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Torn end grain? I don't know.

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Forum topic by MrJKristo posted 04-05-2018 02:51 PM 770 views 0 times favorited 8 replies Add to Favorites Watch
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MrJKristo

2 posts in 502 days


04-05-2018 02:51 PM

Topic tags/keywords: torn grain help carbide sassafras


I’ve just about had it. I’ve been turning bowls from sassafras tree that has been dried for around two years. I use carbide tools primarily and recently tried my older steel round nose scraper. The two images I posted show the problem I’m having. The images show what happens when I start sanding. I can sand and sand and it doesn’t go away.

I’ve tried minwax wood hardener, saturating with water and then sheet cutting when wet, sheet cutting when dry, round nose steel scraper, and also using paste wax to lubricate the cut. The only thing that seems to work is using the wood hardener and then sanding it completely off with sixty grit and then do my final sanding. This process takes forever and uses a ton of material cost.

I’ve had it with this problem. Any help with this issue would be very appreciated. It usually only happens on the inside too. I’ve also thought my tools just weren’t sharp but it happens no matter what. My thought is is just the wood. Even if it is just the wood there still should be some sort of technique to fix this.

-Jordan


8 replies so far

View Wildwood's profile

Wildwood

2691 posts in 2585 days


#1 posted 04-05-2018 03:41 PM

just think you are rushing or forcing the cut and cutting edge is skipping over early/late wood and seeing tool bevel rubbing and burnishing the wood.

Don’t know much about carbide tools, but if scrapper is dull will get same burnishing with dull scraper.

-- Bill

View WyattCo's profile

WyattCo

93 posts in 554 days


#2 posted 04-05-2018 03:58 PM

Carbide turning tools aren’t cutters, they are scrapers.

View walnutles's profile

walnutles

13 posts in 647 days


#3 posted 04-05-2018 07:39 PM

As stated above by using the carbide and the scraper your pulling out the fibers in the wood when you should be cutting the fibers. You could try shear scraping at a 45 degree angle with a light touch as doing this cuts the wood and it does not create as much tear out.
Or you could power sand it out with a drill and a pad with some 80 grit Velcro backed sand paper.

Can I ask you, are you using your carbide cutter at a 45 degree angle or are you using it flat on the tool rest.
If your using it flat then you will tear the fibers and if you using it on its side at 45 you will be cutting the fibers.
I hope that this helps Les

View unclebenny's profile

unclebenny

45 posts in 2327 days


#4 posted 04-05-2018 07:58 PM

I’ve had the same trouble on bowls from time to time. Only successful solution I’ve found is using a very sharp bowl gouge and a light touch. Haven’t had much luck with carbide tool for final finish cuts. Hope it turns out for you, end grain can be frustrating.

View LesB's profile

LesB

2151 posts in 3893 days


#5 posted 04-05-2018 08:54 PM

On some woods the end grain seems to tear no matter what you do. The sassafras your are working with is like hickory in that the end grain has a rather “fibrous” texture so you are getting a fuzz like tearing. You might try coating it with a diluted shellac and then sanding to see if that helps. That fuzz is hard to eliminate.

I have a lot of Big Leaf Maple which makes some beautiful turnings, especially when spaulded, but the tear out is a real problem and the more spaulded or decayed the wood it the worse it becomes. My solution has been to use 60 or 80 grit sandpaper to remove the tearing and work on to 320 or 400 grit to finish.
Other things that can help is higher turning speeds and very sharp tools with light passes. If your lathe is reversible I find that I can remove about half of the tearing by cutting lightly in reverse.

Carbide scrapers to not make as fine a cut as high speed steel so I finish all my scraping work with the high speed steel.

-- Les B, Oregon

View MrJKristo's profile

MrJKristo

2 posts in 502 days


#6 posted 04-05-2018 09:07 PM

Thanks everyone so far. I have the set from Harrison tools (https://www.harrisonspecialties.com/beginners-set-of-3-carbide-turning-tools-hollower-rougher-detailer-plus-handle/) and also their shear cutting head.

For the outside of the bowl in use the square tip flat for shape and then angled to shear cut. Works pretty good most of the time. There is on occasion where even when using the angled cut I still get tear out.

Inside of bowl i use square tip to remove most of material followed by round tip top smooth to final shape. Then I attempt to shear (angled at 45- but maybe I’m not always) with the round tip or the shear cutting tip with little to no change in surface smoothness. I think I’ve already dulled my shear cutting tip trying to learn the best way to use it. The shear cutting head is supposed to mimic s bowl gouge btw. I’m going to try the round head angled more on the inside later tonight.

I have tried the power sander approach. It takes forever and wears down the drill attachment very fast. I’m not looking for perfection but that crap is so frustrating. The most frustrating is that I have a few bowls from the same darn log with zero tear out from doing the same method as before but for some reason … Tear out. stupid sassafras s.o.b.

View Klondikecraftsman's profile

Klondikecraftsman

52 posts in 502 days


#7 posted 04-06-2018 12:14 AM

For wood like this I wet with mineral oil then I turn it with a high speed steel round nose scraper sharpened to leave a wire edge. The scraper is 1” wide and either 5/8 or 3/4” thick. Keep your tool rest close to avoide vibration and turn just slightly below center. Take very fine cuts and make sure you keep enough oil on it to ensure you are not turning dry wood where the tear out is. Wet sand with mineral oil as well.

-- It is a sin to covet your neighbor’s wife, but his woodpile is fair game.

View Madrona's profile

Madrona

123 posts in 1345 days


#8 posted 04-06-2018 12:36 AM

Sharp, high-speed steel tools and good technique will take care of this problem. I’ve found carbide tools do a pretty good job of roughing, but you have to stop early and finish with high-speed steel to get a good finish cut.

-- Living In The Woods Of Beautiful Bonney Lake, Washington

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