Bowl turning problem -- what am I doing wrong?

[BuckeyeDennis]

I need some advice from you experienced turners. I'm trying to turn my first bowl -- a present for a niece. The blank is ash. I cut the blank two or three years ago, and have been storing it in an unsealed plastic bag ever since. Moisture content is currently about 14%, and there is no checking at all. Except for some spalting near the surface, it's a nice solid piece.

Bowl 1.JPG (676.63 KiB) Viewed 14456 times

I made pretty good progress rough-turning it to shape. But now I'm unable to get a finish without a lot of end-grain tear-out. I've tried tweaking the tool-rest height, sharpening my lathe tools, and experimenting with cutting-edge angle. I get the best results using a bowl gouge (as sharp as I'm able to get it), oriented such that the cutting edge is almost vertical where it contacts the wood. But that's not saying much. The photo below shows some of the tearout, and that's after spending a few minutes trying to sand it out with 60-grit.

Bowl 2.JPG (832.46 KiB) Viewed 14456 times

Can anyone tell me what I'm doing wrong?

[ERLover]

BD I dont know what you are doing wrong, but the MS had a tip a while back for turning and eliminating tear out, use a Cabinet Scraper to finish off b4 sanding.
Might just be the piece of wood??
Good luck

[rpd]

I haven't got to bowl turning yet, but I have been watching a lot of videos.
This one might have some answers.
[youtube]https://www.youtube.com/watch?v=qnym1IyOPgE[/youtube]
Also, the turners I watch seem to keep the speed up as high as they can without getting vibration, slow while roughing in and faster once the blank is fairly well balanced.

[ChrisNeilan]

Try applying a coat or two of finish, preferably lacquer sanding sealer. Let it really soak in and dry. Then sheer cut with a sharp tool. That should help.

[benush26]

Some woods will have tear out. If a small block plane can make a smooth cut, no tear out, then it's probably the chisel. However if a sharp plane still results in tear out you can presume it's the wood and not the operator.

If you think it might be the lathe chisel, have you tried a skew? I prefer a skew for finish cuts. You say that you have the chisel angle nearly vertical. I would do that with a roughing gouge once the piece is nearly round for quick removal, but unless you have REALLY swept wings, it doesn't sound comfortable.

Looking at the bowl, I don't know that a pull cut would be any help, though used lightly it can produce nice cuts.

Anyway, I think a skew might give you better results if the wood isn't the culprit.

Be well,
Ben

[BuckeyeDennis]

ERL: I couldn't find the Shopmith tip about using a cabinet scraper, but I did find a couple of good how-to's on putting a sharp burr on a lathe scraper. Also mixed reviews as to whether a scraper is the right tool for the job. I'll give it a try and see for myself.

Ron: Judging from the video, I think my gouge presentation was pretty good, after I experimented for a bit. But watching the guy cut off fine shavings while turning the spindle by hand, I don't think my gouge was that sharp. I sharpened it freehand on a 1" belt sander, and could feel a burr when done. I've heard that super-fine grits aren't necessary, but I have some, and will give them a try.

Chris: Stabilizing the grain by applying a sealer sounds like the ultimate solution -- I've never had this problem with the handful of other woods that I've turned. But I'm short on time, and will have to go to Plan C for a gift next weekend if stabilizing is necessary. And unfortunately, I don't have any shearing-cut skills. If they are what I think they are, I've been afraid to try, for fear of a getting a really bad catch. Do you know of any good instructional videos?

Ben: I have a freshly-sharpened block plane, and will try your test. Matter of fact, last night I was wondering If I could use it freehand as a lathe tool, kinda like a veggie peeler. I had already decided that a safety string, anchored to a joist overhead, would be in order! This particular plane has an adjustable mouth, so I can close it way down to help support the grain. Also, I did try a freshly-sharpened skew. It did a great job of cleaning up the profile, but if anything the tearout was a bit worse.

I'm not going to give up. Together, we can defeat this thing!

[masonsailor2]

I use the roughing gouge to get the basic shape and then use the scew chisel for the final cutting. The key word is cutting or shaving and not scraping. If you are using the scew to scrape then you will get tearout. It is the same concept as using a plane. The scew needs to be very sharp. Just as sharp as your hand plane irons. You may also want to experiment with different profiles on your scew chisel. I prefer a slight arc to the profile instead of a perfectly straight edge. That allows me to cut with a smaller portion of the edge rather than the entire width of the blade. If you are using SS chisels I would also suggest you turn a new and longer handle for it. I personally prefer a longer handle which gives me finer control over the cutting angle. Hope this helps !
Paul

[Mike907]

Some woods are just going to tear out, no matter what your technique. If your bowl is balanced, try removing the speed reducer so that you can up the rpm, then use your sharp bowl scraper in sheer cutting mode that you already described. That may be the best you will be able to get using turning tools.

A note of caution - even experts with a skew, like Alan Lacer, recommend against using one on bowls. A catch with a skew on spindle work is exciting enough, but if you catch the skew in the end grain of a heavy bowl, you could be looking at a trip to the emergency room. Likewise with using a roughing gouge on a bowl. The tang on a roughing gouge is not strong enough to take a catch on a bowl and can snap. Stick with bowl gouges that are made from round bar stock.

Mike

[Mike907]

This won't help you in time for this project, but if you like to spend money on tools, you could buy a shear scraper from Al Stirt.

You can see him describe and use the shear scraper starting about the 20 minute point in this video.

Mike

[beeg]

A note of caution - even experts with a skew, like Alan Lacer, recommend against using one on bowls. A catch with a skew on spindle work is exciting enough, but if you catch the skew in the end grain of a heavy bowl, you could be looking at a trip to the emergency room. Likewise with using a roughing gouge on a bowl. The tang on a roughing gouge is not strong enough to take a catch on a bowl and can snap. Stick with bowl gouges that are made from round bar stock.

Mike

I wholeheartedly agree with Mike on this. Now you could use both of those gouges, just remember to take before and after pics of your trip to the ER, or announce your RIP.