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T2 knob turning


kevin gilmore

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I decided to finish off the one with the crack in it, and found out

something very interesting. At the same speeds and feedrates

that i use for the LV and Rosewood, and with the same carbide

tools, the ebony gets stinkin hot. WAY WAY hot. Even

with 5 thousandth passes.... Might need some kind of cooling...

AH well, on to other hardwoods.

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That'll be superb once turned. I'm always amazed when a grotty piece of wood completely changes character once cut. That is part of the joy and grief - what is inside? Make a guess and hope you get the cut right.

I hit a goldmine recently at my local wood and tools shop. He'd just got a shipment of Cocobolo turning blanks, about 8-10 inches square and around 2 1/2 inches thick. I got to them first! I rooted around and picked up the best figured pieces - about 15 in all, some smaller, some larger. Cost me £140 for the lot, which is pretty fantastic value. Also picked up some ebony and african blackwood too.

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That'll be superb once turned. I'm always amazed when a grotty piece of wood completely changes character once cut. That is part of the joy and grief - what is inside? Make a guess and hope you get the cut right.

I hit a goldmine recently at my local wood and tools shop. He'd just got a shipment of Cocobolo turning blanks, about 8-10 inches square and around 2 1/2 inches thick. I got to them first! I rooted around and picked up the best figured pieces - about 15 in all, some smaller, some larger. Cost me £140 for the lot, which is pretty fantastic value. Also picked up some ebony and african blackwood too.

Nice! What are you going to turn?

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I'm not into turning - cabinetmaking (just recreational) is my thing. The cocobolo will probably be used in things like lids of jewelry boxes, storage boxes etc, or small cabinets. I'm a follower of Krenov's philosophy of buy wood. Then buy more wood. Then look at it for a long time until a piece suggests itself. Ebony and blackwood I use for contrasting wedges in through tenons. Against a paler wood (and most wood is paler than those!) it is a superb effect.

One of the more disappointing woods to work with is purpleheart. Looks absolutely stunning bright purple when first cut, but oxidises slowly to a kind of muddy brown.

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http://gilmore.chem.northwestern.edu/woodies2.jpg

The redheart started cracking about an hour after machining, including

the original block. So this one needs to dry out a few years.

The olivewood also started cracking, but much smaller cracks.

And the bocote started out much lighter and is getting darker as

it exposes to air.

The bocote and the cocobolo should work out great.

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I'm not into turning - cabinetmaking (just recreational) is my thing. The cocobolo will probably be used in things like lids of jewelry boxes, storage boxes etc, or small cabinets. I'm a follower of Krenov's philosophy of buy wood. Then buy more wood. Then look at it for a long time until a piece suggests itself. Ebony and blackwood I use for contrasting wedges in through tenons. Against a paler wood (and most wood is paler than those!) it is a superb effect.

One of the more disappointing woods to work with is purpleheart. Looks absolutely stunning bright purple when first cut, but oxidises slowly to a kind of muddy brown.

I've heard this from several people and it always intrigued me. Here in Texas when I cut Purple Heart it is muddy brown, but within a day it turns a gorgeous Purple color. When I plane it that's really fun...within 5 minutes the little brown shavings turn bright purple. Maybe it's the salt air, temp or humidity down here, but it seems to be the opposite of what most describe.

Agreed Kevin, the Cocobolo and Bocote are beautiful!

Edited by swt61
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I've heard this from several people and it always intrigued me. Here in Texas when I cut Purple Heart it is muddy brown, but within a day it turns a gorgeous Purple color. When I plane it that's really fun...within 5 minutes the little brown shavings turn bright purple. Maybe it's the salt air, temp or humidity down here, but it seems to be the opposite of what most describe.

In the UK we sit at the triple point of water - so a hell of a lot wetter than Texas. So you're right, maybe what happens to purpleheart is an environment thing.

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Why not coat the knobs with a light coat of clear varnish/lacquer to lock the moisture in and prevent oxidisation?

Sealing wood is a dangerous thing. As a natural material it likes to breathe, and wax, shellac, danish or teak oil are fine - but polyeurethane is asking for trouble and does not look good either (IMNSHO). The only difficulty is that the wood needs to be well seasoned and without internal tension - if it has that you can actually hear the click or ping as it cracks as you work it. That is the precise instant before you swear like a marine and walk out of the shop to calm down.

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Sealing wood is a dangerous thing. As a natural material it likes to breathe, and wax, shellac, danish or teak oil are fine - but polyeurethane is asking for trouble and does not look good either (IMNSHO). The only difficulty is that the wood needs to be well seasoned and without internal tension - if it has that you can actually hear the click or ping as it cracks as you work it. That is the precise instant before you swear like a marine and walk out of the shop to calm down.

Not to mention that certain woods (Cocobolo & Bocote to name two) do not need any finish, due to the oil/resin levels occurring in the wood naturally. You can simply buff either of these woods to a beautiful sheen.

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So the diamond tools came in today. And i have a chunk of marble and granite

to try and turn into knobs. Should be fun. After that i'll go and find some fancy

stone. The redheart is shrinking and the cracks probably won't be visible in

about 2 weeks. Should be able to make a few aluminum mounts tomorrow.

Need to change the title of the thread to just T2 knob turning biggrin.png

since i've already done a titanium one, and a 18k gold one.

one of these days .9999 fine platinum.

Edited by kevin gilmore
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