We have just completed the first operation 6 on the trunnion. It has also pointed out a few minor differences. When we started this project all we had was an original trunnion in very bad condition and a collection of out of spec drawings with incorrect dimensions.
Later a trunnion in very good condition showed up from a friend to help move this project along.
So as we have gone through each step of the process of reverse engineering a MP-44 trunnion and making a series of them we correct our solid model and it’s dimensions have rewritten and the machining program changed as well. This is the trunnion as completed on the first sample of op.6. There is a great deal that is correct with this sample, however there are more changes to be made.
The top radius for the gas tube needs to be looked at.
All the machined dimensions are correct.
The angle and radius for the magazine to fit in is spot on
Just check out the finish. These will be perfect when they go out.
The finish on the upper radius is perfect.
So now on to the changes that have to be made. The first is that we have to machine down the side a little more.
A greater radius needs to be added.
We took of a little to much.
We mark each trunnion this allows us to keep track of each change as we make it from trunnion to trunnion. This is the first trunnion that we made.
This is the second trunnion. The magic marker notes the size of the chamfer.
One more sample to finish to correct the last of the small items.
When you talk of the incorrect drawings floating around on the internet are you talking of the supposed original German prints floating around? I took them and built the complete MP44 in Solidworks and every thing seemed to match up. Now there is another set out there that was done by a guy supposedly from the German set but I have found numerous errors in his prints and you can see many mate up problems.
Given that you are making trunnions, might we assume that someone is trying to introduce a domestic made version of the MP44? The stamping of the receiver components looks like it will be a real bear.
Hello Mongo.
I have looked at a number of drawings of the MP-44 and they all have problems. They look correct when compared to the rest of the drawings but when compared to original parts they will not match up.
I can’t say about a domestic MP-44. Currently I am only contracted to make correct trunnions. However, Ian at forgotten weapons just interviewed someone that is going to make a look a like, sort of, of the MP-44. There was some talk of reverse engineering a few other components as well. We will see.
If you have a correct set of drawings I would love to have a copy as it would make my life easier.
i too am interested in them
What grade steel, and heat treatment is used on these ?
The original trunnions are very soft steel, they can be cut with a file. The first 6,which are the test pieces,are made out of 1018, the actual run of trunnions will be made of hardened 4140.
I added my Solidworks file of the trunnion to the drop box folder for you. I think I did that one in SW2011 and I do nto think I have saved it since I upgraded to 2015 version.
Mongo, Thank you very much
Looking better and better Chuck!
Pete
Wait until you see them in person.