- Joined
- Oct 14, 2013
- Messages
- 979
This weekend I needed to cut an 8 pitch thread on my "new" Hardinge TL-10. A check of the quick change chart led to a sinking feeling; the coarsest pitch was _11_! I opened up the change gear cover and found that not only did I not have the change gears, I didn't have the bracket to put them on!
After some cussing and a LOT of thinking, I realized that my 3D printer was the answer! I carefully measured the change gear shafts and spacing, and figured out what the ratio was from the spindle to the first shaft (0.8 reduction in mode 1, in case you need to know). I laid out a pair of gears with the correct center to center dimensions, the largest possible face width, and tooth ratio, then printed them. After the first mistake of diameter vs radius (oops), the second set fit perfectly! I cut the 8 pitch thread last night! This set of gears will also allow me to cut 16 and 32 pitch threads using the three position mode lever. One irritation of this method is having to remove the collet draw bar, as you can see in the picture.
After some cussing and a LOT of thinking, I realized that my 3D printer was the answer! I carefully measured the change gear shafts and spacing, and figured out what the ratio was from the spindle to the first shaft (0.8 reduction in mode 1, in case you need to know). I laid out a pair of gears with the correct center to center dimensions, the largest possible face width, and tooth ratio, then printed them. After the first mistake of diameter vs radius (oops), the second set fit perfectly! I cut the 8 pitch thread last night! This set of gears will also allow me to cut 16 and 32 pitch threads using the three position mode lever. One irritation of this method is having to remove the collet draw bar, as you can see in the picture.