Lathe Tool Sharpening - JL Rodgers Designs in Wood...– Sharpening, The Complete Guide, J. Kingshott, Guild of Master Craftsmen, 1994 – The Complete Guide to Sharpening, Leonard

© JL Rodgers, Inc. 2010

Lathe Tool Sharpening

An introduction to sharpening


Session Objectives

•By the end of this class you will know

how to:

•Set up a sharpening station

•Use basic sharpening techniques safely

•Practice sharpening the 5 basic turning

tools

•Learn the procedure for hand sharpening

gouges


Agenda

• Discuss the value of sharpening

• Set up a sharpening station

• Discuss and practice sharpening

• Scrapers

• Traditional grind gouges

• LUNCH BREAK

• Setup fixtures and practice sharpening

• Irish grind gouges

• Skew chisels

• Practice hand sharpening techniques

• Process questions about sharpening


Safety Rules for Sharpening

• Wear safety glasses at all times

• No long sleeves or loose jewelry

• Never touch a rotating wheel

• Never place your hands between a

sharpening fixture and the grinding

wheel

• Wear a dust mask when truing or

cleaning a grinding wheel

• Do not interrupt another person while

they are sharpening


Turning Basics

• Anchor– Proper stance and holding of the tool.

– Focus on tools position rather than muscle and

force


Turning Basics


– Focus on tool position rather than muscle and

force

• Bevel – A Clean Bevel protects the wood that you are not

discarding

– Provides Control and proper placement of the

cutting edge


Turning Basics



force

• Cut– Sharp well positioned edge will slice the fibers not

not scrape the fibers

– Sharp tools are safer –

• Require Less Brute Force


discarding


cutting edge


Turning Basics



force

• Cut– Sharp well positioned edge will slice the fibers not

not scrape the fibers




discarding


cutting edge


Turning Basics



force

• Cut– Sharp well positioned edge will slice not scrape



• Bevel– A Clean Bevel protects the wood that you are not

discarding


cutting edge


Turning Basics



force

• Cut– Sharp well positioned edge will slice not scrape




discarding


cutting edge


Grinders

Picture Credits: Wikimedia Commons

Christopher Soghoian.

• Speed

– 1725 RPM vs. 3450 RMP

• Vibration is what’s important

• Slow Speed less Heat

• Cost

– $79 - $800

• Stones

– 8” Aluminum Oxide

• Jigs

– Wolverine or Home Made

• Setup

– Height – At least Height of Lathe Spindle

• Color


Grinders Maintenance

• Grinder Station:

– Position at height (or higher) as your Lathe Spindle

– Good lighting

– Safety Gear in reach

• Glasses

• Mask

• Wheels

– Select your Wheels

• Soft Bonding for easy break away

• Breaks leave sharp edges

• Grit: 60 Shaping

• Grit: 80 Gouges

• Grit: 120 Small Tools & Skews

– Test your Wheels

• Bell test

– Seat your Wheels

– Dress your Wheels

• Keep Wheels Clean, Flat & Sharp

Aluminum

Oxide, Al3O2

Aluminum

Oxide +

Cobalt

Aluminum

Oxide +

Chromium

Oxide

J or K Hardness


Grinder Setup

7

4”

• Proper Installation of Jigs

– Take the time properly set up your Jigs

– Oversized Stable Table

– All Components are at Correct

– 2/4/7 Rule for Fingernail Jigs

12345689101112


Grinder Setup


Grinders Maintenance: Dressing

• Build a simple dresser jig1. Reference Point

2. Adjustment

– Adjust the dresser to take off just

the high points on the wheel

– Move the dresser along the table

– Soften the wheel’s corners

Reference Point Adjustment


Three Groups of Lathe Tools

1. Gouges

2. Scrapers

3. Skews & Parting Tools


Spindle Roughing Gouges

•Forged tool with small tang

•Ground straight across

•Used only for roughing out spindles


Shallow-fluted Gouges

•Traditional grind•Straight across

•Used for beads & coves

•Swept back (fingernail)

•Greater access to work

•Detail gouge

•Severe bevel

•High flute

•Used for fine detail


Deep-fluted Gouges


Gouges

~60º

Fingernail Grind Dated back to 1897


Gouges


Scrapers

Burr

Burr

•Hardwoods

•Remove Burr

•Softwoods

•Burnish

•Straighten and build burr


Scrapers: Box Scrappers

Keep 85º - 89ºG

rind

Grind

Square

Nose

Scraper

Two cutting edges

– Left Side Edge

– Top Edge

As you grind the side, also

grind the top to maintain a

consistent angel

Slightly less than 90 º


Scrapers: Negative Rake

Add a Top Side Grind to Scrapper

– Changes the angle

– Less aggressive

– Great for finishing

– AKA Hardwood Scrapper

Negative Rake Bevel

Burr

Traditional Scraper


Skew chisels

Round Over

Soften Edge, Keep FlatHone Points

70º Angle

Bevel = 1½ x Thickness of the Skew

Thickness


Skew Grinds

Traditional Grind

Radius Grind

• Used for planing and pealing cuts

• Requires hand shaping

• Used for V-cuts, detail work

• May be sharpened with a fixture


Parting tools

•Standard parting tool

•Beading & parting tool

•Diamond shaped tools

•Fluted parting tool


Sharpening Theory 101

1. Shape

2. Hollow Grind

3. Sharpen and Flatten

4. Hone


1. Shape

– Using course stone

• 60 – 80 grit

– Grind the shape that is

needed for the

application

– Watch temperature

– Cool with water

2. Hollow Grind

3. Honing

4. Stropping


Shape


1. Shape

2. Hollow Grind

• The wheel creates a

concave shape in the

tool. – Single Facet

• Take care not to over

heat. Watch your Toe

• Repeatability or ability

to return to the stone

in the same position is

the key.

3. Honing

4. Stropping


Hollow Grind

Toe

Heal


1. Shape

2. Hollow Grind

3. Honing

– Rub Heal an to with flat

stones increasing in grit

– Rub both side of tool to

remove burr or wire bead

– 1st Touch Heal

– 2nd Touch Toe

4. Stropping

Toe

Heal


Honing


1. Shape

2. Hollow Grind

3. Honing

4. Stropping

• Rubbing on Leather

• Reshape or break way

the wire burr created

by sharpening


Stropping

Toe

Heal


When do you stop Sharpening?

Effort Time & $


When to stop Sharpening?

Law of Diminishing Marginal Returns

• Over sharpening is an inefficient use of time

Shaping Honing StroppingGrinding CNC

Laser

Effort Time & $

Lathe Gouges

Lathe Scrapers

Hand Carving Tools

Surgical Tools

Garden

Tools

Lathe Skews


Effects of heat on your tools:

• Carbon Steel

– Over heating will turn the edge Dark Blue and compromise the temper.

– An over heated edge needs to be grinded off. Reshape…

• High Speed Steel

– Don’t worry blue-ing will not hurt temper.

• It just looks ugly, unless you are an abstract post-modernist artist

ºF 410 437 464 491 509 527 545 563 590 626 1000

ºC 210 225 240 255 265 275 285 295 310 330 538

Carbon

Tool

Steel

High

Speed

Steel


How do you know if your tool is sharp?

Look for a glint


References

– Sharpening, The Complete Guide, J. Kingshott, Guild of

Master Craftsmen, 1994

– The Complete Guide to Sharpening, Leonard Lee, The

Taunton Press, 1995

– Woodturning Techniques, Mike Darlow, Fox Chapel

Publishing, 2001

– Woodturning Notes. Alan Batty, Allan Batty publisher,

undated

– The Dark Side and the Sweet Side of the Skew, Alan Lacer

video

– One Way Manufacturing, Verigrind video, © 2003-09

– AAW Video, Fundamentals of Sharpening, ©2000

– Negative Rakes scrapers, American Woodturner, Spring, 2000

Questions

Lathe Tool Sharpening - JL Rodgers Designs in Wood...– Sharpening, The Complete Guide, J. Kingshott, Guild of Master Craftsmen, 1994 – The Complete Guide to Sharpening, Leonard

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