ratio to angle math question

[countryguy]

Ouuuyee. Love the caves and dim light of the fire. Lol. Had a good chuckle on that. Nice one! CG.

Merry christmas friend.
Cg.

If you are stuck without a calculator Ratios can also be converted using pencil and paper. 1/12 just means a rise of 1 (unit of measurement) along a line of 12 (units of measurement) So draw a straight line 12" long, at one end measure up 1", then draw a line from there back to the start point of the first 12" line. Now you have a long narrow triangle that you can measure with a protractor. Works the same in feet, yards, miles, heck even in metric, if you americans ever drag yourself out of the middle ages

Cheers Phil

 

[eightball]

If we americans come out of the Dark Ages does that mean we have to destroy our shapers and manual lathes and mills and convert to CNC? No Thank You!

 

[uncle harry]

If you are stuck without a calculator Ratios can also be converted using pencil and paper. 1/12 just means a rise of 1 (unit of measurement) along a line of 12 (units of measurement) So draw a straight line 12" long, at one end measure up 1", then draw a line from there back to the start point of the first 12" line. Now you have a long narrow triangle that you can measure with a protractor. Works the same in feet, yards, miles, heck even in metric, if you americans ever drag yourself out of the middle ages

Cheers Phil

Heck Phil,

Middle Ages ??? Don't give us too much credit here, & If you ever need it, I have an original copy of the recipe for dirt.

 

[SE18]

since 4.76 and a lower # were given, I think my best bet is to grab some alum rod and try both angles out and measure the diameter over a given distance. I'll do that before boring.

regarding metric, I recall back in the early 70s when there was a lot of discussion in the US about going completely metric. In the military and science, metric is used a lot so in effect we have to use both systems, which doesn't make much sense to me but all my tools and WWII lathe use imperial measure so at this time it would be a hassle to go metric (you'd have to throw away a lot of tools)

 

[uncle harry]

since 4.76 and a lower # were given, I think my best bet is to grab some alum rod and try both angles out and measure the diameter over a given distance. I'll do that before boring.

regarding metric, I recall back in the early 70s when there was a lot of discussion in the US about going completely metric. In the military and science, metric is used a lot so in effect we have to use both systems, which doesn't make much sense to me but all my tools and WWII lathe use imperial measure so at this time it would be a hassle to go metric (you'd have to throw away a lot of tools)

An interesting form of complicating things between metric & imperial systems is what is called "soft metric" Some years back I incorporated some encoders in a machine design. The shafts were .375 while the mounting hole threads were metric and on metric mounting centers. Not really the best of both worlds in my view.

 

[Mark in Indiana]

since 4.76 and a lower # were given, I think my best bet is to grab some alum rod and try both angles out and measure the diameter over a given distance. I'll do that before boring.

regarding metric, I recall back in the early 70s when there was a lot of discussion in the US about going completely metric. In the military and science, metric is used a lot so in effect we have to use both systems, which doesn't make much sense to me but all my tools and WWII lathe use imperial measure so at this time it would be a hassle to go metric (you'd have to throw away a lot of tools)

I remember in the 70s the government wanted to go to the metric system. As a kid on family vacations, I'd see speed limit signs with both metric and standard speeds. Even back then I thought that that was stupid because no one would bother read the metric numbers. At least in Canada they just changed the signs and you had to learn the system.

I feel fortunate that my working years were before and during a time when machinery manufactures built machines that were "world class." Meaning that all of the fasteners were metric. It forced us to be fluent in both systems.

 

[mws]

Just an addendum here: I was looking up some taper info yesterday and noticed that the angles noted were "Angle to Center" which would be the cross slide or taper attachment angle for turning a taper whose diametric angle would be twice that.

I also was investigating making some graphite rocket nozzles (I have three young boys...) and much of what I read indicated nozzles having a hyperbolic or some exponential flare. The angles seemed to be in the range of 5-10 degrees initially which seems to fall in line with your flare or 4+ degrees overall.

I'm also looking into the anglular dimensions and expansion rates of venturis for another project, but have found very little detail on venturi designs as of yet.

So, what what was the outcome of your burner experiments thus far?

Mark S.

 

[caster]

Hi SE,

a 1:12 flair can be considered as a right triangle with the first side being 1" and the second 12". By solving the triangle (S,A,S) you get these dimensions: 1", 12", 12.042" angles: 4.76, 90, 85.23. The taper you need to cut is 4.76 deg



Caster

 

[davidh]

Agreed. Feet, inches, pound and pints were used by the working man because the units of measure were found to be useful. Metric was invented by some French scientist guy with the express purpose of screwing up the Brits) and it eventually worked.

was this french guy related to LUCAS ?

 

[uncle harry]

If you are stuck without a calculator Ratios can also be converted using pencil and paper. 1/12 just means a rise of 1 (unit of measurement) along a line of 12 (units of measurement) So draw a straight line 12" long, at one end measure up 1", then draw a line from there back to the start point of the first 12" line. Now you have a long narrow triangle that you can measure with a protractor. Works the same in feet, yards, miles, heck even in metric, if you americans ever drag yourself out of the middle ages

Cheers Phil

Let me see if I can be helpful. I'm old enough to remember the original recipe for dirt!