3D solid modeling a PPSH-41... assistance?

What are you doing? I wonder since you need a milling machine also..

Well Jason41987, I can tell you from experience from my work with a major firearm manufacture; not much has changed at least with the company that I have experience with.

Blue prints are a thing of the past but Cad prints are still being used.
With 3D modeling the Manufacturer I worked for refuses to embrace technological changes.

Build it and hope it works by testing it is the motto.
Actually I was told by my Director "It doesn't matter as long as we have the testing data". ??????
Sad thing is that the testing is limited to 5-10 hand built firearms prior to production, then we wonder why there are recalls.
When issues pop up on the 5-10 test mules the standard response is to write it off as I know what caused it and change the design without much further testing.
Then production builds the rifles and finds all kinds of problems and the engineering response is "If was built to engineering specs it would work!"

It's only a matter of time before the designing is sent over-sea's for a lower price and a better product. But we will still manufacture the product in the US due to our firearm laws protecting the industry.

There are Americans capable of doing the job correctly, but are held back by leaders with limited perspectives. Technology is not embraced by the not so intelligent that refuse to try to understand it.

And to answer your question about missing dimensions,

In working with the older prints you'll find dimensions on just parts and some on the assemblies. To complicate it you'll also find dimensions on the casting prints and forging prints.

So you may not have all the prints you need to get a true 3D model.

Sorry for my earlier rant; just frustrated with the current direction of business management in the U.S.

Jason,
This is a cool project, mainly because you'll learn exactly how all the parts interact as the action cycles. I find these mechanisms fascinating since guns are really the last remaining purely mechanical devices in our modern, servo-controlled world.

Tolerances are extremely important for such complicated machines, and the fact the parts, as dimensioned, don't fit well may be due to their need to be fitted/adjusted at installation. As mentioned, cast/forged parts may be dimensioned strangely due to their need for followup machining and refinement.

Don't take the plans for granted; I make engineering drawings for a living, and they are far from perfect. People made those prints by hand, and they are therefore even more fallible than today's computer aided designs (especially if you are looking at bad photocopies). If you don't have every last revision and addendum to those drawings, you won't have the correct configuration. You should at least be able to develop a very close proximity to what was actually made. Depending on how thoroughly you perfect the model you are making, you could probably replicate something better than a "built to specs" PPSH (I'm not familiar with their quality, but I have seen how carefully other Soviet guns were fitted ). You will have to approach the drawings with the intent of "reverse engineering" them, as opposed to simply duplicating them.

As far as legality goes, if it is legal to possess the paper drawings of these parts, then logically, a CAD model would be treated equally (someone please correct me if I'm wrong). Just don't go trying to fabricate an auto-sear or sell something made from these plans, and you should be fine.

Good Luck!

TCB

You used to be able to find free original prints (pdf's) of a Gatling gun on line. I modeled one in Solidworks about 15 years ago, machined the bolts and breech block then lost interest. Pretty neat to model all the parts (gun, carriage, etc).

Still have everything on an old hard drive somewhere, I'll post a pic if I run across it.