Holescreek
Titanium
- Joined
- Aug 27, 2004
- Location
- Centerville,OH
An upcoming project requiring 1.5mm thread pitch forced me to take a look at my lathes again. At one point in time I considered buying an import machine for metric threading capability but I couldn't bring myself to do it.
Browsing the Traytop PDF manual online I saw that metric threading was possible with just 2 additional gears. My 12.5x18" traytop has been super noisy since the day I purchased it with high pitched ringing from the worn out change gears. The
The original setup has a 33 tooth gear on the spindle, a 120 tooth idler and a 66 tooth gear on the gearbox shaft for a 2:1 ratio spindle to gearbox. The manual states that for metric threading the 33 tooth spindle gear is kept but now drives a 127 tooth gear pinned to a 120 which drives an 88 on the gear box. I opted to go with 16DP 14.5 PA gears because there is a large tooth count selection available. I knew I'd have to be creative mounting them, the new gear OD's are much smaller that the originals. The spindle gears had to be bored out and welded to adapters and the 33 tooth gear in a 16DP size isn't a whole lot larger than the OD of the spindle shaft. Also (due to the smaller diameters)I had to make a new banjo to provide swing for adjustment.
After thinking about it for a bit I decided to change things up a bit. Instead of switching between the 66 and 88 on the gearbox I decided to eliminate the 66 altogether and leave the 88 in place, but switch between a 33 and 44 on the spindle. I also run the 127 tooth gear as the primary idler and leave the 120 pinned to it for metric use. So now for inch threading I run 44-127-88, and for metric I run 33-127/120-88.
I found a photo of a metric chart on the LathesUK site but I didn't get the same results with my lever positions. One difference I noticed was my A-B positions are marked opposite of those in the photo on the net. So using my DRO to give table movement per spindle revolution I created a new chart for my lathe.
I've for several hundred dollars tied up in gears but now the lathe runs very quiet, has metric capability, and was a whole lot cheaper than buying a new lathe.
Browsing the Traytop PDF manual online I saw that metric threading was possible with just 2 additional gears. My 12.5x18" traytop has been super noisy since the day I purchased it with high pitched ringing from the worn out change gears. The
The original setup has a 33 tooth gear on the spindle, a 120 tooth idler and a 66 tooth gear on the gearbox shaft for a 2:1 ratio spindle to gearbox. The manual states that for metric threading the 33 tooth spindle gear is kept but now drives a 127 tooth gear pinned to a 120 which drives an 88 on the gear box. I opted to go with 16DP 14.5 PA gears because there is a large tooth count selection available. I knew I'd have to be creative mounting them, the new gear OD's are much smaller that the originals. The spindle gears had to be bored out and welded to adapters and the 33 tooth gear in a 16DP size isn't a whole lot larger than the OD of the spindle shaft. Also (due to the smaller diameters)I had to make a new banjo to provide swing for adjustment.
After thinking about it for a bit I decided to change things up a bit. Instead of switching between the 66 and 88 on the gearbox I decided to eliminate the 66 altogether and leave the 88 in place, but switch between a 33 and 44 on the spindle. I also run the 127 tooth gear as the primary idler and leave the 120 pinned to it for metric use. So now for inch threading I run 44-127-88, and for metric I run 33-127/120-88.
I found a photo of a metric chart on the LathesUK site but I didn't get the same results with my lever positions. One difference I noticed was my A-B positions are marked opposite of those in the photo on the net. So using my DRO to give table movement per spindle revolution I created a new chart for my lathe.
I've for several hundred dollars tied up in gears but now the lathe runs very quiet, has metric capability, and was a whole lot cheaper than buying a new lathe.