Maintenance of the mini-lathe

 

Don't get the idea that you are going to just use the mini-lathe and have a ball with little or no maintenance. It is a maintenance intensive tool. If it is to remain in proper alignment and operate smoothly for a reasonably long period of time, it will require regular cleaning, lubrication and adjustment. Right up front, get yourself a spare drive belt. Littlemachineshop.com carries them. The ways must be kept clean and coated with a good grade of light machine oil. I prefer Hoppe's #9 gun oil. It is a much more highly refined product than 3-in-1.

The motor must be checked periodically and its position and belt tension adjusted. I mention the position because it is impossible to adjust the tension without messing with the motor position. This is a cranky task. Check the instructions included with the lathe. Periodically the cross and compound slides must be taken apart and cleaned and lubed. Wet your finger with oil and wipe it over all the areas that slide together. With regular use, this must be done at least once a month. The gibs will need adjusting to maintain the proper fit of the sliding components. Proper adjustment puts even pressure end-to-end on the gib plate maintaining a little resistance to movement. Too loose a fit allows the cutter to chatter and/or the handle setting to creep. Too tight a fit is just simply irritating to operate.

I find myself pulling the carriage apart and cleaning out the underside and the ways about once every two weeks, more often if in daily use. Take off the turning tool holder and remove the two retaining screws that hold the sliding component to the gear unit using a 6mm hex key (T-handle is best). Slide the upper section off the end of the ways. Wipe down all contact surfaces and blow out chips with 20-30 pounds of air pressure. Wipe down the ways and scrape the rear flat area as indicated on my hint page. Don't forget the underside of the ways where the retainer plates slide. Using the wet finger system, as above, oil all contacting surface areas.

Reassemble the slider to the ways and slide it end to end noting any non-smooth areas. There is probably a tiny bit of swarf lodged somewhere if it does not move smoothly over the whole run. This is a good time to check the adjustment of the retaining plates, before re-attaching to the gear drive unit. I find it easier to adjust them with an Allen wrench that has the small end cut off to about only 3/8 of an inch after the bend. you can easily touch up the plate settings and slide by hand to test tightness before attaching to the gear unit. It should not clunk when yanked up and down nor should it bind when slid back and forth. Now re-attach it to the gear unit with the two large socket head screws. Latch in the half-nuts before running the screws fully in to make sure you have the two pieces properly aligned. This will prevent the half-nuts from binding to the lead screw.

It goes without saying that all running shafts such as lead screw, drive gear shafts and carriage drive gear need a bit of oil on the shafts from time to time. Take care not to have oil draining all over the machine. A little dab will do, but must be replenished regularly. The spindle uses sealed ball bearings and needs no lube. If it ever gets to running rough, the bearings need to be replaced. Don't forget the chuck. If it ever feels rough while tightening, it must be fully disassembled, cleaned and lubed. Failure to do so will cause many problems, not the least of which is the inability to clamp raw stock fully centered. Use a chip brush regularly on the chuck jaws to keep out the swarf that sticks to the jaws and causes stock to lock in not on center. A tool I find very helpful is a wire brush made for cleaning shotgun barrels attached to a home-made handle that is just a piece of knurled 3/4 inch aluminum rod drilled and tapped to fit the brush. If a piece of material does not want to lock in to exact center on the chuck just run the brush through the jaws to clean out the swarf.

I personally recommend not using the offset feature of the mini-lathe tailstock. It is just too troublesome to get exactly back on center. Failure to keep it well centered will result in work held in centers to taper. The position clamping method used for the mini-lathe tailstock does not lend itself to easy alignment.

As a final thought, keep a Shop-Vac handy and never leave the lathe dirty between uses. This is a little guy and while fairly well built, it does not have hardened ways or chip wipers. To assure a reasonably long service life, it must be kept clean. The mini-lathe is a well built piece of precision machinery and will give you many years of fun use if you maintain it properly. Give it what it needs and it will give you many hours of hobby fun.