I’m back to my normal weird self, somewhat. I’m revisiting an idea I had awhile back. Now forbb no the request. Anyone and everyone who has a mp650 I need pics of how it works. Detailed with measures would be even better. My idea is to convert either a mp400 or mp600 into one that works like the mp650. I’m sure this has never been done but I have to try or it will drive me crazy. Well crazier anyway 
So if you have one and can please do. Metric or standard measures will work as I can work with both. Thanks MTO

Challenge accepted. Give me a little time.

That is quite the ambitious project !

If you can, it is better to copy the "military" version (the one with the spring loaded handles) the retaining clips for the removable heads on this version are a lot more robust than the clips on the "civilian" version (these are often broken because people don't know how to release the heads, so they try to use force, thus breaking the clips).

Well not sure exactly what you wanted for dimensions...so I took a few photos that hopefully will help you. I agree with gregozedobe...that is rather ambitious.

From left to right: Civilian MP650, Military MP650, MP600, MP400.
20210626_223150A by Chako, on Flickr

20210626_223236A by Chako, on Flickr
 
From left to right: MP650, MP600, MP400.
20210626_223346A by Chako, on Flickr

Closer look at the MP650 mechanism.
20210626_223418A by Chako, on Flickr

20210626_223424A by Chako, on Flickr

20210626_223444A by Chako, on Flickr

20210626_223451A by Chako, on Flickr

20210626_223505A by Chako, on Flickr

20210626_223520A by Chako, on Flickr

20210626_223559A by Chako, on Flickr

20210626_223805A by Chako, on Flickr

Close up of an MP600 mechanism.
20210626_223952A by Chako, on Flickr

20210626_224000A by Chako, on Flickr

20210626_224103A by Chako, on Flickr

 

Ambitious huh  but I do like a challenge. I have about 10 gerbers laying around in pieces. Might as well figure out how to make them work

Thanks Chako I was hoping it would be you! 

If there is anything you want me to focus on more closely in regards, to this...just ask. 

My thoughts are this. I have plenty of extra gerbers probably to many. I will grind down the tabs with the ramps like in the 650. Then make a spring piece and rivet it in place. Getting everything to work correctly is the hard part.

 

Chako. If you can please. A close up of the locking mechanism. Maybe push on the tab so I can see how it works. Or a short video would be great as well.

You got it.

The mechanism works this way:
- Press on the two locking mechanism levers, removes an inner metal tab that locks the plier head down. This allows you to remove the head and exchange with another one.
- On the inside of each handle, is also a guide that guides the plier head into the right position and stops it at the right location. This looks like two upsweep fingers in the civilian model, and a more beefed up rectangle in the military version.
- Sliding the plier head into the handles, engages the two inner guide pieces, and when fully seated, will push the inner locking tab into a recess on the plier head. This metal tab locks the plier head into each handle. Pressing down on the outer tabs unlocks the plier head from the handle as this will push up the inner locking tab, thereby releasing the plier head for removable.

1. Photo 1 shows the inner locking tab (Arrow). This is directly attached to the outside lever. Pressing down on the lever pushed this tab away from the plier head. The tab fits into a section of the removable plier head.
20210627_202151A by Chako, on Flickr

2. Looking on the outside of the handle, the arrow shows the locking tab and the lever are 1 piece. Press down on the lever, rocks the tab on a pivot, pushing the tab outwards, releasing the plier head. Release the lever and the locking tab goes back to its resting position due to the spring steel tension, locking the plier head in.
20210627_202218A by Chako, on Flickr

3. Here I am pressing down on the locking lever, and you can see how it pulls the inner locking tab upwards to unlock the plier head from the tool.
20210627_202241A by Chako, on Flickr

4. Top arrow points to the inner guides. Bottom arrow points to the inner locking tab. The tab goes in or remains at rest (locking position seen here) depending on if you press the outer lever or just leave it alone.
20210627_202304A by Chako, on Flickr

5. Here is a side profile of the lever/locking tab piece. Note it has a built in pivot much like a teeter totter in a park.
20210627_202318A by Chako, on Flickr

6. Now for a closer look at the plier heads. The bottom of the removable plier heads have an inner part that fits into the inner guiding rails of the handles. The locking mechanism interacts with the outer part of the bottom section. The circle section/cut out is only there for the use of a button for the Gerber sliding mechanism. If the MP650 used regular plier heads, than the inclusion of this section is expected. However, if they are specially modified for use with the MP650, then the outside ramps that interact with the inside locking tab might not be present in other plier heads. I have never taken apart a regular MP600 plier head to see if those ramps are in place. If not, this system will not work.
20210627_202333A by Chako, on Flickr

7. The locking tab mates with the plier head where the arrow is pointing at. Note that this outer section is ramped as to push the locking tab gently open when you press down on the plier head to seat it into the handle. As you press, the locking tab is pushed away until it reaches the end of the ramp, where it will spring into that end section (the channel), locking the plier head into the handle.
20210627_202343A by Chako, on Flickr

20210627_202351A by Chako, on Flickr

On the left is the military version, on the right is the civilian version. Note that the military version is not only beefier, but there is an inner metal section that also extends to act as an inner spring. These sections meet together, acting as a spring to keep the plier heads a little open.
20210627_202526A by Chako, on Flickr

20210627_202542A by Chako, on Flickr

 

I'll add that as far as I can tell all MP650 heads are just regular MP600 heads that have been modified.  The front pin (for the oblong C clip that retains the plier heads ) is ground off completely, while the rear pin is ground down to form a sloped ramp (as shown in Chako's very clear photos).

Excellent, I have never seen a disassembled MP600 plier head to compare them to those that come with the MP650. 

Upon closer inspection of photo set 7, I can now see where they ground off the front pin, and partially ground off the back pin to make a ramp.

My thoughts are this. I have plenty of extra gerbers probably to many. I will grind down the tabs with the ramps like in the 650. Then make a spring piece and rivet it in place. Getting everything to work correctly is the hard part.

That's one major mod of you can accomplish this  I dun have the slightest idea how that can be done. 

Perfect Chako!! That’s exactly what I needed.  Now the fun begins. It will probably take me some time as I work full time now but we all have our problems 

Best of luck and if successful, be sure to tell us about it.