Ron's Brain Dump

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== Stuart's 7 Fundamentals of the Perfect Cut ======

with additions humbly added by Ron Reynolds

This list was originally created by the 3rd-generation professional woodturner Stuart Batty with whom I and many others (including some professionals) have studied in order to improve our woodturning techniques.  They are listed in order of importance and will be expounded upon a lot below.
  # Grain
  # Chucking
  # Sharp and Proper Tool
  # Tool Rest
  # Speed
  # Stance and Movement
  # Technique

1. Grain
The grain direction of the wood mounted on the lathe dictates a lot in how the piece should (and should not) be turned.  The grain is typically considered to run in the direction of growth of the tree (up/down).  There are 2 basic grain directions:
tree is oriented parallel to the axis of the lathe
tree is oriented perpendicular to the axis of the lathe
Of course there is always the 3rd option, "tree is oriented neither parallel nor perpendicular to the axis of the lathe".  This is considered "wonky" and "dangerous" and isn't typically covered but in cases where the piece is a burl or warped or simply not a "normal" piece of wood the general rule of thumb is to consider the whole thing end-grain.
A typical piece of wood also has 3 basic grain "faces":
end-grain (looking at the piece along the axis of growth) in which case you see the annual rings as circles
face-grain/side-grain (looking at the piece perpendicular to the axis of growth)
the difference between face-grain and side-grain is subtle and is whether you're looking directly at a growth ring or tangential to a growth ring but in neither case should the growth ring look like a circle as it does in end-grain orientation

2. Chucking
The goal of chucking is for the piece to be mounted securely and accurately on the lathe.  This can be done in many ways:
Chuck
Almost always griping in compression on a tenon or cylinder (depending on if the inside of the chuck jaws are dovetailed or straight/serrated) or in expansion inside a mortice or recess (again, the shape of which should match the outside of the chuck jaws).  The part being gripped by the jaws should be strong enough to support the piece during turning and cutting and as solid as possible.  This can be anything from a 1/8" shallow mortice on a platter to a 3/8" high tenon roughly 1/3 - 1/2 the diameter of the piece but it should never hit the bottom of the jaws or chuck as that will prevent the piece "seating" properly into/onto the jaws and will thus not be accurate.
Chucks in the United States typically come in 3 spindle sizes:
1" diameter 8 threads-per-inch
1.25" diameter 8 TPI
a manufacturer-specific threaded recess to which an adapter is added to fit your lathe's spindle  
Jaws (typically sold in matched and ordered sets of 4) come in all sizes from less than 1" to over 5" in diameter.  Most jaw sets are numbered and should be attached to the chuck in the same order in which they're numbered so that the jaws are arranged exactly as they were machined and then cut apart.
Drive Center
Almost always these are a morse-2 taper that fits inside the lathe's spindle in the headstock.  There are other "standards" but they are quite rare.  Drive centers typically contain a center spike and 2-4 spurs or a ring of teeth to dig into the wood to transfer torque from the spindle into the piece.
Face-plate
A flat disk that threads onto the spindle and is drilled with holes for screws by which it's attached to the piece.  These can come in quite handy for pieces that are otherwise difficult to mount with a drive-center (due to weight or out of balance) or a chuck.
Screw-chuck or worm-screw
A bolt-size wood thread screw that's threaded into a pre-drilled hole in the piece which is either mounted into a chuck or a plate similar to, but typically smaller than, a face-plate.
Vacuum-chucks, glue-blocks, etc
There are various other ways to attach a piece to the spindle of a lathe including rubber-ringed chucks to which a vacuum pump is attached to hold the work via vacuum, blocks of wood glued to the piece, and various other solutions.


3. Sharp and Proper Tool
The gouge or similar tool you’re using should be as sharp as possible (or at least reasonable), shaped properly, and the correct tool for the grain and cut being made.
Tool parts
Bevel - the sides of the cutting edge of the piece
Flute - a groove ground into the top of the rod from which a gouge is made, typically shaped like an ellipse, parabola, U, or V.
Wing - the sides of the flute of a gouge which can be ground straight (as in the 40-40 grind) or curved back (as in the Irish grind) and various other shapes in between.
Skew
A flat piece of steel, typically 1" wide, with a diagonal bevel that's always used with spindle-oriented grain and typically used for fairly flat cuts.
Gouge
Created from a round steel bar, gouges come in many shapes and sizes from 3/4" in diameter down to 1/4" or less.  
Bowl, Spindle, Detail, Bottom-bowl
Scraper
Conventional vs Negative-Rake
Spindle Roughing Gouge
A poorly-named tool made from a flat bar that is curved into what is mostly a circle such that the walls are even-thickness.  It is used exclusively for roughing down spindle pieces into cylinders and sometimes for turning shallow coves.


4. Tool-Rest Height and Position
the tool rest is properly positioned, both height and location; tool-rest position/height dictates tool-extension and leverage


5. Lathe Speed
a lathe speed that is fast enough for a good cut but doesn’t put you in danger


6. Stance and Movement
your feet are positioned for the cut and any body movement needed
path of cut dictates body movement; foot position supports body movement


7. Technique
push-cut, pull-cut, sheer-scrape, hands performing proper action, body movement, etc.
right-hand for drive and control, left-hand for positioning and stability


References
Stu's Videos

Description
URL
Stu's Vimeo Collection
https://vimeo.com/woodturning
Perfect Cut Principles
Broken :(
7 Fundamentals of Wood-turning
https://vimeo.com/137484615


Curly & Burly
https://vimeo.com/68784521 - bottom bowl gouge (50-55%) best on figured wood; negative-rake scraper best for burl
Tapered End-Grain
https://vimeo.com/68654444 - Spindles; light cuts; be sure to anchor cut at beginning to avoid edge skidding backwards
https://vimeo.com/68647903 https://vimeo.com/68647902 - Bowls/Platters; sides of bowl-oriented blanks are 80% end-grain; the faces are side-grain; NEVER cut end-grain "uphill"
Grain Direction
https://vimeo.com/68647901 - Spindles
https://vimeo.com/68642332 - Bowl Blanks
https://vimeo.com/68642331 - Cutting into End-Grain
Chucking - secure and accurate
https://vimeo.com/69018287 - Tenons; tenons in spindle-work
https://vimeo.com/68649135 - Recesses; best and worst shapes for recess mountings in bowl work
https://vimeo.com/68649130 - Jaws & Chucks
https://vimeo.com/68649128 - Drive Centers
Sharpening - cutting angle (40 degree bevel), shape size, type
https://vimeo.com/68652446 - why it's good to sharpen
http://floridawoodturningsymposium.com/wp-content/uploads/2013/07/Bowl-Gouge-Handout.pdf - 40/40 Bowl Gouge grind; excellent visual of 40/40 grind
https://drive.google.com/open?id=1BtcJZujexsbC40IoV7RJzpo_EJhCH6n0 - 40/40 Bowl Gouge grind on Thompson V
https://drive.google.com/open?id=1fr-bZG7wl1kt-2WZmk5UDyub6gSFvG6C - 40/40 Grind video
https://drive.google.com/open?id=17TW1252euQNi1YOkh8SeKyP2KNbB9lq2 - 40/40 Grind photos
https://drive.google.com/open?id=1EOftoEZj26WiTUiyla707WXHb7VNk0-Q - Bottom-Bowl Grind
Tool Rest - height, distance, angle
Scraper - Overhang
Handle-length Overhang & Diameter
Lathe Speed - fast but safe
Stance - position of feet and how they support movement
https://vimeo.com/68707660 - spindle cuts; roughing down a spindle; planing spindle with roughing gouge, then skew, and then bowl gouge. facing cuts on spindle with bowl gouge. curved face cuts
https://vimeo.com/68707662 - bowl cuts; roughing down a bowl blank; facing bowl blank; curved outside cuts; 14:29 is ogee cut video
https://vimeo.com/68707661 - ogee cuts; cutting an ogee curve on a spindle and on a bowl
Technique - straight, concave, convex
Left Hand
https://vimeo.com/69018284 - Cutting; using the left hand to start the cut & keep the tool stable and NOT controlling it while it's cutting
https://vimeo.com/69018281 - Braking; using the left hand to stop a cut so that the last fibers are cut before they break
Right Hand
https://vimeo.com/68784524 - the right-hand provides the driving force & 4 controlling actions: lift (Z-axis), push (Y), swing (X), & twist (Y-rotation)
Defects
https://vimeo.com/69018279 - spirals & ridges; over-rubbing the bevel, no bevel contact, dull tool
https://vimeo.com/69018280 - ??
https://vimeo.com/68784527 - Push-cutting & Bevel-floating (bowl); this video does say "sharpening" but it's mostly about how good technique can be impacted by dull tools (and bad technique)
https://vimeo.com/68784528 - Push-cutting & Bevel-floating (spindle); this video does say "sharpening" but it's mostly about how good technique can be impacted by dull tools (and bad technique)
Demonstrations
https://www.youtube.com/watch?v=N7BjRcSDurM - Mid-Maryland Woodturners; Large thin bowl, 40-40 grind, excellent video on how to turn a really thin-walled bowl
https://www.youtube.com/watch?v=QMVGankeK0I - Rocky Mountain Woodturners/How Gouges Cut; intro to 7 principles, 40/40 grind, basic bowl turning
https://www.youtube.com/watch?v=MHvAa5Q73Iw - Spherical Box
Off-Center Square Bowl - how to make one of Stuart's signature bowls (3 parts)
https://drive.google.com/open?id=1PuXsNaUiGACfutao_wVC_ZyOE0TpcTKt https://drive.google.com/open?id=1dmuyzh7NxC2wj7Tp0LXxfw-Z57rhzOtN https://drive.google.com/open?id=1ExzwikbySMBrlQL5rQinhHxe0kB42pFF
Richard Raffan
https://www.youtube.com/watch?v=jOvF5f1phhY - Catches; cautionary tale showing how various catches (but not the worst of them) can occur
Bowl Turning (2 parts)
https://www.youtube.com/watch?v=TIvROyV2n6w https://www.youtube.com/watch?v=nPPvtP2bbkg
Cindy Drozda
https://www.youtube.com/watch?v=4_KDSIDAtGc - 40-40 Grind (spindle gouge)
http://www.cindydrozda.com/handouts_Pdfs/handouts/demo%20handouts/negative%20rake%20scrapers.pdf - Negative Rake Scraper Article
Ashley Harwood
http://www.carolinamountainwoodturners.org/articles/480 - Demonstration For Carolina Mountain Woodturners
Alan Batty (Stuart’s dad)
https://youtu.be/-0iEd0kD0S4 - hand-chased threads
https://www.youtube.com/watch?v=KfeLAHQSbqk&vl=en - skew and cabriole leg