Little Machine Shop Mini Mill, User Manual

Page 1: ...The premier source of tooling parts and accessories for bench top machinists Mini Mill User s Guide from LittleMachineShop com ...

Page 2: ...ghts reserved Photos Copyright 2006 PhotoBoost com All rights reserved Written by Chris Wood of LittleMachineShop com LittleMachineShop com http www littlemachineshop com 396 W Washington Blvd 500 Pasadena CA 91103 800 981 9663 Fax 626 797 7934 2 ...

Page 3: ...arse Feed Handles 11 Z Axis Fine Feed Knob 11 Z Axis Lock Lever 12 Adjustments 12 X Axis Gib 12 Y Axis Gib 13 Z Axis Gib 13 Tramming the Mill 14 Motor to Intermediate Gear Adjustment 15 Lubrication 16 Lubricating the Transmission Gears 16 Changing Spindle Tools 17 Squaring a Vise 18 Using Parallels 19 Clamping with a Clamping Kit 20 Finding the Edge of a Workpiece 20 Drilling 22 Milling 23 Convent...

Page 4: ...Common Accessories 25 End Mills 25 Work Holding 26 Vises 26 Clamping Kits and Accessories 27 Setup Tools 28 Maintenance 28 Cleaning 28 Motor Brushes 28 4 ...

Page 5: ...m 7 Spindle tilt 45 45 Motor power 350 W 0 47 HP Spindle speed Low range 0 1100 rpm 0 1100 rpm Spindle speed High range 0 2500 rpm 0 2500 rpm Spindle taper 3MT or R8 3MT or R8 T slot width 12 mm 7 16 Weight net gross 50 68 kg 110 150 lb Package size L x W x H 560 x 500 x 740 mm 22 x 19 7 x 29 2 Safety Considerations Always use common sense when using a power tool Review the safety instructions tha...

Page 6: ...peed shifter 4 Motor controls 5 Spindle 6 Drill chuck 7 Table 8 Saddle 9 X axis lock lever 10 Y axis hand wheel 11 Z axis fine feed knob 12 Z axis coarse feed handle 13 Z axis lock lever 14 Column 15 Z axis travel stop 16 X axis hand wheel 17 Y axis lock lever 18 Base 8 9 17 18 10 6 ...

Page 7: ...ure to remove the grease 1 Wipe most of the grease off with rags or paper towels 2 Clean the surfaces with mineral spirits paint thinner 3 Coat the surfaces with oil See the Lubrication section on page 16 for specific recommendations for lubricants Mounting Your Mill The mini mill must be bolted down to the workbench because it is top heavy It is unsafe to operate the mini mill if it is not bolted...

Page 8: ...so that you can remove the table off the right side of the mill The table moves to the left so that the right end of the table is almost flush with the saddle The following diagram shows the holes required to mount the mill and the clear area around the bolt pattern to allow use and maintenance of the mini mill Mount the mill to the workbench with 3 8 or 10 mm bolts The bolts should be about 1 25 ...

Page 9: ... control potentiometer that forces you to return the control to minimum speed when starting the mill Always turn the speed control to the minimum speed position before starting the mill Starting the mill with the speed control set to a higher speed can damage the speed control circuit board To power up the mill 1 Turn the speed control to the minimum speed position 2 Turn on the power by sliding t...

Page 10: ...dle slightly by hand as you move the high low speed shifter to engage the gears X Axis Hand Wheel The X axis hand wheel moves the table to the left or right depending on which way it is turned Use this hand wheel to position the table The dial on this handle indicates the relative position of the table The graduated dial can be repositioned for convenience Each division of the dial represents a mo...

Page 11: ... hand wheel moves the table 0 050 Y Axis Lock Lever The Y axis lock lever is on the right side of the saddle behind the X axis hand wheel Use this lever to lock the Y axis so it does not move inadvertently Pulling out on the lever and simultaneously turning it can change the locked position of this lever Pulling out disengages the lever from the locking screw and allows it to move to a different p...

Page 12: ...adjust the screw in the base of the lever to make this adjustment Adjustments Keeping your mini mill in adjustment is an on going process You should check all the following adjustments when you set up your mill and then periodically as you use your mill X Axis Gib A gib is a strip of metal placed between the bearing surface of two machine parts to ensure a precision fit and provide adjustment for ...

Page 13: ... move 5 While holding the setscrews from turning tighten the lock nuts 6 Test by turning the hand wheel Loosen or tighten both setscrews the same amount until the saddle moves freely but without play in the dovetail Z Axis Gib The Z axis gib provides adjustment for the mating dovetails on the column and the head assembly that provide the Z axis vertical motion To adjust the Z axis gib 1 Loosen the...

Page 14: ...or or better a dial test indicator The indicator is mounted so that it rotates with the spindle and reads against the table at the farthest distance possible from the spindle The indicator can be mounted with a test indicator holder or with a simple shop made holder To tram the mill 1 While supporting the head and column loosen the large nut at the back of the base of the column 2 Tighten the nut ...

Page 15: ... within 0 001 6 Tighten the large nut at the back of the base of the column Motor to Intermediate Gear Adjustment A metal gear on the motor drives a plastic gear on the top of the intermediate shaft If these gears are not meshed properly they can make a lot of noise It is easy to adjust the mesh to minimize the noise To adjust the motor to intermediate gear mesh 1 Slightly loosen the four socket h...

Page 16: ... points with Mobil 1 or other suitable oil Oil the column dovetail and rack The following points on your mini mill require lubrication Location Lubricant Frequency Notes Table and other machined surfaces Mobil 1 motor oil Daily Oil lubricates and prevents corrosion Table dovetails Lithium grease Yearly Table feed screws and nuts Lithium grease Yearly X axis thrust bearings Mobil 1 motor oil Yearly...

Page 17: ...10 Release the Z axis locking lever and lower the head assembly until it engages the rack 11 Continue to lower the head assembly using the Z axis coarse feed handles 12 Replace the cap screw and plastic bushing that limits the upward travel of the Z axis Changing Spindle Tools The tools you work with are held in the mini lathe spindle by the taper It is either an R8 taper or 3 Morse taper Morse ta...

Page 18: ...p on the top of the spindle Squaring a Vise When you mount a vise on the mill table it is important that it be mounted square to the table If your vise is not square to the table you will not be able to produce accurate work The vise is usually mounted with the long axis of the vise perpendicular to the long axis of the table Thus the jaws are parallel to the X axis of the mill To square a vise on...

Page 19: ...the point is above the vise jaws 11 Tap the vise with a dead blow hammer to rotate it in the appropriate direction to reduce the reading on the dial test indicator 12 Repeat steps 5 through 11 until the reading on the dial test indicator is acceptable to you You should be able to reduce the reading to 0 001 or less 13 Tighten the vise mounting bolts Using Parallels Precision parallels are used to ...

Page 20: ...endicular to the mill table When clamping with step blocks and clamp bars the end of the clamp bar on the step block should be just a little higher than the end on the workpiece This ensures that the end of the clamp bar makes contact with the workpiece The stud should be located as close to the workpiece as possible so that the majority of the clamping force is exerted on the workpiece and not th...

Page 21: ...t the solid body of the edge finder in a collet or drill chuck in the mill s spindle 2 Offset the movable end of the edge finder so that it is not concentric with the body 3 Move the edge finder so that it is clear of the workpiece beyond the left edge 4 Lower the mill s head so that the smaller diameter section of the movable end of the edge finder is next to the workpiece 5 Turn the mill on and ...

Page 22: ...You may want to rotate the pointer so that it aligns with one of the tic marks on the scale This is the zero point for your X axis movements Drilling There are several ways to locate the position at which you want to drill a hole You can use your layout tools to scribe crossed lines at the hole location and then use a wiggler to align the mill s spindle over the intersection of the scribed lines Y...

Page 23: ...end mill s shank Because they fit the end mill closely end mill holders ensure concentricity Collets are less expensive than end mill holders and so can be replaced when they wear out End mill holders are more robust than collets and are less prone to wear out It s fun juggling an end mill a collet and a drawbar all at the same time It is easier to replace an end mill in an end mill holder because...

Page 24: ...re moving in the same direction the milling cutter tends to pull the workpiece away from the driving device if there is any backlash This can overload the cutter and stall the machine Or it can simply leave a poor surface finish On light mills like the mini mill use conventional milling for all but the lightest cuts Then take your final cut of one or two thousandths of an inch using climb milling ...

Page 25: ...en take a few cleanup passes to widen the slot slightly wider than the end mill diameter Your final passes should be climb milling passes on each side of the slot Surfacing Surfacing is used to square a workpiece and to provide a good looking surface as well as to change the size of a workpiece If you are trying to make a good looking surface use as large a diameter cutter as is practical While a ...

Page 26: ... slot that does not extend to the edge of the part Center cutting end mills are easy to identify If the flutes meet in the middle of the end of the end mill it is a center cutting end mill In some cases one of the flutes will be longer reaching right to the center If the flutes stop short of the center leaving a space with no flutes in the center it is a non center cutting end mill Virtually all 2...

Page 27: ...hey usually come in matched pairs Place one parallel adjacent to each jaw in the vise and place the workpiece so it rests on the parallels Clamping Kits and Accessories Clamping kits and their accessories including 1 2 3 blocks are the Erector Sets of work holding Use the various pieces of the clamping kit as you see fit to hold workpieces to the mini mill s table In many cases you need to lift th...

Page 28: ...ance Maintenance of the mini mill is simple but important Regular maintenance will keep your mini mill working like new for many years Cleaning The maintenance you perform most often is cleaning Keeping swarf off of wearing surfaces is the most important thing you can do to prolong the life of your mini lathe Use a 1 paintbrush to remove swarf from the machine as you work Clean swarf from the mill...