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Blanking Dies


#1

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! :slight_smile:

Rick Hamilton


#2

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

#3

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


#4

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).

  1. Tan A equals a/b
  2. Tan A equals .125/.020
  3. 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


#5

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