Myford Lathe Changewheel Sets: Guide to Leadscrew Driven Sets for Series 7, Super 7, ML7, and More (EN)

Technical Support Explaining changewheel sets for Lathes with changewheel driven leadscrews The following gives the quantity and number of teeth of the changewheels supplied as standard equipment with new lathes. We also explain which changewheels are fitted as standard and feed rate achieve. The remaining changewheels in each set are supplied loose with the standard equipment for each Lathe. Series 7 Lathes The set up is as follows: Tumbler Reverse Driver – 20T 1st Stud Driven 65T – Driver 25T 2nd Stud Driven 70T – Driver 20T Leadscrew 75T Lathes fitted with 8 tpi Imperial Leadscrews Current Models: Super 7 Sigma, Super 7 Plus Leaving 8 loose Changewheels:

30T, 35T, 38T, 40T, 45T, 50T, 55T, and 60T (no loose changewheels supplied with the original small bore Super 7 Sigma). Non Current models: ML7, ML7-R, Super 7, Super 7 Sigma The number of changewheels supplied with each machine is 14. Note: When cutting metric threads the Leadscrew half nut/clasp nut must be kept permanently engaged and the Carriage returned to the starting point by reversing the Headstock Spindle. The changewheel train is set to give the finest feed of .0037" per revolution. Myford Super 7 Plus ‘Big Bore’ Lathe Myford Super 7 ‘Standard Bore’ Lathe The technical support team is based at our Beeston Factory in the UK.

We are happy to supply technical assistance to every Myford user. All enquiries please see www.myford.com/support or call +44 (0) 115 925 4222.

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Explaining changewheel sets for Lathes with changewheel driven leadscrews Super 7 and ML7 Inch Pitches/Metric Pitches – The Charts INCH PITCHES LEADSCREW 8 THREADS PER INCH • Not a standard gear. Available as an extra. ** 12/30T Fine feed Tumbler Sleeve Gear for all ‘Standard Bore’ Super 7 Lathes are available, Part No A1974A/1 ** 12/25T Fine feed Tumbler Sleeve Gear for all ML 7 Lathes are available, Part No A1974/1 ** 12/38T Fine feed Tumbler Sleeve Gear for all ‘Big Bore’ Super 7 Plus Lathes are available, Part No 15327 The technical support team is based at our Beeston Factory in the UK. We are happy to supply technical assistance to every Myford user.

All enquiries please see www.myford.com/support or call +44 (0) 115 925 4222. T.P.I. Feed per Rev.

Driver 1st Stud 2nd Stud Lead Screw Set-up Driven Driver Driven Driver 8 0.1250" 20 Idle 75 Wheel - - 20 1 9 0.1111" 40 Idle 60 Wheel - - 45 1 10 0.1000" 40 Idle 60 Wheel - - 50 1 11 0.0909" 40 Idle 60 Wheel - - 55 1 12 0.0833" 40 Idle 50 Wheel - - 60 1 14 0.0714" 20 Idle 70 Wheel - - 25 1 16 0.0625" 20 Idle 70 Wheel - - 40 1 18 0.0556" 20 Idle 70 Wheel - - 45 1 19 0.0526" 40 38 20 Idle 55 Wheel 50 2 20 0.0500" 20 Idle 70 Wheel - - 50 1 22 0.0455" 20 Idle 70 Wheel - - 55 1 24 0.0417" 20 Idle 70 Wheel - - 60 1 25 0.0400" 40 50 30 Idle 45 Wheel 75 2 26 0.0385" 20 Idle 70 Wheel - - 65 1 28 0.0357" 30 35 20 Idle 50 Wheel 60 2 32 0.0313" 30 40 20 Idle 55 Wheel 60 2 36 0.0278" 30 45 20 Idle 55 Wheel 60 2 40 0.0250" 30 50 20 Idle 55 Wheel 60 2 44 0.0227" 20 55 30 Idle 50 Wheel 60 2 46 0.0217" 20 46 • 30 Idle 45 Wheel 75 2 48 0.0208" 20 60 35 Idle 45 Wheel 70 2 52 0.0192" 20 50 25 Idle 55 Wheel 65 2 54 0.0185" 20 45 20 Idle 55 Wheel 60 2 60 0.0167" 20 50 25 Idle 55 Wheel 75 2 64 0.0156" 35 40 20 60 30 70 3 72 0.0139" 25 50 30 45 20 60 3 80 0.0125" 25 50 35 70 30 75 3 88 0.0114" 30 40 25 55 20 75 3 92 0.0109" 20 46 • 30 50 20 60 3 96 0.0104" 30 40 20 60 25 75 3 104 0.0096" 20 50 30 60 25 65 3 0.0087" 20 55 30 60 25 65 3 112 0.0089" 25 50 30 60 20 70 3 120 0.0083" 20 50 30 60 25 75 3 0.0058" 20 55 25 60 20 65 3 0.0043" 20 60 25 65 20 75 3 0.0037" 20 65 25 70 20 75 3 0.0018" 12** 65 20 70 20 75 3

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Explaining changewheel sets for Lathes with changewheel driven leadscrews Super 7 and ML7 Inch Pitches/Metric Pitches – The Charts METRIC PITCHES • Not a standard gear. Available as an extra. The tumbler reverse lever should not be shifted during thread cutting operations, as such movement may alter the position of the headstock spindle relative to the leadscrew, thereby causing split threads. The charts are read as follows: The column headed SET-UP refers to one of three set- up arrangements of gears and spacers required. SET- UP diagrams 1,2 & 3 are given below. The thread pitch, or feed, to be set up will be located in the first two columns under the headings T.P.I. and FEED PER REV.

In the third column under the heading DRIVER is listed a number of teeth in the Changewheel which should be placed on the tumbler sleeve gear. Note: When setting up the gear train sufficient backlash between each pair of meshing gears should be allowed. When the Lathe is is operation the play in the gears is automatically taken up according to the direction of travel. The amount of gear clearance does not influence the accuracy of thread cutting. Gear noise can be reduced by the application of grease, preferably Moly grease. In the fourth and fifth columns under 1st STUD and 2nd STUD are given the gears or pairs of gears which should be placed on the relevant studs.

The sixth column gives the gear to be placed on the LEADSCREW. The technical support team is based at our Beeston Factory in the UK. We are happy to supply technical assistance to every Myford user. All enquiries please see www.myford.com/support or call +44 (0) 115 925 4222. Feed per Rev.

Millimetres Driver 1st Stud 2nd Stud Lead Screw Set-up Driven Driver Driven Driver 0.20 21 • 50 30 60 21 • 70 3 0.25 30 40 21 60 21 70 3 0.30 21 60 45 50 21 70 3 0.35 35 40 21 50 21 70 3 0.40 21 50 21 Idle 60 Wheel 70 2 0.45 45 40 21 50 21 70 3 0.50 21 50 45 40 20 60 3 0.60 21 50 45 40 30 75 3 0.70 21 50 21 Idle 60 Wheel 40 2 0.75 45 40 35 50 21 70 3 0.80 21 50 45 Idle 40 Wheel 75 2 0.90 45 25 21 40 21 70 3 1.00 45 40 21 Idle 50 Wheel 75 2 1.10 45 50 55 40 21 75 3 1.20 45 25 30 50 21 60 3 1.25 45 40 21 Idle 50 Wheel 60 2 1.30 65 25 21 40 21 70 3 1.40 45 25 35 50 21 60 3 1.50 21 50 45 Idle 35 Wheel 40 2 1.60 45 25 21 Idle 55 Wheel 75 2 1.75 45 20 35 50 21 60 3 1.80 30 40 45 25 21 50 3 2.00 60 40 21 Idle 55 Wheel 50 2 2.25 45 40 60 40 • 21 50 3 2.50 45 30 21 Idle 50 Wheel 40 2 2.75 55 20 30 40 21 50 3 3.00 45 25 21 Idle 60 Wheel 40 2 3.50 60 20 35 40 21 40 3

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Explaining changewheel sets for Lathes with changewheel driven leadscrews Left is shown the Set-Up for the standard bore Super 7 Lathe, variations across the range of Series 7 Lathes are shown in brackets 1 – Tumbler Reverse Lever 2 – Tumbler Reverse Gears 3 – 30T Spindle Gear (ML 7 = 25T, Super 7 Plus ‘Big Bore’ 38T) 4 – 30T Tumbler Sleeve Gear (ML 7 = 25T, Super 7 Plus ‘Big Bore’ = 38T) 5 – 1st Stud Gears 6 – 2nd Stud Gears 7 – Leadscrew Gear 8 – Spacer The technical support team is based at our Beeston Factory in the UK. We are happy to supply technical assistance to every Myford user. All enquiries please see www.myford.com/support or call +44 (0) 115 925 4222.

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