I have finally put out the second installment of the tutorial. I had to break up the video into two sections in order to fit it onto youtube.
In this part I begin work on the tap by making the guide block. The lumber you want to use for the guide should be a hardwood at least 2” thick. Depending on the size of screw you will be making the block can be 3” – 6” wide. It only needs to be surface on one face and one edge. Then drill the hole for the tap dowel in the centre of the guide block. The hole you drill will be the size of the internal diameter of your screw. For my 1” diameter screws with 4 tpi the internal diameter is 3/4”. Then cut the guide to length at about 5” – 8” long.
After the guide has been drilled and cut to size you can turn the dowel for the tap on the lathe, or buy a dowel of the proper size. Just make sure the dowel you use fits the hole in the guide nicely with little slop.
Then you can lay out the spiral on the dowel. To do this get a piece of paper (preferable grid paper but not at all necessary) and wrap it around the dowel and mark where the first edge meets the paper. The rest of this process may make more sense to see in the video than in explanation, so I won’t bother. Just remember when marking the diagonal lines on the paper make sure to go from bottom left to top right, otherwise you will get a screw that tightens counter clockwise. When making a 4tpi thread pattern go up by 1/4’s, with 2 tpi go up by 1/2’s, and when making 1 1/3 tpi go by 3/4’s.
In the next segment I will finish up the guide and possibly the entire tap with the cutter made. If anyone has any questions just ask. And if anyone wants to be notified of my next videos just go onto youtube, if you have a youtube account, and subscribe to my account.
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