Inch Vs. Metric Calibrations on Sherline Tools

Choosing a System of Measurement

All Sherline tools are available calibrated in either inch or metric divisions. The system you choose to work in will most likely be determined by your cultural background, training and requirements of the work you do. The system we were raised with usually remains the most comfortable, but there are also some other considerations when choosing a system that you may not have considered.

Despite the current movement to standardize the world on the metric system, my own preference is the inch system. Here's why. When working in metal, .001" (one thousandth of an inch) is a tolerance that can be achieved with cutting tools, and .0001" (one ten thousandth of an inch) is a tolerance that can be achieved by grinding. The numbers don't come out quite so neatly in the metric system. 1mm equals .03937", .1mm equals .0039" and .01mm equals .0004". The tolerance of .1mm (.004") is too coarse for most work, and .01mm (.0004") is too fine. Therefore, you end up with tolerances too tight or too loose because the draftsman often calls out a tolerance of .1mm when it should be .25mm.

The inch system was developed by craftsmen who took into consideration the materials they were working with as they developed their system. Did you ever watch a seamstress measure cloth from her nose to her fingertips? That human dimension is normally about 36" or a "yard of cloth". It would take a basketball player with arms over 3" longer to measure meters that way. If you have been using the inch system all your life, I wouldn't consider buying a metric machine unless the requirements of your work force you to do so. You will have enough new terms to learn without having to learn a new measuring system at the same time.

Differences Between Inch And Metric Sherline Tools

The difference between inch and metric models of the lathe and mill are not just the handwheel markings, but include the leadscrews, nuts, inserts, handwheels and tailstock spindle. (It is important to remember that a "nut" can be a complicated machined part, not just a simple hex nut. The tailstock spindle is an example of this.)

The handwheel on the inch models moves the slide .050" per revolution and has 50 graduations of .001". The metric model moves the slide 1mm (.03937") per revolution and the handwheel is graduated into 100 divisions. Even though the metric handwheels have finer graduations, this doesn't necessarily make them more accurate, as you don't have to stop exactly on an engraved line. You can interpolate between lines.

Coordinate Your Equipment With Your Measuring Tools

I recommend using the system you are most familiar with and for which you have the measuring tools. Don't buy a metric tool and plan to use an inch micrometer with it. Converting dimensions is a constant headache and a source of errors.

If most of the drawings you will be working with are dimensioned in metric measurements, it might be wise to buy a metric tool, even if you have to buy all new measuring tools to use with it.

Converting A Sherline Machine From One System To Another

Parts are available to change any Sherline tool from inch to metric or vice versa. Included is a list of the parts you will need to make a conversion. On the lathe, the tailstock spindle will be replaced as an assembly.

As you can see from the parts list below, quite a few parts need to be changed to make a conversion. The time spent deciding which system to use before purchasing a machine is "time well spent" if it eliminates making a change later on.

Joe Martin
President and Owner


SHERLINE PARTS CONVERSION KITS

LATHE

Inch P/N

Metric P/N

DESCRIPTION

PRICE

40200

41200

Leadscrew (Model 4000/4100)

$24.00

(44200)

(44230)

24" Leadscrew (Model 4400/4410)

30.00

40170

41170

Saddle Nut

8.40

44210

44220

Slide Screw

12.00

40890

41890

Slide Screw Insert

2.40

40220

41220

Feed Screw

8.40

4111A

4111M

Complete Tailstock with brass gib (Includes handwheel)

78.00

40050

41050

Crosslide Handwheel (1 req.)

10.80

40080

41040

Leadscrew and Feed Screw Handwheels (2 req.)

10.80

(34230)

(34240)

Crosslide Handwheel Collar only,
(Adjust. zero handwheel, Models 4400/4500--disassemble and use other components from your existing handwheel or purchase complete handwheels listed below.)

18.00

(34260)

(34270)

Leadscrew and Feed Screw Handwheel Collars only
(Adjustable zero handwheel, Model 4400, 2 req./ Model 4500, 1 req.--disassemble and use other components from your existing handwheel or purchase complete handwheels listed below.)

18.00

3428 2429 Complete 2" adjustable zero handwheel, X axis (crosslide screw on 4400 lathe) 35.00
3455 3459 Complete 2.5" adjustable zero handwheel, Y axis (long leadscrew on 4400 lathe, also used for Z-axis on optional vertical milling column) 40.00

VERTICAL MILL

Inch P/N

Metric P/N

DESCRIPTION

PRICE

50170

51170

Leadscrew, "X" Axis (all mill models)

$18.00

50160

51160

Leadscrew, "Y" Axis (Model 5000, 10" base)

12.00

(54160)

(54170)

Leadscrew, "Y" Axis (Model 5400, 12" base)

14.00

45010

45160

Leadscrew, "Z" Axis

14.00

40080

41040

Handwheel, "X" Axis (Model 5000)

10.80

40050

41050

Handwheel, "Y" Axis (Model 5000)

10.80

3400

3410

Oversize Handwheel, "Z" Axis (Model 5000)

15.00

50130

51130

Backlash Nut, "X" Axis

2.40

40890

41890

Nut, "X" Axis

2.40

50140

51140

Backlash Nut, "Y" Axis

2.40

50200

51200

Nut, "Y" Axis

2.40

40170

41170

Saddle Nut, "Z" Axis

8.40

(34260)

(34270)

Leadscrew Collar only, "X" and "Z" Axes (2 req.)
(for Adjust. zero Handwheel, Model 5400--disassemble and use other components from your existing handwheel or purchase complete handwheels listed below.)

18.00

(34230)

(34240)

Leadscrew Collar only, "Y" Axis
(for Adjust. zero Handwheel) (Model 5400--disassemble and use other components from your existing handwheel or purchase complete handwheels listed below.)

18.00

3420 2430 Complete 2" adjustable zero handwheel, Y-axis 35.00
3428 2429 Complete 2" adjustable zero handwheel, X axis 35.00
3455 3459 Complete 2.5" adjustable zero handwheel, Z-axis 40.00

(54180)

(54190)

Mill Table, Engraved (Model 5400) (Optional)

76.20

(54020)

(54120)

12" Mill Base, Engraved (Model 5400) (Optional)

144.00

56160 56150 Leadscrew, Y-axis, (Model 2000 Mill) 18.00
45011 45161 Leadscrew, Z-axis (Model 2000 mill) 18.00
56010 56020 14" Mill base (Engraved, Model 2000--Optional)` 180.00

(Items shown in parenthesis are upgraded or optional items which would be used instead of the standard item which may be also listed.)

COMPLETE CONVERSION KITS

Instead of purchasing the individual parts listed above, you can order prepared kits for most machines. See below.

LATHE

P/N

DESCRIPTION

PRICE

33100

4100 Lathe (M) to 4000 (I) Conversion

$144.00

33200

4000 Lathe (I) to 4100 (M) Conversion

144.00

33150

4410 Lathe (M) to 4400 (I) Conversion

216.00

33250

4400 Lathe (I) to 4410 (M) Conversion

216.00

VERTICAL MILL

P/N

DESCRIPTION

PRICE

33300

5100 Mill (M) to 5000 (I) Conversion

$116.00

33400

5000 Mill (I) to 5100 (M) Conversion

120.00

33350

5410 Mill (M) to 5400 (I) Conversion*

154.00

33450

5400 Mill (I) to 5410 (M) Conversion*

154.00

33500 2000 Mill (I) to 2010 (M) Conversion* 176.00
33550 2010 Mill (M) to 2000 (I) Conversion* 176.00

* Does not include engraved base or table.

Prices subject to change.

Return to Lathe Accessories Section


Copyright 1996, Sherline Products Inc. All rights reserved.
No part of this web site, including the text, photos or illustrations, may be reproduced or transmitted in any other form or by any means (electronic, photocopying, recording or otherwise) for commercial use without the prior written permission of Sherline Products Inc.