Jet J-2221VS Operating Instructions And Parts Manual

Also see for J-2221VS: Operating instructions and parts manual Operating instructions and parts manual

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Jet J-2221VS Operating Instructions And Parts Manual Manual pdf 12 page image

12Feeds for DrillingThe feed of a drill is governed by the size of the tooland the material drilled. Because the feed ratepartially determines the rate of production and also isa factor in tool life, it should be chosen carefully foreach job. In general, the most effective feeds will befound in the following ranges:Diameter of Drill Feed per Revolution(inches) (inches)Under 1/8 .....................0.001 to 0.0021/8 to 1/4 ...................... 0.002 to 0.0041/4 to 1/2 ...................... 0.004 to 0.0071/2 to 5/8 ...................... 0.007 to 0.015Indication of Extreme Speeds and FeedsA drill that splits up the web is evidence of too muchfeed or insufficient tip clearance at the center as aresult of improper grinding. The rapid wearing awayof the extreme outer corners of the cutting edgesindicates that the speed is too high. A drill chippingor braking out at the cutting edges indicates thateither the feed is too heavy or the drill has beenground with too much tip clearance.Speeds for High Speed Steel DrillsSpeedMaterial In SFPMAlloy Steel — 300 to 400 Brinell ...................... 20 - 30Stainless Steel ................................................. 30 - 40Automotive Steel Forgings ............................... 40 - 50Tool Steel, 1.2C ............................................... 50 - 60Steel, .4C to .5C ............................................. 70 - 80Mild Machinery Steel, .2C to .3C ................... 80 - 110Hard Chilled Cast Iron ..................................... 30 - 40Medium Hard Cast Iron ................................. 70 - 100Soft Cast Iron ............................................. 100 - 150Malleable Iron ................................................. 80 - 90High Nickel Steel or Monel .............................. 40 - 50High Tensile Bronze ....................................... 70 -150Ordinary Brass and Bronze ........................ 200 - 300Aluminum and its Alloys .............................. 200 - 300Magnesium and its Alloys ............................ 250 - 400Slate, Marble, and Stone .................................. 15 -25Plastics and similar material (Bakelite) ........ 100 - 150Wood ........................................................... 300 -400Titanium Alloys ................................................ 10 - 25Titanium Alloy Sheet ........................................ 50 - 60In cases where carbon steel drills are applicable, thedrill should be run at speeds of from 40 to 50 percentof those given above.Operating PrecautionsThe following operating and safety precautions mustbe observed in order to avoid harm to the operator ordamage to the drill press.1. The head assembly must be locked to thecolumn so the thrust produced by drilling will notforce the head assembly up the column.2. The work table must be locked to the column soit will not be forced down the column.3. Before drilling, release the quill lock nut topermit free travel of the quill.4. Be sure the belt is tightened to the propertension.5. DO NOT start to drill the workpiece until makingcertain the workpiece is held down securely.6. MAKE SURE THE DRIVE MOTOR IS RUN-NING BEFORE turning the speed controlhandwheel in either direction.7. Point of operation protection is required formaximum safety. This remains the responsibil-ity of the user/purchaser since conditions differbetween jobs.8. Make sure the drill is secured in the spindle orcheck before attempting to use the drill press.9. Make sure the spindle taper is clean and free ofburrs, scoring, and galling to assure maximumgripping.10. Lock the quill in position when using and side-loaded tool.Drilling RecommendationsSpeeds for DrillingThe speed of a drill is usually measured in terms ofthe rate at which the outer periphery of the toolmoves in relation to the work being drilled. Thecommon term for this is Surface Feet per Minute(SFM). The relationship of SFM is expressed in thefollowing formulas:SFM = 0.26 X rpm X Drill Diameter (in inches)RPM = 3.8 x ________SFM__________Drill diameter (in inches)In general, the higher the speed the shorter the drilllife. Operating at the low end of the speed range fora particular material will result in longer life. The mostefficient speed for operating a drill depends on manyvariables:1. Composition and hardness of material.2. Depth of the hole.3. Efficiency of the cutting fluid.4. Type and condition of the drilling machine.5. Desired quality of the hole.6. Difficulty of set-up.