# Category Archives: Geometry

## Radius Measurement Using Roller Gages

This post will demonstrate how to measure the radius of an arc using two roller gages. While I am a very amateur machinist, I have on occasion needed to measure the radius of an arc (i.e. partial circle) and have not been sure how to approach that measurement. It turns out to be simple given two equal diameter roller gages and a surface plate. You can determine by taking one measurement and knowing the roller gage diameter. Continue reading

Posted in Construction, Geometry, Metrology | 3 Comments

## Gift Wrapping Math

My sister works as an event planner/wedding planner. She wrote me an email today with the following gift wrapping question.

I need to wrap 375 boxes. 16x14x6. The wrapping paper is 30 inches wide. I say I need about 1700 feet. People are telling me I only need half that. Continue reading

Posted in Geometry, Paper Machines | 21 Comments

## Circular Saw Depth-Of-Cut Formula

I recently bought a battery powered, 6.5-inch diameter, circular saw from Milwaukee. I REALLY like this saw. I have been using it at my cabin in Northern Minnesota, a place where dragging around electrical cords is painful. This saw has quickly become one of my workhouse tools. Continue reading

Posted in Construction, Geometry | 16 Comments

## Tree Height Measuring Example

I have been testing a number of Android applications that are intended to measure the size of objects knowing their range or vice versa. One application that I have found particularly useful is called Baumhöhenmesser – Tree Height Meter (my translation) – which is an application written by a German developer. I have found this application particularly useful, and I thought I would review its operation here. It is part of a suite of Android applications intended for forestry management. This app makes excellent use of the Android's ability to measure angles. Continue reading

Posted in General Mathematics, Geometry | 3 Comments

## Banana Equivalent Dose

I recently have been reading quite a bit about the hazards of traveling to Mars – one of the major hazards is radiation. This Mars reading has driven me to write a number of posts that look at the effects of radiation exposure in our daily lives here on Earth. Continue reading

Posted in General Science, Geometry | 2 Comments

## Beautiful Spiral

Quote of the Day If a mistake is not a stepping stone, then it is a mistake. — Eli Siegel, "Damned Welcome" I have always been amazed at the beautiful curves that relatively simple functions can generate. I saw this … Continue reading

Posted in Electronics, Geometry, Humor | Comments Off on Beautiful Spiral

## Clever Way of Putting on a Duvet Cover

My wife and I put on a Christmas-themed duvet cover last night using the technique shown in this video. The approach reminds me of some topology demonstrations. The method worked as advertised. Continue reading

Posted in General Mathematics, Geometry | 2 Comments

## South Pole Communication

Quote of the Day The gem cannot be polished without friction, nor man perfected without trials. — Chinese Proverb Introduction I find the subject of Antarctica very interesting and I read as much as I can about it – especially … Continue reading

Posted in Astronomy, Geometry | 2 Comments

## Drawing a Perpedicular Out in the Wild

My most satisfying applications of geometry occur in my construction projects. Previously, I have discussed how to find the radius of circle on construction projects. In this post, I will discuss four methods for constructing a perpendicular to a line. … Continue reading

Posted in Construction, Geometry | 2 Comments

## Measuring Countersink Diameter Using Gage Balls

I am still working through some examples of using gage balls for machine shop work. The following reference on Google Books has great information on using gage balls (Figure 1) in measuring the characteristics of a countersink and I will be working through the presentations there. These are good, practical applications of high-school geometry. Continue reading

Posted in Construction, Geometry, Metrology | 18 Comments