Mortise or Tennon

[Dan Wiggin]

Hi all, I slid my headstock down on my Powermatic 2014 to rough turn this 18” behemoth of green Mahogany. I always use tenons but have never turned one this big on my lathe. Would I be better off to use a mortise instead? It seems it would be stronger. It’s very wet and heavy. Thanks in advance!

 

[Alan Weinberg]

Your tenon should be 30+% of the diameter of the piece. Yours is too small. Mortise isn’t necessarily stronger. Good luck.

 

[Dean Center]

Tenon vs. mortise seems to be one of those personal preferences topics, and you'll get recommendations for both here on the forum.

Personally, for an 18" rough blank, I would use a 4" tenon in my large chuck. Some folks can get away with a smaller tenon, if it's really well made. If so, I would suggest you keep the tail stock up as long as you can. Maybe that's not feasible on a 20" bed.

 

[Richard Coers]

My advice, stop trying to true the black from the outside diameter. Start cutting on the face and continue onto the O.D. Much less shock on your hands and the lathe. The answer to your question is do what you prefer. I use larger diameter jaws with my Oneway chuck when I do that size bowl. A stack of 18” bowls in soft maple.