|
|
|
|
test news
|
The Mid-Columbia Woodturners obtained a grant from the American Association of Woodturners to assist a local school program. The Jubilee Christian Academy is a private school that was set up to help troubled youth (teen-age boys) turn them around. Most of the students are from broken families and have been isolated and unaccepted in their homes, school and communities. Many have had a disregard for rules, have declining grades and most likely, a history of substance abuse. Jubilee offers a fully accredited Washington State High School Diploma. More than 100 boys pass through the program each year.
Vocational education is part of the classes offered to the students. Wood technology is one of the five vocational programs. While the school has the wood technology program it lacks resources for wood turning. The Mid-Columbia Woodturners have already donated two small bench lathes to the school. The grant was used for tools and accessories so the lathes can then be used for classroom instruction. The Mid-Columbia Woodturners also held a fund raising event and received $300 from the sale that was applied to help the school with the lathes.The instructor for the Wood Technology Program had asked our club for assistance with the youth in his classes. Our club members were given a tour of the facility and were introduced to the Director of Education. We discussed the various types of assistance that could be provided by club members tutoring, demonstrations, and donations of wood. Our chapter has assisted the school with the lathes by having members provide demonstrations to the various classes. Such demonstrations included lathe safety, proper use of tools, sharpening tools, basics of spindle and faceplate turning and finishing. The club also helped to supply the school with various woods for student projects. Woodturning has the benefit of providing the beginner with positive and immediate feedback they can produce a useful item first time at the machine. The students can grow with their experiences at the lathe. They will learn lot about the various kinds of wood and they will learn about the proper proportions, aesthetics, finishing and even marketing. The vocational programs are designed to provide the students with the skills needed to get a job after graduation. These "at-risk" youth are in a desperate need for a second chance and our club believes that by enhancing the Wood Technology program these youth will have an even greater opportunity to succeed.
|
|
This is an article written by Channel Island Woodturners. However when Stuart Batty Visited us last year he went over the same information on tools and grinding
1) Gouges: He recommends that the gouge be ground at a 40°-42° angle. His optimum angle is 40°. [He uses this on the spindle roughing gouge, spindle and bowl gouges and only switches to a 60° grind for the very bottom of a bowl.] Below 40° the gouge gets too aggressive and grabby. He also grinds away the bottom of the bevel at the gouge nose so that he can make tighter curves inside a bowl. He sharpens often [free hand without jigs] and always before the final cut.
2) Types of cuts: He uses the push cut mostly since it produces a cleaner cut and doesn't tear out end grain but he uses the pull cut to rapidly remove material. When using the push cut, the hand guiding the tool at the tool rest is used primarily to keep the tool on the rest. He emphasized not to push the gouge into the wood but to let it cut at its own speed. When the gouge is pushed into the wood [by riding the bevel too firmly] the wood at the point of contact is compressed and this will result in uneven cutting and produces an undulating surface (I'm an expert in this technique.) He showed that when this occurs, stop, back up and gently cut through the undulation. Feed the gouge slowly over the surface for the best finish.
3) Tools and Sharpening: He uses M-2, M-4 and A-11 steel tools. He believes that the higher Vanadium steels become more brittle and doesn't recommend V-15, 2030 or 2060 tools. For sharpening he recommended SG ceramic aluminum oxide abrasive wheels that are J or K hardness and stressed never grind on the side of the wheel. He pointed out that the color of the wheel doesn't tell the full story and it is necessary to read the label on the wheel. [SG stands for seeded gel- see comment section below the photos*.] He uses 46-60 grit to shape his tools and 80 grit to sharpen them. He uses a fine diamond dresser that has a rectangular cutting edge and slides the dresser across the wheel. As a safety feature when he first mounts and turns on a new wheel he does this from behind the grinder to prevent accidents from a wheel that was cracked in shipping. Also don't over tighten the nut holding the wheel (the paper on the side should be left on both as a cushion and to identify the wheel) as this can crack the wheel also.
4) Chucks 4-jaw and jam: Always make a square shoulder on the wood to seat properly on the 4-jaw chuck. The chuck has to fit against the wood shoulder in order to work. [See the handout that Al has brought to the past two meetings regarding proper use of chucks.] When he uses the 4-jaw chuck, the jaws are nearly completely closed in order to achieve maximum gripping of the wood. He doesn't orient the wood grain in any special way in a 4-jaw chuck. For jam chucks he makes a positive shoulder and a constant size inner diameter body which projects ½" ± beyond the shoulder into the work piece. This projection will keep the piece aligned on the jam chuck if it moves slightly away from the shoulder. He also used masking tape to secure his pieces to the jam chuck.
5) Tool use: Stuart believes that the length of the tool handle should be longer as more of the tool hangs out over the tool rest. He expressed this in ratios which were hard to follow, but as two examples, he thought the handles on parting tools (particularly the 1/16" thick short ones) where much too short since even with the tool rest close to a spindle, you are parting to the center line and the tool is way out over the rest. Also he felt that the handles on some spindle gouges and beading tools were too long since the tool rest is near the work and a long handle hits your body when you are trying to do fine work with your hand and wrist turning the tool, unlike bowl turning where a long handle is ideal and braced against you hip as you move in an arc in front of the lathe as you rock from one foot to the other as the cut proceeds.
He uses the skew chisel only for lay out and shear scraping. For pommel cuts he prefers the spindle gouge and for beads either the spindle gouge or a Bedan type square beading tool or parting tool. He doesn't like the diamond shaped parting tools because the two sides are often asymmetrical and thus wider than the actual cut. Since the typical roughing gouge has a small tang in relation to the size of the gouge it is prone to breaking and should only be used for spindle work when taking square stock to round. A thick bowl gouge does the same work and is much less likely to break.
|
| |
|
|
Some Notes on Finishes
(The information was obtained from the book: “Understanding
Wood Finishing”, author Bob Flexner, Rodale Press)
Finishes:
There are 3 types and they are classified by how they cure: evaporative, reactive and coalescing.
Evaporative finishes have solvents of alcohol, acetone and lacquer thinner. The main kinds are shellac, lacquer and wax.
Reactive finishes have thinners that are mineral spirits and naphtha and are often listed as petroleum distillates. The main kinds are linseed oil, tung oil, oil-varnish blends, wiping varnish, varnish, and polyurethane.
Coalescing finishes use glycol ether as the solvent and water as the thinner. The main kind is water-based finishes.
Classification:
TYPE FINISH TYPE OF CURE
Film Shellac Evaporative
Film Lacquer Evaporative
Film Varnish & Polyurethane Reactive
Film Water Base Coalescing
Film Conversion(conversion varnish and catalyzed lacquer) Reactive
Penetrating Oil and Oil-Varnish Blends Reactvie
What happens during curing?
Evaporative finishes are made up of long, spaghetti-like molecules that pack together and interlock when the solvent evaporates. When the solvent is reintroduced, the molecules separate, and the finish returns to liquid form. Evaporative finishes thus have solids that have been dissolved in a solvent. They cure from the bottom up, so the top is the last part to cure.
Reactive finishes undergo a chemical change during the curing process. The molecules link together in a tinker-toy-like network that can’t be broken by reapplying the thinner. Chemists call this reaction crosslinking or polymerization. There are 2 categories of reactive finishes: those that cure by reacting with oxygen and those that cure when a chemical catalyst is introduced (much like the way epoxy cures). Catalyst curing finishes are called conversion finishes. They are not as well known or commonly available as other finishes and are mostly used by professional finishers.
Coalescing finishes, typically water-based, are more complex than the other 2 types. They are sort of a combination of the other two types. They are tiny dispersions of a cured finish emulsified in water. Glycol ether is added so the droplets can cure as a film. As the water evaporates, the tiny droplets come together and the solvent, which evaporates more slowly than the water, softens the drops so that the molecules of a drop can interact with the molecules of another drop. It will take several weeks to achieve a maximum bond.
Solvents and Thinners:
A solvent will dissolve a cured finish, a thinner won’t, it thins a liquid solution.
SUBSTANCE SOLVENT FOR THINNER FOR
Mineral spirits, naptha, and turpentine Wax Wax, oil , varnish
Alcohol Shellac, lacquer, water base Shellac
Lacquer thinner Shellac, lacquer, water base Lacquer, catalyzed lacquer
Glycol ether Shellac, lacquer, water base Water base
Water --- Water base
Lacquer:
Pros: very fast curing; excellent clarity and depth; excellent rubbing properties
Cons: high solvent content that is toxic and flammable; only moderate resistance to water, water vapor, heat, wear and solvents; poor film build up – only about 10-20 % of the film you apply will remain as a solid film
Why people like lacquer:
• Easy to apply
• Very quick drying time; 3-4 coats in one day
• Ease of repair
• Exceptional film clarity, producing the appearance of great depth
|
|
Grinding Wheels
GRINDING WHEELS (from Jerry Johnson)
Abrasive Types:
A = aluminum oxide
C = silicon carbide
Z = aluminum-zirconium oxide
Bond Type:
B = resinoid
BF = resinoid reinforced
O = oxychloride
R = rubber
RF = rubber reinforced
S = silicate
V = vitrified
SG = seeded gel
Abrasive Size:
Coarse: 8, 10, 12, 14, 16, 20 and 24 grit
Medium: 30, 36, 46, 54, 60
Fine: 70, 80, 90, 100, 120, 150, 180
Very Fine: 220, 240, 280, 320, 400, 500, 600
Grade Scale:
ABCDEFGHIJKLMNOPQRSTUVWXYZ
Soft Medium Hard
High Speed Mild Steel
Steel
Structure:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Dense Open
So, a A80H8V wheel is aluminum oxide, 80 grit, relatively soft, with a medium density of abrasives and is vitrified.
Preferences:
Mike Mahoney and Martin Pidgen use a 46G.
Stuart Batty uses 60 grit for gouges and 80 grit for scrapers
Speed of Grinder: Mike M, Martin P, Stuart B and Bonnie Klein all use 3400 rpm grinders while Lyle Jamison and John Jordan use 1750 rpm.
From Stuart Batty: never use side of wheel; don't remove paper from side, and always
stand to the side when you turn on the grinder
|
|
|
Jett Sett
Jett Sett was described by Eric Von Bargen, a plastic/ceramic fixturing material mainly used by jewelers as an aid in holding difficult pieces for turning. He uses it as a way to hold items such as burls.
 To see Eric's full Article please click the link below: Jett Sett
|
|
| | << Start < Prev 1 2 3 4 5 Next > End >>
| | Results 28 - 36 of 40 |
|
|
|
|
test news 
