Hollowing problems

[Quinn McCarthy]

I am trying to turn a segmented bowl and am having trouble shaping the return toward the top of top bowl. This is the bowl I am trying to turn except it has one more ring in the middle and is a little bigger in diameter. http://www.turnedwood.com/images/Bowl0671a.jpg. Being kind of a newbie to the sport I didn't have a hollowing tool so I built one. I followed the instructions from Bill G's and Bill Stevners threads from last week. I used a 3/8" round bar stock and drilled a 1/4" hole in the end of the bar at a right angle. I used a 1/4" drill bit for the cutter and turned a beefy black ash handle for it. I sharpend the cutter to about 30 degrees with a little radius to it. It looked like a great tool. It cut but not reel fast. When I got further from the tool rest the vibration got so bad a could hardly hold onto it and it left like a chattering on the inside of the bowl. It took quite a bit of 80 grit gouge work to clean it up. What am I doing wrong? It did work OK on truing up the opening of the top ring. I tried holding the cutter at 90 degrees and 45 but it didn't seem to make much of a difference. Thanks!

[Ron Ainge]

you may have the cutting edge of your tool to low when it is inside the bowl. try raising your tool rest so that it is above the center line of the bowl. then start cutting somewhere above the center line with the cutting tip dipped slightly downward. this should stop the chattering action and will prevent a catch becasue it will allow the tool to turn down instead of digging into the wood like it would if it is below the center line of the bowl. i hope you can understand this if not let me know and and i will try to do a better explanation.

[Bill Stevener]

Hi Quinn, don't know how you were approaching the work, what ever you did, the final product sure reflects you won-out. The specie Oak??, is not one that is very forgiving, or presents a gentle ride, no mater what tool one is using.
If you try the tool approach Ron has noted, you will find the tool will behave considerably better.
The first time is only the beginning in the learning curve, in time everything just seems to line out. ( I didn't want to use the word "flatten - that's not going over to well hear lately)

Very nice bowl, thanks for letting us have a look,

Bill,>>>>>>>>>>>>>>>>>>>>>>>>

[Quinn McCarthy]

Thanks for the responce. The picture is the one I fashioned mine after. I got that from somebody elses web page. I really liked the design and thought it would be a fun one to start with. The one I am dong is hickory and cherry. I will give it another try at a different angle.

[John Hart]

Ron's suggestion to raise the tool rest is probably the key to the whole thing. It made a world of difference for me anyway. I might also suggest, now that there's chatter already in there, to approach it very lightly at first, to get all the rough stuff out. That tool configuation doesn't like a deep cut....light and sweeping. In my limited experience of course!

[Quinn McCarthy]

Thanks John

I tried raising the tool rest last night and that made a big difference. What tool would I use to hog out material a little quicker?

[John Hart]

Thanks John

I tried raising the tool rest last night and that made a big difference. What tool would I use to hog out material a little quicker?

This is just me Quinn, as so many other accomplished turners use a hollowing device similar to what you are already doing, only with a capturing device that limits the chatter and provides better control overall. But a while back, I made a tool that we lovingly refer to as "Big Bertha". http://www.sawmillcreek.org/showthread.php?t=26673

This tool eats up whatever I throw at her. I'll get the lion share of material hogged out with Bertha then use the Sorby to do the fine stuff. This is mainly because I haven't mastered the Sorby yet.....But I keep working at it.

[Quinn McCarthy]

John

Cool looking tool. I was looking the other night at a hooked scraper like that. Cept not that big. If I could round up some tool steel I could make one myself. Is tools steel the same as high speed steel?

[John Hart]

...Is tools steel the same as high speed steel?

First off Quinn...let's clarify something. I am a steel moron.
The guys who gave it to me said "tool steel" and I just said, "cool...ok". I recently tried to find where they bought it and it comes from McMaster-Carr at http://www.mcmaster.com

The part numbers are
3/8" --- 6253K32
1/2" --- 6253K52
5/8" --- 6253K56

This is Hardened Precision 440C Stainless. I don't know what that means other than it doesn't rust and you only have to hit someone with it one time.

I think they use it for drive shafts for various motor applications.
Hope this helps!

[Quinn McCarthy]

Thanks for the links John. I am at the same level when it comes to steel.