hurricane 125 limitations on big bowls

[Richard Demler]

I'm in the process of turning a pretty big oak bowl..So far it's on a faceplate and the outside is pretty much to shape..I want to use my hurricane 125 chuck to do the inside..I'm sending pics and the size is approx. 20 in. by 10 in.I will have a void where a branch went through it otherwise very solid piece of oak. Any thoughts are welcome,thank you.

[Roger Chandler]

What jaws are you planing to use? I have used my HC-125 on large bowls like that, but have the 5" bowl jaws that I use. If your wood is nice and solid, and you have it well balanced, the stock dovetail jaws will probably be okay, but stop frequently and check to make sure your hold is secure.

[Richard Demler]

I have the stock dovetail jaws. The wood is very balanced now and solid on the bottom..Thanks for the reply Roger!!

[Dwight Rutherford]

I agree the chuck you have should work well, in compression mode not expansion mode.

[Bob Bouis]

I can say from experience the chuck can handle that just fine. As far as the jaws, though, the ones that come with are made for a 2.5" tenon, or so, IIRC. That sounds really scary -- use the tailstock, at least!

I would stick it in a bag and get the extra large dovetail jaws, asap.

Also, I'm not sure what the swing of your lathe is, but make sure you leave enough room for the bowl to warp if you're going to twice turn it. 'Cause if you don't you might not be able to spin it after it warps.

[Olaf Vogel]

When I do these, and first put it in the chuck, I drive in the tailstock firmly and clamp it.
then start digging out the inside, leaving a centre piece for extra stability.
once enough has been hollowed out, I cut the centre and move the tailstock.
at that point, the weight should be much lower. Takes me stress off the chuck.

olaf

[robert baccus]

Screw your faceplate to a 3-4" dia. glueblock--face it true and the bowl bottom, and use plenty of thick CA. Use strong hardwood 2" thick and 1.5" screws(10 size)

[Brice Rogers]

I can say from experience the chuck can handle that just fine. As far as the jaws, though, the ones that come with are made for a 2.5" tenon, or so, IIRC. That sounds really scary -- use the tailstock, at least!

I would stick it in a bag and get the extra large dovetail jaws, asap.

Also, I'm not sure what the swing of your lathe is, but make sure you leave enough room for the bowl to warp if you're going to twice turn it. 'Cause if you don't you might not be able to spin it after it warps.

Bob, I'm wondering about the shinkage. If the wood is shrinking more in one orientation but also shrinking (rather than expanding) it would seem like no matter what happens, the wood will get smaller. Maybe I'm incorrect and missing something, but I think that if something can be "spun" green that when it dries, it will still "spin". I'm open to comments based on science and personal experience.

[brian zawatsky]

Bob, I'm wondering about the shinkage. If the wood is shrinking more in one orientation but also shrinking (rather than expanding) it would seem like no matter what happens, the wood will get smaller. Maybe I'm incorrect and missing something, but I think that if something can be "spun" green that when it dries, it will still "spin". I'm open to comments based on science and personal experience.

All wood warps to some extent as it dries. As the cells lose their moisture they change shape, thus the wood changes shape. It will shrink, but not evenly. Oak is one of the species that moves considerably more than others, and if it doesn't crack you can bet it is going to warp like heck. I'd bet 5 bucks on your bent penny that at that diameter it will end up as much as an inch or so wider in one direction than the other (depending of course on how thin you turn the walls)

[Bob Bouis]

I can't really explain it -- beyond saying that wood doesn't really shrink in length (i.e., in the direction of the grain). But I'm hardly the only one who's noticed that it does happen.

[Brice Rogers]

Brian,, you're right. I wasn't thinking about the warpage of the roughed out bowl.

[Reed Gray]

For a 20 by 10 inch bowl, I would suggest a 5 inch tenon (1/4 to 1/3 the diameter of the bowl). For a recess, I would go 4 or so with at least a 1 1/2 inch shoulder, and both should be enough for coring. If you use the McNaughton, and are not 'master' level, you may want more. Part of what you have to overcome as far as forces go is the 10 inch depth which really puts the rim a long way off the headstock and chuck mount. Lots of potential vibration with the longer lever.

robo hippy

[robert baccus]

Bryce, I have turned hundreds+ green bowls and mostly vases to 100+ lbs. with this setup. This includes hollowing to 20" and finishing. I roughturn, endseal the outsides and rims, dry3-6 months with the glueblock on the blank. I have had 2-3 glueblocks crack due to getting in a hurry and using half dry glueblocks. Easy to catch when remounting to finish turn. I also turn this size pieces on a glueblock and mounted with a nova single screw with no problems. It took a while to work up to this method I admit. Also I use ring type screw chucks with a glueblock- Enables the use of an expanding chuck-probably the best as it mounts and dismounts easily as I sand and finish on the lathe. Also the glueblock prevents endchecking on the vase--that's a freebe.

[Richard Demler]

I wanna thank everyone for the great replies..I have the bowl down to 18 1/2 in X 8 1/2 in. and the walls are around 1-1 1/4in. thick. What are the recommended thicknesses for a bowl that big??I personally like thicker bowls..Thank you again for all the info..