• August 2025 Turning Challenge: Wooden Version of Non-Wood Item! (click here for details)
  • Congratulations to David Croxton for "XOXOXO" being selected as Turning of the Week for August 11, 2025 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Grain alignment

Macon Monroe

Macon Monroe

Joined
Dec 1, 2019
Messages
21
Likes
3
Location
Robbins, NC
I've read several posts that mention grain alignment and inspecting the grain before putting it on the lathe.

What am I to look for?
 
Grain alignment is done with the growth rings. Ore the bark edge( biggest growth ring)

When these are centered a bark edge bowl
One axis has the two high rims equal heights off the table
The other axis has either the two low rims at equal equal heights or the center of the growth rings centered at the bottom, or split the difference. In a blank with nice symmetric grain these are the same. When the center growth ring is lined up the grain pattern of concentric ovals is centered in the bottom of the bowl.

On cut rim bowls I center the grain on the bottom. Major axis an endgrain growth ring is lined up so that it is perpendicular to the lath bed. This has makes a grain pattern symmetric through the bottom ion one axis - usually pleasing. The second axis when lined up on a growth ring at side grain will produce the hyperbola shaped grain pattern in the bottom.

To line ip the grain I start turning between centers. In the roughing stage I line up the grain. Put my thumb nail vertically on the tool rest aligned with A growth ring, not moving my thumb I rotate the bowl 180 degrees check where my thumbnail lines up with the same growth ring on the other side. Loosen the tailstock and move the tail stock center so that the two end points will both be on my thumb nail when I rotate the bowl.

Easy to see the grain withe the sapwood growth rings line up on the bowl and hollow form
B9807530-A132-46D1-BE07-87444FC1EFB6.jpeg 7D64CCAD-C592-40B0-BC08-4A11A7516234.jpeg
 
Inspecting before you mount

Be sure the wood is structurally sound

Ring shakes or wind shakes and bark inclusions are the grain related defects you need to watch for

A ring shake is a separation of the growth rings these are extremely dangerous
Also often hard to see on s chainsaw cut

Our club showed a YouTube for our safety talk posted by an ignorant woodturner
The guy holds up a blank with an obvious defect. Mounts the bowl, cuts through the connection of solid wood and a big chunk hits him inthe head
He could have easily been killed
 
I had a large diameter sassafras tree on my property. It needed to be cut to make way for our new house. So I cut it into bowl blanks, nearly every one had rather severe ring shakes. I mentioned this to a retired forester in my tuning club and without knowing anything more, said it grew on top a hill didn't it. It did. he said it is common for some species to be worthless for turning if they came from a windy hill top. Walnut from the same hill however was nearly all great for turning. there were a few pieces with ring shake.
 
You must log in or register to reply here.
Back
Top