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Continuing the MP-44 trunnion

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.

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DSC_6044csDSC_6045csDSC_6046cs

Later a trunnion in very good condition showed up from a friend to help move this project along.

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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.

DSC_6056csAll the machined dimensions are correct.

DSC_6061csThe angle and radius for the magazine to fit in is spot on

DSC_6064csJust check out the finish. These will be perfect when they go out.

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DSC_6071wsThe finish on the upper radius is perfect.

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DSC_6074csSo now on to the changes that have to be made. The first is that we have to machine down the side a little more.

DSC_6076wsA greater radius needs to be added.

DSC_6078wsWe took of a little to much.

DSC_6079wsWe 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.

DSC_6081cwsThis is the second trunnion. The magic marker notes the size of the chamfer.

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DSC_6088cwsOne more sample to finish to correct the last of the small items.

10 comments to Continuing the MP-44 trunnion

  • 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.

    • Chuck

      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.

    • Chuck

      If you have a correct set of drawings I would love to have a copy as it would make my life easier.

  • Rufus Chucklebutty

    What grade steel, and heat treatment is used on these ?

    • Chuck

      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.

  • Pete F.

    Looking better and better Chuck!
    Pete

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