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View Rink's profile

Turning log into bowl with pith in the middle

by Rink
posted 06-19-2020 08:25 PM


16 replies so far

View ibewjon's profile

ibewjon

1950 posts in 3643 days


#1 posted 06-19-2020 08:49 PM

I was wondering about drilling out the pith, and replacing it with a dowel. Making glasses, and the dowel would be a contrasting stem. But how much to drill out? With a 4-6” dis log, would I need to take out 1/2, 3/4, or maybe a full 1”? I guess we both will have to try our ideas and see what happens over time.

View MrUnix's profile (online now)

MrUnix

8212 posts in 3049 days


#2 posted 06-19-2020 10:46 PM

I turn end grain bowls frequently – pith and all. Whenever I down a tree, I always cut me up some nice cookies to dry, and yes, they most always crack no matter what you do. I just embrace the cracks and turn them info design features. Filled with tinted epoxy, they can provide a dramatic contrast and really enhance the beauty of the bowl.

In the video linked to in the original post, it shows turning them using a faceplate; but for thinner cookies, there may not be enough meat for the screws, or the cookie may not be deep enough to turn out the screw holes once removed… which is where threaded glueblocks really work great. Not only do you eliminate the screw holes, but you can mount/remount the blank as many times as you like without alignment problems like when using a regular chuck. The bowls above were all made using threaded glueblocks:

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View janvlen's profile

janvlen

10 posts in 96 days


#3 posted 06-20-2020 01:45 AM

Well Brad, that answers that question too! I’ve several cherry logs that I’ve been carting around to more than 20 years and want to make bowls from them. As soon as they were cut I painted the open ends with wood glue and left the bark on. They seem dry now! And do not have any cracks to speak of. That’s two to you!!!

-- Old man turner

View Rink's profile

Rink

198 posts in 888 days


#4 posted 06-20-2020 03:03 AM

Noodling around, I found this. Interesting method, although I think it would work better with a hollow form than a large bowl. I think I’ll give it a try, though.

View Wildwood's profile

Wildwood

2890 posts in 2985 days


#5 posted 06-20-2020 12:15 PM

There is not easy answer to your question we don’t know wood species, wet or dry etc. So just go for it!

If go to wood Database and take a look at Laburnum wood find this is great wood for turning. Andy Phillips merely tuned a foot on his bowl and didn’t use a plug. https://www.wood-database.com/laburnum/

Here are two examples of hollow turn vases with pith showing!

https://www.lumberjocks.com/projects/160090
https://www.lumberjocks.com/projects/163562

-- Bill

View Rink's profile

Rink

198 posts in 888 days


#6 posted 06-24-2020 10:01 PM

So, I decided to go for it, but I think I bit off a little too much. this is so big that it’s giving the motor problems.

View MrUnix's profile (online now)

MrUnix

8212 posts in 3049 days


#7 posted 06-24-2020 10:11 PM

Naw – you just need to get it roughed out and balanced bit more ;)

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Aj2's profile

Aj2

3336 posts in 2648 days


#8 posted 06-24-2020 10:46 PM



So, I decided to go for it, but I think I bit off a little too much. this is so big that it s giving the motor problems.

- Rink

Safety alert Safety alert.
I hope your joking that spur center doesn’t look big enough.
When the grain is orientated in that direction long ways isn’t that spindle turning ?

-- Aj

View Rink's profile

Rink

198 posts in 888 days


#9 posted 06-25-2020 03:22 PM


Safety alert Safety alert.
I hope your joking that spur center doesn’t look big enough.
When the grain is orientated in that direction long ways isn’t that spindle turning ?

- Aj2

You are right that the spur center is too small. I don’t have a larger one. I’m just using it to get the blank relatively round and get the end square so I can put a faceplate on it. Yes, it does lose grip and I have to keep re-tightening it. I don’t think of it as a safety issue – it’s more an annoyance issue.

This is the largest piece of wood I’ve worked with and I’m not sure where I’m going with it. Maybe a double sided bowl of some sort (egg timer shape?), or a shallow bowl on a pedestal shape…. I’m thinking that I should avoid having to hollow out the whole blank. It seems like that could take a very long time. A hollow form would be nice, but to go that deep I’d need heavier duty hollowing tools than what I have.

David

View Wildwood's profile

Wildwood

2890 posts in 2985 days


#10 posted 06-25-2020 06:45 PM

Not uncommon to get slippage with a 4-prong drive center.

I bought this drive center more than 25 year ago and still have the original point in it.
Advantages are: good on both dry & wet wood, gets a better bite than 4-prong center. Also end of the blank does not have to be perfectly square for center to get a good bite! I use this center for roughing out or finish turning on bowls, hollow forms, and spindles.

https://www.woodturnerscatalog.com/p/107/313/precision-machine-2-Prong-Drive-Center?term=2+prong+drive+center&term=2%20prong%20drive%20center

Also own this Jumbo center and have only used it once:
https://www.woodturnerscatalog.com/p/107/2116/axminster-Jumbo-Drive-Center?term=2+prong+drive+center&term=2%20prong%20drive%20center

Drilled the end of a log with forstner bit to get a square surface got little slippage so back to the 2-prong center.

While this lathe has the swing not much distance between centers makes using a drive center a good op. My lathe doesn’t have that much swing but lot more distance between center depending on the wood have no worries about using a drive center. I can get my 16/42 cast iron bed & legs plus added weight rocking roughing out of round wed wood.

-- Bill

View EmAre's profile

EmAre

2 posts in 149 days


#11 posted 06-25-2020 07:37 PM

I often turn the log with pith in the centre but I usually turn green to finished in one step. That said cracking is an ongoing fact. I used to leave the finished piece wrapped up in at least 3 paper bags and hope for the best. Recently I found that a bit of Cyanoacrylate glue, maybe gel with some fine sawdust, stops the cracks very effectively especially if I check the piece daily.! All this to say that the pith has never been a big part of my problem. As someone mentioned earlier, species is big. Rink, just a little envious of that Nova DVR!
This piece is spalted holly and you can see the crack at 5 o’clock is more serious than one in the pith.

View MrUnix's profile (online now)

MrUnix

8212 posts in 3049 days


#12 posted 06-25-2020 10:44 PM


- EmAre

I see a dog in that wood… nose to the left, eyes mid center, little doberman type ears, etc… or is it just me?!??

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Rink's profile

Rink

198 posts in 888 days


#13 posted 06-27-2020 04:39 PM

So, I’ve been roughing this out, feeling my way along. Bowl on top, heavy base to keep it upright. Still looks a little heavy to me. The heavy looking grain doesn’t help. I’m hoping that the grain in the bowl’s interior is worth the trouble. I’ll keep roughing. After I dig out the bowl and flatten out the bottom, I’ll use some CA glue or epoxy to try to avoid (or repair) cracking. Turning something this big is a pain. Time consuming, mounds of sawdust, tired hands, physically exhausting. After this, back to smaller stuff.

And, that looks more like a bear to me than a dog.

View EmAre's profile

EmAre

2 posts in 149 days


#14 posted 06-28-2020 07:20 PM

Rink, I sympathize, turned a large Western Hemlock bowl. It wasn’t my usual choice since the wood had dried, but it had very close grain for a softwood so I thought it would be interesting. It ended up being hard work. I guess a combination of dry wood and close grain made for a much different experience than the easy cut, green wood I usually turn. Hopefully you are getting a nice clean surface so not too much sanding. It looks great so far!

View OSU55's profile

OSU55

2658 posts in 2840 days


#15 posted 07-01-2020 07:07 PM

Turned several pieces that size on my Nova Galaxi – no problem with motor power. For a drive center for big stuff I like the Elio 3 point drive, https://woodturningtoolstore.com/product/elio-dr-safe-drive-2-5/. Works really well for non- perpendicular ends. Turned end grain bowls, platters, HF’s with pith in. Rough turn wet, ca glue the pith, sack up and dry. On HF’s sometimes drill out the pith with 3/4”, and use that hole to turn the OD, make a tenon, then chuck mount. Sometimes leave the hole open, sometimes use a dowel.

View Rink's profile

Rink

198 posts in 888 days


#16 posted 07-02-2020 06:38 PM



Turned several pieces that size on my Nova Galaxi – no problem with motor power. For a drive center for big stuff I like the Elio 3 point drive, https://woodturningtoolstore.com/product/elio-dr-safe-drive-2-5/. Works really well for non- perpendicular ends. Turned end grain bowls, platters, HF’s with pith in. Rough turn wet, ca glue the pith, sack up and dry. On HF’s sometimes drill out the pith with 3/4”, and use that hole to turn the OD, make a tenon, then chuck mount. Sometimes leave the hole open, sometimes use a dowel.

- OSU55

That Elio looks different and interesting. I need to think about that. Different animal, but I also like the looks of this one, too.

So, I took my piece off the lathe, left it in the chuck. Put it on the floor with chuck on the floor and bowl facing up. I put CA in the very small pith crack in the center of the bowl to stop it from cracking further. The next day, I could not get the chuck back on the lathe. Turns out that the CA glue went completely through the piece, into the chuck. I wasted 3 hours trying to remove the epoxy inside the chuck. I won’t make that mistake again.

David

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