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Why did John Deere convert to metric bolts?

And when they converted, why did they decide to put 13mm, 15mm, and 18mm heads on their bolts?

Before I came across the CTS II, the only time I had to use a 15mm was when it was actually a Whitworth bolt. And a lot of tool sets don't even have a 18mm.

Worse still, when you replace a bolt with one from a fastener supplier, it will have a different size head than the John Deere ones. JD M10 is 15mm, generic M10 is 16mm. Then when you get into nyloc nuts it gets worse. M10 nyloc is 17mm. M12 bolt head 18mm, M12 nyloc 19mm.

I thought the USA was still using UNC and UNF?

The 7720 was good, 5/16 bolts have 1/2 heads, 3/8 bolts have 9/16 heads, 1/2 bolts have 3/4 heads, wherever you buy them, you can substitute bolts and still be able to use the same size spanners. UNF/UNC nyloc nuts are the same size as the bolt heads too.

Does anybody know what they were thinking????????
 

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Believe it or not the US uses more metric in manufacturing them Canada and we are supposed to be metric...

John Deere around here has been metric since the mid '80s I'd say and American made automobiles since about that time also.

18mm have been used since the introduction of metric I'm manufacturing in North America and I have no idea why it is still missing from sets, drives me nuts! They could do away with 8, 13, 19 and 24 because they are the same as 5/16, 1/2", 3/4 & 15/16. There is some stupid logic out there...
 

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When I was with deere I got told that in the eighties the US govt were going to pass a bill forcing all manufactures to go metric, so JD thought they would get ahead of the game and started swapping before bill was passed..then it got knocked back...the persisted as I guess mst of there export markets are metric? Nt sure how true any of this is, never researched it.

Ant..
 

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Metric fasteners allow deere to source parts to China easier.

There are actually 3 significant metric hardware standards and several smaller standards. They are not completely interchangeable. The Japanese use JIS, the Europeans use ISO, and the Germans use DIN. And then there are USS standards such as carriage bolts that didn't exist in metric, so deere had to invent them.

If any American equipment manufacturer would have put the engineering effort into designing better equipment that they wasted in changing to metric, the rest of the world would have been glad to overlook our fasteners to buy our good equipment.
 

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Metric would be an easier pill to swallow if you could actually stock the nuts and bolts that you need. Metric bolts have different thread widths and pitches, it makes it impossible to stock a decent bolt bin with them. Unless I am just being told that by the bolt supplier and he is just packing me full, but he had discouraged me from doing it. Oh well, I guess for now its give me SAE or give me death! OK, maybe a bit dramatic.
 

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The problem not only becomes the tools required to work on any given piece of equipment, its not being able to turn to a bolt rack and have the right bolt with both SAE and Metric, then metric bolts with different sized heads/nuts for the same thread specifications. Am I right in saying that quite a few of the metric bolt sizes are made in three different thread pitches ? Uh, I see CPT beat me to the similar thought, it would be insane to have that much inventory in bolts kicking around a farm.

I think what's made it worse is that there has been no continuity in making the leap in a relatively short few years from SAE to Metric and all the mixed up hardware of an engine that is metric and accessories on the engine bolted on with metric, then move away from the engine and its SAE. This has been going on for years as our JD 9600 is metric, then a JD cultivator bought in more recent times is SAE, same with the Farm King auger using all standard hardware. How is that for progress as it just keeps us in this maze of fasteners we need to acquire.
 

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Metric fasteners allow deere to source parts to China easier.

There are actually 3 significant metric hardware standards and several smaller standards. They are not completely interchangeable. The Japanese use JIS, the Europeans use ISO, and the Germans use DIN. And then there are USS standards such as carriage bolts that didn't exist in metric, so deere had to invent them.

If any American equipment manufacturer would have put the engineering effort into designing better equipment that they wasted in changing to metric, the rest of the world would have been glad to overlook our fasteners to buy our good equipment.

Very true!
does anyone remember British Whitworth or had the fun of working with that standard?
 

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metric n'n bolts

I think brent's post pretty much some up Metric. A couple of years ago either Hodgins,Kramer, or Richie bros were selling tool cabinet's, partial stocked with tool's as an opening to their auction's. A buddy of mine decided to too throw his number out on one of these chests. After a few months my ol buddy made the comment that the tool chest was not much good and the tools in the cabinet were of no use as the tools didn't fit bugger all!
 

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I'd rather have one or the other and I don't care which. I can adapt to one or the other I just hate the mix of both on one piece of equipment.
Exactly!

I keep harping on our guys that if they are adding a bracket to an all-metric machine, they better darn well be using metric hardware! Don't start mixing SAE and metric on a machine!

Andrew
 

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I remember back in 1992, I was pulling the transmission on a Chev half ton truck. I was pulling the bolts that attached the transmission to the engine, I knew the engine was english and the transmission was metic. I pulled the lower bolts no problem, they were 9/16" heads. as I worked my way to the top (which of course was very tight and I couldn't see but I knew there were bolts with threads going both directions, the end of the bolts had nuts on them to hold retainers for the harness running over the top of the transmission. The bolts themselves were definitely 3/8"NC, I thought the stud part I thought would be 1/4". No way could I get the nuts off using both 7/16" and 3/8", nothing would work. THE STUPID THINGS WERE 10mm, GM actually went through the trouble to make the same stud english on one end and metric on the other. How much do you think something like that cost to develope and manufacture?
 

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I am currently trying to repair a Betterbilt honey wagon that was built in the early 70's (if you think metric is bad, don't get me going on obsolete parts). Naturally everything on the outside is American made and standard, but the pump was imported from Italy so it's metric. I'm thinking of making a crash cart style toolbox to use around the equipment in the sheds with metric tools on one side and SAE on the other. Same deal with the combine... 9500 with a 912 header. The header is older and all SAE while the combine is (mostly) metric.
 

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I'd rather have one or the other and I don't care which. I can adapt to one or the other I just hate the mix of both on one piece of equipment.
I agree. I have no problem with metric but the mix is undesirable. I'm used to it from 17 years of working on 9600s and newer but you still need to carry more tools up the ladder. I find JD hardware to be superior to something like the generic SAE you would find on Brands Macdon or Farm King though. You hardly ever see the m8 or m10 bolts fail for no reason. The flange heads seem to help with bolt stability and holding strength. I hear quite a few complaints about the way an open end wrench fits on these bolts but I use hi quality sockets that are made to fit these heads so I rarely have an issue.
 

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I've certainly noticed that wrench slipping issue just mentioned on the hardware of the 9600 as our example, not only the open end but a 12 point box end that could have too much of a chamber built into it vs a very top end quality wrench due to "manufacturing allowance tolerances" creating even more of a potential slip of the wrench and then its rounding off the bolt and guess what, I usually don't have another one to replace it with as that's a hundred mile round trip to get. So if possible although not always possible, I try to use the 6 point sockets as much as I can on the hardware. The problem I see is that the nut or bolt head is not really much deeper in total vs an equivalent non flanged head and the flange molded on it certainly takes away more side surface to engage with the tools. If they made the bolts with a decent head length to engage with, along with that flange, that would be ideal.

I wished I owned a few sets of Snap On wrenches to have around, 12 and 6 point with the flank drive plus open end as I am told they grip a lot better. Unfortunately I own exactly zero Snap On wrenches as the price for one set is out of this world.
 

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Almost all metric bolts in use are the course thread pitch, which is around the same pitch as a UNC bolt. In certain applications metric fine is use, very like UNF is used in some application, in the larger sizes are are two 'fine' pitches but again this is sufficiently I have never had an issue. Simply stock a range of metric course (typically just call metric) and you will find you have no more parts than with a UNC selection.

Daniel
 
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