Finally got the selector gears all back together in my Modiale Cletic lathe and today had a project envolving gear cutting. I could not get a cut to save my life. The gear dial has 1-4 numerals, and even when I select the 1 every time, the cuts would get off and shred the work.
At first I thought it was wear in the half nuts. This is not the case. I then checked wear in the lead screw...no significant wear.
I started just turning consecutive screw cuts until I figured out what is going on. I am turning 1.5mm pitch, and my pitch gage shows it is cutting right on...of course that is based on a 1/2" section, so there could be a slight discrepancy that I cannot measure. I discovered that so long as I start the cut on a number 1,2,3, or 4...it makes no difference which number I use to engage the following cuts. Either all 4 line up or none do. They all have the same alignment. But the weird part I cannot figure out is that the screw pattern advances each pass. In other words, I can make a cut on any number. If I immediately run the next cut, the tool is advanced ahead of the first cut. If I wait about 1 minute at 800 RPM, the alignment comes back into phase and I can run another cut right on the first. To run a third cut inline, I again must wait about 1 minute.
I considered the thread indicator, but it is too simple to have any issues. Even if it was screwed up, I should be able to get the same cut alignment if I select the same number each pass.
The problem must lie in the leadscrew gearset, but I am not sure how to go about figuring it out. Or, am I doing something completely wrong? I have been out of the game for several years, so I could be screwing something up.
At first I thought it was wear in the half nuts. This is not the case. I then checked wear in the lead screw...no significant wear.
I started just turning consecutive screw cuts until I figured out what is going on. I am turning 1.5mm pitch, and my pitch gage shows it is cutting right on...of course that is based on a 1/2" section, so there could be a slight discrepancy that I cannot measure. I discovered that so long as I start the cut on a number 1,2,3, or 4...it makes no difference which number I use to engage the following cuts. Either all 4 line up or none do. They all have the same alignment. But the weird part I cannot figure out is that the screw pattern advances each pass. In other words, I can make a cut on any number. If I immediately run the next cut, the tool is advanced ahead of the first cut. If I wait about 1 minute at 800 RPM, the alignment comes back into phase and I can run another cut right on the first. To run a third cut inline, I again must wait about 1 minute.
I considered the thread indicator, but it is too simple to have any issues. Even if it was screwed up, I should be able to get the same cut alignment if I select the same number each pass.
The problem must lie in the leadscrew gearset, but I am not sure how to go about figuring it out. Or, am I doing something completely wrong? I have been out of the game for several years, so I could be screwing something up.