4 ms·

I believe 1911 (handgun) slides and frames still have to be hand fit to one another. Though there is a company claiming tight enough tolerances that theirs don

I believe 1911 (handgun) slides and frames still have to be hand fit to one another. Though there is a company claiming tight enough tolerances that theirs don’t. I have two identical 1911, but have not tried it. I wonder how original Colt 1911 were produced for military orders? I can’t see hand fitting those. The AR-15 is fully interchangeable, but I have read of takedown pins on Colts not fitting more modern lowers receivers. Also wonder if the gas system has to be tweaked? The FN-FAL has an adjustable gas block, but that may be due more for ammo than parts compatiblity.

dsfyu404ed 7y ago
Sounds like an urban legend. Colt and John Browning shipping something that needs to be hand fit doesn't pass the smell test. Major world powers don't adopt a gun that can't have parts interchanged as their standard sidearm in the early 1900s. For a specialty weapon of 30yr earlier maybe but only the cheapest of "boring old small arms" were still being hand fit around that time and even then it was rare in industrialized countries. Edit: adjustable gas systems are in fact there to tune for ammo variations and fouling.
- madengr 7y ago
  I don’t think the original 1911 were hand fit, but all of the modern, upper tier 1911 claim to be hand fit. Why the purpose behind this; reliability?
  - dsfyu404ed 7y ago
    If you're really lucky hand fit translates to "our QA department is stocked with measuring tools and they actually use them to confirm parts meet spec before being assembled, maybe if you're lucky they write down how over/under something is so that the assembly guys can pick combos that work well". (If you're paying big bucks this is hopefully the case.) More likely it means someone cycled the thing to make sure it worked before slapping their "qa by <unintelligible scribble>" sticker on the product or packaging It's mostly just marketing mumbo jumbo to make it seem like a fancy hand crafted product. Back in "the day" the marketing people would have advertised that things were made by precision machines. Today labor is expensive and machines are cheap so they're advertising that they put a lot of labor into it in part to justify the price (and the reverse would have been true in the early 1900s, they'd emphasize the machine contribution). Firearms are tight like a retired hooker compared to the kind of tolerances any reasonably modern manufacturing operation of that sort (mostly machining and stamping/forming) is capable of working in (they need to be loose so all those steel on steel parts will move like they're supposed to). Loose fitment tolerances translate to less need for super precise parts to begin with. Say you have a slide that wants .010"+.002"/-0001" of clearance. Sure you can make that part to .0005 but insisting on that level of consistency just adds unnecessary cost to do so when you have an entire .0003" space to shoot for. For ultra high precision stuff tighter tolerances and more consistency are used but that's mostly limited to the pressure bearing parts of the action that touch the case/bullet (the goal is to get that cartridge to fit in there the same way each and every time). Some of the most reliable firearms out there use very loose tolerances. For a 1911 I feel very safe saying that the modern high end ones do it more because they can than because it improves performance in any measurable way. High end guns almost by definition will never see enough use to get to the point where manufacturing it more precisely could ever effect reliability.
beerandt 7y ago
I remember a piano repairman telling my parents (when I was way too little to understand) that replacement parts had to be within a certain window of serial numbers to fit. It wasn't because of deliberate changes in manufacturing, but had to do with wear and drift in the templates (or molds or presses or whatever). He described it as a "living" process, and that it worked because it cascaded in a complementary way; a small deviation in the shape of one key was "absorbed" and compensated for by the next key. It also prioritized consistent tuning (result) over persistent shape (method). Put another way, the manufacturing process had built-in methods for self-correcting systematic error. They just weren't guaranteed to be consistent in the long term. (I'm sure there's got to be a more technical description for this, but it's beyond my knowledge). I know semi-modern (opto-mechanical) survey equipment is manufactured on similar principles of self-correcting deviation (although these also tend to be dependent on strict method of operation for it to work itself out). It wouldn't be a stretch to think a firearm as old as the 1911 was manufactured in a similar fashion as some point. Especially if there was a way to keep the long term deviation centered within spec. But that's just my guess.

dsfyu404ed 7y ago

Sounds like an urban legend. Colt and John Browning shipping something that needs to be hand fit doesn't pass the smell test. Major world powers don't adopt a gun that can't have parts interchanged as their standard sidearm in the early 1900s. For a specialty weapon of 30yr earlier maybe but only the cheapest of "boring old small arms" were still being hand fit around that time and even then it was rare in industrialized countries. Edit: adjustable gas systems are in fact there to tune for ammo variations and fouling.

madengr 7y ago
I don’t think the original 1911 were hand fit, but all of the modern, upper tier 1911 claim to be hand fit. Why the purpose behind this; reliability?
- dsfyu404ed 7y ago
  If you're really lucky hand fit translates to "our QA department is stocked with measuring tools and they actually use them to confirm parts meet spec before being assembled, maybe if you're lucky they write down how over/under something is so that the assembly guys can pick combos that work well". (If you're paying big bucks this is hopefully the case.) More likely it means someone cycled the thing to make sure it worked before slapping their "qa by <unintelligible scribble>" sticker on the product or packaging It's mostly just marketing mumbo jumbo to make it seem like a fancy hand crafted product. Back in "the day" the marketing people would have advertised that things were made by precision machines. Today labor is expensive and machines are cheap so they're advertising that they put a lot of labor into it in part to justify the price (and the reverse would have been true in the early 1900s, they'd emphasize the machine contribution). Firearms are tight like a retired hooker compared to the kind of tolerances any reasonably modern manufacturing operation of that sort (mostly machining and stamping/forming) is capable of working in (they need to be loose so all those steel on steel parts will move like they're supposed to). Loose fitment tolerances translate to less need for super precise parts to begin with. Say you have a slide that wants .010"+.002"/-0001" of clearance. Sure you can make that part to .0005 but insisting on that level of consistency just adds unnecessary cost to do so when you have an entire .0003" space to shoot for. For ultra high precision stuff tighter tolerances and more consistency are used but that's mostly limited to the pressure bearing parts of the action that touch the case/bullet (the goal is to get that cartridge to fit in there the same way each and every time). Some of the most reliable firearms out there use very loose tolerances. For a 1911 I feel very safe saying that the modern high end ones do it more because they can than because it improves performance in any measurable way. High end guns almost by definition will never see enough use to get to the point where manufacturing it more precisely could ever effect reliability.

beerandt 7y ago

I remember a piano repairman telling my parents (when I was way too little to understand) that replacement parts had to be within a certain window of serial numbers to fit. It wasn't because of deliberate changes in manufacturing, but had to do with wear and drift in the templates (or molds or presses or whatever). He described it as a "living" process, and that it worked because it cascaded in a complementary way; a small deviation in the shape of one key was "absorbed" and compensated for by the next key. It also prioritized consistent tuning (result) over persistent shape (method). Put another way, the manufacturing process had built-in methods for self-correcting systematic error. They just weren't guaranteed to be consistent in the long term. (I'm sure there's got to be a more technical description for this, but it's beyond my knowledge). I know semi-modern (opto-mechanical) survey equipment is manufactured on similar principles of self-correcting deviation (although these also tend to be dependent on strict method of operation for it to work itself out). It wouldn't be a stretch to think a firearm as old as the 1911 was manufactured in a similar fashion as some point. Especially if there was a way to keep the long term deviation centered within spec. But that's just my guess.