question about oak

[Jason Ledbetter]

I have been "commisioned" against my will to make some offering plates for my church. I was trying to get out of this because I'm not confident I am experienced enough to do this yet, but someone delivered a 5' long board of oak that is 2.5" thick and 11" wide, so I guess I'm committed.

My question is this. The gentleman that delivered the wood said that they told him at the lumber company to rip the board in half and glue it back together and that would keep it from warping. I've never heard of this.
Any ideas?

The wood is furniture grade oak (not sure what kind), and dry (racked in a storage shed for about 5 years).

 

[pencheff]

...they told him at the lumber company to rip the board in half and glue it back together and that would keep it from warping.

I'm sure they didn't mean to just glue the board back together along the rip line. That certainly wouldn't do anything to prevent warp.

Is this timber a flat sawn board from close to the center of the tree? That would tend to cup in the middle along the length. Maybe they were referring to the old flat work trick of ripping it down the middle, jointing the outside edges then gluing those together so that the portion with the greatest tendency to cup is now on the outside edges.

Don't know what that would have to do with making offering plates though. Did the lumberyard know that is what the lumber was intended for?

With material that size you should be able to make 5 real nice 10" wide by 2" deep plates/bowls. Sounds like fun.

 

[cweddig]

That would be my guess too, by looking at the end grain and making sure the rings are curving in opposite directions when reglued back together, it's supposed to help with the warping. My thought then is when turning, your grain is coming at the tool in different directions which in my experience can cause tear out on one side of the seam. If the wood is really dry, it shouldn't want to warp that much anyway.

-Chris

 

[arbud]

The "magic" number

Jason, if you either have or can borrow a moisture meter then check the moisture content at several places along the plank including the end grain. If the moisture content is 10% or less then the chance of warpage is very small, especially if you use an oil finish such as tung oil, watco, etc.

Also, being the "spin it fast" person I am, I have found that after roughing the piece spinning it at 1,500 to 1,800 rpm reduces the "tear out." However, if turning at higher speeds is out of your comfort zone then don't do it. Either stay in your comfort or practice with "scrap" wood.

You have fun and turn safely.

 

[georgetroy]

I would not rip that board in half. A one piece platter would look better than a joint down the middle. The lumber yard people are not wood turners. You live in North Carolina and that state is full of wood turners and woodturning clubs. Work out your design before turning. The little old ladies who are really the ones who support a church would not be pleased if their concept did not match yours. GT

 

[Frank Kobilsek]

Gotta love the old ladies

Jason
An older woman who has been very generous ($) to many of my volunteer organizations saw a bowl I donated to a church auction and showed up at my house with a trunk full of 1 by planks and said "Make me some plates." The boards were cut off her Grandfather farm and had sentimental value.

My advice:
Do not 'oversand' the oak. It will get wavey between the growth rings / grain.

Finish with a semi-gloss. Mostly because its hard to get smooth a shiney enough for a high gloss finish but because of the wear and tear the offering plates will get. (at least I hope they get alot of use)

Go slow! There is no reason to turn a 10" plate over 1000 RPM. It safer, less vibration and its safer. About 650 seems perfect for me.

Only commit to the number they need. If you say you can get 5 plates from that board you'll be guarenteed to turn right through the bottom of one of the blanks and everyone will be disappointed when you only deliver 4. If they want 2, one for each isle promise two.

Back to my plates: I made about a dozen plates from 9 to 12" in diameter. Have blanks for maybe a dozen more. Called her last September to come see what I made for her. She still hasn't come by. I figure she gets her choice of 2 for free (her and her sister < another generous donor>) then $20 each after that.

Good luck and I suspect you'll get a couple of nice homemade pies from the ladies at Church the Sunday after they first use your new offering plates.

Frank

 

[MichaelMouse]

The advice is what is often given for flatwork. Good advice for poorly secured table tops, silly for bowls.

Looking at the rings is a good idea. I'm sure you've noticed that if you cut with the heart side up, the rings seem to expand in the hollow section, while cutting with the rings down makes them look narrower. Design consideration, given you have both options available.

Moisture content is pretty much a non-player, as it's certainly way below the fiber saturation point. What it is is what it is (sounds Clintonesque), what it will become in the near future is what corresponds to the EMC at the relative humidity where it's worked and stored. What it will become in the summer is something yet again. Treat it as if it were semi-green lumber, hollowing to a quarter inch or so above desired dimension. If you hollow heart up, the sides will drop with loss of moisture, raise with gain. If the opposite ... the opposite. Leave it for one week and then check movement. Turn to final dimension if it hasn't moved much. FPL says 1% per week moisture change in a 1" thick board, and you'll be well below that from your first turning, with lots of end grain to lose moisture even more rapidly.

I'd use penetrating oil rather than a surface finish for renewability, and be sure to put the felt in the bottom. People don't always have bills to contribute, and the sound of change will be muted that way. Means they'll give something rather than let it pass.

Oak is brittle, so you want to watch your cutting angles. Don't expect long twisty shavings, look for short ones mixed with dust as you cross the end grain. Don't press with gouge or paper, especially if you go for broad ring, or you'll get the wave. If white oak, the rays will also be hard like the rings. I sort of like oak. It's a good seller for me, though rare in my woodpile.

 

[georgetroy]

Jason more ideas on your project. Make some drawings to show the church people a variety of platter designs, you can do this on graph paper. I hope you are getting paid for the platters. You would be opening a can of worms if you don't. I make some quick sketches on some platters. You can also take some photos or do a search for more ideas. You and your turnings are on the line so good luck. Don't let them rush you. GT

 

[George Balock]

Collection Plates

Jason,
Along with all of the other advice (I wouldn't cut the board either) ther was an article abpout making stacking collection plartes in the AAW journal, Collection plates, 17.3:50–53. I hope this helps.

 

[TEK]

Warped plates

I would rough turn them 1/4" to 3/8" thicker than the finished product. Then let them sit for a week in a warm place inside the house. Then I would finish turn them to final thickness. The wood may not be evenly dry all the way through or may have other built up stresses. Letting the rough turned pieces set for a week, or better two weeks, will let the wood dry more evenly and let any internal stresses relax through warping. The finished platters should be more stable that way.

 

[pfduffy]

turning plates

My only caution would be to turn the plates in the rough form, let them stabilize for a couple weeks and then finish turning. Wood, no matter how old, always seems to want to twist and turn to some degree when a new form is forced into the grain. If you must proceed directly, then try the DNA drying method, it will only cost you a week. OBTW, the stabilization process I am recommending is the same as the flatwork guys use after buying new wood and bringing it home to their shop. Phil

 

[Jason Ledbetter]

More Information

Thanks for the advice. I will rough turn one blank and see what happens before proceeding. I'm on no time frame and I was given enough wood, so I have time to experiment. I'm not sure where the little old lady and free pie references came from, neither is the case.

The size and shape of the plates isn't for debate, I have the original ones as prototypes (I'm making these to add to the present collection). I am not getting paid, and there will be no pie (unfortunately for me, I'm a pie guy).