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#6-48 and #8-40 Rant

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Topic: #6-48 and #8-40 Rant
Posted By: Scrumbag
Subject: #6-48 and #8-40 Rant
Date Posted: January/16/2020 at 12:41
All,

Can anyone tell me why oh why optics and mount manufacturers keep trying to use these threads on optics mounts?

They are basically unobtainium outside the US bar specialist gun supply stores which charge a horrendous mark up. Can US makers not go over to the M designations that can be easily got in the US and the rest of the world that has gone Metric? It would really help us out here and would stop some stupid retailers in the US claiming that some specific screws are ITAR controlled just because of the damn thread! (Taylor's, I'm calling you out on that one!)

Ilya, please have a chat with Burris particularly on this!

Scrummy


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Was sure I had a point when I started this post...



Replies:
Posted By: Rancid Coolaid
Date Posted: January/16/2020 at 12:51
The metric conversation is an interesting one. Basically there are those who have put a man on the moon - and those who use metric.

Carry on.

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Freedom is something you take.
Respect is something you earn.
Equality is something you whine about not being given.


Posted By: RifleDude
Date Posted: January/16/2020 at 13:24
I agree totally. I don’t know why they weren’t converted over a long time ago. 6-48 and 8-40 are ridiculous choices for fasteners, used virtually nowhere else on the planet except firearms, and even then, basically only on scope mounts. Half of US manufacturing has switched over to metric units some time ago. The metric system makes infinitely more sense, with every unit relating to the other units in increments of 10.




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Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Rancid Coolaid
Date Posted: January/16/2020 at 16:01
I was trying to make a joke and you had to go and ruin it with ration and logic.

Thanks for that!

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Freedom is something you take.
Respect is something you earn.
Equality is something you whine about not being given.


Posted By: tahqua
Date Posted: January/16/2020 at 16:31
Richard cranium!

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Doug


Posted By: Scrumbag
Date Posted: January/17/2020 at 04:54
Hi RC, if it's any consolation I thought it was funny!

The think that bugs me is I have heard quite a few times people talk about US made rings / mounts and complain "They're nice but good luck getting spare screws"

It's literally costing companies sales... for a historical hangover...

Is there a technical reason for say #6-48? I don't imagine it can be fastly superior to M3.5 can it?

Scrummy


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Was sure I had a point when I started this post...


Posted By: budperm
Date Posted: January/17/2020 at 08:41
Well it is SAE vs Metric.  
I surely wouldn't mind if they switched over on the screws.

I can tell you, growing up SAE, it's surprising how hard it is to get that inherent feeling for sizes and volumes in metric that I have for SAE sizes.

It's been painful at times trying to shop on-line buying metric or European sizes....


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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson





Posted By: Kickboxer
Date Posted: January/17/2020 at 09:20
Lobbyists, "good ole boy"-ism and machine costs define the problem.  Metrics, obviously, are the units to standardize on, but there are significant changeover costs and issues.  There is also a philosophy of "un-American" in using metrics.  While with the F/A-18 program, I worked for several years to make the conversion to metrics and could not overcome the politics and the significant cost add-ons.  The big problems come when programs are allowed to use both (JPL and Lockheed Martin cost us a MARS test spacecraft because of a failure to make proper conversions... guess it was actually LM's fault, but JPL did not double check the math).  Resistance to conversion is still strong, though misguided. I doubt I will live to see it happen.

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Opinion,untempered by fact,is ignorance.

There are some who do not fear death... for they are more afraid of not really living


Posted By: budperm
Date Posted: January/17/2020 at 09:29
Have to agree with you on that one, not in our lifetime...  

Good ol JPL!  I came very close to working at JPL in Columbia, MD  Interesting place!


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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson





Posted By: Kickboxer
Date Posted: January/17/2020 at 09:31
I believe you would have had fun there, Bud.  Lots of interesting stuff going on.

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Opinion,untempered by fact,is ignorance.

There are some who do not fear death... for they are more afraid of not really living


Posted By: RifleDude
Date Posted: January/17/2020 at 11:05
Originally posted by Scrumbag Scrumbag wrote:

Hi RC, if it's any consolation I thought it was funny!

The think that bugs me is I have heard quite a few times people talk about US made rings / mounts and complain "They're nice but good luck getting spare screws"

It's literally costing companies sales... for a historical hangover...

Is there a technical reason for say #6-48? I don't imagine it can be fastly superior to M3.5 can it?

Scrummy

The reason the gun mfgs went with such an odd pitch in #6 and #8 is so that they could get a lot of thread engagement in a short screw, to both provide fastening strength and to resist vibrating loose. Those were valid choices back in 1930, but today we are only clinging to them because "that's the way it's always been." You're 100% correct that M3.5 X 0.6 and M4 X 0.5 metric screws are so incredibly close dimensionally to 6-48 and 8-40 respectively, both in diameter and pitch, that there is no technical reason that the imperial size screws would be superior in any way. For all practical purposes, each are interchangeable in terms of tensile strength, thread shear, vibration loosening resistance, etc. And you can get those metric screws everywhere. It isn't done because it will upset the apple cart, old farts who are resistance to change and dislike everything metric will b!tch and moan...and it makes too much sense.


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Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: koshkin
Date Posted: January/17/2020 at 12:35
I am totally on board with switching to metric, but people do not like change.  SAE sizes confuse the hell out of me.

With gun companies though, I think there is also an element of sadism there.  I think they are actively trying to find the most silly way of doing things just to see their customer run from hardware to hardware store trying to locate 7/64 and 9/64 hex wrenches and only finding 1/8 on the shelf.

By the way, that should also switch to metric.

ILya


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http://www.opticsthoughts.com - www.opticsthoughts.com
http://fb.me/DarkLordOfOptics - Facebook
https://www.instagram.com/darklordofoptics/ - Instagram


Posted By: koshkin
Date Posted: January/17/2020 at 12:36
Originally posted by Rancid Coolaid Rancid Coolaid wrote:

The metric conversation is an interesting one. Basically there are those who have put a man on the moon - and those who use metric.

Carry on.

If we used metric, we'd probably get to the moon a couple of years earlier and already have a functioning base on the surface.

ILya


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http://www.opticsthoughts.com - www.opticsthoughts.com
http://fb.me/DarkLordOfOptics - Facebook
https://www.instagram.com/darklordofoptics/ - Instagram


Posted By: tahqua
Date Posted: January/17/2020 at 12:43
Interestingly enough, Scrummy's homies brought us the Imperial measurement system. As far as I am concerned, the only Imperial measurement left should be the pint. A half litre of ale just doesn't sound right.

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Doug


Posted By: koshkin
Date Posted: January/17/2020 at 12:44
Originally posted by tahqua tahqua wrote:

Interestingly enough, Scrummy's homies brought us the Imperial measurement system. As far as I am concerned, the only Imperial measurement left should be the pint. A half litre of ale just doesn't sound right.

Litre of ale sounds about right to me, so you can safely do away with the pint too.

ILya


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http://www.opticsthoughts.com - www.opticsthoughts.com
http://fb.me/DarkLordOfOptics - Facebook
https://www.instagram.com/darklordofoptics/ - Instagram


Posted By: tahqua
Date Posted: January/17/2020 at 12:47
A liter of lager in Munich is a good thing. But, a pint of ale rings true.

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Doug


Posted By: koshkin
Date Posted: January/17/2020 at 12:57
Originally posted by tahqua tahqua wrote:

A liter of lager in Munich is a good thing. But, a pint of ale rings true.

I am sure you will get used to it...

ILya


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http://www.opticsthoughts.com - www.opticsthoughts.com
http://fb.me/DarkLordOfOptics - Facebook
https://www.instagram.com/darklordofoptics/ - Instagram


Posted By: Son of Ed
Date Posted: January/29/2020 at 05:57
Originally posted by Rancid Coolaid Rancid Coolaid wrote:

The metric conversation is an interesting one. Basically there are those who have put a man on the moon - and those who use metric.

Carry on.


           Bucky


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Visit the Ed Show


Posted By: Dogger
Date Posted: January/29/2020 at 06:20
The metric system makes sense but I was raised on Imperial and am still not comfortable with it even after many years. Part of the problem is our mixed bag of metric and imperial. Go into any  store to buy building supplies and all lumber and hardware (nails, screws etc.) are in feet and inches. Then look online for Canadian building codes and specs are shown in metric, with smaller sidebar showing standard sizes. Really screws with your mind.

Love it when I visit my son in Miami because weather is shown in Fahrenheit and winds in mph - much easier for me to relate to. My kids think I’m a dinosaur, their generation was schooled from the start in metric so that’s all they know - I do building projects for them, so they don’t understand my frustration.


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God save the Empire!


Posted By: Scrumbag
Date Posted: January/29/2020 at 08:00
I could murder a beer... I've been talking to the insurance companies...


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Was sure I had a point when I started this post...



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