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high spot at bottom of bowl

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Forum topic by Karda posted 09-22-2018 06:00 AM 474 views 1 time favorited 14 replies Add to Favorites Watch
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Karda

1279 posts in 696 days


09-22-2018 06:00 AM

Hi, I cannot figure out and easy fix for this. When I am flattening the bottom of a bowl on the lathe I get a high middle and low sides. The best I can do is create a flat area large enough for my recess. No matter what I do as my gouge travels from out side to inside the gouge cuts shallower as I move towards the middle. I get the same thing when trueing the out side. any idea what I am doing wrong thanks


14 replies so far

View Nubsnstubs's profile

Nubsnstubs

1403 posts in 1872 days


#1 posted 09-22-2018 01:56 PM

Mike, my fix for that would be to start making tenons and forget about using recesses…........Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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Jack Lewis

326 posts in 1220 days


#2 posted 09-22-2018 02:38 PM

1 up vote for Jerry’s. When you are flattening, use a straight edge to check cuts and compensate on the shallow passes. You can do it that way and still leave the tenon by stopping your cut at the tenon area cut and check the straight edge on the cuts. I prefer a tenon because it can be removed and not leave a trace of how the bowl was held. But a recess is there forever. I have had tenons separate from the blank and to maintain the center I drill a small hole just a little deeper than the tenon and at the center of the tenon when I am making it to use as re centering point if it does separate or when removing later. I also make a dual tenon and recess when possible so I can hold either way. Afterwards the T and/or R are removed when I set the Jerry’s Tailstock Steady Rest and clean up the bottom.

-- "PLUMBER'S BUTT! Get over it, everybody has one"

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MrUnix

6921 posts in 2341 days


#3 posted 09-22-2018 03:54 PM

Hi, I cannot figure out and easy fix for this. [...] No matter what I do as my gouge travels from out side to inside the gouge cuts shallower as I move towards the middle. I get the same thing when trueing the out side. any idea what I am doing wrong thanks
- Karda

That is just physics; The wood is traveling much slower in the middle than it is out towards the edges, so you are cutting a lot more wood as you move further outward. Typical cut would be to start at the middle, then slowly moving outwards, speeding up the outward movement gradually as you get further out—or start outside and gradually slow down inward movement as you get toward the middle. Only fix I can suggest is to alter your technique to compensate for the speed difference. You will get the hang of it with practice. YMMV.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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Karda

1279 posts in 696 days


#4 posted 09-22-2018 06:05 PM

thanks for your suggestions, i’ll try starting in the center. I always thought proper technique was to start on the out side on the bottom

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Lazyman

2486 posts in 1529 days


#5 posted 09-22-2018 08:37 PM

A good sharp scraper is sometimes a lot easier for me to use in the final stage of flattening the bottom than the bowl gouge. As mentioned, working from the middle out may allow you to set the depth at the middle and adjust the slope as desired as you move outward. To get the best cut and finish from a scraper, it is important to burnish a hook on the edge.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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Karda

1279 posts in 696 days


#6 posted 09-22-2018 10:23 PM

ok thanks, this one I had to do a tenon because there is a crack running right through the recess and I don’t want to open it any more

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LeeMills

598 posts in 1443 days


#7 posted 09-23-2018 01:31 AM

If you put a straight edge on the bevel (from the heel to the cutting edge) that is the way it wants to cut. Point it straight and it will cut straight.
The key is stance, not cutting with your arms. If your body moves straight the cut will be straight (flat).
I believe Stuart Batty covers this in one of his three parts on stance in his videos on Vimeo.

As to recess or tenon… to each his own. I have never had any more of a problem removing a recess than removing a tenon. Six of one, half dozen of the other AFAIK. I do use a recess on about 75% of my face work.

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

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Karda

1279 posts in 696 days


#8 posted 09-23-2018 02:27 AM

I’ll try the straight edge,I I don’t see how I can not use my arms since that is the only thing that will move I am leaning over the lathe as it is. I have watched Battys videos and frankly he doesn’t relay tell me much. I have watched other as well and I just can’t do it. What I need is somebody with me to show me, and I doubt that will ever happen.

I like to use recesses because they are neat clean and when I am done I am done

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LeeMills

598 posts in 1443 days


#9 posted 09-23-2018 03:26 PM

I am miss-reading again. You may have to lean over the lathe, at the very least reach over the lathe, to make the curved cut hollowing a bowl. You do have to move your arms for that.

This cut is for a straight cut whether with a gouge pushing, pulling, or scraping or with a scraper.

I refer to Stuart a lot because he is the one who addresses cuts as the topic and not part of a project. He also talks about foot position to maintain a comfortable balance.
In his Stance 1 about 7 minute mark and in Stance 2 about 6 minute mark.
https://vimeo.com/woodturning/videos/sort:alphabetical/format:thumbnail

Most do on talk about it because the viewer is wanting to see the curies come off the wood. For the same reason few show the body movement but only the tool tip.
If you have time take a look at Nick Cook at about 2:30 and 9:00 minute marks.
https://www.youtube.com/watch?v=PFYe0kdyvVU
He may be making a long push cut, pull cuts, or scrapes.

Here is Mike Peace…
In segment 1 it starts with a pull or scraping cut (intro), about 7:40 is facing off.
In segment 2 it shows the body about 4:30 and 6:00. Note that even for the short cut on the rim about 1.5” long he moves his body and keeps the arms lightly tucked in.
https://www.youtube.com/watch?v=DMWHhMmHafA

Maybe the above will help. Do not feel bad if you can’t make a completely flat cut, it almost always need some tune up.
A production turner who post about a video a day keeps a block of wood on the lathe to check for flatness in the bottom (I keep a few various lengths sections of soft aluminum). He may turn 10 bowls a day to make a living. It almost always requires lighter cuts with a gouge or light scraping cuts to get it as flat as possible.

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

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Nubsnstubs

1403 posts in 1872 days


#10 posted 09-23-2018 03:58 PM



I ll try the straight edge,I I don t see how I can not use my arms since that is the only thing that will move I am leaning over the lathe as it is. I have watched Battys videos and frankly he doesn t relay tell me much. I have watched other as well and I just can t do it. What I need is somebody with me to show me, and I doubt that will ever happen.

I like to use recesses because they are neat clean and when I am done I am done

- Karda

Well, Mike, if I’m still alive and still able to drive across country in a year and a half, count on a visit from me. All I can do is lead you astray with how I do things.

What I think we need to do is set up a ”#Please visit Mike” page. You know, something like an obligatory thing to do for his sake. ............ Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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TheDane

5521 posts in 3805 days


#11 posted 09-23-2018 05:24 PM

Well, Mike, if I m still alive and still able to drive across country in a year and a half, count on a visit from me. All I can do is lead you astray with how I do things.

Jerry … maybe you could route yourself through Green Bay and show me a thing or two! January is always nice here.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Jack Lewis's profile

Jack Lewis

326 posts in 1220 days


#12 posted 09-23-2018 06:10 PM



I ll try the straight edge,I I don t see how I can not use my arms since that is the only thing that will move I am leaning over the lathe as it is. I have watched Battys videos and frankly he doesn t relay tell me much. I have watched other as well and I just can t do it. What I need is somebody with me to show me, and I doubt that will ever happen.

I like to use recesses because they are neat clean and when I am done I am done

- Karda
You might try extending a finger down from the tool to the tool rest and let the pressure help guide you. I like the both bottoms slightly con caved so that the soup runs to the center and outside so the vessel rides on the rim.


-- "PLUMBER'S BUTT! Get over it, everybody has one"

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Karda

1279 posts in 696 days


#13 posted 09-23-2018 08:54 PM

Hi Jerry anything you say is informative if it works for you thats good. You are getting me to think unconventionally. I am looking twice as wood I wood have thrown away 6 months ago. i learn alot from every body. Thanks for the links lee I will take a look at them before I tun again. Thanks for the help.

View Nubsnstubs's profile

Nubsnstubs

1403 posts in 1872 days


#14 posted 09-24-2018 03:29 AM



Well, Mike, if I m still alive and still able to drive across country in a year and a half, count on a visit from me. All I can do is lead you astray with how I do things.

Jerry … maybe you could route yourself through Green Bay and show me a thing or two! January is always nice here.

- TheDane

Gerry, I can’t even get my wife to go up into the mountains here in the winter. She was born in Erie, Pa, and has this snow fear. The slightest mention of snow, and she panics. She went elk hunting with me 3 times, and needless to say, snow was on the ground, and didn’t bag any elk. The last time I hunted elk, without her and snow on the ground, I was eating elk for months.

So, in about 18 months, say April-May, maybe I’ll show up. Not without warning though. At least 15 minutes, and prepare for me to stay at least a month. hehehe…........... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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