When did gunmakers “standardized” their gun parts for all their guns to have the same specs?

An evolutionary thing perhaps, as technology is.
As simple as a black smith or furniture builder setting up a jig to reproduce parts to increase production.
Henry Fords contribution was the assembly line where those parts were installed on a moving line by individuals doing repetitive jobs.

We might look at how LATE it was before you could accomplish interchangeable parts. The Colt 1911 wasn't - in fact, there was no blueprint until contracts were let in the late 1930s and it was discovered the Browning family basically machined them by hand until they agreed on Johns idea of a prototype, then distributed the parts to the individual plant machinists who duplicated what they were given. No prints. It was Singer and others who finally made a print and they handed off to Remington and Ithaca with instructions on mass production - and it worked. Singer however couldn't do it, scrapped 25,000 guns and only got a handful accepted.

We still have to gunsmith 1911's, there are no "drop in" parts. The M16 actually made it a reality.

Winchester was having a lot of expensive issues, their parts weren't interchangeable, the specs weren't followed well and it took a lot of laborious hand fitting to get one finished. They were losing money because of all the "craftmanship," ie badly made parts that literally required hand filing to make work. In 1963 they went thru a major upgrade in QC on the plant floor, replaced some high cost parts with stampings, and in 1964 actually made a buck with parts that could drop in and work. For their efforts, collectors disparaged the improvements and praised the older guns for their "bespoke" quality. A part will likely fit i a newer gun, in the older ones, a gunsmith could be needed as it simply won't fit or work right.

It's been a slow trend over time to get manufacture up to the point where you can buy parts from either end of the country, and some from the middle, dump them on the kitchen table, assemble a firearm and have it actually function and fire. You can do that about 97% of the time with the AR15. I've had them pin together, and I've had them need some massaging to get the second pin to drive into the hole. Makers are still assembling them in sorted batches of complementary parts which look and seem to be well done, when in fact they are matching parts with the opposite tolerances to keep the total "stack" tolerance inside the working dimensions.

Now we are building a lot of guns from parts - SIG's, Glocks, etc and for the most part even the custom parts drop in and function most of the time. It''s actually taken all this time since Eli Whitney to accomplish. It's never been the fault of the parts tho, it's been the fault of the machinery, it's operation, and the cost of assembly. When it was cheaper to pay labor, they made the parts with a bit less precision to keep costs down. Now, labor is expensive (in the US) and the parts are drop in precise to lower the costs. Our ability to make those parts more precise has also gotten cheaper with computer controls and newer processes.

MIM does that, so does injection molding polymer. A MIM part when cured is finished no further polishing, like triggers and sears. The better triggers in Smith 3rd Gen autos are MIM, not machined with tooling marks and gritty finishes. Same with a lot of other guns, too, altho the MIM detractors don't like to admit it. Polymer has also done a lot to reduce costs - despite the retail, a grip unit is low cost, literally pennies compared to an extensively machined alloy pistol frame, hence the $100 disparity in retail price. Forging also helps as much of the finished shape is done when released from the die. Both are high quantity production methods tho and require making many more than a machined part to recover the costs. In small lots a CNC part can be close to the same cost - but the forging will produce tens of thousands more that are drop in capable for less money.

Military designs are the benchmark of real parts interchangeability and when you look to assemble one with no fitting or filing, the first to actually accomplish that may be the M16 - it took that long, and that sophisticated a design using aerospace manufacturing methods to finally achieve it.

Tirod said:

it was discovered the Browning family basically machined them by hand until they agreed on Johns idea of a prototype, then distributed the parts to the individual plant machinists who duplicated what they were given. No prints. It was Singer and others who finally made a print and they handed off to Remington and Ithaca with instructions on mass production - and it worked. Singer however couldn't do it, scrapped 25,000 guns and only got a handful accepted.

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That is an interesting version of the history. I have read of the difficulty in getting all the wartime contractors to make consistent guns, recently saw that Colt didn't have blueprints but made parts to match a standard set, methods of comparing said parts not stated.

I never heard of the Browning family making pattern parts for manufacturers. And Singer scrapped 25000 guns to get out the 500 gun Educational Order, really? Where may one read more on these revelations?

The statement "there are no drop in 1911 parts" is patently incorrect.

I know several people that have made reliable M1911A1s with Rock Island parts kits from SARCO with out "gunsmithing" them. All the parts dropped in and worked properly.

Most high end 1911 parts are oversized so a perfect fit-up can be achieved, but this a manufacturing choice, not a design requirement. That's like saying Springfield Armory couldn't make interchangeable parts for M14 because they hand fit the match rifles.

And no, it was not the M16 that was the first to have interchangeable parts. When the US re-did the drawing for the HS404 20mm, Oerlikon, 20mm and the 40mm Bofors they when to great pains to tolerance the parts so parts where interchangeable as they knew the Navy on smaller ships far from industrial centers would require drop in spares. Also, 100% interchangeability was required in the M1, M1918, M1919, and M2 production.

Getting away from guns, Ford re-did all the drawings for the Rolls-Royce Merlin so that there was no requirement for hand fitting during engine assembly, i.e., totally interchangeable parts.

And, don't confuse a part being hit by a belt sander by hand as an indication of it "requiring hand fitting". If you look at a 3rd gen S&W automatic, there are non-critical areas, places where the tolerance are fifteen to twenty thousands, where it doesn't matter, that are roughly finished with a sander or grinding wheel. Sometimes it is just cheaper to hand grind a part that set it up on a machine.

And, Singer did not scrap 25,000 guns to get 500. The only place 25,000 comes into the Singer M1911 story is that they were given a contract in 1925 to assess the shop-space, tooling and man-power requirements to support a 25,000 unit per month production. In 1939, a few years after that study was completed, the War Department gave Singer the 500 pistol educational order to see if they could reach rate 100 pistols per day. They did not reach the 100 per day rate, but they did show that such rates were possible. After the conclusion of the educational order, all tooling and information was turned over to the War Department

tark said:

I think we were "standardized" , by either definition, long before the 1930s.

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Standardized "we" did early.
"Fully interchangeable" was a longer process.
1903 generally was, but, that was from having Springfield Armory set the machine tool standards and Data Package.
That was very formalized with the Garand in 1936, to where all the parts were to sheet numbers,and meant to QC to a single spec, not matter who made the part.
The 1911 kind of missed this boat--how much due to Colt winds up in irresolvable arguments--which is part of why Singer had such troubles getting their production going.
One of the largest and most significant portions of the American Victory in WWII was in standardizing weapons parts down to fully interchangable at as many levels as possible.

I don't think Singer had that much trouble. Remington Rand and Ithaca thrashed around a good deal even with the Singer study to go by.

A lot of people - Singer sewing machines, McCormick reapers, Samuel Colt, among others - claimed to have interchangeability, and did a lot of hand fitting on the quiet.

A lot of production info was in the gaffers' notebooks, and in their heads. And when they died or retired, it went with them.
Winchester were driven mad trying to figure Colts production methods for making 1911's, and they didnt succeed before WW1 ended.
Henry Ford achieved interchangeability, and made a profit on it.
The Ordnance Department determined before the Civil War that 'we must have interchangeability, regardless of cost' but they didn't have to make a profit. Some of the Civil War suppliers, domestic and foreign, produced 'interchangeable Enfields' but most of them didn't.

tark said:

You sure about those dates CapnMac ? I'm not sure what "standardized" is suppose to mean. Fully interchangeable parts? Or does it mean adopting a weapon that meets certain criteria but doesn't necessarily have interchangeable parts? I think we were "standardized" , by either definition, long before the 1930s.

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France was getting into the process well before WW2. They started with a semi-auto rifle around 1936 after the depression was done kicking their economy square in the teeth and had it ready by 1938. It would eventually be quite successful and reliable in the form of the MAS-49 and 49/56. However, they also wanted a simpler weapon for their rear echelon troops and created a modern bolt action in 1936 named the MAS-36. It seems silly now to tool up to produce a bolt action on the eve of the switch to semi auto when everybody was going semi-auto, but the French do what they want much of the time and everyone else be damned. Things like skimping on weapons production and building the Maginot Line instead, le oops. However, the MAS-36 ended up being a very good rifle and when you consider that their existing stockpile of rifles were basically Lebels and converted Berthiers, having a 2nd line weapon which your entire army was familiar using actually makes good sense. Maybe not as much sense as just pushing the semi autos into full production and using those everywhere but c'set la vie. This was also the time the French adopted the 7.5x54 cartridge and standardized on it.
They also had a very nice pistol in the form of the Modele 1935 which was chambered in 7.65 French long. Also, the French submachine gun the MAS-38 was also chambered in this caliber making standardization a top priority. They now had two standard cartridges.
After the war, the French dumped the bolt actions from regular service fairly quickly and modernized their MAS-40 rifle into the MAS-44, MAS-49 and MAS-49/56 where it served reliably all over the world until the release of the FAMAS. The MAS-38 was expensive for a submachine gun and the French took note of the benefits of stamping and simplification. They produced the MAT-49 in 9mm. The MAT-49 is similar to many of the WW2-post war era subguns but bears some striking similarities to the M3 grease gun and the M1A1 Thompsons. You can definitely see what the French were after and it ended up being a reliable, rugged weapon. The Modele 1935 pistol got some simplification and improvements and became the MAC-50 and served all the way into the 1970-80s when it was replaced by a license-built copy of the Beretta 92.

Cliff Notes: the French were very interested in ditching their hodge podge of weaponry before WW2 but were delayed by economics, questionable choices and invading Nazis. After the war, they kicked themselves in the ass and standardized on high quality weapons that served their armed forces quite well for decades.

Darth-Vang said:

When did they obtain the technology to make all their guns to have the same exact specifications?(no longer “handmade”) Just curious to know so that I can get a general idea of the timeline of when gun specs were “standardized.”

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I wanted to give Whitworth the nod, as he standardized screw threads in the United Kingdom. But it may be that the French were first.


The History of Interchangeable Parts in the Industrial Revolution
https://interestingengineering.com/the-history-of-interchangeable-parts-in-the-industrial-revolution

Since I can't read French, or any other language, it is possible that there is in fact an earlier claim. The basic problem with history is, every society claims their guy was first, or the best, and writes a history to support that, that no one else reads as few are interested in firearms history, and fewer firearm fans are multilingual. Unfortunately I only read one language, but there may be an Ottoman who came up with the idea. Or an Indian , or a Chinese.

Get a used copy of this book. It pretty much lays it all out in an easy to understand format. Must read for anyone serious about the subject. Should be around 10-15$.

lysanderxiii said:

The statement "there are no drop in 1911 parts" is patently incorrect.

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Operations to assemble the 1911 involve staking and fitting. That is gunsmith level work and those parts are not drop in. The plunger tube for one.

There are other histories of the Singer operation, and whether the 25,000 parts were meant to prove a point about assembly, it would seem a huge investment for the demonstration. It remains a fact that they were scrapped - not assembled. Why waste a signifcant resource? They did no meet inspection standards. Other historians have pointed out the parts were not acceptable and the rejection of that entire lot left only 500.

25,000 1911's is a significant loss and basically a failure on their part to demostrate how it SHOULD be done. Using the typical industrial value added method of costing parts sent to the next station for assembly, that was in todays dollars about a $10,000,000 loss. Having done something similar I well know how management views that. A batch of lost parts because the next station can't even cobble them together is a loss.

Goes to, the legend of Singer 1911's as being highly handcrafted yet they still couldn't do it, which is the reason for their collectibility and incredible values. But Singer and it's poor quality really isn't the story here. Its all about can you order parts from multiple sources and make a firearm with them? To my knowledge, you cannot just assemble a 1911 and expect it to perfectly function right off a kitchen table. I can't find any assembly instructions on line which promise that.

An AR15, yes, most of the time, with little problem. What does crop up are parts selected for their social provenance not their dynamic operation, and those rifles tend to have cycling issues. The main culprit is mismatched gas length and buffer weights, which is not readily understood by the beginner looking to make a gun that is visually impressive. Therein lies the cause of failure. Too many see the AR as a static manual action gun, when the reality is it cycles like an internal combustion engine. Correct selection of parts requires understanding timing of the cycle, dwell location of the gas port, and weight of the buffer/bolt carrier group assembly. How cool the parts are has no bearing any more than what color you choose for a carburetor. The jetting and air bleeds are much more important.

Singer fulfilled their contract, Remington and Ithaca proved the process worked with millions made. And a plunger tube isn't a drop in part.

M1819 Hall rifle. John Hancock Hall had proposed the idea to the military of having guns with interchangeable parts. The concept was around before but I'm not sure anyone built a US rifle with that capability before this.

Tirod said:

Operations to assemble the 1911 involve staking and fitting. That is gunsmith level work and those parts are not drop in. The plunger tube for one.

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No, that is assembly line worker level. You could teach somebody to stake grip screw bushings or plunger tubes in pretty short order and with proper tools, it would be hard to get wrong. Oh, and don't forget the staked in front sight. And they didn't even have Youtube.


This is the only place I have ever heard of a missing 25000 Singers.
It seems to have escaped Mr Clawson. Can you provide a link or cite?

Jim Watson said:

This is the only place I have ever heard of a missing 25000 Singers.
It seems to have escaped Mr Clawson. Can you provide a link or cite?

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I looked up the Singer contract in Clawson's book. I wonder what this denigration of Singer is based on. Singer and other contractors were approached and funded to learn how to make 1911's in anticipation of large scale war production. Singer's pistols were all successes according to Clawson and issued.

Singer decided to focus on items that they were better suited to make, and was needed to for the war. Was it artillery range finders?

Something that Clawson did not address was how important sewing machines were to the war effort. Shooters and gun owners are all about small arms and ammunition, and nothing else. They more or less act as though food, trucks, clothing, are un needed in a war. Right? all you hear is how the gun won the war, and nothing else was necessary for victory. A narrative that is extremely limited. Every solider wore uniforms, carried equipment and holsters that were all sewed together. Never mind canvas tents, tops, parachutes, blankets, ammunition belts, back packs, etc, etc. I am quite certain Singer also had a prodigious output of sewing machines that produced war goods, that without, a bunch of naked guys without shoes, a gun in one hand, and ammunition in the other, would never have won the war.

Slamfire said:

Singer decided to focus on items that they were better suited to make, and was needed to for the war. Was it artillery range finders?

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Very close.

It was fire control computers for the Navy. These were mechanical computers, and if you have ever seen the inside of a mechanical computer, it very much like a sewing machine, lots of small gears, cams, and other assorted levers and cogs.

Tirod said:

Operations to assemble the 1911 involve staking and fitting. That is gunsmith level work and those parts are not drop in. The plunger tube for one.

Singer fulfilled their contract, Remington and Ithaca proved the process worked with millions made. And a plunger tube isn't a drop in part.

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You have a mistaken definition of "drop-in part".

A "drop-in part" is a part that fits into any assembly without hand fitting, or other alteration, in order for the entire assembly to work properly.

A "permanent assembly" is an assembly that once assembled is not intended the to disassembled for the life the the assembly.

The M1911 front sight, plunger tube, and grip screw bushings are both "drop-in" and "permanent". There is no alteration of any the parts required to fit them together (provided they were made correctly). "Staking" is not an alternation of the part, it is an assembly method, like screwing, welding, or brazing.

An M16 carrier key is a "semi-permanent assembly", the key and carrier assembly should remain together for the life of the carrier, however, if the key is damaged, it can be replaced. The staking of the key screws is indicative of the intended permanence.

Tirod said:

Operations to assemble the 1911 involve staking and fitting. That is gunsmith level work and those parts are not drop in. The plunger tube for one.

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An argument over definitions of "drop in" or "drop out" is fruitless. The mechanical ineptitude of the infantry has to be seen to believed. A lot of training has to be conducted for the average knuckle dragger to learn how to assemble or disassemble their firearms, and diagnosing problems and fixing them is beyond them.

The military has a real problem with these guys keeping the booger hook off the trigger and not shooting themselves, or others. It is hard to find the number of negligent discharges that result in death, but at one time in Iraq, those exceeded combat causalities. Never mind these guys fitting a slide to a frame, or tuning a trigger.

And, who carries extra plungers, front and rear sights, plunger expanders, hammers and punches into the field?

Hand fitted factory guns were standard up until the Smith and Wesson 39/59 series.
Davis/Raven/Jennings semiautomatics were drop in due to the huge tolerances in the design
Glock was probably the first that was so simple that even a person with limited skills could do a complete takedown and swap out parts

All revolvers required some hand fitting for proper timing and sear engagement
The 1911 needed the barrel link sized properly plus the sear engagement
The BHP had to have the thumb safety fitted to work right

JONWILL said:

Hand fitted factory guns were standard up until the Smith and Wesson 39/59 series.
Davis/Raven/Jennings semiautomatics were drop in due to the huge tolerances in the design
Glock was probably the first that was so simple that even a person with limited skills could do a complete takedown and swap out parts

All revolvers required some hand fitting for proper timing and sear engagement
The 1911 needed the barrel link sized properly plus the sear engagement
The BHP had to have the thumb safety fitted to work right

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No and no.

A simple look at the drawings shows that the standard 0.278 inch link, P/N 5013191, will always lift the barrel into proper engagement with the slide. The only time the military worried about other link length was with the match pistols.

People confuse what is required and and what is desired, tweaking guns to get better accuracy and a crisper trigger is a very different thing from hand fitting to get things to work.

lysanderxiii said:

No and no.

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Correct and correct. I was 45Bravo in the Army. I rarely had to fix anything on a 1911 but there was only one size link in my parts drawer.

lysanderxiii said:

......Getting away from guns, Ford re-did all the drawings for the Rolls-Royce Merlin so that there was no requirement for hand fitting during engine assembly, i.e., totally interchangeable parts......

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I think this may be erroneous based upon my source information, Allied Aircraft Piston Engines of WWII by Graham White.

Rolls-Royce was not up to the challenge of meeting WWII production demands. "To meet this challenge, Ford Motor Company in England was approached to build Merlins under license, and, rather surprisingly, Ford built Merlins to closer tolerances than Rolls-Royce did! The reasoning for this apparent anomaly was the fact that Ford was geared to produce inexpensive cars at a high volume, and therefore all parts needed to be interchangeable, whereas Roll-Royce relied on highly skilled craftsmen to hand fit all assemblies." No mention of Ford re-doing the drawings, just better tolerance control.

Rolls-Royce drawings were redrawn by Packard Car Company in USA for licensed production in the USA. The redrawing was "... in order to convert them from first-angle projection to the third-angle projection used in the United States and to include manufacturing specifications in American terminology". Packard also made significant improvements to their version of the Merlin such as the use of the Bendix injection carburetor.

tark said:

Correct and correct. I was 45Bravo in the Army. I rarely had to fix anything on a 1911 but there was only one size link in my parts drawer.

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Yup, me too. One size fits all link for the standard sloppy 1911.

lysanderxiii said:

No and no.

A simple look at the drawings shows that the standard 0.278 inch link, P/N 5013191, will always lift the barrel into proper engagement with the slide. The only time the military worried about other link length was with the match pistols.

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Yup, only after attending National Match School at Rock Island did the Army let me play with parts that were not drop-in.

Nom de Forum said:

No mention of Ford re-doing the drawings, just better tolerance control.

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Ford did redo the data package, they had to, where else where they going to record the new, better tolerances, and improved production methods?

The R-R prints were covered in drawing notes like "Fit to part XYZ . . ."(and by fitting, this meant hand scraping), that had to be replaced with flatness, roundness, and other proper tolerance values.

lysanderxiii said:

Ford did redo the data package, they had to, where else where they going to record the new, better tolerances, and improved production methods?

The R-R prints were covered in drawing notes like "Fit to part XYZ . . ."(and by fitting, this meant hand scraping), that had to be replaced with flatness, roundness, and other proper tolerance values.

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What is your source supporting your statements? Where have you seen drawings or text about the specifications? Where have you seen in print that Ford re-drew the drawings. Are you just assuming Ford would have to create new drawings rather than consistently building to specification? Please provide documentation supporting your statements. Seems odd my source would specifically mention Packard making drawings but not mention Ford previously doing the same.

Edit: I believe stories of Rolls-Royce using a significant amount of hand fitting are exaggerations. Wish I had a more authoritative and detailed source.