At 01:14 AM 1/23/97 -0600, you wrote:

G’day; - And I thought that the method I wrote about was my

idea! Is there nothing new under the sun? However, with all due

respect to Lee, the method I outlined had nothing to do with high

quality engineering and volume production; it is simply a device

which most jewellers could tackle to produce around 30 stamped

blanks which, as I pointed out, would need a bit of further work

to be done on them yet would still save time and ‘bore-freedom’

Lee, in keeping with the aims of this forum, is being modest.

His company not only makes small hydrolic forming presses but

also the guided sawframe hand saw that you described. His website

is quite informative about his products- and if memory serves has

the link that was how I found Orchid. Your point is great though-

for a small number of identical parts your process is fine (I

tend to cast components instead, having come from jewelry

modelmaking training) and for production his press would add

speed and flexibility.

I’m learning from both of you!

Rick Hamilton

Made a couple of blanking dies years ago in school and would like to make

some now and was wondering if anyone has a chart or something giving blade

size to metal thickness to angle of cut. I have 1/16" tool steel as

recommended on Bonny Doon site and have done some searches in Orchid

archive but can’t seem to find more info. Any specifics would be greatly

appreciated.

Thanks for any help

Lorne

- on Sunny Vancouver Island

Lorne:

The way I initially figured the angle for cutting dies with jewelry saw

blades was to draw the necessary dimensions on a piece of graph paper. I

used a micrometer or a dial caliper to measure the thickness of the tool

steel I was cutting and then I measured the width (width not depth) of the

sawblades that I wanted to use. For ease of drawing I multiplied each of

these measurements by 100. I drew these dimensions onto the graph paper.

The metal thickness represented vertically and the blade thickness

represented horizontally. I would then draw a line across the portion

representing the blade thickness from the upper right hand point across to

the lower left hand point or vice versa. This would give me the proper

angle to use to saw a blanking die. This way you can figure for metal and

blade thicknesses not on charts.

This is very easy to do. I’m just not sure if I have explained it simply.

Kenneth Gastineau

@Kenneth_Gastineau1

Hi Kenneth,

Thanks for posting a methodology for calculating the saw angle for blanking dies.

I would then draw a line across the portion

representing the blade thickness from the upper right hand point across

to the lower left hand point or vice versa. This would give me the

proper angle to use to saw a blanking die. This way you can figure for

metal and blade thicknesses not on charts.

Let me rephrase it in my words to see if I understood it correctly.

Consider the thickness of the metal to be cut as the length of one side (

a) of a right triangle. Use the blade thickness as the length of the other

side (b) of the triangle. Now use your high school trigonometry ( you do

remember it don’t you?) to calculate the angle. It real easy with a calculator

that has trig functions.

Example:

0.125 (1/8") steel thickness

0.020 # 7 saw blade thickness (see “The Complete Metalsmith” page 183)

Draw a right triangle with a height of 0.125 inches (side a) and a base

0.020 inches long (side b).

Now calculate the angle A (that’s the one at the intersection of side b &

the hypotenuse (side c).

- Tan A equals a/b
- Tan A equals .125/.020
- Tan A equals 6.25

A equals 80.9 degrees (rounded to the nearest tenth)

Step 3 can be done with a calculator or looked up in a table of Natural

Trigonometric Functions. The calulator is the quickest.

Let us know if this is incorrect.

Thanks,

Dave

Dave:

Gee Dave, I didn’t even think of using trigonometry. Do you think that is

why I didn’t make it through engineering school? Maybe I will set up a

spreadsheet to do these calculations for me. Thanks for pointing out the

obvious. I guess I couldn’t see the cosine’s for the sine’s.

Kenneth Gastineau

@Kenneth_Gastineau1

http://www.ud.net/gastineau