tool rest vibration

Karda

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Any possibility of some one videoing you to show us exactly what is happening. Hard to figure out and you sound very knowledgeable so maybe a video would help us help you 🤔
Ill do a video tomorrow, about the knowledgeable I doubt it I am foundering my lathe is a Grizzley and I felt no play in the bearings. High speed ha no effect on the vibration
 
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woodtickgreg

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Just for comparisons sake just chuck up a piece of soft wood and see what it does.
 

pargyle

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Have a look at some of the less favourable reviews for the Grizzley wood lathe on Amaxon ... a number talk abou,t excessive vibration if the blank is not perfectly regular and centred ...

 
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Mr. Peet

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Mike,

Dad used to say, place the handle on the headstock and hold the tool end in hand while at turning speed. Feel a steady vibration? Remove the the blank, do the same. If vibration still present, check bearings and spindle. If the vibration disappears, it is the blank out of balance. If it is the blank, you repeat the blank build. Check with just the face-plate, or jaw chuck and build back up to the blank.

You said your tool rest was dented. Sand it to re-establish smooth safe edges. Harmonics can hamper you too. I've watched Dad clamp smooth jaw vise-grips on the bottom of the tool rest post to change harmonics. He also used a tail-stock wing arm with mechanical advance to remove the human reaction. Often a users arm and hands absorb shock but also undulate adding to the chatter. The mechanical motion removes such, allowing the cut to smooth out and balance the piece so the user can return to hand tools.

Hope you figure it out soon.
 

Karda

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I don't have any soft wood other 2 x4s. I also have some bass wood that I can make a small bowl blank with but that will mean upchucking what I am working on
 

pargyle

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Hi Mike ... have you got the bowl on a faceplate or mounted in a chuck ?
Whichever you are using are you sure that the chuck or the faceplate is sitting tight up to the register ? If there is no play in the headstock spindle and there is no run out on the spindle nose then the next place to look for any non-human cause for the vibration is the mounting - check that the faceplate or chuck is running true on the headstock. If you don't have a dial gauge clamp a piece of metal onto the tool rest tight up against the edge of the faceplate or chuck and turn the lathe by hand ... check to see if the gap between the piece of metal and the edge of the mounting stays constant as you rotate the lathe. Any gapping or tightness and you have a problem.

You have my sympathy ... these problems are really annoying and you just have to methodically work through the likely causes. I bought a converter so that I could use a chuck with a different thread on my Hegner lathe ... the run out was so obvious you could see it let alone measure it. What it turned out to be, eventually, was that the exert was not bedding down on the register - it was just coming to end of the threads and the run out on the exert was massive - none at all on the register. I have to shim the register out when I use this converter.
 

Karda

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I checked every thing seems to be seated correctly, i upped the speed and I was able to finish the sides an most of the bottom but when I get close to center that is when the vibration get so bad I have to quit turning. Here is a pic of the inside. the base of the cone is when the vibration starts

pedistal2.jpg
 

Eric Rorabaugh

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Unless my eyes deceive me, the center looks oblong just a little. I that's the case, I'd say there ay be some plsy in the bearing and causing the chatter.
 

Mr. Peet

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I checked every thing seems to be seated correctly, i upped the speed and I was able to finish the sides an most of the bottom but when I get close to center that is when the vibration get so bad I have to quit turning. Here is a pic of the inside. the base of the cone is when the vibration starts

View attachment 238441
Run your tailstock in and support the center. Or have you been doing that?
 

pargyle

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Unless my eyes deceive me, the center looks oblong just a little. I that's the case, I'd say there ay be some plsy in the bearing and causing the chatter.
If you look at the chisel marks on the base they don't look concentric either ..the centre definitely looks a bit oval to me as well. My money is still on something out of alignment.
 

woodtickgreg

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It may even have a bent spindle.
A dial indicator is your friend.
 

trc65

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Mike, my perception of your problems is that the biggest problem you are having has more to deal with hard dry wood you are turning with variation in grain coupled with maybe holding/pushing too much on the bevel because of the bouncing you get when twice turning hard dry wood. It's tough to tell without watching you turn, but that is a common problem that I have until I force myself to relax my grip and take very small cuts until I have a smooth surface to guide the bevel.

Of course, check the lathe itself when you get the piece off it, but the fact that the lathe is new leads me more to the wood and perhaps tool presentation.

Mark made an important point about smoothing out the tool rest, little dings can cause lots of problems. I usually use a file to smooth out dings, but coarse sandpaper works as well. It's a matter of how deep are the dings.

As to getting rid of the center mass, I took a couple pictures of how I do that.

Position the tool rest so you are cutting just above center and point the bevel towards you at about 9:00. You are going to be cutting with the bottom edge of the tip and the bottom wing. Start at the center and work down towards the bottom while you are pulling the gouge towards you. Start with small bites (1/8") and take larger bites if the wood allows you to. I'm assuming of course you are using a gouge that you sharpen with wings.



My apologies if I'm telling you something you already know or have tried, just trying to cover all the bases. Wish I lived closer, a lot of times having a second pair of eyes can figure out a problem much quicker.


PXL_20230224_220124412.jpg PXL_20230224_220127256.jpg PXL_20230224_220140648.jpg
 

Karda

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thanks for your insight that helps a lot I frequently turn from center out but have noticed that some times the gouge will move by it self almost like I have no control. I put a piece of dry basswood on , about 6" and whe I faced of there was no noise or vibration near the center. could this be a tenon problem, maybe i didn't true well. video coming when done processing
 

trc65

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Could very easily be a slightly off true tenon, especially with the hard wood. It doesn't take much. Another thing I use to have problems with was not getting a good flat on the shoulders of the tenon for the jaws to rest against. With the hard wood a good tenon and shoulders are important as the jaws won't compress the wood much and if slightly off, could allow the piece to move slightly.
Something else that can cause problems is a tenon that is slightly too tall that bottoms out on the base of the jaws preventing the top edge from registering against the shoulder of the tenon.
 

pargyle

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Could very easily be a slightly off true tenon, especially with the hard wood. It doesn't take much. Another thing I use to have problems with was not getting a good flat on the shoulders of the tenon for the jaws to rest against. With the hard wood a good tenon and shoulders are important as the jaws won't compress the wood much and if slightly off, could allow the piece to move slightly.
Something else that can cause problems is a tenon that is slightly too tall that bottoms out on the base of the jaws preventing the top edge from registering against the shoulder of the tenon.
Look back to Post #1 and 4 .. this is not an isolated instance on this one bowl ...it would be odd if the tenons on other bowls were all off as well. There's something odd going on here or there are a consistent set of coincidences which seems unlikely ?

Also, if the tenon was at fault the place you would notice the out of true would be at the rim of the bowl ... Mike had no problems with turning at the rim ... it's in the centre - where anything out of true would be least noticeable.
 
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2feathers Creative Making

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Just spit balling here, but I would try the solutions offered for the " dry, hard work with a constant grain orientation change" problem and see if that helps. If the basswood worked better, it could easily be due to less difference in hardness between end grain and side grain. I am just a fledgling turner so don't expect magic from my comments. I have merely been trying to make sense based on what I read and the little turning I have done.

Dry apple bowls for feeding rabbits had a bit of chatter but I didn't mind as long as the rabbits didn't file complaints...
 

Karda

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Hi, this also happened with my other lathe, it could be tenons, that is something that I don't do real well. N close turning club and I don't drive here is the video I promised than

 

Karda

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how do I post a video here, i have it on utube but can't get it here
 
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