I'm in the US, shells are made with SAE hardware and the universal standard is 1/4-20 using 7/16 socket. European shells are metric with the standard M6 using 10mm.requiring lock washer.
How did this evolve? Pocock used a heavy hex nut for rigger nut, basically a 1/4-20 but with a 1/2 inch exterior socket. The reasoning was less torque required to hold nut in place thus preventing over-compression of the shoulder and not
I only guess that other builders went to standard hex because of the expense and availability, I don't really know.
Is there some reason European boats are M6 rigger bolts/nuts and not M7?
Or vice versa, why 1/4-20 US and not #10?
Just curious.
On 23/02/2021 10:29, sully wrote:lock washer.
I'm in the US, shells are made with SAE hardware and the universal standard is 1/4-20 using 7/16 socket. European shells are metric with the standard M6 using 10mm.
How did this evolve? Pocock used a heavy hex nut for rigger nut, basically a 1/4-20 but with a 1/2 inch exterior socket. The reasoning was less torque required to hold nut in place thus preventing over-compression of the shoulder and not requiring
I only guess that other builders went to standard hex because of the expense and availability, I don't really know.
Is there some reason European boats are M6 rigger bolts/nuts and not M7?
Or vice versa, why 1/4-20 US and not #10?
Just curious.
Answers to the last first:
There are preferred sizes in the metric system, with non-preferred sizes
in between. So we get M3,4,5,6 then M8, 10, 12, 14 and so on. These
refer to the millimetric overall diameter of the bolt.
Rowing used to use 1/4" OD bolts for riggers worldwide. And these often
had square nuts, flat on one face & slightly domed on the other face.
The doming was so that the corners _didn't_ scrape on the rigger and
only the ignorant put the nuts on t'other way up. And to tighten &
loosen the nuts you had a longish tube, one end of which was forged into
a square that fitted the nut while the other end was inserted into a
round wooden handle.
This was totally practical:
The 1/4" bolt was solid enough not to get bent when you caught something against it or while fiddling to put the rigger onto the boat. The
square nut worked beautifully without a protective washer. And the lack
of leverage ensured that even the biggest wally in the boat couldn't overtighten the nut.
But in those far-off days all bolts were carbon steel, which is much
tougher than today's stainless steel, although rust could be a problem.
With the dominance of the metric system, most nations switched to M6,
the closest approximation to 1/4" (=6.35mm). But there were none of
those handy but confusing square nuts. And the thread pitches were different, so an Imperial nut would not screw onto a metric bolt (& you shouldn't mix carbon & stainless steels). So hex nuts it was.
Unfortunately, that put spanners (US = wrenches) into the hands of crew gorillas. And we all know that, unless we severely overtighten a nut,
that rigger is sure to fall off.... As I said, stainless is relatively
soft, so the gorillas started stripping rigger bolts & nuts, because
they could. Why not give every nut that extra little tweak before you
go afloat? With a hunk of beef swinging on the far end of that handy
lever? What could possibly go wrong?
You get a similar fear-driven lack of grasp of the limitations of
stainless steel when people overtighten the nuts on their pins, and elsewhere. And sometimes they really do. But engineering nous is far
too fancy for us simple rowers.
Does that answer that particular question, Sully? The sad reality is
that it is the US which is out of step with the world, not the other way around. Metric rules, even in space exploration. But thank you for
looking after our Imperial system, even though you've dumped our
beautiful Whitworth version in favour of SAE.
Cheers -
Carl
On Tuesday, February 23, 2021 at 6:48:55 AM UTC-8, carl wrote:lock washer.
On 23/02/2021 10:29, sully wrote:
I'm in the US, shells are made with SAE hardware and the universal standard is 1/4-20 using 7/16 socket. European shells are metric with the standard M6 using 10mm.
How did this evolve? Pocock used a heavy hex nut for rigger nut, basically a 1/4-20 but with a 1/2 inch exterior socket. The reasoning was less torque required to hold nut in place thus preventing over-compression of the shoulder and not requiring
I only guess that other builders went to standard hex because of the expense and availability, I don't really know.
Is there some reason European boats are M6 rigger bolts/nuts and not M7?
Or vice versa, why 1/4-20 US and not #10?
Just curious.
Answers to the last first:
There are preferred sizes in the metric system, with non-preferred sizes in between. So we get M3,4,5,6 then M8, 10, 12, 14 and so on. These
refer to the millimetric overall diameter of the bolt.
Rowing used to use 1/4" OD bolts for riggers worldwide. And these often had square nuts, flat on one face & slightly domed on the other face.
The doming was so that the corners _didn't_ scrape on the rigger and
only the ignorant put the nuts on t'other way up. And to tighten &
loosen the nuts you had a longish tube, one end of which was forged into
a square that fitted the nut while the other end was inserted into a
round wooden handle.
This was totally practical:
The 1/4" bolt was solid enough not to get bent when you caught something against it or while fiddling to put the rigger onto the boat. The
square nut worked beautifully without a protective washer. And the lack
of leverage ensured that even the biggest wally in the boat couldn't overtighten the nut.
But in those far-off days all bolts were carbon steel, which is much tougher than today's stainless steel, although rust could be a problem.
With the dominance of the metric system, most nations switched to M6,
the closest approximation to 1/4" (=6.35mm). But there were none of
those handy but confusing square nuts. And the thread pitches were different, so an Imperial nut would not screw onto a metric bolt (& you shouldn't mix carbon & stainless steels). So hex nuts it was.
Unfortunately, that put spanners (US = wrenches) into the hands of crew gorillas. And we all know that, unless we severely overtighten a nut,
that rigger is sure to fall off.... As I said, stainless is relatively soft, so the gorillas started stripping rigger bolts & nuts, because
they could. Why not give every nut that extra little tweak before you
go afloat? With a hunk of beef swinging on the far end of that handy lever? What could possibly go wrong?
You get a similar fear-driven lack of grasp of the limitations of stainless steel when people overtighten the nuts on their pins, and elsewhere. And sometimes they really do. But engineering nous is far
too fancy for us simple rowers.
Does that answer that particular question, Sully? The sad reality is
that it is the US which is out of step with the world, not the other way around. Metric rules, even in space exploration. But thank you for
looking after our Imperial system, even though you've dumped our
beautiful Whitworth version in favour of SAE.
Cheers -Yes, thanks Carl. One thing that you pointed out that didn't occur to me was that M6 was the closest diameter bolt to 1/4", I thought M7 was, an assumption based on how closely the outside diameter of the 1/4" and M7 hexe nuts match.
Carl
Yes, I remember when there was a push for US to go to metric in the late 60s, it was certainly a communist plot meant to rob us of our precious bodily fluids... :^)
On Wednesday, 24 February 2021 at 05:48:00 UTC, sully wrote:lock washer.
On Tuesday, February 23, 2021 at 6:48:55 AM UTC-8, carl wrote:
On 23/02/2021 10:29, sully wrote:
I'm in the US, shells are made with SAE hardware and the universal standard is 1/4-20 using 7/16 socket. European shells are metric with the standard M6 using 10mm.
How did this evolve? Pocock used a heavy hex nut for rigger nut, basically a 1/4-20 but with a 1/2 inch exterior socket. The reasoning was less torque required to hold nut in place thus preventing over-compression of the shoulder and not requiring
nuts were a thing, some boat builder would have adopted them, but only for the bow rigger on pairs on alternate Wednesdays. (Apologies in advance Carl).Yes, thanks Carl. One thing that you pointed out that didn't occur to me was that M6 was the closest diameter bolt to 1/4", I thought M7 was, an assumption based on how closely the outside diameter of the 1/4" and M7 hexe nuts match.Answers to the last first:
I only guess that other builders went to standard hex because of the expense and availability, I don't really know.
Is there some reason European boats are M6 rigger bolts/nuts and not M7? >>>>
Or vice versa, why 1/4-20 US and not #10?
Just curious.
There are preferred sizes in the metric system, with non-preferred sizes >>> in between. So we get M3,4,5,6 then M8, 10, 12, 14 and so on. These
refer to the millimetric overall diameter of the bolt.
Rowing used to use 1/4" OD bolts for riggers worldwide. And these often
had square nuts, flat on one face & slightly domed on the other face.
The doming was so that the corners _didn't_ scrape on the rigger and
only the ignorant put the nuts on t'other way up. And to tighten &
loosen the nuts you had a longish tube, one end of which was forged into >>> a square that fitted the nut while the other end was inserted into a
round wooden handle.
This was totally practical:
The 1/4" bolt was solid enough not to get bent when you caught something >>> against it or while fiddling to put the rigger onto the boat. The
square nut worked beautifully without a protective washer. And the lack
of leverage ensured that even the biggest wally in the boat couldn't
overtighten the nut.
But in those far-off days all bolts were carbon steel, which is much
tougher than today's stainless steel, although rust could be a problem.
With the dominance of the metric system, most nations switched to M6,
the closest approximation to 1/4" (=6.35mm). But there were none of
those handy but confusing square nuts. And the thread pitches were
different, so an Imperial nut would not screw onto a metric bolt (& you
shouldn't mix carbon & stainless steels). So hex nuts it was.
Unfortunately, that put spanners (US = wrenches) into the hands of crew
gorillas. And we all know that, unless we severely overtighten a nut,
that rigger is sure to fall off.... As I said, stainless is relatively
soft, so the gorillas started stripping rigger bolts & nuts, because
they could. Why not give every nut that extra little tweak before you
go afloat? With a hunk of beef swinging on the far end of that handy
lever? What could possibly go wrong?
You get a similar fear-driven lack of grasp of the limitations of
stainless steel when people overtighten the nuts on their pins, and
elsewhere. And sometimes they really do. But engineering nous is far
too fancy for us simple rowers.
Does that answer that particular question, Sully? The sad reality is
that it is the US which is out of step with the world, not the other way >>> around. Metric rules, even in space exploration. But thank you for
looking after our Imperial system, even though you've dumped our
beautiful Whitworth version in favour of SAE.
Cheers -
Carl
Yes, I remember when there was a push for US to go to metric in the late 60s, it was certainly a communist plot meant to rob us of our precious bodily fluids... :^)
I presume at the point of switching over to M6 nuts all the boat builders were distracted and had their minds elsewhere - it's the only possible explanation for their adopting something approaching a standard. I'm sure if anti-clockwise tightening M7
Andy
On Tuesday, February 23, 2021 at 6:48:55 AM UTC-8, carl wrote:lock washer.
On 23/02/2021 10:29, sully wrote:
I'm in the US, shells are made with SAE hardware and the universal standard is 1/4-20 using 7/16 socket. European shells are metric with the standard M6 using 10mm.
How did this evolve? Pocock used a heavy hex nut for rigger nut, basically a 1/4-20 but with a 1/2 inch exterior socket. The reasoning was less torque required to hold nut in place thus preventing over-compression of the shoulder and not requiring
Answers to the last first:
I only guess that other builders went to standard hex because of the expense and availability, I don't really know.
Is there some reason European boats are M6 rigger bolts/nuts and not M7? >>>
Or vice versa, why 1/4-20 US and not #10?
Just curious.
There are preferred sizes in the metric system, with non-preferred sizes
in between. So we get M3,4,5,6 then M8, 10, 12, 14 and so on. These
refer to the millimetric overall diameter of the bolt.
Rowing used to use 1/4" OD bolts for riggers worldwide. And these often
had square nuts, flat on one face & slightly domed on the other face.
The doming was so that the corners _didn't_ scrape on the rigger and
only the ignorant put the nuts on t'other way up. And to tighten &
loosen the nuts you had a longish tube, one end of which was forged into
a square that fitted the nut while the other end was inserted into a
round wooden handle.
This was totally practical:
The 1/4" bolt was solid enough not to get bent when you caught something
against it or while fiddling to put the rigger onto the boat. The
square nut worked beautifully without a protective washer. And the lack
of leverage ensured that even the biggest wally in the boat couldn't
overtighten the nut.
But in those far-off days all bolts were carbon steel, which is much
tougher than today's stainless steel, although rust could be a problem.
With the dominance of the metric system, most nations switched to M6,
the closest approximation to 1/4" (=6.35mm). But there were none of
those handy but confusing square nuts. And the thread pitches were
different, so an Imperial nut would not screw onto a metric bolt (& you
shouldn't mix carbon & stainless steels). So hex nuts it was.
Unfortunately, that put spanners (US = wrenches) into the hands of crew
gorillas. And we all know that, unless we severely overtighten a nut,
that rigger is sure to fall off.... As I said, stainless is relatively
soft, so the gorillas started stripping rigger bolts & nuts, because
they could. Why not give every nut that extra little tweak before you
go afloat? With a hunk of beef swinging on the far end of that handy
lever? What could possibly go wrong?
You get a similar fear-driven lack of grasp of the limitations of
stainless steel when people overtighten the nuts on their pins, and
elsewhere. And sometimes they really do. But engineering nous is far
too fancy for us simple rowers.
Does that answer that particular question, Sully? The sad reality is
that it is the US which is out of step with the world, not the other way
around. Metric rules, even in space exploration. But thank you for
looking after our Imperial system, even though you've dumped our
beautiful Whitworth version in favour of SAE.
Cheers -
Carl
Yes, thanks Carl. One thing that you pointed out that didn't occur to me was that M6 was the closest diameter bolt to 1/4", I thought M7 was, an assumption based on how closely the outside diameter of the 1/4" and M7 hexe nuts match.
Yes, I remember when there was a push for US to go to metric in the late 60s, it was certainly a communist plot meant to rob us of our precious bodily fluids... :^)
Yes, I remember when there was a push for US to go to metric in the
late 60s, it was certainly a communist plot meant to rob us of our
precious bodily fluids... :^)
On Tue, 23 Feb 2021 21:47:59 -0800, sully wrote:
Yes, I remember when there was a push for US to go to metric in the
late 60s, it was certainly a communist plot meant to rob us of our
precious bodily fluids... :^)
There is a body of people in this country (not excluding one or two
prominent parliamentarians, who would be termed "legislators" in the US)
who would like to see this country return to feet, inches and the rest.
They see the "Metric system" as a European thing, y'see, and therefore anathema.
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