WWYD?

[Mike Novak]

I have this crotch slab. I’d love to make a large once turned platter. It would have the pith in 4 places and some very nice grain. Most of the bark inclusion would get turned away.

I’m concerned about the inclusion, I’d need to keep speed way down ~300 rpm? Im also concerned that the pith areas would split badly instead of just warping.

What would you do?

 

[Richard Coers]

I would split it on the inclusion and make smaller items. If it splits under power you are looking at serious injury. Pretty wood is not worth serious injury to me.

 

[Randy Anderson]

Apart from the safety issue I wouldn't turn it as a single piece since there's very little solid material under the inclusion to stabilize it while working with it and you would need all of what is there for the platter which means no working material on that face for a tenon, mortise or foot. Even if you did manage to get it done it's almost certain to warp or split after done. The old saying - do you want to make a big piece or a beautiful piece. I often sacrifice size for shape and appeal.

 

[hockenbery]

I’m number three - too dangerous to turn

The structural strength of Bark is about the same as and air gap.


Before turning you would need join the two halves with biscuits or pewas that you would not cut through when turning
I should think a minimum of 2 inch spacing between them

 

[Mark Jundanian]

2’ spacing

Did you mean 2"?

 

[JeffSmith]

Well, I would spend about a day and a half pouring 50 bucks worth of West System epoxy (tinted black or Brown or even using a little ground up bark as filler) into the inclusion until it would accept no more. Then, make a custom template for some good sized, extra deep dutchmen as insurance on the inclusion - span the crack by at least an inch both sides. Cherry is nice for the dutchmen. another couple of days down. Then its on the lathe to produce an obviously flawed piece that will probably live on my "why did I do that" shelf for a few years.

My opinion? save the time and bucks and cut into two pieces and get something smaller but useful...I've done the former, recommend the latter

 

[Vincent Vogel]

I agree this is a iffy project for a large platter. If you have to do it I would put a large glue block like 10 to 12 inches on the bottom side and mount that to a faceplate in addition to the suggestions above. 300 would be a maximum rpm. Definitely stay out of the line of fire. I would probably cut it in half and make two plates from it.

 

[Mike Novak]

Sounds like everyone is in agreement. I’ll make something else with it.

 

[hockenbery]

Did you mean 2"?

Yes

 

[Leo Van Der Loo]

You could hammer a steel staple in the ends to keep the parts from separating, place the first one in the lower half, then turn the top halve first to half the thickness, and remove the staple to the other half you just turned.

A faceplate screwed on or a glued on piece that will be used to hold the faceplate.

However that is not the end to the problems of your blank, you do have at least one pith totally in the wood, even if you can turn most of it away, the wood will shrink this piece of wood into a wavy plate.

Anyway I do agree with the advice given above, split it and make two pieces from it and use it to turn some special pieces out of this, but, it can be turned.

 

[Michael Brown]

Well, I would spend about a day and a half pouring 50 bucks worth of West System epoxy (tinted black or Brown or even using a little ground up bark as filler) into the inclusion until it would accept no more. Then, make a custom template for some good sized, extra deep dutchmen as insurance on the inclusion - span the crack by at least an inch both sides. Cherry is nice for the dutchmen. another couple of days down. Then its on the lathe to produce an obviously flawed piece that will probably live on my "why did I do that" shelf for a few years.

My opinion? save the time and bucks and cut into two pieces and get something smaller but useful...I've done the former, recommend the latter

I would go a very similar route, but I would use 2P-10 thin ca glue and flood the bark and the occlusion. Backing it with parchment paper to keep from bonding it to the work surface. Give it a week to really cure in and then have fun.

 

[Brian Gustin]

I would go a very similar route, but I would use 2P-10 thin ca glue and flood the bark and the occlusion. Backing it with parchment paper to keep from bonding it to the work surface. Give it a week to really cure in and then have fun.

Heh.. way higher risk tolerance than mine... I'd never trust CA glue that much and especially across that much thickness. I'd as soon try to turn a piece of glass - I'd expect similar results.

 

[hockenbery]

I would go a very similar route, but I would use 2P-10 thin ca glue and flood the bark and the occlusion. Backing it with parchment paper to keep from bonding it to the work surface. Give it a week to really cure in and then have fun.

I would not trust CA for this. Too risky for me.
Over time our risk tolerances change with both our skill level and experiences.

When I use CA to attach a glue block - I remove the glue block with a flat chisel in the glue line- the glue fractures leaving both pieces of would intact.
Gluing the pieces with CA - A catch could easily launch half of the blank

CA has a lot of tensile strength and very little shear strength.

 

[Brent@TurnRobust]

I agree with everyone that says this piece is not safe to turn. Every now and then we should all read this: https://www.woodturner.org/common/Uploaded files/Safety/AW2903-2014p27-29.pdf A PDF should download when you click the link.

 

[Michael Brown]

I would not trust CA for this. Too risky for me.
Over time our risk tolerances change with both our skill level and experiences.

When I use CA to attach a glue block - I remove the glue block with a flat chisel in the glue line- the glue fractures leaving both pieces of would intact.
Gluing the pieces with CA - A catch could easily launch half of the blank

CA has a lot of tensile strength and very little shear strength.

I can definitely appreciate this concern. With the older gorilla glue and crazy glue brands, I can completely agree.
I have had such a starkly different experience with the 2P-10 mix and specifically the thin blend. I have allowed this to absorb into the fibers, but not rely on void filling, and have experienced essentially turning nearly ironwood hard. I have never had a piece of wood which I use the thin CA 2P-10 to fracture or release, it has always scraped and shaved.

 

[Darryl Fective]

Don't give up too quickly. If it were me, I'd be tempted to set up a router or dado blades to pass thru and glue some hardwood cross pieces. You might have to strap it across the ends and turn it enough to establish your axis so the cuts are all same depth/plane.

Years ago I turned a hollow form that was destined for an unplanned rapid disassembly. I made a sort of "chute" to fit my trim router that attached to a vertical pipe in my banjo. I made 3 passes on each side with a 1/4" straight bit and glued in strips of ipe. After letting the glue cure overnight, I finished the outside cut, then hollowed the piece to 1/4" thickness. Each void now has 3 curved 1/4" square bars holding it together. Still to this day, nearly 20 years later, that gift has to be my finest piece of work.

 

[robo hippy]

If I wanted to turn a solid platter out of that piece, I would use a sled on the table saw to rip out the bark inclusion, then glue the two halves back together again. Probably not worth the effort. Also, the pith on the right side is a problem area that will crack eventually. The left side, not so much.

robo hippy

 

[Dean Center]

I'm generally in agreement with everyone else, but will point out one different way of looking at it. The end of the blank that we can see is the very deepest part of the inclusion in the whole piece. This is where the branches were at their farthest apart. The other end of the blank would be where there is a single trunk and single pith. It's possible the part of the blank we can't see is adequately sound.

 

[Gary Hack]

I agree with everyone that says this piece is not safe to turn. Every now and then we should all read this: https://www.woodturner.org/common/Uploaded files/Safety/AW2903-2014p27-29.pdf A PDF should download when you click the link.

Thanks for this link... Everyone does dangerous things; I try to remind myself how and why these things are dangerous to help control the risk, and to keep learning what indeed is dangerous

 

[hockenbery]

The end of the blank that we can see is the very deepest part of the inclusion in the whole piece. This is where the branches were at their farthest apart. The other end of the blank would be where there is a single trunk and single pith. I

You may be right.
Photos can deceive. A look on the other side would confirm your look.

I see it the other way - the pencil lines go further apart - assuming the pencil lines are on the piths.

 

[Leo Van Der Loo]

You may be right.
Photos can deceive. A look on the other side would confirm your look.

I see it the other way - the pencil lines go further apart - assuming the pencil lines are on the piths.

You are absolutely right, the bottom of the picture is the closest to the log and it is opening up from there, I would say, going by the grain, it is even more so than what the pencil lines indicate.

 

[Mike Novak]

Don't give up too quickly. If it were me, I'd be tempted to set up a router or dado blades to pass thru and glue some hardwood cross pieces. You might have to strap it across the ends and turn it enough to establish your axis so the cuts are all same depth/plane.

Years ago I turned a hollow form that was destined for an unplanned rapid disassembly. I made a sort of "chute" to fit my trim router that attached to a vertical pipe in my banjo. I made 3 passes on each side with a 1/4" straight bit and glued in strips of ipe. After letting the glue cure overnight, I finished the outside cut, then hollowed the piece to 1/4" thickness. Each void now has 3 curved 1/4" square bars holding it together. Still to this day, nearly 20 years later, that gift has to be my finest piece of work.

I’m not understanding. Do you have a picture?

 

[Mike Novak]

The pencil lines are the pith

 

[Dean Center]

You may be right.
Photos can deceive. A look on the other side would confirm your look.

I see it the other way - the pencil lines go further apart - assuming the pencil lines are on the piths.

OOPS! I looked at the two piths and assumed I was looking at the Top of the "Y", and you are correct--we see the bottom of the Y and this piece is definitely not safe. In my defense, I'm seeing the ophthalmologist next week and I think my cataracts have progressed. Or maybe my glasses are dirty.

 

[Darryl Fective]

I’m not understanding. Do you have a picture?

 

[Mike Novak]

Darryl

All I can say is WOW!

 

[Vincent Vogel]

If you want a large platter and a safe way to do it use a router or a planer wheel for an angle grinder. That's how I make dough bowl platters for the girls.