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Discussion Starter #1
I used to be a toolmaker's apprentice about 12 years ago, and I know that there is a conversion formula to take say, a measurement of 1.875 thousandths, and convert it to metric by multiplying it times a metric conversion, which if I remember right, the #'s were something like 0.5242, or something like this, and you would multiply the fractional times the this number, and get a metric answer. I also would like to be able to go backwards and forwards too, meaning, I'd like to convert metric to good ol' American inches. The reason why, is I got an old 83 VT750C rim (rear), and I wanna use my manual vernier dial indicator calipers to measure the I.D. of the brake drum to see if it is still got some life left in it or not, before I spend any time getting it ready for powdercoating. SOo that means I gotta tale my measurement in inches and convert it to metric to see if I'm still in spec. Thanks peoples!!!
 

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25.4mm = 1 inch

~0.040 inch = 1mm

That's pretty much the only two you need to know.
You can figure all else from those.
If you want precise it's actually 0.03937 inch = 1mm
 

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Approximate values.....pffft! That is for machinists! EXACT values are for INSPECTORS!! The only thing you need to know is .50 inch = 12.7 mm. THAT is a deadnuts conversion. To find other values using that the comparison formula is
.50 (inches) : 12.7 (mm) AS (insert caliper value in inches here) : N

.50 : 12.7 :: .01 : N

12.7 X .01 divided by .50 N = .254mm
 

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Steve157 said:
The only thing you need to know is .50 inch = 12.7 mm. THAT is a deadnuts conversion.

Last time I checked 1.00" = 25.4mm would be the exact same ratio as 0.50" = 12.7mm

All that math you threw up sure is a lot of work.

If your caliper is 1.875 inches and you want to find the mm equivalent,
all you have to do is multiply it by 25.4.

1.875 * 25.4 = 47.625mm
 

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litnin said:
Steve157 said:
The only thing you need to know is .50 inch = 12.7 mm. THAT is a deadnuts conversion.

Last time I checked 1.00" = 25.4mm would be the exact same ratio as 0.50" = 12.7mm
Yes, that is exact but it is easier to remember using calibres of firearms. A .50 BMG bullet is a 12.7 NATO. I thought bikers and guns went together nicer.
 

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Steve157 said:
litnin said:
Steve157 said:
The only thing you need to know is .50 inch = 12.7 mm. THAT is a deadnuts conversion.

Last time I checked 1.00" = 25.4mm would be the exact same ratio as 0.50" = 12.7mm
Yes, that is exact but it is easier to remember using calibres of firearms. A .50 BMG bullet is a 12.7 NATO. I thought bikers and guns went together nicer.
Yep, but bullet sizes are not exact by a LARGE margin when compared to machining specs.

Hand-gun ammo:

30 cal is actually .308

32 cal comes in .311, .312, & .314

44 cal comes in .427 & .430

45 cal comes in .451, .452, & .454

Rifle rounds are just as bad...
 

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litnin said:
Steve157 said:
litnin said:
Steve157 said:
The only thing you need to know is .50 inch = 12.7 mm. THAT is a deadnuts conversion.

Last time I checked 1.00" = 25.4mm would be the exact same ratio as 0.50" = 12.7mm
Yes, that is exact but it is easier to remember using calibres of firearms. A .50 BMG bullet is a 12.7 NATO. I thought bikers and guns went together nicer.
Yep, but bullet sizes are not exact by a LARGE margin when compared to machining specs.


30 cal is actually .308

32 cal comes in .311, .312, & .314

44 cal comes in .427 & .430

45 cal comes in .451, .452, & .454

Rifle rounds are just as bad...
\

That is why I used the .50BMG, it is the only exact value to the metric 12.7.
 

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litnin said:
Yep, but bullet sizes are not exact by a LARGE margin when compared to machining specs.

Hand-gun ammo:

30 cal is actually .308

32 cal comes in .311, .312, & .314

44 cal comes in .427 & .430

45 cal comes in .451, .452, & .454

Rifle rounds are just as bad...
Well, many bullets and barrel bores like the 30 cal are both .30 and .308. One is the measurement from the lands (.30") the other is the measurement from the groves (.308").
MarkC
 

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Re: Metric measurement

biglpierson said:
Yoy can use a metric vernier dial indicater, works great.
You mean dial caliper? Most dial indicators don't go that high.
 

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Discussion Starter #16
Schweet!!! Thanks alot guys. This helps out BIG time. Thanks again for the help, I even learned a lil' bit more about guns and bullets. I love shooting a .45 cal revolver, or .500 cal Desert Eagle. Lotso FUNNNN! (And a nice big flame too...)
 

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Shogun said:
...I even learned a lil' bit more about guns and bullets. I love shooting a .45 cal revolver, or .500 cal Desert Eagle. Lotso FUNNNN! (And a nice big flame too...)
I never got in to the DE 50 too much...
It's an awesome hand gun... and very impressive and intimidating.

I never thought they had any more kick than a good hot loaded .44 mag.
I'm sure it's because it's an auto and the slide absorbed a lot of the kick.

I've got a model 29 S&W and a Colt Anaconda .44 mags and always
thought both had more than the DE 50. And the Anaconda has a
cylinder and barrel flame that will light up the night!

I know I wanted a .50, but I just couldn't bring myself to buy a DE.
I was seriously looking the S&W 500 revolver when I had a chance
to shoot the Barrett 50. A couple of shots and that's all it took.
I saved my money and bought a Barrett .50 instead.
It puts anything I've ever shot to shame.
It's a LOT more expensive to shoot ($1.50 a round), but it's a lot of fun.

It doesn't kick any more than a 12 gauge, but holy cow what it does
on the other end is a massive difference.

Gotta have LOTS of room to shoot too!
 

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Discussion Starter #18
I wisht I owned these guns, I don't. A buddy of mine likes to go shooting and one or twice a year, I'll tag along, can't hit the broadside of a barn much, but I love shooting 'em. The DE is a ball, the others you mention, I've never fired. As far as guns go, I'd like to try shooting an AR-30, and maybe a coupla other mil-spec rifles.
 

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Re: Metric measurement

litnin said:
biglpierson said:
Yoy can use a metric vernier dial indicater, works great.
You mean dial caliper? Most dial indicators don't go that high.
I think he does mean caliper, but you either have a "dial" caliper, in which you read the dial, or a "vernier" caliper, in which you read the vernier scale.

Yall ride safe...
TJ
 

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Re: Metric measurement

TJMac said:
I think he does mean caliper, but you either have a "dial" caliper, in which you read the dial, or a "vernier" caliper, in which you read the vernier scale.
That's what I was thinking. That would be a BIG dial indicator.
I've seen some that are that big and BOY are they expensive!

Even most "dial" calipers are vernier.
They dial is used for the .00x and .000x readings.
The x.000 and x.x00 measurements are still on the vernier scale.
 
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