Definition of 'ghost'

When turning a non-round item, as it turns you see the parts furthest from the axis only part of the time. The rest of the time, you see past the wood. Consider a square blank. The wood near the corners only blocks your sight for part of the rotation, so it appears translucent at high enough speeds. This translucent part is the ghost.

So, for out of round parts, the ghost represents the wood that has to be removed to make the part truly round again.

It's hard to photograph ghosts, because most cameras take fast enough photos that you get a "frozen" picture of the wood. If the above doesn't adequately describe the ghost, I can try to take a long-exposure photo of it to show you.

Your guess is right. Chuck up a square piece, and turn on the lathe--the ghosted part is everything from the corners down to the dimensional size of the square.

Ken Grunke SW Wisconsin

Ghost pictures with the piece not even in the lathe is actually quite easy!

...Photoshop is your friend....

--Rick

An> As I read (and possibly learn a little) I keep encountering the term

You can make the "ghost" a bit more obvious by keeping a light background and a dark background available. The reason for this will become obvious the first time an empty space shears the skin off your knuckles.

The ghost also applies to interrupted edge turnings, which are even more knuckle-hungry. There you can use the ground (more down than back) to more clearly define the place where the first point of contact between gouge and wood will take place, so you can avoid a grab and throw.

Don't know why an article discussing the matter wouldn't take a low shutter speed shot for illustration.

Yes, Bill, the ghosts of turning past float all around our shops. Some are friendly and benign, others are the shades of less happier times. Look carefully with an open mind and you will glimpse a few in the dusty mist. The images are vague and foggy, but be assured they are there. I've spotted these drifting about my shop:

Happy ghosts: Holtzapffel, Pain, Osolnik Lindquist, and all their early descendants. My Dunlap lathe and storebought chisels. The day when riding the bevel, leading the flute, lagging the scraper and gentle sharpening finally dawned on me. My first ball bearing spindle, revolving tail center, scroll chuck, bowl gouge, hollowing tool and cammed banjo. That first bowl. My turning clubs and departed good friends. AAW's birth. The warm welcome to my first RCW post. Induction into COC.

Unhappy ghosts: Mercifully they dim quickly. Bodger's treatment and long hours, Isolation. Secretive turners. Slowly accepted turned wood art. Leaky sleeve and babbitt bearings. Machinist's chucks. Independent jaw chucks. Prejudice against scrapers. Scorn of shine. Early chucks that required tenons more precise than the work turned. Chucks that needed a beaded tenon. Rotten RCW posts. Cutting tools designed for profit instead of use. Unsafe safety devices. Dangerous untried turning advice. Authority not from experience. WebTv is a mixed bag.

What images, good and bad, float around your shops? Mine isn't air conditioned so it's more comfortable to type than turn on a July day in Florida, although I'll probably be indicted for abuse of bandwidth.:( Arch

Fortiter,

Thanks, but it won't be necessary. The lighting in my 'shop' (corner of the basement ... at the moment the nearest lights are behind me) means that I am totally familiar with the appearance of ghosts. I just wanted to make certain I was understanding the reading I have been devouring. :-)

Bill

It wasn't a discussion of ghosts ... they were just incidental to it. Actually, I thought it might have had something to do with cutting end grain inside a bowl, as that is what the photo was of. That's what threw me off.

BTW ... aren't you supposed to turn the workpiece by hand before powering up? I had assumed that part of the purpose of that exercise was to locate the closest portion of the workpiece and the other part was to eliminate those crashing sounds the switch makes when you turn it one without checking the clearance to the tool rest.

Oh well, I won't get time to do any turning tonight but I was reading an excellent article about turning bowls between centers last night and since those are the tools I have available (until those expanding collet chuck thingies arrive from PSI), tomorrow night I intend to give it a shot with some smaller chunks I have sawn for the express purpose of making decorative firewood.

As I look around my house I realize that I may also have to invest in a fireplace.

Bill

Hey, not only do I turn it by hand first, I make sure I'm out of the throw zone when I turn the lathe on. Further, I'm so much a chicken that I cut from tail to headstock without ever stepping back into the line of fire if I can help it.

========================== Arch, I understand about the July day in Fl, since it is not that much different than that same day in Central TX. The obvious curfe for that in the past has been to wait until the evening, then turn until mid nite or past. However, the arrival of West Nile in our county has caused some trepedidation on my part, even when using DEET repellants. Is this affecting anyone else's activities in outside or non sealed environments??

Ken Moon Webberville, TX

Yep, saw that page a couple days ago.

I have about 8 hrs. total on a lathe in the past week or so. And about 40 years between those hours and the ones that preceded them in Junior High School. Today I installed a fluorescent fixture over my lathe so I can see what I am doing and formed my first beads and ogees ever. I also made my first bowl (well, almost ... it blew up). Thursday is booked solid. I'll try again Friday. Right now, I am still at the 'turning finished lumber into decorative firewood / curly mulch' stage although I did hold a parallel to .010" taper over 2 inches today. Not perfect, but not bad either. They are just practice pieces to learn a new skill on (previously I have been a railroad conductor, computer instructor and a die-maker).

It won't be long until I am turning firewood into decorative items, too. For now, though, I'm turning the dunnage 3x4 lumber I get from work into mulch and firewood.

BIll

Never thought I would hear words like that on a woodturning group! What are you planning on making out of wood??

That is an excellent attitude for a novice. I wish I had had the same when I started out.

A living. :-)

My background is in the precision machine trades (prototype, tool & die).

I'll never get to that point with wood, but it would be nice if my work was known for being technically good.

Bill