Variable Speed Lathes: A Low-Budget Alternative

Because I have a compulsion to improve thingswhether they are cars, kitchen utensils, or guns—my wife calls me "Mr. Modification Man." I’ve always had this compulsion. When I was a kid, I was messing with home-made SCUBA gear made from war-surplus aircraft oxygen regulators. That was followed by years of science-fair projects made from everything but the kitchen sink. Later, when I was in college, I super charged my Pontiac Tempest with parts from an aircraft cabin pressur izer.

So, I guess it was inevitable that I’ve now repowered the lathe in my gun shop with the guts from a treadmill. Let me back up here for a minute. A few months ago, I was looking through a surplus electronics catalog I got somewhere, when I noticed a variety of 1- to 2-horsepower DC motors. (A DC motor can have its speed varied by changing the voltage applied, whereas an AC motor cannot.) Elsewhere in the catalog I found SCR-based speed controllers.

The SCR (silicon controlled rectifier) changes the motor supply voltage to DC, and incorporates a speed (voltage) control. This is perfect for providing a nice variable-speed drive for a lathe, drill press, or millas was discussed at length in the September 99 issue of American Gunsmith. I remembered reading the article, and while I found it interesting, I thought the project was a little too expensive for my budget at the time.

And so, for that matter, were the motors in this catalog; together with the appropriate speed control, heat sink, and other parts, a variable-speed setup for a lathe would have cost more money than I wanted to spend. However, as I read, a light bulb switched on in my head. I noticed that many of the motors were made for treadmill-style exercise machines.

After a moment’s thought, I reasoned that treadmills were large cumbersome items that people bought with good intentions and used a few times, and many of them would probably end up A simple cylindrical sheetaluminum fan guard (not shown) was made to surround the area between the fan and heat sink to improve cooling and protect fingers.

gathering dust in dark basements. I further reasoned that the motors ran off direct current (DC) so the exercise speed could be easily varied with an SCR circuit. So, my next move was to the classified ads in my local paperthe little budget-type ads where people announce garage sales, advertise their old Beta Max, Elvis records, and stuff like that. Yep. There they were, used treadmills! One advertisement even read: "Free…You Haul." Now, "free" is my kind of price.

A phone call confirmed that it worked fine, but was just taking up too much space in the spare bedroom. I picked up the free treadmill, and took it apart right away, being careful to label any wires I had to disconnect (few, as it turned out). The motor was rated at 1-1/2 horsepower, (more power than the original motor on my lathe) and at pulley was about half the size of the pulley on my existing lathe motor, however, so the resulting maximum input speed to the lathe was fineand would produce more torque to boot.

Can you believe that the pulley’s belt size was the same as the one on my Atlas lathe? As a result, the motors were easy to swap, and having tagged the wires, hooking up the power and speed control was also easy. I mounted the treadmill’s speed-control rheostat and knob at a convenient spot on the lathe’s drivebelt enclosure, with the treadmill’s on-off switch next to it.

An SCR unit usually has a finned aluminum heat A Word to our Readers about American Gunsmith’s Mailing-List Policy Like many other publishers, we make portions of our customer list available to carefully screened companies that offer products and services we believe you may enjoy. Indeed, in all likelihood, we were able to first reach you only because another company graciously permitted us access to its customer list.

If, when we make our list available, you do not want to receive those offers and/or information, please let us know by contacting us at American Gunsmith Opt-Out Program, Norwalk, CT 06854-1631. Please be sure to include your current mailing label. sink to keep it cool. Mine did, too, and I placed it next to a small fan attached to the motor (see photo). Other treadmills may have a self-contained "muffin fan," like the one used in the earlier American Gunsmith article.

Either way, make sure you make some provision for a guard or fan cover to prevent fingers from interfering with the fan. (My gunsmithing work often requires 12 or more fingers. Seven or eight would be tough to work with.) In addition to the variable-speed benefit of DC motors, they are also easily reversible: You simply swap the two power-supply wires.

This can make the actual placement of your new powerplant even easier. (You certainly wouldn’t want your lathe to run backwards, just because you wanted to mount the new motor with its drive pulley on the left.) There were a few other little benefits of my free treadmill. With a little modification, the treadmill’s mast and "dashboard" made a great new floor stand for my small bench grinder, giving me more bench space.

And the treadmill’s rubberized fabric belt (mine was 18 by 102 inches) is great for making a non-mar workbench cover, lining tool box drawers, or even for making grips for semi-auto grips. How does the new variable-speed lathe work? Terrific! I can now start a cutting operation carefully—at a crawl—and then dial up the speed as I wish. In fact, I’m already watching garage sales and classified ads, looking for a bigger treadmill to repower my milling machine. ■

Antique/Replica Firearms Browning Model 1885 High Wall, Disassembly of the June 04 Centurion Coach Gun, Working the July 04 Cimarron Model 1872 Open-Top Revolver, The Nov 04 Colt’s Cowboy Single-Action: New Slant on Old Std.

July 04 Henry Big Boy Rifle, Working the Nov 04 Henry Golden Boy Rifle, Disassembly of the Feb 04 Italian SA Revolver, Nuances of the Aug 04 Richards-Mason Cartridge-Conversion Revolvers Sept 04 S&W’s .32-Caliber New Departure/Safety Hammerless Feb 04 Spencer Slide-Action: Working the First Pump Shotgun Apr 04 Steyr 1895 and 95/34 Straight-Pulls, Troubleshooting Mar 04 Reviews/Special Reports Basic Air-Gun Repair Feb 04 Testing the Kart EZ-Fit Barrel June 04 The Case of the ‘De-Accurized’ Ruger M77-17 May 04 Why Doesn’t This 12-Gauge Kick Like a 12-Gauge?

Nov 04 Tech Topics Book Review: Ball’s Mauser Military Rifles of the World Oct 04 Book Review: Campbell’s Holsters for Combat Mar 04 Book Review: Gun Digest’s Assembly/Disassembly Oct 04 Book Review: Krause’s Cartridges of the World Oct 04 Book Review: Kuhnhausen’s Ruger SA Revolvers Oct 04 Brownells Top Dead Center Finder Mar 04 D&L Sports CQB Iron Sight for AR-15/M-16 Flattops Mar 04 Laser Magic II Scope Ring and Base Alignment Tool Mar 04 Poly Dunk-Kit Polymer Frame Cleaner Mar 04 SL-100 Mag Laser Bore Sighting System Mar 04 Do-It-Yourself Projects Applying Metal-Lined Bushings, Bedding, and Shims Apr 04 Converting a Percussion Revolver to Centerfire Apr 04 Do-It-Yourself Takedown Tools Sept 04 Get a Grip on Older Colt D-Frame Revolvers Feb 04 Making a Smoke-Free Muzzleloader Ignition Module June 04 Making an Action Wrench for the Weatherby Mark V Oct 04 Variable Speed Lathes: A Low-Budget Alternative Dec 04 Editorials Hunter Participation Grew in 2002 Jan 04 Taurus Enters High-Tech Partnership Feb 04 Women and Guns Mar 04 NRA Foundation Awards $10.7 Million Apr 04 Strong Sales Mark 2004 SHOT Show May 04 Anti-Gun Amendments Derail Crucial Bill June 04 Win Chuck’s "My Cold Dead Hands" Rifle July 04 NRA Program Aids Disabled Veterans Aug 04 S&W Introduces Disabled Marksman Award Sept 04 Jury Clears Beretta in Accidental Shooting Oct 04 Failed ‘Assault Weapon’ Ban Ends Nov 04 Placeholder Dec 04 Gun-Servicing Features Beretta U22 NEOS, Taking Down the Mar 04 Browning Model 1885 High Wall, Disassembly of the June 04 Centurion Coach Gun, Working the July 04 CZ P-01 Semi Auto: Dissecting the Smallest CZ Sept 04 CZ-52, A Complete Guide to Take-Down/Reassembly May 04 Henry Big Boy Rifle, Working the Nov 04 Henry Golden Boy Rifle, Disassembly of the Feb 04 Marlin T900-Series Small Bores, Working the Aug 04 Para-Ordnance LDA Carry Companion, Part 1 Dec 04 Remington Model 12, Working the Oct 04 Remington Model 14 and 14-1/2, Maintaining the May 04 Star Model F .22 LR Pistol, Troubleshooting the Dec 04 Taurus Model 62 Rifle, Working the Jan 04 Taurus Model 63, Disassembly/Reassembly of the Apr 04 Taurus PT24/7, Exploring the New Oct 04 Winchester Model 50 and 59 Shotguns, Working the June 04 STATEMENT OF OWNERSHIP, MANAGEMENT, AND CIRCULATION (Required by 39 U.

S. C. 3685). 1. Title of Publication: American Gunsmith 2. Publication No.: 0008-4530. 3. Filing Date: 9/30/04. 4. Issue Frequency: Monthly. 5. No. of Issues Published Annually: 12. 6. Annual Subscription Price: $49.00 in U. S. 7. Known Office of Publication: Greenwich, CT 06836-2626. 8. Headquarters or General Business Office of the Publisher: Greenwich, CT 06836-2626. 9. Publisher: AG Media, Inc., Greenwich, CT 06836-2626. Editor: Keith Lawrence, AG Media, Inc., Greenwich, CT 06836-2626.

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Issue date for circulation data 22-Caliber Rimfire Barrel Dec 04 Making a Smoke-Free Muzzleloader Ignition Module June 04 Making an Action Wrench for the Weatherby Mark V Oct 04 Making and Using a Receiver-Facing Mandrel May 04 Modify the New Model Blackhawk for Cowboy-Action Jan 04 Modifying the Winchester Model 97 Shotgun Sept 04 New Life for Remington 11-48 and Sportsman 48 July 04 Nuances of the Italian SA Revolver Aug 04 On Slides and Tightening Jan 04 Proper Epoxy Bedding Techniques May 04 Repairing the Colt Ace/Conversion Unit Magazine Aug 04 Replace Those Fragile Flat Springs in SAA Copies Nov 04 Retaining Screw Blues Feb 04 Rib Work on Double Shotguns Aug 04 Scope Mounting: The Right Way Apr 04 Scoping the Hi-Point Model 995 Semi-Automatic Rifle Jan 04 Simple Pump-Shotgun Fixes: An Armorer’s View Oct 04 Testing the Kart EZ-Fit Barrel June 04 The Bulged Chamber: A Simple Fix Aug 04 Understanding the Savage Accu Trigger Dec 04 Using Precision Measuring Instruments Mar 04 Variable Speed Lathes: A Low-Budget Alternative Dec 04 2004. 15.

Extent and Nature of Circulation (Average No. Copies Each Issue During Preceding 12 Months/ No. Copies of Single Issue Published Nearest to Filing Date): a. Total No. of Copies Printed (20250/20000) b. Paid and/or Requested Circulation: 1. Paid/Requested Outside-County Mail Subscriptions Stated on Form 3541 (19347/19144). 2. Paid In-County Subscriptions (0/0). 3. Sales Through Dealers and Carriers, Street Vendors, Counter Sales, and Other Non-USPS Paid Distribution (11/12). 4.

Other Classes Mailed Through USPS (0/0). c. Total Paid and/or Requested Circulation (19358/19156). d. Free Distribution by Mail: 1. Outside-County as Stated on Form 3541 (311/414). 2. In-County as Stated on Form 3541 (0/0). 3. Other Classes Mailed Through the USPS (0/0). e. Free Distribution Outside the Mail (0/0). f. Total Free Distribution (311/414). g. Total Distribution (19669/19570). h. Copies not Distributed (581/430). i. Total (20250/20000). j. Percent Paid and/or Requested Circulation (98%/98%). 17.

I certify that all information furnished on this form is true and complete. Sr. VP of Circ.: Greg King 9/15/04.