of the 1" thick bar at the given horizontal position. I then kept the 0.12" thickness on the top left end and placed a 0.25" radius circle via the top quadrant at the specified horizontal position. This made the circles close but not touching. So I then drew a line tangent to both circles, trimmed off the excess, and voila. I assume this was how it was supposed to be done, because any other way I tried was not working out well. Although I finished that part, I still have confusion on the two dimensions given in the assignment drawing to the right of those radii -- 0.12" vertical dimension, and 0.25" vertical dimension. I am not sure what these are for, it seems like these may have been there to somehow help me place these radii properly, but as you can see on my drawing these two dimensions are missing because I did not know what they were or were used for. Also incorporating the fact that you can barely tell where the extension lines are to define what the dimension is really for. -- so this was an issue I somewhat solved but missed some things and am curious if I even interpreted/drew my drawing the correct way. PLEASE HELP CLARIFY / CORRECT MY DRAWING.

3. I want to know if I am properly drawing the hex head bolts and nuts as required for the end of chapter 10 assignments. My concerns are the details in the threading and the shape/arcs in the head. 

I watched a bunch of youtube videos on how to read these callouts, but this one was a little tricky. I drew this hex head bolt from assignment 10-4 DOUBLE BEARING ASSEMBLY. I am not sure if I am properly drawing these. Given the dimensions and specified callouts, did I translate the drawing properly? What information is assumed based on the callout for a hex head bolt of - 1/2-13 x 2 1/4 UNC-2A?

--  I did similar drawings for hex bolts/nuts in drawing assignment 10-5, and am still unsure if I drew these right either. Could someone check and let me know if these are 100% right or if I missed some details? PLEASE CHECK/CLARIFY/HELP ME!

BOOK REFERENCES:

Screenshots of page 482-483 of Discovering AutoCAD 2020 by Paul Riley -- Assignment 10-5: SCOOTER ASSEMBLY

Screenshots of page 481 of Discovering AutoCAD 2020 by Paul Riley -- Assignment 10-4: DOUBLE BEARING ASSEMBLY

MY DWG FILES FOR THESE ASSIGNMENTS:

DRAWING 10-5 SCOOTER ASSEMBLY.DWG

DRAWING 10-4 DOUBLE BEARING ASSEMBLY.DWG

Thanks,

Antonio T.

[Washingtonn]

I only started to look at this and realized that the dimensions given are very misleading and incomplete.

The R0.25 apparently references the outside surface, The 6.38 references the inside surface both of which are difficult to see on the information given.  That will clear up much of the problem indicated for the kick stand.  The hole location was not given but I guess you could make an assumption - but note that it isn't clearly defined.

[Washingtonn]

Once again, poor graphics. but R0.25 and R0.12 along with the 1.00 dimension set the center points of the arcs.

The center point of the R0.25 arc should not be based on the 0.25 dimension but should be taken from the same edge as the 0.25 dimension.

[Washingtonn]

If you will be doing a lot of mechanical drawing, a good personal resource would be a copy of Machinery's Handbook.  The book will have a lot of different fasteners with dimensions, thread profiles, etc... there are used ones you can pick up off the internet.  

[antonio_traverso885]

there has to be some mathematical error here. Or I am just blind. the first one above shows the left vertical dimension correct, and the right dimension incorrect, and the second shows the right correct and reflecting the distance on the left being incorrect now. What is this madness? 

[Washingtonn]

Before you start drawing set you precision to the correct number of decimal places  per the original diagram. This step is critical as the 6.38 dimension could actually differ from the 6.380 you show (due to possible rounding) - same for all of the other dimensions including the 12 degree angle.

Concentrate on only the top half of the object, if that works, you can mirror to complete it.

Send me a message if you need further assistance.

[Washingtonn]

Last thing to draw is the angled lines - draw a line from the flat and osnap to the tangent point on the radius - you will find the angle is more like 12.19 degrees but with rounding it will report 12 degrees.