Bowl inside sanding

[Ross Berning]

After roughing dozens of bowls I’m working on finishing cut skills. Feeling better about my progress on outside finish quality than interiors. I’ve got this soft maple piece on the lathe with what seems like tear out. With both hand and power sanding this area is 98% as smooth as the surrounding area but it isn’t really getting smaller. I’ve spot power sanded with 120grit. Other tool marks came out fairly easy. Is this a just keep sanding situation or would some sanding sealer or other technique help? I have not sanded in reverse as the chuck grub screws have gone missing.

I appreciate your wisdom here!

 

[John K Jordan]

Do you have a curved negative rake scraper? That might fix it, perhaps turning in reverse.

 

[Alan Weinberg]

Looks like tool marks. Keep sanding. Use 100 grit.

 

[hockenbery]

More sanding on this one,

In the next ones.
Hollowing the inside rim takes practice. It’s an interrupted cut. Taking a big cut will pull fibers. Difficult to maintain the bevel through the air space. Too much bevel contact drags the tool down a bit setting up a vibration.

I Face off the rim before hollowing. I start each hollowing cut slowly until i nibble away a space for the bevel to float over.
Light cuts, sharp tools, float the bevel
Grinding the heel of the gouge reduces bevel drag.

If you own a small bowl gouge 3/8 diameter - try that tool for the first 1-2” of the inside wall.
The smaller tool is sharper, takes a small cut, has a short bevel usually makes a clean tear free cut.
Jimmie Clewes’s teaches this in some of his classes with a traditional grind on a 3/8 bard bowl gouge.

See the light cuts
Light cuts with bowl (5/8 bar) gouge. Finnish cut 3/8 bar bowl gouge

I return a dried sycamore bowl in a demo video a tips thread on working with green wood
You can see how I do it and the use of the small gouge.

Working with green wood

The August 2015 AAW JOURNAL has great article by David Ellsworth on working with green wood. This is followed by 11 marvelous ways turners turned cracks into features. One of David's themes is that the deck is stacked against newer woodturners successfully working with wet wood. Might be a nice...

www.aawforum.org

 

[Mark Jundanian]

I have not sanded in reverse as the chuck grub screws have gone missing.

You can probably find replacements at your local hardware store. If you don't know the grub size, take the chuck, and a set of allen keys with you. It will likely be metric.

This looks like end grain, to me. In any case, I find alternating forward and reverse sanding to be more effective.

As suggested, a NRS could do a lot to smooth the area.

 

[hockenbery]

With both hand and power sanding this area is 98% as smooth as the surrounding area but it isn’t really getting smaller. I’ve spot power sanded with 120grit.

I’ll assume you don’t have a negative rake scraper.

I sand with a low lathe speed 30-50 RPM. If your lathe doesn’t go that slow go as low as you can.
If 120 isn’t doing the job try 80.
Use sharp paper - it will shoot a stream of dust off the disc.
Press lightly against the wood.
If you don’t see the stream of dust - time to put on a fresh disc.

 

[robo hippy]

Oh, the joys of turning soft maple! There is a lot of big leaf maple here, and one reason I don't like it is because it is prone to tear out, no matter how sharp your tools are. I have never taken a gouge to the levels that I take my hand planes to though.... For sure, I ALWAYS finish with a shear scrape, and have one video dedicated to that. As for NRSs, they do a good job when sweeping across the bottom. However, when going up the sides of a bowl, they are still scrapers, and you have unsupported fiber, so there is still going to be some tear out. Time for the 80 grit gouge. As always, a fresh gouge for the final finish cuts is necessary. For a long time, I figured that a smaller gouge would not be any advantage. But, as some one who has to experiment. I tried a 1/2 inch gouge, exact same geometry as my 5/8, and I did seem to have an easier time making smoother cuts on the inside of the bowl. It didn't seem to make any difference on the outside of the bowl. This may be because on the inside of the bowl, you have 3 areas to cut. One is the side wall which is similar to the outside of the bowl, two is the transition, and three is the bottom of the bowl. Slightly different grain orientations for all 3.

robo hippy

 

[Michael Anderson]

I have not sanded in reverse as the chuck grub screws have gone missing.

I don't use my grub screws, but I still sand in reverse all the time (and sometimes turn in reverse). I've never had an issue with the chuck coming loose, and my lathe does not have a very slow stop. That said, I do use the snap method when putting on my chuck. Make sure the mating surfaces are clean and then give the chuck a little hand-spin to seat it against the spindle shoulder. Not everyone agrees with this though, but it works for me.

A lot of other good advice here. I would also add that you don't necessarily need a negative rake scraper. A normal round scraper usually works fine, especially if you rotate it so that it is cutting at a somewhat shear angle. Hold your scraper flat against the toolrest, and rotate it counter clockwise until the right edge points up to 1/1:30 on the clock. Works like a charm.

 

[Dave Delo]

Don't know what your remaining wall thickness is but if you have enough meat left, as others have said, NR scraper with the lightest whisper pressure as possible might help a little bit. That knot doesn't help you out as it's different hardness than the surrounding wood. Looks as if you have a nice curve on the inside so I'd probably just power sand it with the lathe off in just that area until it blends in with the curve (if NR scraper doesn't work.) I'd use 120 grit. Takes a little longer but getting 80 grit scratches out afterwards can be a real pain.

 

[Bill Boehme]

Here are a few thoughts:

• Gouge might need sharpening and without realizing it, you're compensating by applying more pressure.
• Gouge might be scraping rather than cutting
• The tool might be cutting below the centerline. The tool's cutting edge on the bowl's inside must contact the wood above the centerline.
• The wood might be vibrating. You could try dampening the vibrations by applying light pressure on the outside with a leather work glove.
• As Robo Hippy said, soft maple can be a PITA.

 

[John K Jordan]

I don't use my grub screws, but I still sand in reverse all the time (and sometimes turn in reverse). I've never had an issue with the chuck coming loose, and my lathe does not have a very slow stop. That said, I do use the snap method when putting on my chuck.

Sounds like you work exactly as I do, sand and turn often in reverse, no screw to lock the chuck to the lathe spindle, and use the snap when mounting the chuck. For years, I’ve been calling it my “calibrated wrist snap” - not too much, not too little.

Even with a heavy blank I also have never had a chuck loosen, although my lathes do have a 5-sec acceleration/deceleration.

I do always use a wrench to remove the chuck - I cringe when I see the chuck key used a lever to loosen the chuck, sometimes by striking it with the hand or a piece of wood (Over the years I’ve seen some damaged from that.) I’ve had people say “just put a board between the chuck jaws” and use it for leverage to remove the chuck. That method doesn’t work to remove the chuck without removing the piece from the jaws! (which I do often)

The only problem I have is one large chuck that has no flats for a wrench. I plan to put it on the milling machine some day and cut some flats.

JKJ

 

[Ross Berning]

Got back to this bowl tonight and followed all this advice. Last session ended in frustration versus ending on a high note tonight!

I have both a round scraper (harbor freight steel doesn’t hold a burr) and a quality NR I had tried already. Those got the me this far but wall thickness was too thin to try again. I went after it with 80 grit but also realized some of the papers weren’t cutting anymore and replaced them. It took a while but at least 90% of those areas sanded out. Walls were getting thin enough to just start glowing through so I stopped.

Scraping up the walls is something I need to build on. There is enough chatter up there to spook me out. Maybe I need to support the wall on the outside? Have plenty of ideas from you all to exercise on the next one. I appreciate everyone’s input! I can feel it helping my skill grow.

Here’s the bowl, just off the lathe. 6 1/2 x 2”, 3 oz

 

[Alan Weinberg]

Got back to this bowl tonight and followed all this advice. Last session ended in frustration versus ending on a high note tonight!

I have both a round scraper (harbor freight steel doesn’t hold a burr) and a quality NR I had tried already. Those got the me this far but wall thickness was too thin to try again. I went after it with 80 grit but also realized some of the papers weren’t cutting anymore and replaced them. It took a while but at least 90% of those areas sanded out. Walls were getting thin enough to just start glowing through so I stopped.

Scraping up the walls is something I need to build on. There is enough chatter up there to spook me out. Maybe I need to support the wall on the outside? Have plenty of ideas from you all to exercise on the next one. I appreciate everyone’s input! I can feel it helping my skill grow.

Here’s the bowl, just off the lathe. 6 1/2 x 2”, 3 oz

check this out.

One of the many useful tools I have.

Hi everyone, I am sure you all know that tools help to make your work easier. I wanted to share a trick that I use and the tool that I use to do this trick. Sometimes when I am turning the inside of a bowl and for what ever reason it will start to chatter and vibrate. I like to go thin on my...

woodbarter.com

I’ve done it and it works.