Goblet and Splitting Wood

Greg, did you turn the goblet with the pith in it? If so, it is almost guaranteed to split. Also, try turning it to 1/8" thickness, or less. Plus, make the stem much smaller, about 3/16" would be about right. These proportions might not be approporiate for the design of the piece (design calls for thicker stem, for example) but from the standpoint of the wood stability, they give you a much higher chance of success.

Regards, James Johnson

Looks as if Archie cursed the goblet ;-)

Yea, the pith was in it. It was just a chunk from someone's yard.

This was basically firewood, and with an overall starting blank diameter of 5", removing the pith would require a log with a cross section of over 12". Kinda rules out most of MY firewood... ;-)

I live in a city, so wood isn't exactly easy to find, particularly when all these evil developers are pouring in here to scrape the earth to the barren clay and truck it off - only to sell back to the idiots that buy their crappy, overpriced, crackerbox McMansions.

So, just as with cutting up lumber for regular woodworking, it appears you still have to split the logs to prevent cracking from radial shrinkage. I have several 6' x 14" chunks of Cherry from a tree from our yard. I had to treat the ends and split them to prevent cracking. I'm still trying to figure out how to shove these things through a 14" bandsaw... ;-)

And I *really* liked the concentric rings of grain around the circumference of the piece. Oh, well...

Point well taken. On this particular design, however, the cup diameter is about 4", and a stem of 3/16" would have looked pretty strange. Same applies to the wall thickness of 1/8". Those proportions would be fine on a wine glass, but this thing is pretty big.

I guess I got some practice on the lathe, anyway... I'll just put a potted plant in it and place the crack towards the wall. :-o

Thanks,

Greg G.

Hmmm... Is this a Harry Potter reference?? I don't have kids...

Greg G.

If you're going to use absolutely green wood, use only wood which has a greater chance of success, like elm, yellow birch or true poplars like aspen. Other woods might require some pre-drying, which is done in the round, with bark on. I suppose you might use shorter, sealed lengths, but I generally just use seasoned firewood.

Help your case in a couple of aspects with the turning itself. Don't center the pith, try to get it outside your stem, where you only have to contend with it in thinner length. Then run some CA into the area to slow checking inside the cup, and consider boring a hole in the base which will include the pith to allow for distortion there.

Oh yes, though it may appear handsome, I've found that having sapwood all around isn't a good idea, but it may have something to do with getting the pith off center, too.

It might have just been the type of wood, Greg.. and since it was free "no name" wood, you can't really tell if that was the problem..

I turn a lot of green firewood and get some splitting, but the worst I've ever had was some almond that a friend bought a cord of.. reasonably dry (didn't have to clean the walls in shop afterwards), and turned easily... sanded without getting fuzzy, etc...

I tough turned 5 or 6 things one night, put them in paper bags... the next night, not only were all of them cracking, but a couple of small goblets with very thin bases had what looked like pie slices taken out of the bases..

Just part of the adventure of this addiction.. umm. I mean hobby is wondering if something will come out of the bag cracked or not..

mac

Please remove splinters before emailing

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Greg,

I have had decent results using LDD (liquid dishwashing detergent) and green, un-split apple wood. I don't think you can find any more reactive wood than that. Check the Google archives for several exhaustive threads on the subject.

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

If he reads all the LDD threads, he won't get to turn again until Labor Day ! :-)

Ken Moon Webberville, TX

Heheh...that's the idea...if he waits until then to turn, his wood will be dry enough to turn w/o cracking!

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

I've managed to read some of the LDD posts, and also came up with an intriguing one concerning the use of alcohol.

No, not the Bourbon kind... ;-)

I may not get to turn till then anyway... Too many hats! Too many working weekends!

I really *hate* bean counters.... ;-)

Greg G.

But it's so much more fun to turn the green wood! It seems so much more effortless and natural...

Greg G.