Help Turning Green Birch

[Mort]

Change one letter in the name of this wood and you will have a better understanding of my current attitude toward this wood.

My tools are sharp those lovely long strands of shavings are coming off the wood. Lathe speed has been varied. I am riding the bevel, letting the wood come to the tool and all of that. I have not had a catch on this piece - a record for me. The results are not good. I am getting what I can only describe as tear out primarily in the redish colored heart wood. The tear out places move. On one cutting pass the tear outs are 2" off the base, next pass the tear outs move to 3" off the base and are at 180 degrees - fill in your own number - from the last set of tear outs. I can't seem to get rid of these tearouts - the blank started at 12" in diameter and is now at 7" - and I am coming to the conclusion that the wood is at fault. Like the old cajun joke - somebody shoot up in this tree, one of us needs some relief.

Is it me or is it the nature of the green birch?

 

[Whit]

Hi Mort,

I turn a lot of green white and yellow birch (we have a lot it here in northern Michigan) with quite good success. You mention the red heartwood so I assume you're working with white or paper birch.

A couple other assumptions. I assume you're using a bowl gouge inside and out. I asume that the wood is nice and solid. Birch can deteriorate very quickly while still very wet. It can get real punky in just a matter of weeks, especially if the tree was not healthy when it came down and the punkiness or softness can be quite random throughout the log. If there's a lot of spalting rot has started.

You mention your tools are sharp and you're riding the bevel with no catches. Good. What kind of grind are you using on your gouge? I use a slightly modified Ellsworth grind ground with an Ellsworth grinding jig and sharpen often. Turning the outside of an 8" bowl, for example, I'll probably resharpen two or three times. About the same, or maybe an extra trip to the grinder for the inside. It only takes a light touch on the grinder to re-establish the cutting edge so I don't spend much steel making absolutely sure the edge is sharp.

In what direction are you cutting. Are you cutting "downhill?" That is, on the outside of the bowl are you cutting from the base to the rim and on the inside from the rim to the base? Cutting in these directions the fibres you're cutting are supported by adjacent fibres. Going the other way (rim to base on the outside, for example) will be tearing unsupported fibres loose.

I don't know if this will be of any help, but these are a few factors which come to mind.

Good luck.

Whit

 

[Erwin Nistler]

I have turned white, papper, birch with little trouble. To keep the bark on I turned downhill, into the bark, where I had to. The bark stayed. This was a fresh, SOLID, tree that was leaning over the cabin. By time the leaves wilt the wood is deterating. Step on what looks like a birch log in the woods and you will find the inside is empty of all but dust. I suspect your log was going bad.

 

[Mort]

I am cutting downhill with a modified ellsworth grind and lightly sharpen while turning. The tearout might be better described as voids as though the wood is going punky. The trees have been down about 3 weeks and appear solid. I can't hand drive [stabbing type motion] a screw driver blade in to the wood either end or cross gain. Guess that I just need to keep trying. There is a lot of wood available to play with. And yes it is white or paper birch.
Thanks for the posts.