I didn't grow up with metrics.

Riverslim · Aug 31, 2018

Tap and die set - Someone ask me if they could borrow a 16mm die. Well, one says 16 - 1.5 and one says 16 - 2. Is that like NC and NF with SAE sizes?

Steve@Advance · Aug 31, 2018

Yes, there are different thread pitches in metrics.

With metrics, the threads are measured as the distance between the threads.

The 1.5 means there is 1.5mm from thread to thread, so that will be the fine thread. The 2.0 is 2mm from thread to thread, or coarse thread.

With SAE threads, the threads are measured as number of threads per inch.

Ken Macfarlane · Aug 31, 2018

There?s at least two competing metric bolt/thread standards which is annoying. Often a metric tap and die set doesn?t have the correct sizes. I think the Japanese stuff is ISO while the euro stuff is Din? I know the North American and European metric stuff is coarser threads than the same diameter Asian bolts.

Farmall plowboy · Aug 31, 2018

Thanks for clearing that up for the metric thread I have often wondered about it.

jeffcat · Aug 31, 2018

Also a lot of the ISO screws from Japan will have a little dimple or punch mark on the head.

matthies · Aug 31, 2018

the there is also 1.25 and 1.75.

37chief · Aug 31, 2018

Now if you really want to get confused work with Whitworth tools. My motorcycles use US, Metric, and Whitworth tools. It drives me nuts especially taps, and dies. Stan

Ian Beale · Aug 31, 2018

But remember that the metric fans tell you that metrics simplify things (/s)

Russ from MN · Aug 31, 2018

It's a very good system once you get used to it, but Japan, Europe, and US don't use the same size wrenches on the same bolts.

Gary in da UP · Aug 31, 2018

reading all the below posts , from people much smarter than me all I can offer is that In my Experience there is fine pitch, coarse pitch and son of a pitch........ good luck

Dune Country · Aug 31, 2018

now where did I put that 10mm wrench?

504 · Aug 31, 2018

And a thread gauge is a cheap way to make sure you are using the right bolt for the nut. I have a thread chaser set for metric and standard,the most used part is the thread file. It is good for cleaning up threads and as a thread gauge.

Philip d · Aug 31, 2018

I started grade school (in Canada) in 1981. Everything was well converted to metric by then. I?ve had 12 years of schooling in metric so I can tell ya all you need to know about metric in the real world. If ya can?t find a 7/16 wrench an 11mm will work. If ya can?t find a 1/2? wrench a 13mm will likely fit. If ya can?t find a 9/16 then try a 14mm. Now if ya can?t find a 3/4 than a 19mm will work just fine. Now for liquids, a 5 gal bucket of oil is exactly 18.9 litres. A gallon of gas is 3.78 litres and a quart is less than a litre. Oh in Canada a 1/4 mile is still a 1/4 mile, 100mph is about 160 km/h and 200 km/h is fast. 55 mph is a little over 90 km/h and paydays Friday.

David G · Aug 31, 2018

Hoenes · Sep 1, 2018

504, ditto on the thread file. I bought my first one, when I still owned my panhead. Harley used a lot of odd bolts back then,uncommon at the hardware store. Thread file was a life saver.

caterpillar guy · Sep 1, 2018

Metric, just another way to say bad mechanic. Nothing is good about it. To many metric systems and nothing converts so each time it is an adventure to deal with it. Like said more than one metric system with more than a few thread pitches and all the other nonsense included.
Phillip is right about those few wrenches interchanging most of the time. Though if th 3/4 wrench is needed and it is tight the 19mm will slip on a 3/4 nut.

Hay maker2 · Sep 1, 2018

Metric system is much easier, think about this....
What is 5mm plus 7mm? Simple answer, right?

What is 7/16” plus 5/8”, most people have to think about this....

What is 0.5625 plus 0.4375, still thinking?

What’s the decimal equivalent to 15/16”?

What’s the fraction equivalent of 0.1875?

So really which is easier?????

There is a fine, medium, and coarse pitch threads on meteric fasteners. You will seldomly ever see the medium pitch thread ....
No difference than the fine and coarse pitch imperial fasteners.

Phillips and a flat head screw drivers are commonly referred to as a plus and minus screw driver in the international community. If you did not know what a Phillips screw driver was, but I bet you could figure out what a plus screw driver is.

Texasmark1 · Sep 1, 2018

The more you use them the more they make sense. Very easy calculations. I wish we would have started out with them.

Fred Werring · Sep 1, 2018

Dune, the same place you used to leave your 1/2 inch wrench

Fred

dr sportster · Sep 2, 2018

You need a standard and a metric thread gauge.

DMartin9N-2N · Sep 2, 2018

Stretching the topic a little bit; In the late 1950's I owned several Indian Motorcycles. I discovered my 1946 Chief had odd bolts on the primary drive housing. The bolts & nuts looked like ordinary hardware store bolts to me, but the 1/4 inch bolts had 32 threads per inch. Normally in my experience a fine threaded 1/4 inch bolt had 28 threads per inch, the 32 looked similar but they could not be mixed. So you had to keep each nut with its bolt when you were tearing down a unit; NEVER toss everything in one bucket! Just a nostalgic comment....

Dennis M. in W. Tenn.

I didn't grow up with metrics.

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