How would you remove this base

[Brian Kent]

Since I didn't leave any room?
How would you cut off the base?

[Roger Chandler]

I would make a jam chuck to go in my scroll chuck, reverse turn with tailstock support until I only had a small nib left where the live center was giving support, then with a sharp chisel take off the nib and sand smooth........works every time! Also, use a piece of rubber or mouse pad to cushion the inside of the bowl and help give drive to the jam chuck. Good luck Brian!

[Brian Kent]

Good. Should the jam chuck be concave or convex? From the second sentence I guess it is a concave chuck inside the bowl.

[Roger Chandler]

Brian......the jam chuck could be either way or straight across.......what you want is something that matches up fairly well on the inside of the bowl form, yet not go up on the sides much.......the flat of the bottom will be enough area for a piece of mouse pad to rest against it and the jam chuck on the other side of it ......it will protect the inside of the bowl and give some bite for drive.........hope this helps!

[Brian Kent]

That did it. I'll get smoother in my technique later, but that is what I needed. Thank you very much.

[Roger Chandler]

Way to go Brian! I guess you are getting that Delta midi finally broken in good! Next time go for more of a curve to a smaller foot......you will like the proportions better........congrats on a new technique.......the jam chuck is important as a weapon in our turning arsenals! :)

[thomas prusak]

Brian,
unless I missed it, you didn't mention the wood type??
Roger,
thank you for the info.

[Brian Kent]

Wood type? It's firewood.

Actually, Sycamore firewood.

[Michael Mills]

You didn’t ask but it appears to me your tenon/spigot in the picture is much too long. The top of the jaws should seat against the wood and there appears to be a gap. The bottom of the tenon should not contact the jaws base. See sketch. It appears your chuck jaws are not dovetailed on the inside so you would cut a straight tenon.

As to the friction chuck (jam chuck) I always make mine concave. If it is convex it may contact the bowl only at one point in the center allowing it to wobble and maybe resting on only ½ inch. If it is concave it will contact around the full outside edge, or on a 3 inch diameter it will have friction from the ten inch circumstance.

[Steve Schlumpf]

Michael - GOOD catch! Creating the proper size tenon is critical for maximum & safe holding power with a chuck!

[Thom Sturgill]

Another tip - get a small (1 or 2") sanding disk like you would use in a hand drill and put it in your drill press. It's easy to hold the bowl and maneuver it against the rotating sanding pad to remove the chisel marks and leave a smooth bottom. Does a better job than holding the bowl stationary and using a sanding pad in a hand drill.

[Doug Herzberg]

Brian, for some reason I was thinking about you yesterday, wondering what you're up to. This morning here you are with the answer. Looks like the grandchild is growing up. Quite a distraction from the shop.

I think you already got all the advice you need. The tenon thing Michael mentioned is critical for your safety and that of those around you. Once you start planning to reverse chuck your pieces, it will start coming naturally.

Glad to see you're well and still at it. Merry Christmas.

[Thomas Canfield]

I did not see it mentioned but leaving a dimple in the center of the tenon is very important for remounting the bowl against the jam chuck. I have made a bunch (at least 50 or more giving a lot away) out of different sizes of 3/4" MDF using an extra boss of 3/4" for 1 1/4" and a 1/2 and 3/4" thickness for 1" drives or you can add a tenon to the boss for use with chuck. You can easily round off the edges to get a fit for different size bowls and they work well with some of the cheap rubber shelf liner for pad.

[Marc Himes]

Since this will be a recurring problem, there are come other considerations. You may want to start using a recess instead of a tenon on the bottom or look into getting other means of reverse chucking your bowls such as Jumbo Jaws (see woodtunerscatalogue.com) or a vacuum chuck. Another step I find useful is to always mark the center of the bottom so you have a center point for the tail stock when you reverse chuck the piece.
Good luck.