Need Technique Advice to Stop Tool Marks

[Eric Jacobson]

I love making bowls except for one thing; sanding out tool marks on the inside of the bowls. boring!

I'm sure my problem is technique. I'm a newbie and prefer to use the same tool (with the same grind) for the entire bowl. I use either a 1/2" or 3/8" bowl gouge. I sharpen it with a Wolverine arm set at 50 degrees (with a Raptor jig) and a Vari-grind on the middle setting. Anyway, it comes out looking like the picture below. I guess it has a 55 degree bevel on the nose.

I try to provide good tool rest support but just can't seem to get smooth curves on the inside of the bowl. I try my scraper every once in a while but I can't seem to make it work either. In the end, I resort to 80 grit sanding discs and it takes 20 minutes to get the tool marks out, which are normally just below the rim on the curvy sides of my bowls.

I've taken some lessons and I've learned some basic things like, pushing straight in with my right hand (not with my left hand), riding the bevel. Keeping the blade a bit above the center point, keeping good tool rest support, slowing down as I near the center, maintaining a sharp tool edge.

My instructor did some weird thing where he grinded out the bottom of the gouge on the side of the coarse grinding wheel so the bevel's heel wouldn't scrape, is that necessary?

I've thought about throwing more money at it like trying one of those curvy bowl tool rests or one of those Sorby 45 degree shear scraper cutters but maybe I need to go take some more lessons?

What do you think?

[Robert McGowen]

You will probably get numerous opinions, so here is mine!

Take that scraper you have and if it is not a round nose scraper, then make it one. When you are ready to finish off the inside of the bowl, sharpen the scraper. Put the tool rest as close to the wood as you can. Hold the scraper so that it is at a 45 degree angle on the tool rest. (The right side of the scraper should be the high side.) You should be able to take off fine whispy little shavings. Start sanding at 220.

Your welcome! :D

[Bernie Weishapl]

I use a P & N conventional gouge. One is 1/2" and the other is 3/8". I sharpen those and take my final couple of cuts and start sanding at 120 or 150.

[Steve Schlumpf]

Eric - I agree with your instructor - grind off the bottom half of your bevel. That may not cure 100% of your tool mark issue - but it will take care of most of it.

You mentioned tool marks just below the rim on your bowls. That can happen when you press to hard (rub the bevel) and can actually distort the rim of the bowl as it turns. The gouge will cut into the softer wood (face grain) and tend to skip over the end grain causing your gouge to dig in a little the next time you hit the face grain. What speed are you turning your bowls at? To slow makes that a very likely occurrence.

Also - make sure that once you start a cut - you continue through it all the way or else you will cause ridges and you'll make some tool marks when you encounter them.

Also - I agree with Robert. A good - heavy duty - scraper can really clean up tool marks well. Make sure you sharpen it and use very light cuts! Good luck!

[Curt Fuller]

All of the above and.....
Practice!

[Reed Gray]

If you don't round off the bottom of the bevel, the sharp edge will bruise the wood, especially if it is wet. You can sand through to the outside of the bowl, and they never seem to go away. Another point is that the closer the cutting edge is to the bevel, the easier it is to control. This is why you have this problem on the inside, and not the outside.

I do use a heavy bowl scraper for shear cuts to clean up what my gouge doesn't. Most of the time, I will use one hand on the outside of the bowl as a steady rest, with very gentle pressure. With the scraper at a 45 degree angle, take very light pull cuts. The tool pressure should equal the hand pressure. It will take a couple of passes to remove the tool marks. On bigger bowls, you should do this in stages as in finish turn down about an inch or so, then clean up, then turn down another inch or so, and clean up again. You will have to blend it in a bit between stop and start places. Even dry wood moves a little.

Most of the time, a burr straight from the grinder will do fine. A burr that is burnished (burnish tool from Veritas/Lee Valley, or a burnisher for a card scraper) on will give a better and cleaner cut.

Note: If your hand is getting hot, that means too much pressure.

Note: round over the rim of your bowl, don't leave it square and sharp as it will cut you.

Note, NEVER use a scraper flat on the tool rest for finish cuts, especially any where near the rim. This causes the rim of the bowl to vibrate, you will get oscilation cut/marks, and in worst case it will vibrate so bad that you get a big catch and your bowl blows up.

robo hippy

[Jon McElwain]

All of the above and +1 on the burr on the scraper. Putting a light burr on a sharp heavy scraper is my "go-to" for tearout, ridges that won't go away, and, well, for those days when my bowl gouge is too lazy to cut straight! ;)

[Sean Hughto]

I invested in Oneway's two curved rest (one geared to outside curves and the other to inside. I think they help a lot, especially on the inside. It's a lot easier to control the tool and make a smooth pass with a rest that is a consistent half inch from the surface than with a striaght rest that can require a significant overhang, especially on large bowls.

Also, different woods and different wetnesses will respond differently to the same tools and techniques. Sometimes tearout is really pretty much a given. It can be minimized with optimal attack angles, sharp tools, and light cuts, but sometimes, ya gonna have to do some sanding.

[David Woodruff]

Ditto what every one has said++++++. That curve just below the rim is a nasty little place. Different techniques for different woods. I generally have good results with a very sharp scraper, down tilt, moving right to left with a pull cut. I have three scrapers I use frequently, 1/2", 3/4" and 1" depending on bowl size. Some turners seem to prefer a gouge with various grinds for everything, I use gouges, scrapers, and even a skew depending on what I am trying to accomplish. If you can, learn to tolerate sanding, that is the only way I know to create a finished piece I will place in competition with anybody. Of course if you have a name like Ellsworth you can finish or not, sand or not, remove tool marks or not. Go figure.

[Steve Harder]

I use a slightly different approach to the scraper suggestions.

I purchased a flat round carbide insert - the one that is used in the EasyFinisher C0 tool - and made a homemade handle for it. With a toolrest that can extend into the bowl, close to the surface, I make light passes with the tool held horizontal and at horizontal centerline.

With patience I can remove all tool marks and have very little tear out.

Also, I was always frustrated when I found a small imperfection after finishing. Then I purchased a pair of 6+ magnifying glasses (cheap ones from ebay) - I always do a last inspection wearing them before taking piece off lathe - and I've had a lot fewer "oops wished I'd seen that" problems.

[Barry Elder]

As usual, you have received great advice to solve your problem. I would like to add that you should find your nearest woodturning club and shorten the learning curve. There may even be a member who lives down the street and would be willing to be your mentor.

[Kyle Iwamoto]

Note, NEVER use a scraper flat on the tool rest for finish cuts, especially any where near the rim. This causes the rim of the bowl to vibrate, you will get oscilation cut/marks, and in worst case it will vibrate so bad that you get a big catch and your bowl blows up.

robo hippy

Wow, thank you for that..... I will have to try that. I've been using my scraper flat, but not by the rim, because of the vibration...... Sandpaper is my favorite tool.

[Michael E. Thompson]

Forgive me if I missed reading this suggestion but make sure your tool stays againsnt your body. Move your body to move the tool, not your arm. You will have so much more tool control. Once I learned this technique, I started sanding with 180 grit.

Mike

[Scott Hackler]

Another thing that helps with tool marks is to start a cut line and dont stop with it through the entire inside curve of the bowl. (riding the bevel) When I first started I sanded a lot and was pretty discouraged with the amount of work it took for a smooth finish, until I refined my tool control and bought a right angle drill for power sanding!

I also really like using my giant Sorby bowl scraper for those open form bowls. It really shapes the inside with a pretty smooth finish. Of course the bur has to be toned down a bit and very light cuts, but it sure saves on time and aggrevation! A small scraper at 45 degrees in a pull cut works very well for end grain tear out and those forms with a overhanging lip where you cant reach very easily with a larger scraper or the gouge.

The last suggestion is to not get discouraged. Practice every chance you get and you'll be surprised how your skills increase. 1 year makes a world of difference, believe me.

[Jake Helmboldt]

Eric, I've had (have) similar problems and Reed's suggestion of finishing the edge before hollowing out the rest of the bowl certainly helps. It keeps the rim from flexing/deflecting as much and the result is a cleaner cut, with gouge or scraper. While I haven't eliminated the problem that certainly has been a big help at minimizing it.