Robust Lathe Review - More Woodturning

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Vacuum Chuck Improvement to Stop Dropped Turnings When thePower Goes Out, & Moreby Bob Heltman, CMW, AAW ©10-2009One of these days you might befinish turning the bottom of a bowlyou have vacuum chucked, and thepower goes out. Thunderstorm.Truck hit a telephone/power pole.Backhoe snagged a power line.Fuse or circuit break blows. Sooneror later it WILL happen. Murphy’srevised law for woodturners says,“The likelihood of the power goingout unexpectedly increasesin proportion to the turning time,effort, and cost of the wood beingturned.”When it happens you haveVERY LITTLE time to react bygrabbing the object you are turningbefore it flies off the lathe and breaksor gets scarred. Or it bonks you inthe face.What to do...here’s my unfoldingstory...One technique is to put anempty tank in the vacuum linebetween the pump and your vaccumchuck. At our CMW ( www.carolinamountainwoodturners. org )club some members have found thatempty Freon tanks, about the shapeof BBQ grill tanks, but 3/5ths thePage 14 More Woodturning February 2010size, can be modified to do the job.The tank provides some extra reactiontime before your bowl comesoff the lathe. CMW Foundingmember John Hill says he therebygets about 7 seconds before thewoodturning drops. Figure 1 showsJohn’s setup, which he has mountedon a wheeled dolly.Also there are larger air tanksthat might be used, modified to storea vacuum instead of compressedair. DON’T use a tank that everhad an explodable gas in it, such aspropane!However, in my shop I havevery little spare room for anothertank anywhere near the headstockend of my lathe; my ShopVac sitsthere. So I wondered if there mightbe another approach.Somewhere in my mottledbackground I remember hearing ofcheck valves; they only allow liquidor air to flow in one direction, andpop shut automatically if the flowstops or tries to reverse. Thus IGoogled “vacuum check valve” andgot a number of hits. These valvesexist in many sizes! A few telephonecalls and emails to the salesand application engineers in two ofthose companies led to my obtaininga couple of suitable valves. The oneI needed retails at around $10.00 andsource details are in the end notes ofthis article.Figure 1. This photo showsJohn’s setup.As I slept on this project itcame to mind that if the vacuum wasTHAT tight I might need a manualbleeder valve so I could relieve thevacuum. Next came consultationwith Danny Williams of our localWilliams Hardware store. This ledto the purchase of a 1/4” Ball valve($11.00), a brass “T,” and couplings.Total $15.84. I had some Teflonplumber’s tape so the total cost ofmy experiment and modification
was about $25.00. Figure 2 showsthe components obtained. Left toRight: piece of vacuum hose with1/2” I.D., ( Note: my 5’ long hoseis NAPA 1/2” multi duty 1 braid250 PSI rubber hose CS091903Y500.), male air hose quick disconnect,aluminum check valve(engraved arrow shows which endshould point to the vacuum pump),threaded coupling, T joint, threadedcoupling, with aluminum bleedervalve below. The whole unit, wheninstalled, adds just 3 1/4” to thelength of the vacuum hose!Let’s pause and look at mytotal vacuum chuck system. Figure3 shows the vacuum pump. Itis a medical aspirator; PrecisionMedical Co. EZ Vac 1/5HP pump,delivering 26inHg, given to me asa gift from a fellow woodturner. Ithas worked fine for 3 years. Theheavy bent wire on the handle allowsthe pump to hang off the outeredge of a nearby table saw, savingfloor space and keeping the pumpaway from floor debris.Figure 3. This photo shows theauthor’s vacuum pump.Going through the hollowshaft of my Nova 3000 DVR lathe’sheadstock is the One-Way vacuumchuck with an EZ Adapter, availableat Packard Woodworks ( www.packardwoodworks.com ). SeeFigure 4. This has also workedfine for about 3 years! The hollowthreaded rod goes through theFigure 2. This photo shows the components the author obtained.Figure 4. This photo shows the One-Way vacuum chuck with an EZAdapterChinese BallToolsI have recently become a dealerfor the Crown Chinese Ball Tools andhave an inventory of sets and extrahandles on hand for immediate shipment.A set includes one handle, fourcutters, a tool to make a taperedhole, and a pamplet written by DavidSpringett. These are priced at $125.00for each set.The handles include a woodenhandle and a metal piece to attach thecutters and ride on the ball. These arepriced at $36.20 each. I recommendthree additional handles.Fred HolderPO Box 2168Snohomish, WA 98291360-668-0976hollow shaft of the headstock. Thealuminum piece at the right endhas a #2 morse taper that fits in thetaper of the headstock’s shaft. Atthe left end is a sharper taper that isturned tight against the left end ofthe headstock’s shaft, sealing all inplace. The aluminum chuck threadsonto the headstock shaft. There is aclosed cell rubber donut around thechuck’s far right, against which thebowl or other turned object rests,being sucked into place by thevacuum.I next assembled all the piecesshown in Fig 2, using Teflon tapeto give an air tight seal at every[Continued on Page 16]More Woodturning February 2010 Page 15
Page 1 and 2: Volume XV, Number 02 February 2010
Page 3 and 4: ContentsRobust Lathe Review........
Page 5 and 6: turning on it for almost 2 years no
Page 7 and 8: Introducing: by Robust ToolsStanda
Page 9 and 10: the depth to which they can be used
Page 11 and 12: Mini-O-Bar and Maxi-O-BarNewsE-mail
Page 13: Pen Turner’s Corner Continuedfrom
Page 17 and 18: chuck and had to wait what seemedli
Page 19 and 20: sculpture and a Southeastern Artist
Page 21 and 22: that I would say that it would bea
Page 23 and 24: Figure 3. The pen has been complete
Page 25 and 26: MAKING A BABY RATTLE — 18th Centu
Page 27 and 28: find them more attractive if theyar
Page 29 and 30: Testing andCertification of LeadCon
Page 31 and 32: with a Forstner drill to begin thed
Page 33 and 34: Editor’s Books for SaleBooks Writ
Page 35 and 36: Tormek AnnouncesT-7 UpgradesThe thr
Page 37 and 38: as on a fulcrum, and gives to the t
Page 39 and 40: Tilt-A-Matic installs in minutes-ju

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