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| Another rainy day (aren't they all?), so spending more time out in the shop. A question I have is: why do 7/16" bolts need a 5/8" wrench but the nuts use an 11/16" wrench? All other sizes seem to use the same size wrenches for both the bolt and the nut, like 3/8" uses 9/16" on both ends, etc. Why is the 7/16ths an oddball?
All this rain and no harvest must be getting to me.
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Eastern NC | I have often wondered the same thing. The conclusion that I came up with is that the engineer was actually using his thinking cap and realized that if he used a different size for the bolt head and nut you could tighten it with one set of wrenches. All the rest require you to have at least two of everything. |
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West Texas | That pisses me off every time I run into that.
I think it's one of the stupidest things about the whole nut/bolt thing next to it not being metric!! I finally kind of got used to it but the Metric system is 100 times easier!! |
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Le Sueur VIA St.Thomas | Generally speaking bolt heads are 1.5 times larger thath the thread diameter. (1/2" bolt, 3/4" wrench) This works well for even 1/8" increments.
Once you get down to 1/16" increments, the theoretical wrench would be in 1/32" increments, not so good....
good luck -jim |
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| The bolt head smaller than the nut was the common standard before WW2 and probably lasted through the war. But to add confusion there are heavy nuts and standard nuts and the heavy nuts are usually one wrench size larger (and a quarter taller) than the standard nuts.
7/16" got used a lot of places that 10mm metric would have been used. With the coarse thread its probably about the same strength as a 10mm standard thread.
Gerald J. |
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Lincoln County. NC | dutch - 9/14/2010 18:51
That pisses me off every time I run into that.
I think it's one of the stupidest things about the whole nut/bolt thing next to it not being metric!! I finally kind of got used to it but the Metric system is 100 times easier!!
The morons who make metric bolts are worse, not better. A 12mm bolt may need a 19 or 18mm wrench or socket depending on who made the bolt. 10mm might be 17 or 16 mm across the flats. Work on NH or Kubota metric fasteners and never use an 18mm wrench. Wrench on Deere and that's all you use. |
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MI | When you go to take a bunch of them out you need to take the two combination wrenches and both sockets for the ratchet. :(
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Leeds, North Dakota | yep what a pita, wish we would just go to metric system and be done with it, i'm sure i will git flamed for this, work on mid 90 vehicles mix match, got wrenchs and sockets all over, coarse never grap the right one or can't find it for the mess, one thing i hate about metric system, three pitches of thread i think, jeez, sure makes that handy, when your out in the middle of nowhere and can't find the nut, scott. |
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Fairfield, Mt | The absurdity of it all. My 3/8" and 1/2" drive metric socket sets.
Edited by gfi 9/14/2010 20:21
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Brazilton KS | 7/16 bolt takes 5/8. 7/16 standard nut takes 5/8. 7/16 heavy nut takes 11/16. 1/2" bolt takes 3/4. Half inch standard nut takes 3/4. 1/2" heavy nut takes 7/8. 3/8 bolt takes 9/16, 3/8 standard nut takes 9/16. 3/8 heavy nut takes 5/8.
The real question is, why it the heavy nut more common in 7/16, while in every other size it is unusual? |
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| I've found from driving fully or partly metric vehicles over the past 46 years is that metric wrenches fit fractional bolts and nuts, but not the other way. 11mm is a good fit on 7/16. 6mm is a snug fit on 1/4", 8 mm is a perfect on 5/16 (goes both ways since they are only .0024 different). 19 mm is a good fit on 3/4" 13mm works on 1/2", 14 on 9/16. 16mm fits 5/8" I've owned at least two sets of wrenches all that time. I don't think any of my farm machinery is young enough to be metric though, but my "domestic" truck is mixed and my VW Golf is pure metric.
Gerald J. |
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West Texas | Probably because there made in China?
When you buy a set of wrenches in Holland it will not include a 14, 16, 18 or a 20. Those are very oddball sizes and you just never see them used there.
Common sizes are 4 thru 13, 15, 17 and 19. Then 22, 24, 27, 30 and 32. |
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SW Iowa | Because everyone has multiple 9/16 wrenches, but no one has two 5/8 or 11/16 wrenches.
Edited by MMiller 9/14/2010 22:05
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NW VA | I know the metric system makes more sense, but like others have said, wrench sizes are much more unpredictable. Seems like any time a metric bolt is replaced, it will invariably use a different size wrench. |
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Brazilton KS | Don't you have Deere equipment in Holland?
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Northwest Illinois | gfi, I have to wonder if they call it 1/4, 3/8, 1/2. 3/4 inch drive in metric countries. |
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Brazilton KS | Don't know...would it be 6.35mm, 12.7mm, and 19mm? edit: Looks like they are 1/4 and 1/2 in France. http://cgi.ebay.com/CLE-CLIQUET-FACOM-S161L-NEUF-/230524749059?pt=LH_DefaultDomain_71&hash=item35ac588503 http://cgi.ebay.com/COFFRET-CLIQUET-FACOM-1-4-/230523896838?pt=LH_DefaultDomain_71&hash=item35ac4b8406
Edited by plowboy 9/14/2010 23:20
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West Texas | Yep, but there has never been any 18's used. At least not when I was last around them of course that's been a few years now. might have changed. I bet though that 20 and 30 series Mannheim tractors don't have any bolts that use 14 or 18 mm wrenches. |
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West Texas | Nope, there called real small, small, big and real big ratchets. lol
To be honest, I do not know or remember what we called the different sized ratchets. Don't remember seeing many 1/4 or 3/8 drive ratchets. |
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Wallis, TX | In Ghana they called rachets by their 'inch' sizes as we do here. |
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SW Saskatchewan | 3/8 square nuts used to take a 19/32 wrench, IH used to use a lot of 23/32 wrenches and 25/32 was a common size.
3/8 bin bolts take an 11/16 wrench.
And never forget that 12 thread per inch 1/2 inch bolts are common now but as recent as the 70's one could find 13 thread per inch in use.
But at least you didn't need a second set of wrenches for a JD! |
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| Sets here don't usually include 18mm, but the sockets and wrenches that size have to be bought seperately.
The 18mm socket is needed for the older New Holland and John Deere discbine's knife bolts, made by Kuhn in France.
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| In Holland they called ratchets by the inch.
Wrenches by the millimeter. Common is 8, 10, 13, 17, 19, 22, 24, 27, 30, 32. The 15 is used for bicycles. you will never see 2 different wrenches for 1 bolt and nut. I thought I was drunk when I needed a 15 and 16 wrench on 1 bolt/nut of a JD combine. When you go metric please don't invent the wheel again. Maybe those engineers need to visit Europe first before the s crew up the whole system. |
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| Redman - 9/15/2010 00:08
And never forget that 12 thread per inch 1/2 inch bolts are common now but as recent as the 70's one could find 13 thread per inch in use.
!
I've think you've got that reversed --- National Coarse Thread for 1/2" I always thought is 13 tpi. I have an old tap and die set that has the obselete 12 tpi. |
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SW Saskatchewan | I'll blame it on being too late! |
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Brazilton KS | Deere doesn't use 14 much, but uses 18 on everything. At least harvester does. Craftsman doesn't include 15 or 18 in wrench sets. PITA if you work on GM and Deere.
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NW Washington | I got a laugh one day when a Dutch student in the US called a Cresent wrench an "English wrench."
My brother's complaint about metric wrenches is that by going in one mm increments you can't eye ball a wrench and be fairly sure of what size it is, ie, distinguish between a 13mm from a 14 mm.
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Humeston, IA | In France I figured they called 1/4' "reason to strike" and 1/2" "March in the streets". |
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SW Ontario | In most sizes the head is 1.5x the bolt diameter. In a 7/16 that would be 10.5/16, so it looks like they went lower on the regular nut, but if you've ever used one you'll find they are very thin compared to other sizes and don't hold up well. 7/16 bolts are only kept in my bin for replacements of old ones where there are tapped holes or it's too much work to bore out to half..... |
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| The rarely used 9/16" bolts also use a different size for bolt head and nut. Don't remember the size. Used on the old Allis Chamlers plow to bolt the frog to the frame. Also used the odd 9/16" plow bolts that go throught the frame, frog, and landside. The frog and new set of landsides had holes to fit 5/8" plow bolts, so I had the machine shop enlarge the frame holes to fit 5/8. |
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A Question About Nuts and Bolts
