Figure 9-17.—Micrometer carriage stop.the lead screw. On the upper end of the shaft is the dial.As the lead screw revolves, the dial is turned and thegraduations on the dial indicate points at which thehalf-nuts may be engaged.Carriage StopThe carriage stop can be attached to the bed at anypoint where the carriage should stop. It is used primarilyfor turning, facing, or boring duplicate parts, as iteliminates taking repeated measurements of the samedimension. In operation, the stop is set at the point wherethe feed should stop. To use the stop, just before thecarriage reaches the stopping point, shut off theautomatic feed and manually run the carriage up againstthe stop. Carriage stops are provided with or withoutmicrometer adjustment. Figure 9-17 shows amicrometer carriage stop. Clamp it on the ways in theapproximate position required, and then adjust it to theexact setting by using the micrometer adjustment. (Donot confuse this stop with the automatic carriage stopthat automatically stops the carriage by disengaging thefeed or stopping the lathe.)MAINTENANCEEvery lathe must be maintained strictly accordingto requirements of the Maintenance and MaterialManagement (3-M) Systems. The first requirement ofmaintenance to your lathe is proper lubrication. Make ita point to oil your lathe daily where oil holes areprovided. Oil the ways daily-not only for lubrication butto protect their scraped surfaces. Oil the lead screw oftenwhile it is in use; this is necessary to preserve itsaccuracy, for a worn lead screw lacks precision in threadcutting. Make sure the headstock is filled to the properoil level; drain the oil out and replace it when it becomesdirty or gummy. If your lathe is equipped with anautomatic oiling system for some parts, make sure allthose parts are getting oil. Make it a habit to CHECKfrequently to see that all moving parts are beinglubricated.Before engaging the longitudinal ‘feed, be certainthat the carriage clamp screw is loose and that thecarriage can be moved by hand. Avoid running thecarriage against the headstock or tailstock while it isunder the power feed; running the carriage against theheadstock or tailstock puts an unnecessary strain on thelathe and may jam the gears.Do not neglect the motor just because it may be outof sight; check its lubrication. If it does not run properly,notify the Electrician’s Mate who is responsible forcaring for it. He or she will cooperate with you to keepit in good condition. On lathes with a belt driven fromthe motor, avoid getting oil or grease on the belt whenyou oil the lathe or motor.Keep your lathe clean. A clean and orderly machineis an indication of a good mechanic. Dirt and chips onthe ways, on the lead screw, and on the crossfeed screwswill cause serious wear and impair the accuracy of themachine.NEVER put wrenches, files, or other tools on theways. If you must keep tools on the bed, use a board toprotect the finished surfaces of the ways.NEVER use the bed or carriage as an anvil.Remember, the lathe is a precision machine, and nothingmust be allowed to destroy its accuracy.BASIC SETUPA knowledge of the basic setup is required if youare to become proficient in performing machine workwith a lathe. Some of these setups are considered in thefollowing sections.Cutting Speeds and FeedsCutting speed is the rate at which the surface of thework passes the point of the cutting tool. It is expressedin feet per minute (fpm).Feed is the amount the tool advances for eachrevolution of the work. It is usually expressed inthousandths of an inch per revolution of the spindle.Cutting speeds and tool feeds are determined byvarious considerations: the hardness and toughness of9-10
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business