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I Forge Iron

Left hand threads

Jim Black

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The same way they made their right hand ones. LOL

I will try to explain the process which is very laborious and time consuming.

In actuallity the process is almost identical to the way the Woodworkers made the Big screws for the printing presses and cider presses etc. Except the material is different.

1. The first order of business was to make the tap. (male threaded part)

2. The circumfrence of the piece was needed first, so a piece of paper was wrapped tightly around the rod and where the body overlapped the end a mark was put.

3. The paper was laid out and the mark was extended with a line parallel to the edge and both the edge and the lap line were marked off in the desired segmental measurements to correspond with the desired threads per inch. (see drawing below)

4. The lines were connected as shown below, ACCURACY was of prime importance in this endeavor.

5. The paper was then glued to the rod and to itself to give a pattern for making the threads.

6. After the glue had dried sufficiently, a thin bladed saw was used to follow the lines, progressing around the rod, here again ACCURACY was extremely important. The cut was made shallow to start with and then deepened to about half the distance of the thread depth.

7. After this scoring was accomplished, a triangular file was used to gradually file the threads into the material going round and round until the part between came to a sharp edge and was uniform in depth and width.

8. After the depth was obtained, some flutes or relief grooves were filed into the rod length ways, to provide sharp cutting edges.

9. Hardening and tempering was the next order of business.

10. After the tool was hardened it was used to make the die (for cutting external threads) and then several relief grooves were filed into it to provide cutting edges and a place for the chips to go as it was being used.

11. Heat treating and tempering where then the order of business to complete a tap and die set.

12. Guns smiths made very small taps and then a die plate with many sizes of threaded holes in one tool.

I hope this explains the process to you.


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