Jos,
It was Europe that changed on us. When everybody was in the inch system, the US
was born, then Europe changed, and wanted us to? We have too many things here
made in the inch system to change even though it's being pushed. Actually, I
find metric harder than inch. Of course that's probably because that's all I've
ever used. Why was the metric system formed and used over the inch system? What
country got the ball rolling as I cant remember? It's just as easy for me to
say water freezes at 32 deg F than to say it does at 0 deg C, or something 1"
long is 25.4 mm. The only thing I despise is having to keep both inch and
metric sockets over the US auto manufacturers using metric. That's kind of
funny in a way, here we invented the automobile, and we're using metric so
folks in Europe and Asia will buy them. Why wont Europe and Asia send the US
autos with inch fasteners? We do have it whipped on the speedometers, they have
both measurements on them! I know when we (J.H. Fletcher Co.) shipped those
roof bolters for the mines to Europe and Asia, they were made with inch
fasteners and were accepted. The reason I know is I helped design a bunch of
them. Looks to me like what's good for the goose is good for the gander.
Best,
Will
*********** REPLY SEPARATOR ***********
On 8/4/05 at 12:10 AM hermans wrote:
>Why you guys dont adopt the metric sys.........? Its that more simple
>for every body.
>Seems European adopted GMT about a century ago in terms of an exchange
>......but they'r still in the expectation.
>
>Jos
>
>-----Message d'origine-----
>De?: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] De
>la part de Will Matney
>Envoyé?: mercredi 3 août 2005 1:46
>À?: amps@contesting.com
>Objet?: Re: [Amps] Another metalwork question
>
>Bill,
>
>Sorry about that! I dont do metric conversions enough to remember
>correctly sometimes. The 6.45 came from a conversion in a transformer
>equation and it should have been divide by not multiply. The inches to
>mm factor is 25.4 (1 inch = 25.4 mm). From the example below 0.045" =
>1.143 mm. The same equation works, it's just you divide by, not multiply
>by in the end to convert from one to another. However, for what you want
>leave dividing 25.4 off at the end and it will be in mm. I know one
>thing, I'll have to stop trying to think when I've been up so late.
>
>BA = (0.0078 * T + 0.0174 * R) * No. of deg. in bend
>
>14 Ga = 1.62814 mm
>
>For 0" radius, 90 Deg bend in aluminum;
>
>(0.0078 * 1.62814 + 0.0174 * 0) * 90
>
>(0.01269949 + 0) * 90 =
>
>0.01269949 * 90 = 1.14295428" or 1.14295428" / 25.4= 0.0449" (0.045")
>or for ending pieces of flanges
>
>Best,
>
>Will
>
>*********** REPLY SEPARATOR ***********
>
>On 8/2/05 at 11:29 AM Bill Aycock wrote:
>
>>Will-
>>Where did the 6.45 come from? I think it is wrong.
>>Bill
>>
>>At 07:14 AM 8/2/2005 -0400, Will Matney wrote:
>>
>>>Martin, I dont think much really changes as those factors are derived
>>from
>>>ratios. You should be able to add a multiplier of 6.45 to the formula
>to
>>>get metric sums. Try that to see what you get and substitute MM in
>place
>>>of the inch measurements then multiple the sum by 6.45. I think you'll
>>get
>>>the same just different measurment systems that way.
>>>
>>>BA = (0.0078 * T + 0.0174 * R) * No. of deg. in bend * 6.45
>>>
>>>Best,
>>>
>>>Will
>>>
>>>
>>>*********** REPLY SEPARATOR ***********
>>>
>>>On 8/2/05 at 5:57 PM Martin Sole wrote:
>>>
>>> >Will,
>>> >
>>> >Thanks for the info, very useful. Do you have the formula in a
>suitable
>>> >form
>>> >for metric material? Haven't worked in imperial measurements for
>over 30
>>> >years and only see it now and again on odd bits of US made kit.
>>Actually I
>>> >am going to make a new plenum for my second Alpha and the original
>is
>>most
>>> >certainly made to imperial measurements but nobody here would
>>understand if
>>> >I tried to replicate it that precisely so the new one will be made
>to
>>> >metric
>>> >dimensions. Would definitely appreciate the drawing and picture,
>mail
>>away.
>>> >
>>> >Thanks
>>> >
>>> >Martin
>>> >
>>> >
>>> >-----Original Message-----
>>> >From: amps-bounces@contesting.com
>[mailto:amps-bounces@contesting.com]
>>On
>>> >Behalf Of Will Matney
>>> >Sent: 02 August 2005 17:29
>>> >To: amps@contesting.com
>>> >Subject: Re: [Amps] Another metalwork question
>>> >
>>> >Martin,
>>> >
>>> >On bending steel, you use 1/2 the material thickness to figure how
>much
>>to
>>> >add in length. In other words you divide the material thickness in
>half
>>> >where there would be an imaginary center line (its neutral axis)
>going
>>> >trough it. Then when the steel is bent, a radius is formed on this
>>> >imaginary
>>> >center line even though the inside bend is a sharp 90 deg bend. So
>>whatever
>>> >the distance is around that small radius in the middle of the steel
>is
>>the
>>> >material to be added. Now aluminum is a different story and there is
>a
>>> >formula for it too. What happens in aluminum, there is a shrinkage
>on
>>the
>>> >inside radius and a stretching on the outside different than steel.
>For
>>> >aluminum see the formula and example below;
>>> >
>>> >BA = (0.0078 * T + 0.0174 * R) * No. of deg. in bend
>>> >
>>> >14 Ga = 0.0641"
>>> >
>>> >For 0" radius, 90 Deg bend in aluminum;
>>> >
>>> >(0.0078 * 0.0641 + 0.0174 * 0) * 90
>>> >
>>> >(0.00049998 + 0) * 90 =
>>> >
>>> >0.00049998 * 90 = 0.045" or about 3/64" or for ending pieces of
>flanges
>>> >make
>>> >it 1/16" from bend line to end.
>>> >
>>> >BA = Bend Allowance
>>> >R = Radius of bend on the inside, not the neutral axis.
>>> >T = Material thickness
>>> >
>>> >I have a pic with this and a drawing if needed I can e-mail it to
>you.
>>Hope
>>> >this helps.
>>> >
>>> >Best,
>>> >
>>> >Will
>>> >
>>> >
>>> >*********** REPLY SEPARATOR ***********
>>> >
>>> >On 8/2/05 at 2:46 PM Martin Sole wrote:
>>> >
>>> >>Well it is actually amp related, or will be at some point I hope
>but
>>> >>seeing how there is a great wealth of resource here it seems a good
>>> >>place to start.
>>> >>
>>> >>Some time back I recall seeing an article, might have been in
>Radcom,
>>> >>might have been in QST. Think it had to be either one of those two
>>> >>though. It addressed the process of marking out metalwork for
>making
>>> >>enclosures and explained how to allow the correct amount of
>material
>>> >>for bends etc. Was within the last year or two I think.
>>> >>
>>> >>Just hoping that somebody might recall where this was or maybe
>point me
>>> >>to another resource with similar information.
>>> >>
>>> >>Tks
>>> >>Martin HS0ZED
>>> >>
>>> >>
>>> >>
>>> >>--
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>>> >>Version: 7.0.338 / Virus Database: 267.9.7/60 - Release Date:
>>> >>28/07/2005
>>> >>
>>> >>
>>> >>
>>> >>_______________________________________________
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>>> >>Amps@contesting.com
>>> >>http://lists.contesting.com/mailman/listinfo/amps
>>> >
>>> >
>>> >
>>> >
>>> >--
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>>> >Version: 7.0.338 / Virus Database: 267.9.7/60 - Release Date:
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>>> >
>>> >
>>> >
>>> >--
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>28/07/2005
>>>
>>>
>>>
>>>_______________________________________________
>>>Amps mailing list
>>>Amps@contesting.com
>>>http://lists.contesting.com/mailman/listinfo/amps
>>
>>Bill Aycock - W4BSG
>>Woodville, Alabama
>>
>>
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>
>
>
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