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vz61 reweld semi auto

21K views 27 replies 6 participants last post by  trickyrick 
#1 ·
started this build tonight.



it is a czech .32 cal automatic pistol. of course mine w/ be a semi auto version.first thing i did was to go to here and read up on history and get a schematic of a semi auto version.

czechpoint usa

i also downloaded a manual for a semi auto from somewhere, can't remember where, but i have one if anyone needs it. here is a manual to a fully auto version. it really helped me figured out what was not needed from f.a. to s.a.

full auto vz61 manual.

now when you get your parts kit, don't get overwhelmed by all the little bitty parts. the manual is very helpful in figuring out what is what and where it goes.

i got a plastic box w/ separaters that went from top to bottom, so when i knock it over, everything stays put. i listed the parts by name and # from manual. this really brings it all into perspective.



on to the fun, here is cut receiver.



here is what i hope it looks like when i'm done. i printed this out to scale so i can use it to help lay out overall length.



first thing i did was to grind off rivet, from the inside, holding trigger guard to receiver. next i took the first 2 pieces that incorporate the mag well into it and put them together w/ mag installed. this gave me an idea of how far apart they needed to be once mag was removed. before removal i measured gap at 2 points on one side w/ a mic. then i clamped the larger part to a piece of brass on the inside of receiver. made my measurements w/ smaller piece in place and clamped it to brass. i use the brass as a backing plate to keep inside of mag well from getting excessive weld material in it, and also to keep from blowing holes in receiver while welding. i also used a piece to span cut at receivers thicker end (bottom). i also used a longer piece as a straight edge to align the top of receiver pieces before welding. when done, i tried mag,(it fit), and flipped it over, repeating process on other side.




 
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#2 ·
i forgot to mention about cleaning up the slag from the torch. this kit was a trade and that had already been done on the first 2 pieces i welded up. here are some pics after the welding. you can see how clean the mag well stayed.





that one wasn't to pretty. i had heat way low because of the fear of burning through. i adjusted heat and next one came out better.





some more pics after a little clean up.







 
#3 ·
before i go any further, i must satisfy batf regs. below is the controller, (manual name), others call it f.a. sear. this fits into a slot in receiver.



i have to cut up and discard it. as well as remove the lug on side of hammer that ties into it's operation. and lastly, fill in the slot in receiver that controller rides in. below are the parts, unmodified. 2nd pic is of controller cut up and stub on hammer removed. 3rd pic is slot in receiver filled w/ cut controller piece and welded shut.







***** NOW, I AM NOT A LAWYER, NOR DO I PLAY ONE ON T.V., ALTHOUGH I DREAMNT I WAS BOB SHAPIRO ONCE...THESE ARE MY INTERPRETATIONS OF A MANUFACTURED SEMI AUTO BASED ON INFO I HAVE READ. YOU ARE RESPONSIBLE FOR FINDING OUT IF THIS IS A LEGAL, BATF APPROVED BUILD AND LEGAL IN YOUR LOCALITY.*****

other than that, i will weld a plate into slot on rear of receiver to deny folding stock.
that being said, if anyone sees an issue or notes that i left any steps out, please feel free to let me know. rick.
 
#7 ·
I did the spacing on the rear sections after fitting the mag. Inserting the pieces into the upper and using modeling clay to help retain the spacing helped.

The machining on the inside where the trigger assembly pin rides is tricky.
 
#8 ·
thanks for the tip, winn. so far, i've been lucky to have parts line up for setting dimensions.
got the third piece added to receiver. below are pics showing parts cleaned up and ready to clamp for welding. the fourth pic shows using the fixing plate, (holds in the trigger pin), to align the 2 sections.









i welded w/ backing and clamping as in the previous post. when welding thin metal, i use a pulse action on the trigger of the mig gun, letting molten metal cool and harden just a split second before adding more wire. metal goes from bright orange to dull, but never to black. this allows wire to start weld immediately instead of trying to get started through the outer flux coating that is left when weld cools to much. i really need to hook up my argon tank but it is a pain when i have welder on a job, up in trusses. then i cleaned it up. i tried to give it the same definition as original while still leaving some excess metal over weld areas.







the inside still needs to be cleaned up but i'll do that as necessary when fitting internals.



put together to set up last welds.





thanks to my wife for fixing the date on camera. :notworthy:
 
#11 ·
got the rest of receiver put together. it went together pretty easy. there was a large gap on one side so i had to add a filler piece. first thing i did was to cut a piece of metal to fit in the dove tail for folding stock. i put it in and welded it in on both sides.



be careful if you do it this way. i should have cut it a little short so it lined up w/ the 2 thick ribs on the inside, rear of receiver. putting the welds on the outside corners where the metal is extremely thin almost caused a burn through into channel that the sheet metal upper sits in. would have been a pain to clean it up.



i did not weld the top of the hole for the safety lever/selector yet as i didn't have a brass rod to use as a backing plate.









i have to clean up selector hole and decide if i need to put in holes for hammer stop pin. i've seen builds both ways. anyone know what would be wrong w/ leaving it out? then i can insert internals and see what else i need to clean up inside receiver.
 
#13 ·
thanks sid, i didn't think i did. makes it easier as it would have to be drilled through the weld. how much recoil is there on one of these? would the rate reducer / buffer be advantageous to keep the weld from cracking? after welding it together last night i threw it in the oven for an hour at 400 to relieve stress.
 
#14 ·
"Rick, I'm always in awe at how fast you progress at these builds. Looking Good! zeb."
zeb, that's cuz i'm ocd when i start one. lol:p most of the time was spent cleaning up the welds. this is definitely a quick one.
i baked receiver in oven at 400 for an hour when i was done welding it last night to relieve stress on welds. i don't have much to say about the upper. i got a barrel in trade that the owner was not happy w/. i figured i could fix whatever wasn't right about the slot he put in it for retaining pin. when i got it, i installed it to see how far off it was and... it wasn't. :p i inserted pin into hole and tapped it into place and it fit perfect w/ no slop or play, (previous owner's complaint), and it lined up perfectly w/ the bolt face. some have had issues w/ diameter of barrel where it fits into trunnion. this has been addressed w/ a lathe or emery cloth, depending on severity of discrepancy. mine slid right in, fit well and pin slot was perfect. don't know if original owner turned it or not. dumb luck, heh?





typically the rate reducer/ buffer are not used on semi auto builds as they are deemed unnecessary. my question to those that have done one of these is this; i know the recoil is not going to be overwhelming, but would it affect the operation of pistol to have them installed? i figure any reduction in recoil is better on welds on frame. any thoughts? thanks, rick
 
#17 ·
today i assembled and installed the innards. first i checked the hole for safety lever. i did not weld the cut through the hole as i didn't want it to blow away. the remaining tabs are more than enough to hold the lever in place as there is no pressure on it ever. it just rotates and blocks sear lever.
#3 is the safety rod in place w/ cuts shown.
#2 is slot that the trigger pin sits in when installed.
#1 is an unfilled hole where one of the retaining springs for the fixing plate are supposed to go. i wasn't sure how that was going to pan out. i am going to put screws through the fixing plate in both locations as the other spring shot out of the hole and i can't find it anywhere. the missing spring was for the full auto sear any way, so it is not needed.



this next pic shows #1, the ramp that the trigger pin rides on as it is pushed down into lower, and the slot it sits in when fully installed below it. #2 shows a bridge that spans the lower from side to side. in this pic you can see the slag that i failed to clean off prior to welding it up. this bridge is what the rear arm of the main sear rides on. w/ this slag in the way, the main sear would not catch the hammer. so i had to put it in the drill/mill and clean it up.



#1 in pic below shows ramp and #2 shows slot for trigger pin and weld blocking it. i was able to clean this up w/ a cut off wheel on a dremmel. you can see to the right of slot, the head of the rivet that holds trigger guard in place. i drove rivet in from below and put a dab of weld on it.



below is the trigger group. #1 is the main sear, #2 is the end of that sear that rides on the bridge, #3 shows the safety sear to the left and the disconnector arm that disengages the safety sear.



below shows the trigger group installed w/ main sear working correctly.



the safety rod has two holes in it that allow it to fire in either semi or auto mode. the lever sits at 20 or at 1 and the middle is 0 (safety). on the replacement receivers there is just a 1 and a 0. i can either weld one of the holes shut in the rod or i can cut a slot in frame at the location shown in pic below where original 0 slot was cut. the safety can be changed either way the lever is pushed.



assembled for trial run.



 
#18 ·
I've left out the third pin.

The slag also was a problem for me at the inside rear of the lower. I've forgotten the end mill size but that was the trick to the rounded corners.

I also filled in the lightning cut on the front.
 
#20 ·
here are some pics of fired primers.



here are some unfired, light hit primers.



here are some shots of the rims that are damaged. all the arrows point to damaged areas.







here is the best pic to show what's happening.



the fired rounds w/o damage all fired the first pull of trigger. i didn't realize it at the time but when i would pull back bolt to reset hammer, the rounds never ejected. i think what is happening is the feed lip is pinching the rim between face of lip and chamber, not letting bolt completely close, hence the light strikes and no ejection on rearward movement of bolt by hand.
 
#21 ·
check headspace.

Close the bolt with a piece of paper trapped between the bolt face and chamber. It should not be pinched.

Check the barrel alignment.
 
#22 ·
I don't know anything about these pistols but like Winn said, something is keeping the bolt from closing on those rounds. I wish I could help more but can't :(

Thanks for the video.
 
#23 ·
well i disassembled it today to see if i could find whats up. w/ the bolt in the upper and turned upside down i would start a shell and let bolt hit home just to see if ejector would seat and grab the rim. all went well.





then i messed w/ the bolt in the upper right side up, holding it over my head so i could see what was happening. i let the bolt slide forward under it's own weight. and this is what i found.







below #1 is side that was hitting on feed ramp.
#2 is gap on right side of rail.
#3 is where rail was hitting feed ramp.
#4 is gap at top of feed ramp on right side.



the bottom of the bolt was catching on the top of the feed ramp on the left side. the top of the feed ramp sits at an angle do to the hole drilled by previous owner. i had noticed this but didn't pay it much concern as it was upside down when i was checking it and all was working well. i filed the top left of the feed ramp down a little and cleaned up the bottom of the bolt. you can see on the right side of the rail for the feed lip, on the feed ramp, there is a little indent where the feed lip was hitting the ramp. i filed down the rail pocket and the rail a little on that side and put a small bevel on it so it would be guided into slot in chamber. these small alterations were easier than welding (and possibly screwing it up more), the barrel and redrilling it. i cycled 4 clips through with no failure to feed or eject by hand. hopefully i'll get out tomorrow to further test.
 
#25 ·
first off, yesterday when i was doing the first trial, i stood in front of my wife's 09 toyota truck. 1st shell ejected up, over my head, and came down on her windshield, putting a nice little chip in it, so keep that in mind.:p went out today after modifications and all went well. i had 2 "situations" that i will address but after that all went well. i used privi and magtech 71 gr. round nose. put 100 round down range w/ no hiccups. tried win. white box 71 gr. semi round, (front is flat) and had feeding issues when fired rapidly. no problems when fired slow and deliberately. nothing that you wouldn't expect from a flat nose or hollow point. only tried the 10 round mag as of right now. here's what you have all been waiting for! (drum roll please).

trickyrick49 - 000 -0274.flv

trickyrick49 - 000_0275.flv

trickyrick49 - 100_3164.flv

trickyrick49 - 100_3167.flv
 
#26 ·
a lesson i learned today: what i am calling the safety lever is actually the controller/selector for a reason.



#1 i'll call the selector rod. lever is on the left in the pic.
#2 is the pawl on rear of trigger. when trigger is pulled, pawl goes into hole 3 of which there are 2 of them.the one in the pic is the hole for the full auto selection. the other hole is on the bottom of rod right above pawl. this hole in this selection is for single shot. if either of these holes do not line up w/ pawl the trigger cannot be pulled, hence the safety. in the pic #4 is the disconnector, which in this position, the lever on rear of disconnector goes into slot allowing the disconnector sear to catch hammer when it is reset. if the lever on selector rod is set to the forward position, hole (#3) lines up w/ pawl (#2) allowing trigger to be pulled and weapon to fire but slot above disconnector lever turns 90 degrees NOT ALLOWING DISCONNECTOR SEAR TO ENGAGE THE HAMMER AS IT IS RESET BY BOLT MOVING REARWARD.THUS PUTTING IT IN THE POSITION TO POSSIBLY GO FULL AUTO. two ways to address this are #1, welding hole (#3) shut, so pawl cannot enter hole and allow weapon to fire until selector lever is pushed fully to the rear or the way i chose, to cut off rear of disconnector lever, so slot position no longer plays a part in operation of weapon. i chose this way so that selector/safety lever can be moved either way of center to be off the safe position.

the pic below shows where i cut off lever on disconnector.



below shows selector lever towards rear. #1 is trigger sear. #2 is disconnector sear. this pic shows trigger at rest.



below shows lever to rear, trigger engaged. notice both sears move forward, (left).



below shows lever to the front, which i thought would be the same as rear WRONG! you can see the disconnector is held back by selector rod holding down lever. this pic is w/ trigger at rest.



below shows trigger engaged. w/ trigger held down there is nothing to catch hammer as it is rest.



below shows disconnector before lever was removed w/ pawl in the back round.

 
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