Tricornered Pecan Bowl

This was turned from another piece of the pecan log in my previous post.  I've turned a couple of small tricornered bowls in the past that were mostly just to see how the process works and I've been wanting to make a larger one out of nicer wood.  This is probably the hardest thing I have ever turned.  Not only is this pecan some of the hardest wood I have turned but the process is pretty challenging, not to mention a little scary with corners whipping around at 900 rpm while cutting air.   

You start with a perfect cube with 2 opposite corners between centers.  In my case, I had a little bit of the live edge on one corner so making this the bottom of the bowl, this area gets turned away.  I did have to cut the corner off so that I had a flat place to put the tailstock. 

The first step was to put a tenon on the bottom of the bowl so that you can mount it in a chuck. My first tenon was too small so I had to turn it away and make another.  I could not get it to fit well either and I must have dismounted and remounted it 5 or 6 times before I had a tenon I could mount in the chuck and started to turn.  I went back and forth between shaping the outside and hollowing the top.  You have to be very careful to retain the 3 sharp corners.  Since you are cutting air, you have to take very light  as you get close to the corners. 

Not feeling too confident in my tenon, I kept the tailstock engaged as long as possible.  Unfortunately, this makes it challenging  to get deep with the bowl gouge so at about this point I decided to start working down the center core so that I could give myself a little more room. 

I decide to use a carbide tool for this and got the only catch during the enter process and broke the tenon out of the chuck.  After a little swearing, I called it a day and picked up the next morning. 

Fortunately, I had gotten just enough of the core turned down for it to act like a tenon that I could mount it in a chuck with the tailstock engaged  to make a new tenon.

Once I had it remounted the correct way in the chuck, I decided to drill a hole to set a depth and act as center should I need to flip it around again.   Without the tailstock, hollowing was much easier.  I put some marker on the corners to make them easier to see at 900 rpm and to sort of set a target wing thickness. 

Once I got the outside shaped and the inside to depth.  I decided that it was time to switch over to the 60 grit gouge to clean up tool marks. 

There were some end grain checks so I decided to use a black CA to seal the cracks.  I had it sitting at an angle using an end vise as a platform and the bowl fell to the ground and broke off a corner.  More swearing and time to call it a day.  When considering options the next day, I thought about cutting all of the corners off to match but the sharp points are part of what makes this cool so I decided to see if I could glue it back on.  Surprisingly a rub joint is all it took.  There was a slight gap where a small piece was missing so after the initial rub joint set, I glued in a piece of veneer from the same piece.  I just used PVA glue but I used the same black CA I used to fill cracks to fill some minor gaps in the joint after trimming and sanding.

My initial plan was to use a Minwax poly sanding sealer as a finish that I would polish but I was not happy with how blotchy it looked after sanding.  I think that I must have sanded through the sealer in some spots so I decided to completely sand away the sanding sealer   I opted to skip the sanding sealer this time and simply polished it with Ack's sanding paste and finishing wax.    I mounted it in a vacuum chuck to remove the tenon and finish the bottom.  

Thanks for looking.