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Forum topic by Karda posted 08-13-2018 05:59 PM 687 views 0 times favorited 18 replies Add to Favorites Watch
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Karda

1303 posts in 723 days


08-13-2018 05:59 PM

Hi, I am trueing the bottom of a bowl blank, however the bottom loos like I carved it out with a wood gouge. Happens with a scrapper, carbide tool and bowl gouge. What am I doing wrong and how to correct it. I am not doing anything I haven’t done before thanks Mike


18 replies so far

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Nubsnstubs

1414 posts in 1899 days


#1 posted 08-13-2018 07:42 PM

In the first picture, if that’s the tool rest height, that could be the problem. If it’s too low, sometimes that will cause chatter. The second picture looks like you brought up the height of the rest, but are getting catches from something loose, or you might be having bounce on a loosely held tool. Also, if you aren’t done facing the blank, don’t worry about it until the whole face has been cleaned up. If it persists, then you can ask questions…......... ..........Jerry (in Tucson)

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

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Aj2

1780 posts in 1967 days


#2 posted 08-13-2018 07:43 PM

To me it looks like your blank is too heavy for your lathe. I say this because when I try to turn something to big on my craftsman lathe I get a chatter that looks similar.
Small bearings = small turnings

-- Aj

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Karda

1303 posts in 723 days


#3 posted 08-13-2018 08:06 PM

the picture is deciding, the blank is only 7” in diameter, I have turned much larger

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mahdee

4004 posts in 1937 days


#4 posted 08-13-2018 08:39 PM

I am thinking either it is not turning fast enough and/or the gouge is dull. Another reason could be that the piece is wobbening. I say that because it appears the digging is more profound on one side (unless the lighting make it appear so).

-- earthartandfoods.com

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OSU55

1915 posts in 2159 days


#5 posted 08-13-2018 08:47 PM

I get something similar when rough turning out of balance blanks at slow speeds. Between the oscillations from the out of balance situation and the slow speed it can be difficult to get a clean cut. Once balanced and speed goes up it cleans right up. More than likely nothing to be concerned about unless you are balanced and up to speed, but it doesnt look like it. More ballast on your lathe close to the spindle end can help.

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Karda

1303 posts in 723 days


#6 posted 08-13-2018 09:37 PM

It could wobble, its on a worm screw and it is a live edge piece. The screw is on a round surface. I am up to 1600 RPMs and it didn’t clean up I’ll try 2200 and see what happens

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OSU55

1915 posts in 2159 days


#7 posted 08-14-2018 12:05 AM

1600 is enough speed. Can you move the piece with hand pressure? Push on the edge of the round inline with the spindle – push hard, it shouldnt move. If so thats a problem, for safety and for cutting.

Is your lathe vibrating causing the tool rest to move? It appears you may be making an interrupted cut. Too much pressure by you on a dull edge can cause it – the tool would feel hard to control. If not tool rest position, tool edge sharpness, bevel angle, tool pressure.

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Karda

1303 posts in 723 days


#8 posted 08-14-2018 02:10 AM

I continued shaping the bottom of the bowl and made the recess. The foot, realy an inch or so area after the recess cleaned up nicely. Thanks for the help, now I know what to look for Mike

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OSU55

1915 posts in 2159 days


#9 posted 08-14-2018 12:02 PM



I continued shaping the bottom of the bowl and made the recess. The foot, realy an inch or so area after the recess cleaned up nicely. Thanks for the help, now I know what to look for Mike

- Karda


What was the cause?

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Karda

1303 posts in 723 days


#10 posted 08-14-2018 04:31 PM

I wiggled the blank and it had a very slight movement so I put a wood spacer between the blank and the chuck, that gave the blank more support and tightened it

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Nubsnstubs

1414 posts in 1899 days


#11 posted 08-15-2018 02:39 AM


I wiggled the blank and it had a very slight movement so I put a wood spacer between the blank and the chuck, that gave the blank more support and tightened it

- Karda

Mike, I have 4 chucks and 4 worm screws. The chucks are well used, but the worm screws are like brand new. Don’t trust them. And since I invented the Chuck Plate, there is not a need for a worm screw.

It’s good you found the issue….......... Jerry (in Tucson)

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

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Karda

1303 posts in 723 days


#12 posted 08-15-2018 03:11 AM

It turned out nice the best I have done. Curious thing the bottom is round but the rim is oblong don’t know how that happened but I like the look I’ll post some pictures later

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Karda

1303 posts in 723 days


#13 posted 08-15-2018 06:13 AM

some pics this little dish 3.5 across the round bottom and 5.25 the long way across the rim.

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Nubsnstubs

1414 posts in 1899 days


#14 posted 08-16-2018 03:10 PM



It turned out nice the best I have done. Curious thing the bottom is round but the rim is oblong don t know how that happened but I like the look I ll post some pictures later

- Karda


‘It happens…............. Jerry (in Tucson)

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

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Karda

1303 posts in 723 days


#15 posted 08-16-2018 03:30 PM

ok

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