Mark, welder here. You know how engineers and welders get along right? 😁 you design it they way it SHOULD work and i tell you how it actually does. 😂 the reason the rail spread is the order that you welded it. The second to last weld on the opposite side was done before the last weld, yet it was further out than the last weld. This means that the grain structure was expanded but locked into a set point by the weld. The last weld tried to expand further, but you had already locked the rail with the second to last weld further out on the rail. Always weld from the center out to push the expansion towards the free ends so they can expands and contract freely, then weld out the ends after the rail has cooled sufficiently and all returned to it’s normal dimensions. Basically if you’d welded the last two in opposite order it wouldn’t have bent when it got hot and revealed the potential energy that was bound up in the last weld - which couldn’t expand due to the weld further out towards the end on the other side. ......was that explanation plain as mud? 😁
What he said, plus any time you heat cycle steal, it can have stresses in it, exactly like wood, you start off with square and true, remove some material, unbeknownst to you, the removed material was counteracting some other force, balancing it, and when you remove it then it's unbalanced and warps. Even without removing material, cheap steel is like chocolate chip cookie dough, and the different flavors of steel behave differently at different temps, so you heat cycle it, and it does just what the bi-metalic strip does in an old timey thermostat, and the steel that gets softer at lower temp gets bent towards the steel that has a higher softening temp.
When I was 16 I did a 2 year course on machining but never worked on the field. It's been 24 years since and I'm happy I found your channel because it reminds me of my time on the lathe and other tools, it is so much fun. Sorry about my English.
Hi Mark, one way to make these would be in your rotary table out of round stock. 2 operations. Leave stock for the center and some in the chuck. Machine it slightly off centered to the stock the rail closer to the center seeing how those pcs warped. Use "High Velocity Machining" side milling the 4 sides you'll have less vibration side milling then "end milling" it's very fast too. A key cutter will cut that slot faster then end milling if your not already. What's nice in the rotary is you can machine one side leaving stock then the others bouncing back and fourth removing the warp as you go. 2nd opp I'd mill the ends off in a 6" vise. Looks like you have a good process and it works well. Thanks great videos! Jason
Also sometimes helps to work with round bar stock, as opposed to square, or rectangular bar. Because the grain structure is more even, as opposed to compressed from being rolled into a particular shape, which is contributing factor when warp is a concern. If you're really worried about it. You can rough the parts so they're within .100" from finish size, and then do thermal cycle/stress relieve the parts to relax the induced stresses in the material. Submerge in boiling water for several minutes, and the dunk in liquid nitrogen(or poor mans method is rubbing alcohol and dry ice...) till it stops boiling, and back and forth 3 times in each. And then finish the part and that should help elviate warp issues.
To OP this is not an internet "correction" adding my 2 cents to yours, I don't think it is the stress from milling. It is the unbalanced releasing of stresses internal to the metal caused by the initial extruding and rolling (or cold rolling). If you do a temperature cycle BEFORE machining to relieve the stress you should remove all this headache. If you look at it from the point view that it is releasing you can better predict when it is going to be an issue. You can also heat the curved out section which will heat it and stretch the curved in section... I know it sounds backwards. You expand the "stretched out" side so that it pulls the "compressed" side. If you do it the way that seems intuitive you will make a complete taco. If you are welding you can adjust your weld heat by welding in a pattern to drive this force to work for you. I am a structural engineer who tinkers with welding and bodywork and other metal things not a machinist. This heat stretching by heating the "opposite" side can straighten 1 inch plate on bridges after high loads hit it... over... and over... and over...
Hey Mark, after the rails were machined, could if made a skin cut on the back to relieve the stress and the rails would have strained out.. and at 23:53. Where the raised material was.. its the same width of the rails, and the cutter may have worn a thousand or so, and when the corner was cleaned up, may of had delection of the material and or cutter, or alignment of part during the second op. And for the spreading of the end, it was mostly one side, it started spreading after the weld. If a tack was at the end, or at the center on the end.. no spread. Great vid! Im a big fan!! Machinist if 24 + years, making obsolete gun parts.
I learned about stress from northeastern university’s night program. It was cool that my engineering materials professor was a day time professor at MIT. It would have been cooler if most of the equipment worked and was calibrated. It caused lots of this doesn’t make any fucking sense moments and semi angry rants in lab reports. Our department head thought it would be also good to not provide lab report procedures. 😂 I can laugh now. This was fun, thanks!
This video is like an extended, totally unedited scene from a Spider-Man or Iron Man flick... yknow the evil genius... the lair... the extended flashing blue light... the buzzing of electrical currents... the maniacal conversation with the voices... 🦇☄️⚡️🏚
I like the ideas. Didnt know about that powder myself. There's a lot more room for improvement to this process but good effort. Fyi I know nothing about heat treatment but from foundry experiance.. let that stuff cool slowly or atlest evenly. (That why it warped again) You lose 1 degry centigrade per second when you casting if in crucible( thumb role). Some old bench die maker (taught in germany) mentioned to me once that back in 60s they made there own die spring (massive) and heat treated them, wraped in foil with i think metal shavings or sawdust packing to even out temp and for thermal insulation when needed. It's a thought. Admittedly f all info online or books avalible for this type of work. Dieing bread
Hey Mark. I am no machinist but I’d like to be someday. My guess on the original warping is due to the heating of the metal during machining. (You can let me know if I’m right) I do know about stress relieving metal however I wasn’t aware of the carborizing process. I’ve always kinda wondered if there was a way to do that. Thanks for the lesson. Keep up the good work!
Hey mark. I wont insult you and state the obvious on warping but after taking it out of the oven and placement of tack welds plus cooling etc. Well you get the pick. Keep on truckin man i enjoy watching and talking to ones self cause i do the same thing.
Cool video! Looks like nice 70 progress. I have the same welding shield, did you get yours at Tractor Supply? I would have probably straightened the cold rolled in the press and then proceeded but to each their own. Just curious if coolant would have prevented this in the first place? Take Care buddy and looking forward to the next video, John
maybe try annealing the metal before machining, all the stress in the steel and only is strong enough to reveal itself till after a large physical change or temperature. we deal with this alot in knife making and generally we spend a good bit of our time letting the steel relax itself especially before heat treating it. would also recommend looking into cryo-treating your steel after your normal heat treat and tempering.
Dose anyone still use kasenit for heat treating the surface? I have seen old timers use leather scraps and bone meal with the part in a tube while doing the heat treat also. But now I will have to look at the stuff you used. Thanks for an interesting video, at least to me. But I really don't think you should have used Val's soup spoon! ;)
Rolled bright steel is full of stresses . You machine it , it bends . You straighten it and then heat treat it it tries to return to the original form . Try low temp stress relieving of the bar before machining and between each process . In ye old days the part to be hardened was wrapped with leather and used bone meal in the mix . As you may or may not know , piss was used amongst other things like dog shit to treat hides to produce leather . Kids were employed by the London tanners to collect dog shit as it was the best for bating (treating) hides . Piss from young beer drinking men was considered best for tanners and dyers alike .Nice work if you can get it ! The leather workers sold their scrap to the gunmakers . If you imagine these constituents , carbon and calcium from bone , urine and carbon and other products from leather you end up with the case hardening powder you buy today that smells like the contents of an abandoned crapper . Lots of good air cool steels out there I use for sears and hammers etc including good old D2 . I use Niobal for more highly stressed parts that require different heat treatment as does S7 . Not totally familiar with your products so it would be nice to know what the part is for , obviously bolt rails of some sort .
Resisual stress in the material from manufacture. Heat treatment or cold working. Edited to add, if you remove material that is in compression or tension due to the residual stress, the remaining stresses are unbalanced, leading to warping.
Could a piece of flat and 2 pieces of angle welded together an then stress relief ??? May i suggest a good vise and a whole lot more D style vise grips ??? There were times 50 wasn't enough for me !!! I prefer the style of your micro to the moveable swivel base type !!! I would love to see the use and installation !!! Like the expensive burro oven !!! Those sharks teeth on the thin stuff are scaple territory !!! Love what ya do !!!
I ordered an 80% PSL receiver and when it got to me I could see it was obviously very warped. It took so long to get I didn't want to give it back with the hopes that the next one wouldn't be warped. I just broke out the propane torch heated up until it glowed cooled it off real fast with a wet face cloth and depending on where you heat it and where you cool it, you can worp the bend so that it becomes straight.
No offense but that's a really bad idea. That receiver was most likely heat treated to a very specific hardness and if you got it glowing and quenched it you probably got it to a much higher hardness than it should be.
I would guess it warped after you heated it, since you changed the structure of the steel in the middle, which causes internal stresses in the steel that causes it to warp. Am I close at all?
No, but thanks for trying! ;-) I made the part from cold-rolled steel which has a lot of internal stresses near the surface. When you machine away one side the stresses on the opposite side will warp it as you saw.
Lol ALWAYS tack the ends .. when I straighten stuff like this, I always start with a hard clamp in the middle, tack on both sides in the middle.. Then I work my way out , alternating each side of the middle tack. All they way to the end and make sure to tack the ends. If you think about it, when you squeeze them together in the middle, it pushes out too. That's why I start in the middle and work out to the ends.. And I know it don't make sense to tack more than you need, but it almost always adds problems when you " just tack where you need it".. it squeezes the metal together as it cools and creates weird points of uneven stress..
15:35 thanks for the reenactment! I was having a hard time envisioning black powder falling into a round hole! Edit: it would have been even funnier if you'd blurred the image like ToT does sometimes when you have something going into a hole
Dumb question: how heavy can a "striker" be so that it does not move the shooter's aim, like an fg42 on semi auto, closed bolt, when he pulls the trigger? Vz 58 striker, i guess weighs 56 grams and gun shoots fine. Do keltec rdb hammer's system jerks the gun like the fg42's op rod? I mean its a 3 moa gun (karl, inrange test shoot). Just asking.
Is the heat greater in that area when shooting warping it? Also not a machinist i wish i got into that in school i guess i should of thought to just read the comments lol always love learning from serbu
Things that will cause this I suspect: 1.Dissimilar alloys used, perhaps; flats alloy softer than rail. 2. If all the same alloy/one piece, the meat of the rail section acting like a spine on the flat causing curvature post heat treating. #2 Do I win!?
*heat treated. Think about the situation where the rifle has had the rear push-pin pulled out and the upper and lower are pivoted open by the front pin. Now just a small lateral force on the end of the buttstock will put enough force on the ears to bend them.
I'm sure you know about this process, but here ya go. You should think about normalizing your steel a few times. This will make your steel's alot stronger in the end result. It relaxes the structure and grains of the steel and resets the memory of the steel.
Buy a few 12' bars of 1144 stress proof. 1" and 2" diameters...just a little more to mill of the sides and top for square parts. There is no warping, free machining and it heat treats great.
edited to add, i was wrong, checked the vid again, and they were spread while still hot. hmmm. Regarding the bending out at the ends.... as the ends are free, perhaps the outside cooled and contracted faster than the inside, the bowed out and retained that outward bow, despite the inside contracting. Once the outside had coold and hardened, it was able to overcome the contraction of the inside cooling material. Hmm. I should check the video to see if the bend is therewhen the part is hot.
@@markserbu from my limited knowledge, how you figure that? Even if spring steal you would soften it machining right wouldn't any machining cause heat stress? Or is this negligible for this progect some what.
It's made by the same company that makes "Wilcarbo" that I'm using here. Cherry Red is geared more towards the hobbyist and works great, from what I hear.
Welding warps the part. It may be an idea to tag weld it to a piece weld on the rails (and then anneal??) and then mill, or grind of the welded part off. That way it shouldnt warp?? Or you could try to reduce the heat input into the piece to begin with. So maybe another welding technique like, gas welding with a wire, or tig welding with a wire (what you used in the video). Or try to make the rails from metal stampings and spotweld by resistance welding.. Usually tag welding suffices to keep the rail in place. Its just there to guide the receiver, not to take the load of a round. Or you could make the part from a billet, but that takes more time, and thus cost, but the part will not warp (the part was however warped, but still make from a billet). That is my conclusion. Yes, it was bend in welding.. (but in the end of the video, the part was machined from a billet... thats odd) Stress relieving, well, it has got to be done at different temperatures for different sorts of steel. So you better do that before the carburizing (well thats how they do it with the m16 bolt, they first stress relieve, and then carburize). The time you carburize is also important, while casehardening is great, while it keeps the ductile core, and give the outside a hard finish. To long a carburization can make the part lose toughness and make it more susceptible to breaking while it is to brittle at the core. Heat treatment is a specialty job, and some companies make it their core business, and that is for a reason. You can get away with guessing, in some not so critical parts, e.g. bolts, you will have to be spot on in your heattreatment. Maybe its a good idea, to read on the subject, and make a game plan on parts, and be methodical with it. I still believe your heattreatment will work though. 21:41 Maybe welding the outer edges would have helped keeping the part straight, now it warped due to the heat. Its good to note. :) Greetings, Jeff
I know exactly why they are warped!.....its because some big huge dude came over after you were done welding amd slapped the rails with his big ole dong! And they bent under the stress. ......either that or its just weld pull, and pretty easily avoided by someone who knows what they are doing.......ohhhhh shit I said that....burn!!!!! I am just messing around i hope you know that. Much respect Mr. Serbu!....thank you for the videos sir!....ohh and how about getting a few diablos out the door because ME WANT ONE REAL BAD!!!!
No offense but that doesn't make sense. The part warps because material with internal stresses is removed and the balance with the other side (that also has internal stresses) is upset. Doesn't matter if the material is removed with a shaper, end mill, saw, file or water jet...same effect is still there.
Wait..this is NOT about trains & homeless people? Or hobo's riding trains? Wtf...you tease! ;-) What your guns don't yell "weld me daddy!" at you? It's just me? oh...hmm...ok then....
What he should have done was hurry the hell up and welded it rather than try and show it off for the camera because there's plenty of time to show it off after you finish doing your spot welds and it's all secure.
Still couldn’t see the 3rd re-enactment clearly, as your thumb got in the way slightly. Please set up different camera angle with better lighting and post 4th reenactment please, thanks. 👹
16:45- it just kept dropping thru. Maybe your angle was bad and you couldn't see but it was just going straight out the bottom!! Maybe you need a technical advisor to set up those kinds of "stunt shots".
True, but it's more basic than that. I used cold-rolled steel which has a lot of internal stresses. If I'd used hot-rolled steel this wouldn't have happened.
They warp and twist until they are literally unusable because just like everything else that is warped, broken, and unusable... the lawyers got to them.
Mark, welder here. You know how engineers and welders get along right? 😁 you design it they way it SHOULD work and i tell you how it actually does. 😂 the reason the rail spread is the order that you welded it. The second to last weld on the opposite side was done before the last weld, yet it was further out than the last weld. This means that the grain structure was expanded but locked into a set point by the weld. The last weld tried to expand further, but you had already locked the rail with the second to last weld further out on the rail. Always weld from the center out to push the expansion towards the free ends so they can expands and contract freely, then weld out the ends after the rail has cooled sufficiently and all returned to it’s normal dimensions. Basically if you’d welded the last two in opposite order it wouldn’t have bent when it got hot and revealed the potential energy that was bound up in the last weld - which couldn’t expand due to the weld further out towards the end on the other side. ......was that explanation plain as mud? 😁
What he said, plus any time you heat cycle steal, it can have stresses in it, exactly like wood, you start off with square and true, remove some material, unbeknownst to you, the removed material was counteracting some other force, balancing it, and when you remove it then it's unbalanced and warps. Even without removing material, cheap steel is like chocolate chip cookie dough, and the different flavors of steel behave differently at different temps, so you heat cycle it, and it does just what the bi-metalic strip does in an old timey thermostat, and the steel that gets softer at lower temp gets bent towards the steel that has a higher softening temp.
When I was 16 I did a 2 year course on machining but never worked on the field. It's been 24 years since and I'm happy I found your channel because it reminds me of my time on the lathe and other tools, it is so much fun. Sorry about my English.
Thank you! Your English is fine!
I second marks comment. Our English is probably better than most of ourselves
Dying laughing at the +/-16 minute mark where Mark recreates the part we couldn't see . . . again.
😂😂
"You can see that!" haha
Hi Mark, one way to make these would be in your rotary table out of round stock. 2 operations. Leave stock for the center and some in the chuck. Machine it slightly off centered to the stock the rail closer to the center seeing how those pcs warped. Use "High Velocity Machining" side milling the 4 sides you'll have less vibration side milling then "end milling" it's very fast too. A key cutter will cut that slot faster then end milling if your not already. What's nice in the rotary is you can machine one side leaving stock then the others bouncing back and fourth removing the warp as you go. 2nd opp I'd mill the ends off in a 6" vise. Looks like you have a good process and it works well. Thanks great videos!
Jason
"I think I'm gonna roll it into a tube" Ah yes, the forbidden burrito.
Mostly from stress of milling one side of cold formed alloy steel stock.
Yeah was going to say the same, maybe reheat then anneal the metal first to relieve the stresses.
Yup. Cold-rolled vs. hot-rolled.
Also sometimes helps to work with round bar stock, as opposed to square, or rectangular bar. Because the grain structure is more even, as opposed to compressed from being rolled into a particular shape, which is contributing factor when warp is a concern. If you're really worried about it. You can rough the parts so they're within .100" from finish size, and then do thermal cycle/stress relieve the parts to relax the induced stresses in the material. Submerge in boiling water for several minutes, and the dunk in liquid nitrogen(or poor mans method is rubbing alcohol and dry ice...) till it stops boiling, and back and forth 3 times in each. And then finish the part and that should help elviate warp issues.
To OP this is not an internet "correction" adding my 2 cents to yours,
I don't think it is the stress from milling. It is the unbalanced releasing of stresses internal to the metal caused by the initial extruding and rolling (or cold rolling). If you do a temperature cycle BEFORE machining to relieve the stress you should remove all this headache. If you look at it from the point view that it is releasing you can better predict when it is going to be an issue.
You can also heat the curved out section which will heat it and stretch the curved in section... I know it sounds backwards. You expand the "stretched out" side so that it pulls the "compressed" side. If you do it the way that seems intuitive you will make a complete taco.
If you are welding you can adjust your weld heat by welding in a pattern to drive this force to work for you.
I am a structural engineer who tinkers with welding and bodywork and other metal things not a machinist. This heat stretching by heating the "opposite" side can straighten 1 inch plate on bridges after high loads hit it... over... and over... and over...
@@someguy2741 those wher some valuable 2 cents, thanks Some Guy
Awesome to see how a puzzle comes together 👍
I really feel like Mark Serbu is my spirit animal...
Your getting so much better at injecting humor in your videos !
Love your videos! Great info and fun to watch.
Hey Mark, after the rails were machined, could if made a skin cut on the back to relieve the stress and the rails would have strained out.. and at 23:53. Where the raised material was.. its the same width of the rails, and the cutter may have worn a thousand or so, and when the corner was cleaned up, may of had delection of the material and or cutter, or alignment of part during the second op. And for the spreading of the end, it was mostly one side, it started spreading after the weld. If a tack was at the end, or at the center on the end.. no spread. Great vid! Im a big fan!! Machinist if 24 + years, making obsolete gun parts.
thanks for the re-enactment of the carbon pouring, very exciting!
I learned about stress from northeastern university’s night program. It was cool that my engineering materials professor was a day time professor at MIT. It would have been cooler if most of the equipment worked and was calibrated. It caused lots of this doesn’t make any fucking sense moments and semi angry rants in lab reports. Our department head thought it would be also good to not provide lab report procedures. 😂 I can laugh now. This was fun, thanks!
Very cool! Even with the crappy equipment.
markserbu especially when she would bring in declassified work she did for the government. That professor rocked!
What ??? I'm setting here in suspense, wondering how the heat treat on the rails went, Damn, You left me hanging !!! Great Video !!!
Excellent video by the way
I would really love to see a collaboration between AvE and Mark Serbu. It would be the funniest machining/fabrication video of all time.
I like your down to earth approach.
Those "boring" videos are a blessing if you plan on falling asleep with a smile on your face. I did.
So kind of like metallurgical ASMR? Now _that_ is an interesting idea. Sounds quite lucrative to me.
The riddle of steel is never an easy one.
Would it work to get sheet metal slats and spot weld the rails like an ak?
This video is like an extended, totally unedited scene from a Spider-Man or Iron Man flick... yknow the evil genius... the lair... the extended flashing blue light... the buzzing of electrical currents... the maniacal conversation with the voices... 🦇☄️⚡️🏚
I like the ideas. Didnt know about that powder myself. There's a lot more room for improvement to this process but good effort. Fyi I know nothing about heat treatment but from foundry experiance.. let that stuff cool slowly or atlest evenly. (That why it warped again) You lose 1 degry centigrade per second when you casting if in crucible( thumb role). Some old bench die maker (taught in germany) mentioned to me once that back in 60s they made there own die spring (massive) and heat treated them, wraped in foil with i think metal shavings or sawdust packing to even out temp and for thermal insulation when needed. It's a thought. Admittedly f all info online or books avalible for this type of work. Dieing bread
Are you going to make barrels and receivers for the AR70/90? Please do, I'd buy some👍
Hey Mark. I am no machinist but I’d like to be someday. My guess on the original warping is due to the heating of the metal during machining. (You can let me know if I’m right) I do know about stress relieving metal however I wasn’t aware of the carborizing process. I’ve always kinda wondered if there was a way to do that. Thanks for the lesson. Keep up the good work!
Amazing video bro!
markserbu thanks for da like buddy!
Hey Florida Man, alligator whisperer and gun nut! Thanks for the video Mr Serbu!
I keep watching and saying to myself "bench vise, bench vise, bench vise." Am I wrong here?
No, you're not wrong. There are a lot of vises around here (and several vices!) but they're all bolted down to things other than the welding table.
And having to watch Mark with midget hookers stressed it the rest of the way 🤣
@@markserbu Your welding table is not complete until you install a vice on it, even a temporary install??
Yea me too a welding fixture with this setting on two parallels would make things so easy.and no errors.
Hey mark. I wont insult you and state the obvious on warping but after taking it out of the oven and placement of tack welds plus cooling etc. Well you get the pick. Keep on truckin man i enjoy watching and talking to ones self cause i do the same thing.
Hey, you're talking to yourself... I'm talking to the camera! ;-)
@@markserbu Hey i even answer myself 😃
Cool video! Looks like nice 70 progress. I have the same welding shield, did you get yours at Tractor Supply?
I would have probably straightened the cold rolled in the press and then proceeded but to each their own.
Just curious if coolant would have prevented this in the first place?
Take Care buddy and looking forward to the next video, John
Thanks! Shield was $32 from Amazon and I love it! I used plenty of coolant...it's a hot-rolled steel vs. cold-rolled steel issue.
maybe try annealing the metal before machining, all the stress in the steel and only is strong enough to reveal itself till after a large physical change or temperature. we deal with this alot in knife making and generally we spend a good bit of our time letting the steel relax itself especially before heat treating it. would also recommend looking into cryo-treating your steel after your normal heat treat and tempering.
Dose anyone still use kasenit for heat treating the surface? I have seen old timers use leather scraps and bone meal with the part in a tube while doing the heat treat also. But now I will have to look at the stuff you used. Thanks for an interesting video, at least to me. But I really don't think you should have used Val's soup spoon! ;)
It warped when thy were cutting it to pieces?
Rolled bright steel is full of stresses . You machine it , it bends . You straighten it and then heat treat it it tries to return to the original form . Try low temp stress relieving of the bar before machining and between each process .
In ye old days the part to be hardened was wrapped with leather and used bone meal in the mix . As you may or may not know , piss was used amongst other things like dog shit to treat hides to produce leather . Kids were employed by the London tanners to collect dog shit as it was the best for bating (treating) hides . Piss from young beer drinking men was considered best for tanners and dyers alike .Nice work if you can get it ! The leather workers sold their scrap to the gunmakers . If you imagine these constituents , carbon and calcium from bone , urine and carbon and other products from leather you end up with the case hardening powder you buy today that smells like the contents of an abandoned crapper . Lots of good air cool steels out there I use for sears and hammers etc including good old D2 . I use Niobal for more highly stressed parts that require different heat treatment as does S7 .
Not totally familiar with your products so it would be nice to know what the part is for , obviously bolt rails of some sort .
Resisual stress in the material from manufacture. Heat treatment or cold working.
Edited to add, if you remove material that is in compression or tension due to the residual stress, the remaining stresses are unbalanced, leading to warping.
Could a piece of flat and 2 pieces of angle welded together an then stress relief ???
May i suggest a good vise and a whole lot more D style vise grips ???
There were times 50 wasn't enough for me !!! I prefer the style of your micro to the moveable swivel base type !!!
I would love to see the use and installation !!! Like the expensive burro oven !!!
Those sharks teeth on the thin stuff are scaple territory !!!
Love what ya do !!!
Late to the party but do have to this every pair of rails for every gun?
I ordered an 80% PSL receiver and when it got to me I could see it was obviously very warped.
It took so long to get I didn't want to give it back with the hopes that the next one wouldn't be warped.
I just broke out the propane torch heated up until it glowed cooled it off real fast with a wet face cloth and depending on where you heat it and where you cool it, you can worp the bend so that it becomes straight.
No offense but that's a really bad idea. That receiver was most likely heat treated to a very specific hardness and if you got it glowing and quenched it you probably got it to a much higher hardness than it should be.
Where did you get the receiver from??? Let me guess.... Rapid Fire of Ohio?
For like half a second I thought you were building a rail gun.
Hey Mark, are there any benefits/cons to using striker fire mechanisms in other firearm types such as shotguns, rifles, smgs, etc?
Yeah, and way too much to talk about in a TH-cam video comment, unfortunately.
I would guess it warped after you heated it, since you changed the structure of the steel in the middle, which causes internal stresses in the steel that causes it to warp.
Am I close at all?
No, but thanks for trying! ;-) I made the part from cold-rolled steel which has a lot of internal stresses near the surface. When you machine away one side the stresses on the opposite side will warp it as you saw.
@@markserbu ooooooh, makes sense. Thanks Mark, appreciate it
"I do yoga to stress relieve, just kidding, I smoke pot in yoga pants..."
warp because cold rolled steel and all material taken from one side releases stresses?
Cold rolled steel is molecularly compressed on the inward side of the roll...it has "set"....heating removes the "set"?
(Edit) I just read the 60 other replies...they said it better than I could regards the bending
Lol ALWAYS tack the ends .. when I straighten stuff like this, I always start with a hard clamp in the middle, tack on both sides in the middle.. Then I work my way out , alternating each side of the middle tack. All they way to the end and make sure to tack the ends.
If you think about it, when you squeeze them together in the middle, it pushes out too. That's why I start in the middle and work out to the ends..
And I know it don't make sense to tack more than you need, but it almost always adds problems when you " just tack where you need it".. it squeezes the metal together as it cools and creates weird points of uneven stress..
15:35 thanks for the reenactment! I was having a hard time envisioning black powder falling into a round hole!
Edit: it would have been even funnier if you'd blurred the image like ToT does sometimes when you have something going into a hole
Dumb question:
how heavy can a "striker" be so that it does not move the shooter's aim, like an fg42 on semi auto, closed bolt, when he pulls the trigger?
Vz 58 striker, i guess weighs 56 grams and gun shoots fine.
Do keltec rdb hammer's system jerks the gun like the fg42's op rod? I mean its a 3 moa gun (karl, inrange test shoot).
Just asking.
I think there are too many variables to give a solid number
That’s what you get when using cold rolled. Need to use hot rolled and it won’t do that. Learned the hard way making pic rail with cold rolled steel.
Is the heat greater in that area when shooting warping it? Also not a machinist i wish i got into that in school i guess i should of thought to just read the comments lol always love learning from serbu
That stainless foil is dangerous.
Mark, do Welders typically have a larger vocabulary of curse words than the ordinary person?
I think that's tradesmen in general
I believe it’s pretty extensive with a special hatred for engineers
Things that will cause this I suspect:
1.Dissimilar alloys used, perhaps; flats alloy softer than rail.
2. If all the same alloy/one piece, the meat of the rail section acting like a spine on the flat causing curvature post heat treating.
#2 Do I win!?
Nope. Just cold-rolled steel with all the machining done on one side. Hot-rolled won't act like that.
nice weather to be flying in to.
Dumb Question but why do the ears need to be heated? They don't look like a load bearing part.
*heat treated. Think about the situation where the rifle has had the rear push-pin pulled out and the upper and lower are pivoted open by the front pin. Now just a small lateral force on the end of the buttstock will put enough force on the ears to bend them.
I'm sure you know about this process, but here ya go. You should think about normalizing your steel a few times. This will make your steel's alot stronger in the end result. It relaxes the structure and grains of the steel and resets the memory of the steel.
Yeah, it's not going to matter for these parts because they're getting case hardened.
Buy a few 12' bars of 1144 stress proof. 1" and 2" diameters...just a little more to mill of the sides and top for square parts. There is no warping, free machining and it heat treats great.
Yup, I use it all the time.
why they are warped?
Put a steel wire thru the smal parts, makes it easy to find tehm.
i like it.
edited to add, i was wrong, checked the vid again, and they were spread while still hot. hmmm.
Regarding the bending out at the ends.... as the ends are free, perhaps the outside cooled and contracted faster than the inside, the bowed out and retained that outward bow, despite the inside contracting. Once the outside had coold and hardened, it was able to overcome the contraction of the inside cooling material. Hmm. I should check the video to see if the bend is therewhen the part is hot.
(Posting while watching): can't you anneal the parts first, then straighten them after hardening in a press/vice?
If they were annealed before machining they wouldn't have warped.
@@markserbu from my limited knowledge, how you figure that? Even if spring steal you would soften it machining right wouldn't any machining cause heat stress? Or is this negligible for this progect some what.
Yes on Cody's lab but he use gold as an example and he was talking about work hardening and stressful leaving metal same same!
Why not just start with a higher carbon steel? Is it less expensive to do it this way?
This could put me to sleep
The part i like best is imagining all the "safety b.tches" wetting their undies as you casualy endanger your liability insurance.
I’ll bet you’ve done quite a few rails in your time mark!
I bet that too. Little ski trips now and then when younger.
I had to look that up...LOL
I bet they warped from getting hot when you welded them
Anybody out there use the Cherry Red brand hardening compound?
It's made by the same company that makes "Wilcarbo" that I'm using here. Cherry Red is geared more towards the hobbyist and works great, from what I hear.
How about making some jaws that have different types of notches in them for the job at hand / the negative of the item your welding ! Just and fyi
Aw yeah, half an hour of application specific metallurgy!
Always learning something 👍
Welding warps the part. It may be an idea to tag weld it to a piece weld on the rails (and then anneal??) and then mill, or grind of the welded part off. That way it shouldnt warp?? Or you could try to reduce the heat input into the piece to begin with. So maybe another welding technique like, gas welding with a wire, or tig welding with a wire (what you used in the video). Or try to make the rails from metal stampings and spotweld by resistance welding.. Usually tag welding suffices to keep the rail in place. Its just there to guide the receiver, not to take the load of a round. Or you could make the part from a billet, but that takes more time, and thus cost, but the part will not warp (the part was however warped, but still make from a billet).
That is my conclusion. Yes, it was bend in welding.. (but in the end of the video, the part was machined from a billet... thats odd)
Stress relieving, well, it has got to be done at different temperatures for different sorts of steel. So you better do that before the carburizing (well thats how they do it with the m16 bolt, they first stress relieve, and then carburize). The time you carburize is also important, while casehardening is great, while it keeps the ductile core, and give the outside a hard finish. To long a carburization can make the part lose toughness and make it more susceptible to breaking while it is to brittle at the core. Heat treatment is a specialty job, and some companies make it their core business, and that is for a reason. You can get away with guessing, in some not so critical parts, e.g. bolts, you will have to be spot on in your heattreatment. Maybe its a good idea, to read on the subject, and make a game plan on parts, and be methodical with it. I still believe your heattreatment will work though.
21:41
Maybe welding the outer edges would have helped keeping the part straight, now it warped due to the heat. Its good to note. :)
Greetings,
Jeff
just looks like fun
Mark : How long have you been a pilot...??
13 years.
I want to see someone weld M249 rails into a receiver
The reenactment 🤣🤣🤣🤣 ever seen mark novak c&r arsenal? He talks often about camera angles etc
about the curve, i know from knifemaking that people who let metal air cool brace the metal in a benchvise to help maintain straightness
Have the rails warped because of the heat 🔫👍👍
No, but nice try.
Remember after watching that midway USA guy he tipped emptied a cage directly into water I believe.
I bet those were hard to make. I bet you messed up a few machining those rails
Nah. Push the button and walk away.
@@markserbu Nha, I bet your machinist messed up a few picitini rails
gun nut and pilot?
Yup. Try Googling "MP5 Cessna".
boys and their toys lol
We never outgrow toys, they just get more expensive 😉😆
I know exactly why they are warped!.....its because some big huge dude came over after you were done welding amd slapped the rails with his big ole dong! And they bent under the stress. ......either that or its just weld pull, and pretty easily avoided by someone who knows what they are doing.......ohhhhh shit I said that....burn!!!!! I am just messing around i hope you know that. Much respect Mr. Serbu!....thank you for the videos sir!....ohh and how about getting a few diablos out the door because ME WANT ONE REAL BAD!!!!
They weren't stress relieved properly, and you only found that out when they were machined.
I like how you keep asking if we know what you are doing. Keeping the mouth breathers interested lol.
I have people laugh because I still use a shaper. Long flat sections stay straight.
No offense but that doesn't make sense. The part warps because material with internal stresses is removed and the balance with the other side (that also has internal stresses) is upset. Doesn't matter if the material is removed with a shaper, end mill, saw, file or water jet...same effect is still there.
If you want to make a nice heat treat oven/foundry check out TAOW on YT. I made mine murican sized 13" cubed.
Wow, I just checked it out...thanks!
Ya know a roller press could've fixed that in minutes.
Wait..this is NOT about trains & homeless people?
Or hobo's riding trains?
Wtf...you tease!
;-)
What your guns don't yell "weld me daddy!" at you? It's just me? oh...hmm...ok then....
What he should have done was hurry the hell up and welded it rather than try and show it off for the camera because there's plenty of time to show it off after you finish doing your spot welds and it's all secure.
Internal stresses!
Still couldn’t see the 3rd re-enactment clearly, as your thumb got in the way slightly. Please set up different camera angle with better lighting and post 4th reenactment please, thanks. 👹
@Chauvin Emmons we really wanna seeeee...
Why don't you you add a match to burn off any oxygen left in there when heat treating it. The match should auto ignite during the process
16:45- it just kept dropping thru. Maybe your angle was bad and you couldn't see but it was just going straight out the bottom!! Maybe you need a technical advisor to set up those kinds of "stunt shots".
The steel was not stress Relieve before it was machined
True, but it's more basic than that. I used cold-rolled steel which has a lot of internal stresses. If I'd used hot-rolled steel this wouldn't have happened.
@@markserbu 10-4 Thanks brother
@@markserbu I love your videos, Lots of good info. Thanks
Got to hot in machining
All this aggrivation is why hardmilling is a thing.
They warp and twist until they are literally unusable because just like everything else that is warped, broken, and unusable... the lawyers got to them.
Lol what? Those are called earholes?
Ears, tangs...whatever.
Jig????
Nope did not know that.