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vibration why

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Forum topic by Karda posted 01-12-2020 10:28 PM 544 views 0 times favorited 25 replies Add to Favorites Watch
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Karda

2030 posts in 1184 days


01-12-2020 10:28 PM

i am turning this piece of dry mesquite and am having issues with a lot of vibration, this has happened before but not this bad and it happens with all my gouges even my round carbide too, my 1/2 inch round scraper not so much. Just started recently and i can’t figure out why.


25 replies so far

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Madmark2

829 posts in 1219 days


#1 posted 01-12-2020 10:33 PM

I see a crack, there could be an internal void throwing the balance out.

M

-- The hump with the stump and the pump!

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Karda

2030 posts in 1184 days


#2 posted 01-13-2020 12:45 AM

ok what do I do

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Madmark2

829 posts in 1219 days


#3 posted 01-13-2020 12:49 AM

Take it easy and hope it doesn’t let go. You could also try a wood stabilizer.

-- The hump with the stump and the pump!

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LesB

2350 posts in 4074 days


#4 posted 01-13-2020 12:50 AM

Mesquite is very hard fibrous wood and turns best with super sharp tools. I suspect the vibration is from the end grain catching or dragging on the tool setting up some sort of harmonic vibration that only builds on itself. Think of military troops marching in step across a bridge. If they don’t go into “rout” step they will eventually build up a harmonic vibration on the bridge.

Try turning at a faster speed and keep you tool very sharp. I would treat that crack with medium CA glue before it gets worse.

-- Les B, Oregon

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Karda

2030 posts in 1184 days


#5 posted 01-13-2020 01:12 AM

thanks less, the crack is filled on the face and I have 2 3/8ths dowel bisecting the crack on the top. I already found out how hard dry mesquite is.

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Aj2

2680 posts in 2428 days


#6 posted 01-13-2020 02:32 AM

My guess is The wood is too heavy to big for your lathe that probably has small cheapo bearings.
I speak from experience because my lathe has the same issue.

-- Aj

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Nubsnstubs

1670 posts in 2361 days


#7 posted 01-13-2020 02:51 AM

Mike, if you are working the outside, bring up the tailstock to assist. That could help in reducing the vibration. Keep your sharp tool, and always keep your piece between centers until the tailstock starts to get in the way….

I don’t agree that Mesquite is a very hard wood. I’ve turned a lot that was fresh kill, and have also turned some that was probably over 70 years dead, and possibly longer. With sharp tools it all cuts fine. You might have to sharpen sooner on some pieces, but it ain’t that hard.

I turned about fifteen 13” diameter plates a couple years ago. Of those, 3 plates were from the same log. I could not make 3 passes across the diameter of those 3 plates without having to sharpen my Thompson gouge. On the other 10 plates, I could turn maybe 2 plates before having to sharpen again. It has to do with what the tree was eating when it was alive. See, diet does matter…......... Jerry (in Tucson)

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

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Karda

2030 posts in 1184 days


#8 posted 01-13-2020 03:25 AM

I have turned lager blanks with no problem and I also get the same kind of vibration from much smaller blanks

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Aj2

2680 posts in 2428 days


#9 posted 01-13-2020 03:33 AM



I have turned lager blanks with no problem and I also get the same kind of vibration from much smaller blanks

- Karda

That’s not good start saving for a better Lathe I think you have outgrown that one. I hope it’s not a horror freight.

-- Aj

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Karda

2030 posts in 1184 days


#10 posted 01-13-2020 04:40 AM

thanks Jerry i should have thought of tail stock.

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Lazyman

4639 posts in 2018 days


#11 posted 01-13-2020 05:30 AM

Don’t turn the stem of the chalice much more until you get the top hollowed and mostly shaped. You want as much mass at the base as you can get while you hollow. After you have the inside shaped the the way you want, you can bring the tailstock back up. You may have to put a rounded block in there to help keep it stable as you shape the outside and then work on the stem and base.

-- 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

2030 posts in 1184 days


#12 posted 01-13-2020 06:03 AM

thanks for the advice this is a first for me I have never done a goblet of any kind. How can I hollow with the tail stock in place.I have formed the chalice a little more, that was an older pic. I want the bowl a little rounder on thew bottom and I have to remove a little more of the rim, can I do that before i hollow. Also i don’t know what to do to round because to do so is going against the grain in either direction. I can do carbide But it is cheating in my opinion

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Nubsnstubs

1670 posts in 2361 days


#13 posted 01-13-2020 01:03 PM

Using Carbide in not cheating. It’s just another process. Easier in my opinion to remove the bulk. Otherwise, it’s just another cutting tool…........... Jerry (in Tucson)

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

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Karda

2030 posts in 1184 days


#14 posted 01-13-2020 04:50 PM

I try to tell myself that

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LesB

2350 posts in 4074 days


#15 posted 01-13-2020 06:04 PM

So now I’m wondering if you are getting vibration of the lathe or “chatter” from the cutting tools contact with the woodl??? Also a factor is small turnings have a slower surface speed than larger pieces at the same RPMs so you need to increase the speed of small items to get the same surface speed.

I agree, carbide is not cheating. I use any method that works, especially for hollowing. I regularly use Munro’s hollowing tool because it is faster, I have more control with the cutting depth settings and the long handle, and it usually produces a great finish cut. Down side of Munro’s hollowing tool the price.

That said I find that carbide does not produce a good finish due to the fact carbide is not quite as sharp as HSS due to the granular make up of the metal, so I have to do the final cuts with HSS steel tools and sand paper. What carbide primarily does is reduce time spend sharpening.

-- Les B, Oregon

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