Page 1

A Portable, Human-Powered LatheDesigned and Built by Scott Lewis

Illustrations by David Heim

Lathe bed

Tailstockpost

Frame brace

Frame base

Tailstock

Drive belt guardToolrest

and banjoHeadstock post

Headstock spindle

Drive belt tensioner

Chair

Bicycle pedals,sprockets,and chain

Drive belt and flywheel

Chain tensioner

Metric dimensions

Page 2The Frame

Headstock post.Space posts140mm apart

152mm

Notch25mmdeep

140mm

122cm

89mm

74cm

34cm

Notch as neededto give clearancearound flywheel

brackets

Frontview

Sideview

44mm228mm

64mm

168cm

Lathe bed

89mm

88cm

64mm 64mm

Tailstockpost

89mm

122cmFrame base

100cm

89mm

37° 53°

Frame brace.Length is approximate

Front view

Side view

44mm

Spindlehole

25mm dia.

Holes6mmdia. for bearing

140 mm

Page 3The Tailstock and Toolrest

46cm

3"

140mm38mm

51mm

38mm

38mm

51m

m

38mm

23cm

76mm76mm

89mm

140mm

89mm140mm

51mm

36cm

114mm

114mm

114mm

57mm

57mm

57mm

Banjo upper arm

Hole 13mm dia.

Hole 13mm dia.

Banjo lower arm

Tailstock wedgeTailstock center section

Tailstockouter

section

Hole19mm

dia.

All boltholes 9mm dia.

95mm

114mm

27cm

Brackets to support dead centerare shown on page 8. One bracketis threaded and one drilled outto make it easy to align the tailstock rod.

Page 4The Flywheel Assembly

51cm BMX bicyclewheel

46cm

66cm

Inner rim.66cm outside dia.,61mm inside dia.,13mm thick

Outer rim,19mm thick

Divider, 25mm x 25mm x 102mm long.Trim for tight fit between wheel and inner rim

After assembly,turn a slight crownon rim to help holddrive belt in place.

Bicycle wheel axlemounts to bracketsbolted to headstock posts

Page 5The Headstock

53cm

25mm

114mm

64mm

1x8tpi threading

This end can bereverse-threadedto hold a grindingwheel

Pulley.Attaches to

headstock shaftwith hose clamps

76mm

Turn a slightcrown on pulleyto hold drive belt

Cutaway view of spindle shaft and pulley

183mm approx.

Bearings boltto headstock

posts.

Center pulleyover

flywheel

Page 6The Belt Guard and Belt Tensioner

89cm

38mm133mm

56cm

38mm

52cm

89mm

38mm

32cm

38mm

Frontview

Sideview

Belt tensioner arm

Belt tensionerroller bracket

Belt tensionerroller

Holes6mm

dia.

Belt guard coverBelt guard side

'Hole6mmdia.

17mm

Belt tensioner pivots on rackets on headstock posts, held bybolts that also hold bearings,

Belt guard held in placeby brackets boltedto headstock posts

Belt guard cleat(Attaches to framebraces)

133mm

83cm86cm81cm83cm

76mm 51mm

Page 7The Pedals and Chair

202cm

140mm

Pedal support

60°

54°60°

87cm

82mm

140mm

251mm

140mm

61cm

89mm 89mm

32cm

89mm

216mm46cm

140mm

Chair seatsupport

Chair back support

Seat & back rest

Seat support cleat

73mm

Chair base block

Chair baseBoltholes6mmdia. 102mm

100mmm

19mm

56cm

Cranks, pedals, and chainwheelssalvaged from old bicycle. Framemembers cut down and weldedto bracket that is bolted to pedalsupport board. Height to center ofcrank, approx. 229mm.

356mm

Chain tensionerstop block 1,screwed to frame base

Chain tensionerstop block 2,bolted topedal support board

Block andwedge adjustchain tension

Chainwheels:28 teeth38 teeth48 teeth (Largestwheel notused)

Drive sprocketat flywheel:70mm dia.,16 teeth

Page 8Brackets and Other HardwareHeadstock bearingfrom Princess Auto

(www.princessauto.com)Part no. 3870185

Tensioner/guard bracket

Top view

Side view

203mm

140mm

51mm

51mm

1"38mm

64mm64mm

13mm

102mm

38mm

Holes6mm dia.

Holes6mmdia.

Tailstock bracket.19mm nut welded to plate. Leave 1 nut threaded, drill out the other, to makeit easier to align dead center.

79mm 64mm

32mm

54mm

25mm

76mm 13mm squaretube weldedto bracket

Toolrestbracket

25mm

127mm

94mm

38mm

Toolrest9mm

25cm

102mm

Banjo locking bar.

13mm threaded rod, withnuts attached.

Flat bar welded to rod

Coupler nutsharpened to point38cm approx.

19mm threaded rod

Dead center

Handle to suit welded to rod

4"

114mm 16mm19mm

117mm76mm

Side view End view

Holes6mm dia.

Flywheel bracket

64mm

25 mm

Page 9Cutlist

Part Qty. Length Width Thickness Notes Frame Tailstock post 1 88cm 89mm 38mm Lathe bed 2 168cm 140mm 38mm Headstock post 2 122cm 89mm 89mm Frame base 3 122cm 89mm 38mm Frame brace 6 100cm 89mm 38mm Length approximate. Cut

angled ends to fit Tailstock Center section 1 46cm 140mm 38mm Outer section 2 140mm 140mm 38mm Wedge 1 23cm 38mm 38mm Toolrest & banjo Banjo upper arm 1 36cm 114mm 38mm Banjo lower arm 1 114m 114mm 38mm Flywheel Outer rim 2 66cm 66cm 19mm Cut out inner circle so rim

overlaps bicycle rim Inner rim 2 66cm 66cm 13mm Cut 1-in. ring Dividers 6 102mm 25mm 25mm Length approximate; cut

to fit Belt tensioner Belt tensioner arm 1 56cm 133mm 38mm Belt tensioner roller bracket

2 89mm 38mm 6mm Can be plywood, MDF, or metal

Belt tensioner roller 1 76mm 51mm 51mm Belt guard Belt guard side 2 86cm 89mm 19mm Belt guard cover 1 83cm 133mm 19mm Plywood Belt guard cleat 1 32cm 38mm 38mm

Part Qty. Length Width Thickness Notes Headstock Pulley 1 114mm 76mm 76mm Chair Pedal support 1 202cm 140mm 38mm Length approximate. Cut

to suit users. Chair seat support 2 56cm 140mm 38mm Chair back support 2 87cm 140mm 38mm Chair base 2 61cm 89mm 38mm Chair base block 2 32cm 89mm 38mm Seat and back rest 3 46cm 140mm 38mm Cut angle on one edge. Seat support cleat 1 216mm 89mm 38mm Cut angle on one edge as

needed Chain tensioner stop block 1

1 32cm 140mm 38mm

Chain tensioner stop block 2

1 30cm 140mm 38mm

Chain tensioner block

1 39cm 38mm 38mm

Chain tensioner wedge

1 231mm 38mm 38mm Taper to point