G0768 Apron Gear Slop

[Garththomas]

The gear that connects the carriage hand wheel to the gear that contacts the rack seem to have excess play, I can turn the handle so the dial reads .45 before the backlash ? is taken up. The gear contacting the rack itself is fine, there is very little play there but the combo gear and the carriage hand wheel gear are the culprits.
Of course there is no adjustment for those gears but I was wondering if there is a fix, maybe like a piece of brass shim stock that could wrap one of the gears that would stay in place some how ? does anyone have experience with this problem.

 

[Wreck™Wreck]

It is not a problem, every manual lathe with a gear train between the hand wheel and the rack will do the same.

Bridgeport modified Romi lathes in the 90's for NC use, they installed loaded ball screws which have no mechanical connection to the hand wheels (which they left on for some reason) which operate a rotary encoder only, resulting in nearly zero lash. These lathes may be ran as a manual machine however power feeding and threading require MDI.
If you find gear lash completely unacceptable replace the gear train with timing belts and sheaves and the carriage rack and pinion with a roller pinion which have very little lash, roller pinions may be found here. http://www.nexengroup.com/nxn/products/prod-nav/lp/Roller+Pinion+System

The reason that manufacturers of manual machines do not use such components is that the machines are not changing axis directions on the fly, interpolating arcs for example. Lash is then not an issue when all axes are moved in one direction at a time.

The Bridgeport EZ Path is an excellent small lathe that may be used as a manual machine for the most part, no lash, no gear changes for threading, built in DRO with 24 tool offsets, spindle brake and a very easy to use conversational control. If you can find one in decent shape buy it. http://www.sterlingmachinery.com/9561/Bridgeport+Ez+Path/

 

[Garththomas]

Thanks for the reply, the slop isn't between the rack and gear but between the two gears in the apron. I just thought it was excessive but I suppose I'll have to learn to live with it.