Open Source Lathe

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Introduction

Here we are showing the details for fabricating a high-performance (2/1000" accuracy), high power (20 hp) lathe. It will be powered from the hydraulic take-off from a tractor - LifeTrac. The design follows that of the Multimachine. Instead of an engine block as the basic structural unit, we'll be using a concrete bed with metal mounting plates. The advantage of this route is that we are avoiding the necessity of sourcing and boring out the engine block. Moreover, the concrete bed will be its own lathe mount structure.

This route allows for the construction of a lathe from stock parts - metal plate, shaft, coupler, bearings, bolts, and concrete. We add a cross slide and chuck on top of that, and use a hollow shaft tube for workpiece feed-through:

Design Rationale

• High power, simple design
• OSE Specifications are met via low cost for replication; a transparent, open source development process; open documentation; product evolution infrastructure
• External power source
• Interchangeable motor - part of LifeTrac infrastructure, motor can be coupled to many different devices
• Hydraulic motor provides high power and torque with full speed control via a flow control valve
• Basic design:
  • Romig type lathe bed made of concrete(see below)
  • Metal plates are used to attach functional parts of lathe to concrete bed
  • Large hollow shaft attached to bearing blocks on plates
  • Two bearings with bearing clamps holding bearings in place:

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• • Clamps as such hold the chuck in place
  • Cross slide is mounted on another plate
  • Tail stock?

Specifications

Lathe_Specifications

Fabrication and Cost

• Ease and low cost of fabrication is the primary goal, as a high-performance lathe is perhaps the most important tool in a workshop
• Construction consists of a concrete bed
• Cost is that of 4 bags of concrete for the bed, chuck, cross slide, and
• Motor cost is included in LifeTrac infrastructure
• Motor coupler to lathe shaft is machined
• Commercial chck is the main cost
• XY table constitutes a cross slide
• Tool post is fabricated
• 2" shaft constitutes a mounting surface for an xy table and for tail stock
• Feed-through shaft is present, but is only 1 foot deep
• Cheap 2 15/16" bearing

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Specifications

• 12" lathe
• 1/1000" accuracy via bearing tolerance and chuck tolerance
• Heavy duty axial thrust acceptable, as determined by 3" shaft and bearings
• Radial thrust determined by set screws on 2 bearings, with 2 extra full split collars

Motor

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Brute 20 horse of turning power is provided by a hydraulic motor powered by LifeTrac

Bearings

• http://surpluscenter.com/item.asp?UID=2009030611222186&item=1-210-30-4-C&catname=powerTrans

Chuck

We will fabricate a chuck from a 1" steel pate, as in:

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• http://www.wttool.com/product-exec/product_id/13768?utm_medium=cpc&utm_source=froog
• http://www.grizzly.com/catalog/2009/Main/590
• http://www.google.com/products?q=lathe+chuck+4+jaw+12&hl=en&scoring=p

Slide

For the lathe to be able to handle large work pieces, the slide itself - which holds the tool post.

• slide review

• Milling Drilling Slide $90
• http://www.google.com/products?q=%22cross+slide%22+-jewelry+-shoes&hl=en&scoring=p&sa=N&lnk=next&start=100
• http://www.shop.com/Cross_Slide_Vises-34856820-45455382-p!.shtml?sourceid=298
• http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=32997&zmam=33951326&zmas=12&zmac=112&zmap=32997

Tool Post

The tool post will have to mount securely to the cross slide.

• http://www.google.com/products?q=tool+post&hl=en

Bill of Materials - Lathe

• • Romig bed lathe type - from Multimachine -
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  • Simple prototype, $486 in materials BOM:
    • 2 bearings, $50
    • 2 mouning plates, 1/2"x6" angle - $40
    • 4 Shaft Collars - $20
    • 2" shaft - $20
    • DOM tubing, 3", 2" ID - $15
    • 8 3/4" bolts for table - $16
    • Chuck plate - $40
    • Bolts for chuck - $20
    • Nuts and bolts for DOM - $5
    • XY table - $70 off shelf at Enco - [1]
    • Tool post - $10
    • table plate - $30
    • 2 bags of cement, 80 lb each - $20
    • sand, gravel - $10
    • TOTAL - $316
  • High performance, 2/1000" accuracy with proper technique, stock parts, 1000 lb radial and 200 lb axial load capacity

Lathe Tools

• Lathe accessories and description of lathe parts and tools

Links

• Light duty toy lathe - http://www.instructables.com/id/100-Homemade-Lathe/?ALLSTEPS