Vibration while turning

[John Torchick]

I'm playing around with a piece of cherry about 2 inches in diameter, 5 inches long in a SuperNova2 chuck. I'm turning end grain with a 3/8" Benjamin's Best bowl gouge. I have the tool rest set at 90 degrees to the bed. When I start the cut, outside to inside, I hear/feel vibration. I checked the chuck and adapter and they are tight. I don't want to do anything that would ruin the bearings in the headstock. FWIW, this is my first time with the bowl gouge. I have cut a shallow "dish" to about 3/4 inch deep. I have been watching Lyle Jamieson's Bowl Basics and Stuart Batty's on the AAW forum videos. Your help and advice is greatly appreciated, as always.

"checked the chuck?" I made a funny!

 

[odie]

John......from the overall description, it sounds like you're attempting a bowl, but "2 inches in diameter, 5 inches long" sounds more like a spindle turning. Got a photo?

-----odie-----

 

[John Torchick]

Here it is. Not really trying to make anything but practicing. This is my first bowl gouge and I'm trying it out to see how it works.
Edit: Not sure if this is relevant but when I tightened the chuck jaws, three spaces between the ends of the jaws are the same but one is wider than the other three. No vibration until I start the cut. Doesn't matter how light the cut, still get vibration.

 

[egsiegel]

sounds to me like you need to sharpen that tool

 

[Clifton C]

John, I'm not sure if I see a tenon on that piece or not, sometimes you can get away without, but, if you are still getting vibrations,chatter after sharpening your gouge, a tenon would be my next best guess...

 

[John Torchick]

No tenon, turned to round and secured in the chuck. Will run it over to the grinder. I thought of that after I posted this. Wonder how many problems are due to dull tools? Can't turn it down any more as the jaws are almost closed.

 

[odie]

sounds to me like you need to sharpen that tool

Sharpening would be my gut reaction, too. Since you don't have the vibration, except when tool meets the wood, then that aspect is the focal point in the equation.

Putting a tenon on there would probably help, as well. That way you can butt the base of the tenon up against the chuck jaws.

The fact that one jaw gap is smaller than the other three will not make any difference, because the act of turning your piece will make it centered to the spindle.......but, I must ask what brand of chuck is it?

If you can get the tool rest in closer to the cutting action, that might help. You're piece is similar to making a box, and might be better served by using a scraper in the interior......? I have made a very limited number of boxes......so, maybe someone like Emiliano would be better to comment about that.

-----odie-----

 

[Bill Boehme]

No tenon, turned to round and secured in the chuck.....

Well, there's the problem. it must have a tenon with a shoulder so that the top of the jaws rests on the shoulder ... otherwise, there's nothing to keep the wood from rocking side to side when you apply tool pressure ... no matter how sharp your tools might be. Even though a bowl gouge will work, I would recommend using a spindle gouge and since this is end grain, I should ask if you are cutting starting from the center and going towards the rim? This is just the opposite of face grain turning. I don't want to hear that you are copying some of my mistakes. I could write a book based on personal experience of the wrong way to do things, but maybe it would be best if I didn't.

 

[john lucas]

The problem is you are turning against the grain. It appears the grain is running parallel to the bed. When trying to get a bowl or goblet shape you should be turning from the middle out. Watch this video and it will explain it.

View: https://www.youtube.com/watch?v=joZJpMQJQ-s
I do this with a detail gouge or narrow spindle gouge. Push it into the dead center. It will act like a drill. Cut about 3/8" deep and then rotate the tool so the flute is about 45 degrees and lever the handle out to the right. it will cut with the lower wing of the gouge. Do this out to the lip. the repeat until you get the depth you want. You can use a bowl gouge but it would be easier if you drill out the center to the depth you cant.

 

[john lucas]

More advice. Why don't you give me a call and come up for a visit. We could play on the lathe. I'm probably 2 hours or less from you.

 

[John Torchick]

1. SuperNova2 chuck.
2. Jaws almost closed completely.
3. No room for a tenon on this piece.
4. Very observant, John. Going from rim to center on this. Thanks for the invitation!
5. odie, will move the tool rest closer. Still learning and a bit shy about getting stationary things close to rotating things.
6. This was a piece of a tree limb that I turned to round, squared one end with a parting tool and put in the chuck. Then I squared to other end with a parting tool and started with the bowl gouge.
7. I think I covered your questions.

 

[john lucas]

Turning into endgrain from the outside will try to kick your tool back unless you are really good with a gouge. Gripping a piece like that is just asking for it to come out of the chuck. Ideally a piece needs a tenon so the shoulders of the tenon will sit on the top of the jaws. This helps keep the piece from rocking. Once it starts to vibrate the jaws just did in deeper and they get loose because there's nothing to stop it from going up and down. The shoulders of a tenon stop that or at least reduce it. So you immediately have 2 things going against you. The best bet on something like that is to glue a scrap piece to it using something like epoxy. Then turn your tenon on the scrap piece. That should help.

 

[Leo Van Der Loo]

Same here, use a spindle gouge and cut from the center out, held with a good tenon, would make this a no problem turning

 

[hockenbery]

View attachment 24820 Here it is. Not really trying to make anything but practicing. This is my first bowl gouge and I'm trying it out to see how it works.
Edit: Not sure if this is relevant but when I tightened the chuck jaws, three spaces between the ends of the jaws are the same but one is wider than the other three. No vibration until I start the cut. Doesn't matter how light the cut, still get vibration.

John
Looks like you are hollowing end grain. This is much the way I would turn a goblet
Cutting into the endgrain will create a lot of vibration.

IMHO turning endgrain is harder - turning face grain is easier.
I usually hollow my goblets with spindle gouge and finish with a Hunter.

Goblet hollowing is easiest to start by drilling a center depth hole with a spindle gouge or drill bit. then cut from the center hole out with the tip of the spindle gouge
All wood likes to be turned with a cross cut.

I often use a Raffan cut to hollow from the bottom to the rim with the spindle gouge.
It’s a lot easier to do than explain. This does away with drilling a center hole.

 

[john lucas]

I've tried the Raffen cut. I don't really see the advantage especially for beginners. I can hollow just as fast using the method I described above. It does take a finishing cut with another tool or more sanding but is a lot safer. Also after you drill the hole and start the cuts if you will cut at about a 45 degree angle instead of straight across you will get greatly reduced chatter. This will be cutting downhill with the grain instead of across the grain and reduces chatter. For the more advance people out there when you start to get thin on a goblet or box and start to get chatter, put 2 or 3 thick rubber bands around the outside. It will reduce or even eliminate the chatter.

 

[Bill Boehme]

1. SuperNova2 chuck.
2. Jaws almost closed completely.
3. No room for a tenon on this piece.
4. Very observant, John. Going from rim to center on this. Thanks for the invitation!
5. odie, will move the tool rest closer. Still learning and a bit shy about getting stationary things close to rotating things.
6. This was a piece of a tree limb that I turned to round, squared one end with a parting tool and put in the chuck. Then I squared to other end with a parting tool and started with the bowl gouge.
7. I think I covered your questions.

Seven good reasons to buy more toys tools and take John up on his offer.

 

[Mike Johnson]

If you don't have room for a tenon on the wood blank why not glue a waste block onto the blank with a tenon?
If you don't have a tenon to brace against the chuck jaws and are bottomed out in the chuck the wood blank
runs a high risk of coming loose when hollowing end grain.

I have a box of wood tenons turned from a wood dowel that are used to glue onto various turning blanks when they are needed on short wood blanks or thin projects like platters, plates, saucers and lids. If I make the tenon long enough I can reuse it several times if I am careful parting the tenon off of the item. It only takes several hours of dry time on wood glue and you can start turning with the assistance of the tail stock supporting the blank. Once the piece is turned round you can usually remove the tail stock and continue turning if you don't get aggressive with the lathe tools. If you are relying on the wood glue on the tenon for support when aggressively cutting the wood blank then you will want to let the wood glue set up for a day before you apply aggressive cuts to the wood blank.

 

[robo hippy]

That particular mount into the chuck can work fine, IF the end is square, and seated all the way down into the chuck so it rests on the bottom/square end. The support is not quite as wide as it would be if you had a dove tail tenon and shoulders to sit on the jaws, but wider than it would be if you went to smaller jaws.

A dull tool would also be a cause for vibration. My preference for some thing like that would be to drill a center hole and do pull to the rim cuts. My favorite tool would be a scraper type hollowing tool rather than a gouge, but gouges do work. Most of the time the spindle/detail type gouges seem to work a little better. I do use scrapers far more than most though.

The video that John linked to up above about unsupported fibers is pretty good. I would love to have a play date with John, but we don't have transporters yet...

robo hippy

 

[John Torchick]

rh, Delta is ready when you are. Need to take a few minutes to watch John's video. Nick did a demo are out club in Dalton, GA. He was saying his shop/studio is near the new Braves stadium. He wasn't too excited about the traffic. Of course, Atlanta traffic is bad any time of day.
I did square the ends with a parting tool so the one end would sit in the chuck. I do need to check to see that it isn't bottomed out.
John is very close to my so a trip wouldn't be out of the question.

 

[Bill Boehme]

?... I do need to check to see that it isn't bottomed out.

Ordinarily that would be a good idea, but given that there is no shoulder (nor tenon for that matter), the only saving grace would be to make sure that it IS bottomed out. That would be far from ideal, but far better than having nothing to prevent it from rocking.

 

[hockenbery]

@John Torchick
Spending some time with John will get you on the right track.
If you have a 3x3piece of fire wood this little video shows a great way to familiarize yourself with the bowl gouge

Video quality is not too good but you can see how the tool edge has to move.
Cylinder with SideGround gouge Push & Pull cuts -

View: http://www.youtube.com/watch?v=I05IYkb06Jc


When I have beginning bowl class the first thing the students,turn is a carving mallet using the bowl,gouge to get close and a spindle gouge tomrefine it.

 

[Jeff Hornung]

The standard 50mm (2 inch) jaws that come with the SuperNova 2 really will require a proper tenon in this instance. If these were multi tooth spigot jaws you could probably reduce the vibration. You are trying to hold round stock with a set of jaws that has a single point on the inside edge, like this arrow shape... >. The only thinf this will do under these circumstances is crush fibers and allow the workpiece to move. You will never have a solid hold with this setup...and if your tool is dull or in the wrong orientation, or if you’re cutting endgrain in the wrong direction, pushing to hard, etc, etc...you’ll only magnify the problem. You’d almost be better starting with square stock and clamping down with the jaw corners, then proceeding to round your stock to work size.

 

[Raul McCai]

View attachment 24820 Here it is. Not really trying to make anything but practicing. This is my first bowl gouge and I'm trying it out to see how it works.
Edit: Not sure if this is relevant but when I tightened the chuck jaws, three spaces between the ends of the jaws are the same but one is wider than the other three. No vibration until I start the cut. Doesn't matter how light the cut, still get vibration.

I'm guessing the rest is too far from the work and you are getting chatter ESPECIALLY as it's end grain

 

[olaf Vogel]

Working the end grain, on dry wood (is it hardwood?) will be a PITA, especially if using a scraper

try drilling a 1" hole in the middle.
then work out with a 1/2" gouge.

should be no problem

 

[robo hippy]

Olaf, I do it with scrapers all the time in sugar maple. I use a hollowing tip maybe 1/4 inch wide, not a full sized scraper though. Pretty simple, but then I am a scraper phycho.....

robo hippy

 

[John Torchick]

Using a 3/8 bowl gouge on seasoned cherry.

 

[hockenbery]

We have all been where you are.......

Hollowing end grain is difficult. Basically cutting tools work best in turning when the fibers are cross cut.
Hollowing a face grain bowl with a curve to the bottom center is easy with a gouge because every fiber is cut crossways.

Flat bottom bowls present a problem because the gouge does not cut into endgrain well tending split the endgrain fibers rather than cut them. Scrapers are often needed for thIs.
This is the issue hollowing an endgrain with a bowl gouge but it can be done sort of split the fibers on entry and quickly turn the gouge to cross cut fibers toward the center. Not fun!

Put s dowel in a vice take a knife and cut it from the side(cross cut.) cut it from the end ( rip cut)
Think of the gouge as a curved knife blade.

Make yourself a small face grain bowl blank 8” diameter is good starting size.
Follow this procedure and you will have a bowl.
Roughing green bowl -

View: http://www.youtube.com/watch?v=Lo0bGSafZq4

If you have a screw center you might drill a hole where I put the spur drive an use the screw center to moun the bowl. This works real well for the first several.

 

[Michael Mills]

The jaws sit in a ring and can rotate (on purpose). Open slightly, maybe 1/4" gap, and loosen the jaw screws about 1/2 turn. Then scroll in tightly for the jaws to align properly; if you see any gap tap that jaw a little, then re-tighten the jaw screws.

For a full and clear explanation of mounting the wood I suggest the three videos by Stuart Batty. Look for the ones on chucks, tenons, and recesses, each are about 10-15 minutes.
https://vimeo.com/woodturning/videos/sort:alphabetical/format:thumbnail

 

[Zach LaPerriere]

I want to thank Bill for his early post suggesting the tenon was the problem. Thank you Bill! Your description got me thinking on a 12" bowl I was having a little more vibration than normal. I checked, and sure enough, my tenon was squirrely. I realized I was getting a bit slack on proper tenon prep.

It is absolutely vital to have the tenon seated against the base of the wood you're holding. Any gap whatsoever will introduce extra vibration. A small gap probably isn't dangerous, but who wants to introduce more vibration and sanding time? I went back and watched Stuart Batty's excellent video on tenon prep...

 

[John Torchick]

Vice? I had lots of them when I was younger.

 

[olaf Vogel]

Olaf, I do it with scrapers all the time in sugar maple. I use a hollowing tip maybe 1/4 inch wide, not a full sized scraper though. Pretty simple, but then I am a scraper phycho.....

robo hippy

I totally agree that if you use scrapers for end grain, then 1/4" tips are the way to go.
For deep hollowing, I do the same using HSS cutters. But it means applying a fair bit of PSI to get it to cut.

Over time, I've focused on techniques that cut across the grain.
In this case, from the centre hole outwards.

My latest fascination is Japanese hook cutters. I'm having a local knife maker create a couple of large ones for me
(in exchange for a 2 hp motor.

 

[john lucas]

Hook tools are good but you spend too much time sharpening them. I use the Hunter carbide tools instead. The small cutter will really remove wood. Not the big shavings you get off of a hook tool but smaller shavings and cut more like using a 3/16" HSS scraper, except you don't have to sharpen it.

 

[Zach LaPerriere]

My latest fascination is Japanese hook cutters. I'm having a local knife maker create a couple of large ones for me
(in exchange for a 2 hp motor.

Me too. I got a Sorby ring and in the process of getting a hook tool from Michael Hosoluk. Keep us posted!

 

[Bill Boehme]

Vice? I had lots of them when I was younger.

OK, I'll admit that I have some vises. But, how serious is it when my vises have vises?

 

[Gary W Miller]

I'm playing around with a piece of cherry about 2 inches in diameter, 5 inches long in a SuperNova2 chuck. I'm turning end grain with a 3/8" Benjamin's Best bowl gouge. I have the tool rest set at 90 degrees to the bed. When I start the cut, outside to inside, I hear/feel vibration. I checked the chuck and adapter and they are tight. I don't want to do anything that would ruin the bearings in the headstock. FWIW, this is my first time with the bowl gouge. I have cut a shallow "dish" to about 3/4 inch deep. I have been watching Lyle Jamieson's Bowl Basics and Stuart Batty's on the AAW forum videos. Your help and advice is greatly appreciated, as always.

"checked the chuck?" I made a funny!

This might sound a bit obvious but why don't you just use a bigger piece of wood and turn a tenon on it?

 

[John Torchick]

That is because the wood was from a small tree limb. As stated, I was just practicing with my new bowl gouge. When I decide to make something functional, I have a good stash of wood to use that is several inches in diameter.