I don't even see a .61 on my grizzly chart, I am sure you could probably get it there are several gear calulators out there for the 9x20. I cannot say I have ever seen an even thread pitch in metric I was under the undertsanding(and could be wrong) that they were are all odd (save .8)and based on .25 increments.
As for your gears, The chart is somewhat interesting to read, if you have a grizzly the gears are marked a,b,c by position, these are the lowest three gears on my lathe. The postion "a" beeing the highest(of the lowest) and smallest, the "b" gear is the lowest or the driven. The "C" (middle or idler)gear should be stacked witht the 120 and 127 tooth gears for metric(always), the A positon should have the 30 tooth gear and the b postion should have the 60 tooth gear for a pitch of .5. You switch the a and b gears out for the different pitches. I cannot cut and paste here but if you go to the grizzly site and download the g4000 manual it gives clear pictures. The "b" gear needs to engage the 120 tooth gear on the outside and must swtiched to the outside with the spacer. For that small amount you are not even going to turn the lathe on, unless you extend the threads out a bunch.
chris  |