Question for those of you who turn large objects, or use crack fillers

[curtis rosche]

i have 2 slab of silver maple that are between 3-4ft across, and about 5-8inches thick. one of them has a crack that is almost halfway across and at least 3 inches wide at the end. i was thinking of making a large bowl or making a natural edge table. the problem is, what to do with them crack, if at all. how to mount it, and center it? and it was just cut at the end of last summer, so how to dry it, it has been in the loft since then and the meter reads about 15-22% moister in the wood, i will check it again since that was a month ago. the last probably the most important question, is will the school lathe be able to turn it? its the Gereral 26020VDR-M2 / 260VDR-M2 -20" AND 12" WOOD TURNING LATHE- 4 Variable/Reversible Speeds With Electronic Control the school has both, obviously it would have to be out board, he have a tool stand, does it need a different face plate?

[Bruce Pennell]

Curtis check out Utube for David Marks video on turning his wall hanging. I think you can go to his website also. Might help it's a real large turning. Sorry I've never turned anything that large. Good Luck....Bruce

[Ralph Lindberg]

I've filled cracks, but never anything that large. It would be, tricky

I looked at buying that lathe, but part of why I didn't was uncertainty about the actual power.
That got re-inforced with the review that Fine WoodWorking did, where they found the actuall inner shaft was only 1 inch, even though the head stock is 1-1/4

[Bernie Weishapl]

Curtis it would probably help if we could see a picture of the crack. If it is 3" wide and long, I would think that would be a little to much to fill and be safe.

[Reed Gray]

Turning big isn't much of a problem, if you have variable speed. Start out slow until the piece is balanced, then turn it up. As far as cracks, that big of a one would probably need to be filled in stages. That much volume will shrink considerably as it drys. Personally, if it has a crack in it, for me it is a piece of art, or I don't use it for a utility bowl. The cracks take a lot of time to fill and sand, and fill and sand, and when put next to one that isn't cracked, it won't sell. It usually isn't worth the effort. If the moisture meter says 15% on the outside of a 8 inch thick blank, it is more than 40% in the center. A piece that thick will never dry on the inside. General rule is at least 1 year per inch of thickness. Over 2 inches, add more time.
robo hippy

[curtis rosche]

i will take a picture of the peice when i get home. the wooood will probably dry quicker though, theres a lot of 20 dry wood inthe loft, and it has started to suck out the moisture. what about the lathe, will either one of those be able to safely turn it? and what about drying it, turn a slight curve in it, and "fill" the bowl with dna, and hope?

[Frank Kobilsek]

Curtis

Your tag line about substituting experience for age may lend some insight here. Remember with the age thing the goal is to keep counting up. If you choose to tackle this large piece of admittly suspect wood be very very careful. We'd all be sadden if you to stopped counting up.

The way you describe the material and your available equipment I'd cut two small blanks, one from each side of the crack. Then at end away from the crack cut the biggest blank possible without reaching the crack. Aim that big blank for the exact center of the grain. if you get the grain lined up right the bowl will warp less and look best.

Sorry to throw doubt on your treasure. There will be many many big blanks in your future as a wood turner.

Frank

[curtis rosche]

i have 2 maple slabs, i know one is cracked, but i dont know about the other. my tag line, i got that from a 1973 newspaper, saying jack ruby had been shot

[Allen Neighbors]

A picture would go a long way... :)

[curtis rosche]

tonight i will post a picture of it

[curtis rosche]

heres the pictures, the crack wasnt as big as i thought it was, there is some mold on the peices, when we first put them in the loft they were next to each other, the mold was so strong we needed a hammer to pull them apart, so now theres slats between them. the one that was on top has the crack in it, the thickness of this one is also shown in the picture of it standing up, the bottom one is thicker, and has no cracks, the top one is at 20% when i stuck the meter in the center, the bottom one was at 16% when i stuck it in the center. i shouldve measured them so i'll be back with numbers

the first pic is the one on top, the second full shot it the one on bottom

[curtis rosche]

the first slab is 30 inches at the widdest point, it is 6 1/2 at the thickest, 5 at the thinest. the crack it 11inches from the tip to the end, 1 1/8 wide at the widest.
the second slab is 36 inches at the widest point, the thickest point is 9 inches, thinest is 6.

the big qusetion, how you you mount these? regular face plate with longer screws? do you need a special faceplate for out board turning?

[Bernie Weishapl]

Picture number two that piece would be firewood in my shop. To many cracks and the one big of a crack. I would use on the one at least a six inch face plate with 1 1/2" screws. I use stainless steel square head screws with my faceplates.

[curtis rosche]

the first peice, the cracks are only around that big crack, not all over. we have a couple 8inch plates, and we normaly use coarse drywall screws, tomany people strip the square

[Allen Neighbors]

What Bernie said!
I'd try to cut the large 'whole' slab to round, and try to get it a little bit balanced to start with. Then I'd use a large faceplate with 8 size 12 screws, and balance it slowly. Remember, end grain doesn't keep screws very well, so you need to have good threads on the screws. I bought some special screws from a fastener outfit that sells to our school system. They have deeper threads, and you don't need to pre-drill for them. Then I'd make what I wanted out of it.

[Jason Clark2]

On the first Piece I'd cut it up into a bunch of smaller blanks for end grain boxes, hollow forms, or something like that. That's a pretty massive crack and would take quite a bit of Epoxy to fill. Use that piece to make a bunch of smaller stuff rather than 1 large piece.

The second piece appears pretty solid. I'll echo what most have said, use a large faceplate and as many screws as possible. I wouldn't recommend drywall screws, they're typically too brittle and tend to shear off fairly easily.

Jason

[curtis rosche]

ok, so, if i turn this peice at 18% moisture content, will it just crack? or it i were able to get it thin enough would it just warp?, there is going to be some spaulting in this, i hope

[Barbara Gill]

On a cross cut piece, especially one as large as that it is not a matter of if it will crack but when it will crack. It is normal for such a piece to develop radial cracks. A good resource book for learning about the different properties of wood is Understanding Wood by Bruce Hoadley. Mounting and turning a piece of cross cut wood that large especially one that has not yet developed visible radial cracks is dangerous.

[Jim Becker]

the first peice, the cracks are only around that big crack, not all over. we have a couple 8inch plates, and we normaly use coarse drywall screws, tomany people strip the square

NEVER use drywall screws to mount a turning blank!! They are britle and can snap off at a moment's notice. Use heavier steel screws, such as sheet metal screws for small work. For large things like you are considering, you may need to use lag bolts, pre-drilling to avoid splitting.

[Glenn Hodges]

I agree with Bernie about picture #2. I would mount the other by getting a good piece of hardwood, turning it round with a flat surface. Then glue this on the bottom of the piece with yellow glue, and wait for 24 hours for it to dry. I center this and put a weight on top it while it is drying. This will give you a good surface to put screws into. I stay away from drywall screws because I was told they are to brittle, I use sheet metal screws which I mount with a driver.

[Greg Savage]

Bernie is right...FIREWOOD!!!! Besides, trying to turn that piece on a General 260 would be like riding a bucking bronco. You would have that lathe dancing across the floor at 200rpm.

[Ed Thomas]

Gereral 26020VDR-M2 / 260VDR-M2 -20" AND 12" WOOD TURNING LATHE


I looked at buying that lathe, but part of why I didn't was uncertainty about the actual power.
That got re-inforced with the review that Fine WoodWorking did, where they found the actuall inner shaft was only 1 inch, even though the head stock is 1-1/4

Different lathe. You're thinking of the General International 650-25, which is not the same as the General.

[curtis rosche]

where do you get a faceplate for outboard?