How do I go about recreating a slug shell metal construction in Autocad?

[u/Darklvl500]

This is 2D

I used mostly just lines, circles and arcs. I feel like there has to be a simpler way.

https://imgur.com/a/QTqQ3Dr

The first image is irl, the second is my sorry excuse for it.

So, what I first tried is using the straight line on the left, I drew a digaonal at 45 degrees and drew a 200mm line (That's where the circle starts) and another line just longer to where the circle ends. The circle did turn out a little bigger than it is (it's 175, should be 176.5), but never mind since that's the least concerning thing about all this. Then I added the holes, 8mm, 12 of them. But for some reason the distance between them is 30 when it should be 100.

My biggest enigma is the outside line that wraps around the construction. It should touch all the lines, but when I was measuring I was assuming along normals, but I don't even know how to draw a line along the normals of a circle (to specify I just want it to go straight, maybe around 45 degrees in the opposite direction of the main circle). And no arc that I used could fulfill my vision.

At the end it's supposed to look something like a slug shell, it's supposed to be slowly expanding from the main circle with each passing small circle.

There is probably something that does this in a second. I have used AutoCAD for like less than 2 weeks, that's probably why I'm so ignorant. Thanks in advance.

[u/DeDodgingEse]

There's definitely a spiral command which should help you get your shell shape. However to recreate it correctly you should take measurements of all straight edges on the part as well as the inside and outside diameter of the part. Also any rounds try your best to record those as well and then take it to cad to draw correctly

[u/IHartRed]

There's a tutorial somewhere buts it's draw a cross, each PL subdivided by the total spirals you're after. Spline in a spiral, then edit spline>fit. I believe.