compound slide wood lathe

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slide rest, lathe Compound slide rest for a wood lathe By WALTER E. BURTON Have you wished you could do metal turning? This accessory lets you do it on your wood lathe. Furthermore, you don't need special metalworking equipment to make the slide rest Upside-down assembly of cross-slide sections assures accuracy. After rails F are joined to end supports and plate J, use assembly as spacing cradle for rails E. Slip paper between gib and rail before clamping to drill for bolts and pins at the right WHEN YOU ADD a compound slide rest to a wood-turning lathe, you expand the tool's abili- ties to include reasonably precise machining of metals, plastics, hardwoods—any turnable ma- terial. The lathe does not need altering unless you must change pulleys or add a jack shaft to pro- duce spindle speeds low enough for metal turn- ing. You'll probably also want to add a chuck or two of the type used to hold metal rods, tubes and rings—say one universal (3-jaw) chuck and one independent 4-jaw type. The compound slide rest shown in use on the facing page was designed to be built in a shop that presently has no metal-working lathe. It's not as complicated as a quick glance at the drawings on the following pages might suggest. The basic materials needed will include: One plate of 3/8" steel and three plates of 1/4" steel (keyed A, J, K and S on the drawings); four 5/8"-square steel bars for the lower slide rails (E and F ) ; four %-in.-square steel bars for the upper slide rails (L and P); strips of 1/8" -thick brass in 5/16" and 3/4" widths, for the gibs and their retaining plates (I and O); eight end supports of 1/4-in. steel (B and C, G and H, M and N, Q and R); pieces of the same stock, to form the tool-post slot; enough 3/8-16 threaded rod (the type sold in local hard- ware stores) to make one 6-in. and one 10-in. To make a curved slot in plate J, secure plate K to it with a pivot bolt and drill a series of overlapping holes through the locking bolt hole, while K is pivoted about 100 deg. Then file away jagged edges and file a hex nut to fit the slot as shown on page 2383 2380

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Build a compound slide for your wood lathe. Turn metal on a wood lathe.

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Page 1: Compound Slide Wood Lathe

slide rest, lathe

Compoundslide restfor a wood latheBy WALTER E. BURTON

Have you wished you could do metalturning? This accessory lets you do

it on your wood lathe. Furthermore,you don't need special metalworking

equipment to make the slide rest

Upside-down assembly of cross-slide sectionsassures accuracy. After rails F are joined toend supports and plate J, use assembly asspacing cradle for rails E. Slip paper betweengib and rail before clamping to drill for boltsand pins at the right

• WHEN YOU ADD a compound slide rest to awood-turning lathe, you expand the tool's abili-ties to include reasonably precise machining ofmetals, plastics, hardwoods—any turnable ma-terial.

The lathe does not need altering unless youmust change pulleys or add a jack shaft to pro-duce spindle speeds low enough for metal turn-ing. You'll probably also want to add a chuck ortwo of the type used to hold metal rods, tubesand rings—say one universal (3-jaw) chuckand one independent 4-jaw type.

The compound slide rest shown in use on thefacing page was designed to be built in a shopthat presently has no metal-working lathe. It'snot as complicated as a quick glance at thedrawings on the following pages might suggest.The basic materials needed will include:

One plate of 3/8" steel and three platesof 1/4" steel (keyed A, J, K and S on thedrawings); four 5/8"-square steel bars for thelower slide rails (E and F); four %-in.-squaresteel bars for the upper slide rails (L andP); strips of 1/8" -thick brass in 5/16" and 3/4"widths, for the gibs and their retaining plates (Iand O); eight end supports of 1/4-in. steel (B andC, G and H, M and N, Q and R); pieces of thesame stock, to form the tool-post slot; enough3/8-16 threaded rod (the type sold in local hard-ware stores) to make one 6-in. and one 10-in.

To make a curved slot in plate J, secure plateK to it with a pivot bolt and drill a series ofoverlapping holes through the locking bolt hole,while K is pivoted about 100 deg. Then fileaway jagged edges and file a hex nut to fit theslot as shown on page 2383

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Page 2: Compound Slide Wood Lathe

Drill rails for bolts and pins, using pre-drilled end supports as templates

feed screw; and two brass blocks, each 3/4" to1" square and about 1" long, for feed-screw nuts, which are stationary.

Start with the cross slide. This half of the as-sembly consists of two rail-and-plate sections.The bottom (fixed) section bolts to the lathebed; the top (sliding) section moves crosswiseto the lathe bed—as for facing cuts—and servesas a mount for the pivoting compound slide. Thegibs, attached to the rails of the sliding section,are adjustable to control any play that maydevelop.

It's important that rails are mounted exactlyparallel to each other and to the plate on whichtheir end supports are mounted. Assemble thetop section first, clamping the rails in positionand using the predrilled end supports for boringtemplates, as in Fig. 1. Note that the gib-retain-ing plates are already attached to the rails. AV-block makes a good clamping support. Afterthese rails are secured, use them as a form forclamping the lower, fixed rails while the latterare drilled for the bolts and pins that fasten themto their end supports (Fig. 2). Before applying

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Page 3: Compound Slide Wood Lathe

slide rest, lathe

The slide rest consists of two units: The cross slide(the color-shaded portion of these two pages) boltsto the lathe bed; the compound slide pivots on top.Each unit has two rail-and-plate sections. The keyletters used in the text refer to the pull-apart assemblyabove and the dimensioned plans on the next page

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The disassembled compound slide is in the fore-ground, with the cross slide to the rear. A detachedgib and retaining strip are at the left, in front of theupside-down feed table

Page 4: Compound Slide Wood Lathe

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Page 5: Compound Slide Wood Lathe

slide rest, lathe

Scribe a scale into the face of plate J, after making an index notch on the edge of plate K.Set the compound slide at accurate angles with a protractor, tapping lightly with a hammerand clamp tight. Use the square edge of the protractor to guide the scriber. To use the scale,be sure the cross slide is clamped at right angles to the headstock axis

compound slide rest, continued

the clamps, place a strip of fairly heavy paperbetween each gib and its retaining strip, to pro-vide clearance for easier assembly. Gib setscrewswill take up the slack when the unit is in use. Ateach point where a setscrew touches a gib, drilla recess about 1/16" deep and not much widerthan the screw tip. These prevent lateral shifting.Position the screws to provide access when therail sections are assembled.

You can use either two 8-32 bolts, or onebolt plus a 1/8" steel pin, to fasten each rail toeach end support. When predrilling the supports,use a No. 29 (tap-size) drill for the bolt hole;then, after the supports have served as boringtemplates, enlarge these holes with a No. 19 bit.Bolt heads are countersunk.

To prepare the bearing for the 10-in. feedscrew, ream out a piece of 1/4" iron or brasspipe until it's round and smooth. Take pains tosee that the end of this pipe is square with endsupport G when screwed tight. Drill and threadthe brass block so the feed screw is parallel tothe top and bottom plates A and J. At the pointwhere the screw rotates within the pipe bearing,coat it with solder or babbitt to fill the threadsand increase the diameter. Then file until thescrew rotates snugly inside the bearing. Two thinnuts, jammed together behind this soldered sec-tion, ride against the inside end of the bearing.The central hole in end support B should belarge enough for these nuts to turn inside it.

In the photos and drawings, different handcontrols are shown on the two feed screws. Thechoice between a two-handled crank or a hand-

wheel is not critical, unless you plan to addmicrometer scales.

Making the compound slide. This—the pivot-ing half of the accessory—is of the same basicconstruction as the cross slide, but on a smallerscale. As shown in Fig. 3, its bottom plate (K)pivots on plate J of the cross slide, for angular,settings. The pivot stud is threaded into plate Jand passes through a bushing press-fitted inplate K; it protrudes enough to permit the use ofa washer and nut..

The completed unit shown was built for an11" lathe. The top surface of the tool-post-slotstrips (T) should be about 1 in. below the cen-ter line of the lathe headstock spindle. Thus,overall height of the accessory shown is about4-1/2" from the lathe bed. The two mountingblocks (D) can be dimensioned to bring thetoolpost slot to the proper height for variouslathes. These blocks are simply 2-in. wide steelbars or strips bolted to the bottom of plate A;length and spacing should be whatever is re-quired for secure fastening with lathe-bed bolts.

Test the unit by turning an easy material suchas wood. Oil any moving parts, and be sure allbolts are tight. Adjust gib screws to take up anyplay in the slides. At first, the feed screws mayturn hard because of slide tightness and rough-ness. Rails not equipped with gibs (which addstiffness) may have a tendency to spring. In theunit shown, rail-stiffening bolts were installedmidpoint on the fixed rails of the compoundslide. They can be seen in the photo on page2382, and are given as an optional detail.

If there's excessive chatter when turningmetal, check the unit for play. Grasp the tool-

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Page 6: Compound Slide Wood Lathe

A standard tool post for a 9-in.metal-turning lathe clamps regulartoolholder. Point of the bit normallyshould be on the center line of the lathespindle. Much work requires no microm-eter collars on feed screws, but theyare easily added, as shown at the right

post and try to rock it in various directions. Ifchatter persists once play has been removed, youmay have to lower the spindle speed. Woodlathes often have a minimum speed that is toohigh for large-diameter metal turning.

You can do a lot of turning without feelingthe need for the angular scale shown in Fig. 4, orfor micrometer collars on each screw to gauge-feed in small fractions of an inch. These featuresmay be added later. The collar shown (Fig. 5) is1-1/4" diameter and 1/2" long. Its matchingindex ring, setscrewed to the bearing pipe, isabout the same size. Each turn of the screwmoves the tool 1/16 (or .0625) inch. Since themicrometer collar is divided into 125 equalspaces, each division indicates a tool movementof .0005 in.—two divisions, .001.

One way to graduate the collar: clamp it in the

lathe chuck, wrap a strip of paper around thechuck body and trim it to exact circumference.Remove this band, divide the circumference into125 equal parts, tape it around the chuck again,and provide a fixed pointer for the division lines.Use a pointed tool in the compound slide rest toscribe equivalent lines on the face of the collar.

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