First (& second) Bowl Questions (PICTURES ADDED)

[Mike Goetzke]

I bought some nice cherry bowl blanks form a member.

For background: I have a Delta 46-460, a set of Sorby turning tools, Tormek grinder (w/dry grinder attachment), 4-jaw chuck with wood-worm screw... (plus I watched the Bill Grumbine videos)

I made two bowls today but not without some minor issues & questions:

1) I re-shaped my 1/2" bowl gough to an Ellsworth grind as defined my Tormek - it has a 60 deg bevel. The sides of the gough seem to be too convex but not experienced enough what this would do to the cut.

2) Also related to the gouge. When I turn the outside of the bowl my tool is always on the front of the ways so with the 60 deg bevel the tool handle can go very low without interferring with the ways. On the other hand when I turned the inside of the bowl the gouge handle at times is on the inside of the ways and I can't ride the bevel correctly. I'm thinking I need another gouge at 45 deg to help? (I have a 5/8" roughing gouge and 3/8" spindle gouge will they work?)

3) Looks like I need to anchor down the lathe - at times it vibrated as I tried to increase speed. I also had some resonance that went away at higher speed.

4) These first two were 9" bowls - what speed should I be using? (I was at 400 to 550RPM - I know probable too slow)

5) For cutting the tenon I had to use a parting tool - I couldn't do it with my gouge (maybe due to the gouge grind).


6) After cutting the tenon and going back to fine tune the shape I noticed on both bowls seemed harder to get clean cut - on verge of a catch. Is this due to green wood or removal of live center?

7) Had a couple catches on the first bowl but none on the second. Also, I got my first catch on the first bowl just as I told myself it needed one more pass.

8) Anchorsealed the bowls - can I just wrap then in packing paper and put them in a box?

9) I left the roughed out bowls with wall thickness at 10% of the diameter like Grumbine did and left the bottom wall thinner. Is this correct? He says this is done to reduce chance of cracking as they dry out.


I though I did OK till I saw Joe Marra's pic of his first bowl (congrats Joe - your a natural). I have 8 more blanks to go through I'll get there. Took a break to see if life will be easier with a few adjustments.


Please make comments on the grind of my gouge (my Tormek spec was #6, A hole, 75 mm) - thanks:

http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0019_zps47bb2bec.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0019_zps47bb2bec.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0020_zpsa9cac4f4.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0020_zpsa9cac4f4.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0021_zps830cf38f.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0021_zps830cf38f.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0022_zps67e0dad2.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0022_zps67e0dad2.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0023_zpsf834a0b0.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0023_zpsf834a0b0.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0024_zpsc32bea9c.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0024_zpsc32bea9c.jpg.html)




Thanks,

Mike

[Dennis Ford]

#1; When you look at the gouge from the side; a convex shape at the tip is not unusual (I prefer it that way). Some people like the shape to be straight when viewed from the side, it should NOT be concave.

#2; You should not use a spindle roughing gouge on a bowl. A 60 deg grind should handle most bowls, you may need one ground at ~70 deg for very deep bowls. A gouge ground at 45 deg is good for an experienced turner but will be more difficult to control.

# 3-4; If the lathe is shaking, slow down; if it is not vibrating, 1200 rpm should be OK for that size bowl. Some weight added can help but will not make an industrial lathe from a portable lathe. You have a nice lathe, just have to respect its limits.

#8-9; I normally use either anchor seal OR paper wrap for rough-outs, using both may be a good thing if you are in a arid area. Cherry is not very forgiving of thickness mistakes or rapid drying, you did good with the 10% rule and slightly thinner bottom.

It sounds like you are doing fine. Keep at it and don't get discouraged with the occasional failures.

[Wally Dickerman]

I'll attempt to answer some of your questions....others may give you different answers.

Using the gouge with the handle low on the outside of a bowl is done by a lot of turners. I use it low but not very low. I try to have the handle riding on my hip. Your Delta lathe has a 12 inch swing. For hollowing you don't need to have the handle low. Experiment with tool rest height to get the bevel riding. Not so very long ago top of the line lathes had 12 inch swings. Well okay 25 years ago:)

Using Anchorsel on the outside of a roghed out bowl is fine. You don't need the packing paper. Putting them in a box is okay but I prefer to keep mine in the open air.

In most cases 10% thickness is a little more than you need. The important part is to have the thickness the same throughout. To avoid cracking, round over the sharp corners at the edge of a roughout bowl. That's where cracks start.

Having 2 gouges, one at 60 deg and one at 45 deg is a good way to go. You can easily hollow most bowls with the 60 deg though.

Do NOT use the roughing gouge on bowls. It's now called a spindle roughing gouge.

Parting tool is just fine for cutting tenons.

[charlie knighton]

good to hear from you, enjoy your learning curve, you already have some good instructions, you say you bought some blanks from a member, is that a member of board or of a turning club? if you post your location we may be able to connect you with one of the many turning clubs

[Mike Cruz]

1) I re-shaped my 1/2" bowl gough to an Ellsworth grind as defined my Tormek - it has a 60 deg bevel. The sides of the gough seem to be too convex but not experienced enough what this would do to the cut.
I don't think that it is the degree of bevel that is bad (if you did it like it is supposed to be done...however that is), rather just using it properly. Practice will help, but having someone help/show you would be your best bet.
2) Also related to the gouge. When I turn the outside of the bowl my tool is always on the front of the ways so with the 60 deg bevel the tool handle can go very low without interferring with the ways. On the other hand when I turned the inside of the bowl the gouge handle at times is on the inside of the ways and I can't ride the bevel correctly. I'm thinking I need another gouge at 45 deg to help? (I have a 5/8" roughing gouge and 3/8" spindle gouge will they work?)
Yes, a second gouge may help a lot. I believe a 40 degree grind is standard. I may be mistaken. Don't use a spindle roughing gouge on your bowls! Use only bowl gouges. The corners of your spindle roughing gouge are catches just waiting to happen. And the gouge is not meant for the stresses that bowl turning will put on it. The part that goes into the handle isn't long enough or beefy enough (from what I understand) and can shatter your handle upon a catch.
3) Looks like I need to anchor down the lathe - at times it vibrated as I tried to increase speed. I also had some resonance that went away at higher speed.
Bolting down the lathe isn't an all bad idea. But the bottom line is that your (any) lathe has its limits. Bolting down is a great way to NOT tip the lathe over from accidentally starting it at a speed that is too fast for a particular blank.
4) These first two were 9" bowls - what speed should I be using? (I was at 400 to 550RPM - I know probable too slow)
Related to the answer above, if 400 rpm is the fastest that your lathe will allow for those blanks, then it was just fine. You'll get a much better cut (and the turning will go much faster) at about 800-1000 rpm for that piece. Many turners will turn that much faster... But experience is a big factor there.
5) For cutting the tenon I had to use a parting tool - I couldn't do it with my gouge (maybe due to the gouge grind).
I use a parting tool to cut tenons all the time. Nothing wrong with that. Bottom line is that you want the shoulder to be clean. Use whatever you want/need to. A skew works well, too...
6) After cutting the tenon and going back to fine tune the shape I noticed on both bowls seemed harder to get clean cut - on verge of a catch. Is this due to green wood or removal of live center?
Green wood is the easiest thing to turn! So, I wouldn't attribute it to that. Not sure why you'd be getting catches then and not before except that your tool presentation is different...even if you "think" it is the same... That is why having someone else watching you is best.
7) Had a couple catches on the first bowl but none on the second. Also, I got my first catch on the first bowl just as I told myself it needed one more pass.
Yes, "one more pass" will ALWAYS cause a catch...:D
8) Anchorsealed the bowls - can I just wrap then in packing paper and put them in a box?
After you Anchorseal the bowls, no wrapping is necessary. You would wrap a bowl after using DNA. After Anchorseal, you just put it on a shelf...an wait.
9) I left the roughed out bowls with wall thickness at 10% of the diameter like Grumbine did and left the bottom wall thinner. Is this correct? He says this is done to reduce chance of cracking as they dry out.
The best is even thickness the whole way. But if you are going to err in one direction or another, erring to thinner at the bottom (rather than thinner at the rim) is the better way to err.

Hope that helps!

[Reed Gray]

I could take a full day hands on session to properly answer your questions. If you find the nearest club, that would really help. Some pointers:

Bevel angles: I use at least 2, one a 45/45 which means 45 degrees on the nose, and 45 degree sweep (not swept back as far as the Ellsworth/Irish/O'Donnel) grinds. This is best for going down the outside of a bowl (convex surface). It is also great for going down the inside of a bowl, but does not go through the transition and across the bottom very well. This is where the 60 (I use 70) degree bevel comes in. It goes through the transition and across the bottom fairly well. A side note here is to grind off at least half of the bevel. A sharp heel will make marks in the wall. Rounding it over really helps prevent this.

You can use the dropped handle cut easily on the outside of the bowl, there is no lathe to get in the way. In the inside, the ways of the lathe, the rim of the bowl, and the tool rest get in the way. Most of us will tend to hold the tool more level. Here, you want the flutes rolled over to about 45 degrees. If they are straight up and down, the wing on the inside can dig in and catch. When you roll the tool over, the tool is more balanced in the cut, so less chance of it catching.

Your lathe speed sounds fine, but if it is walking across the floor and vibrating, the feet may not be leveled up properly. If you can wiggle your lathe with nothing running on it, this is the most likely cause. A level, a wrench or two, and some time down on the old prayer bones can fix this. This step is as important as adding weight to your lathe. Get it seated level before adding weight.

I have a couple of clips up on You Tube showing some turning techniques. Type in robo hippy.

robo hippy

[Pat Scott]

Here's my two cents.

1) I re-shaped my 1/2" bowl gough to an Ellsworth grind as defined my Tormek - it has a 60 deg bevel. The sides of the gough seem to be too convex but not experienced enough what this would do to the cut.
I would not use 60 degree for general use as it's too blunt. You'll find it harder to use because the blunt angle doesn't cut through the wood as easily. 45 or 50 degree is better for general use. 40 degree cuts through the wood even easier, but I think it's too aggressive and harder to control. With a blunt angle (ie: 60 degrees), you'll find that in order to maintain bevel contact, you'll end up pushing harder on the tool which means you're pushing the tool into the wood instead of along or through the wood. On the outside of a bowl you may start pulling it through the cut with your left hand, instead of pushing with your right.

I do use a 60 degree gouge, but only for the very bottom of a bowl. When making an entry cut on the inside rim of a bowl, a 60 degree bevel is not the ideal angle because again in order to maintain bevel contact you'll have to push harder on the gouge. Pushing will cause bouncing or spirals. A 45 degree angle works better for the top inside.

2) Also related to the gouge. When I turn the outside of the bowl my tool is always on the front of the ways so with the 60 deg bevel the tool handle can go very low without interferring with the ways. On the other hand when I turned the inside of the bowl the gouge handle at times is on the inside of the ways and I can't ride the bevel correctly. I'm thinking I need another gouge at 45 deg to help? (I have a 5/8" roughing gouge and 3/8" spindle gouge will they work?)
Like has been said already, don't use a spindle gouge on a bowl. A 5/8" roughing gouge sounds small IF it's a spindle roughing gouge. But, I want to say for the inside and outside, don't drop the handle so much if it's hitting the ways or is hard to maintain bevel contact. Grumbine uses a 45/45/45 approach on the outside: handle at 45 degrees, bevel angle 45 degrees, flute open to 45 degrees. On the inside you won't be able to drop the handle that low.

3) Looks like I need to anchor down the lathe - at times it vibrated as I tried to increase speed. I also had some resonance that went away at higher speed.
Bolt it down and/or add extra weight to the bench or stand that it's mounted on will all do wonders to reduce vibration.

4) These first two were 9" bowls - what speed should I be using? (I was at 400 to 550RPM - I know probable too slow)
Depends on how out of shape or how out of balance the blanks are to start. 400 might be a good speed while you remove unevenness and get the blank rounder. Once you have it round then you can increase the speed which will result in a smoother and cleaner cut. Dale Nish had a good starting formula for speed that said take the diameter of the bowl times the RPM and the result should be 6000 to 9000. So a minimum speed (once balanced): 9" x 675 rpm = 6,075. Maximum speed: 9" x 1000 rpm = 9,000 rpm. Again this all depends on your skill, tools, tool control, lathe, vibration, wood, etc.

5) For cutting the tenon I had to use a parting tool - I couldn't do it with my gouge (maybe due to the gouge grind).
I'm not surprised you couldn't cut a tenon with a 60 degree bowl gouge!


6) After cutting the tenon and going back to fine tune the shape I noticed on both bowls seemed harder to get clean cut - on verge of a catch. Is this due to green wood or removal of live center?
So the bowl was turned around and gripped in the tenon and you were hollowing out the interior? You will get more vibration without the tail stock, meaning you can't take as big of cuts. And a 60 degree bevel would be harder to remove the bulk of the interior of a bowl.

7) Had a couple catches on the first bowl but none on the second. Also, I got my first catch on the first bowl just as I told myself it needed one more pass.
Practice, practice, practice will reduce the frequency of catches.

8) Anchorsealed the bowls - can I just wrap then in packing paper and put them in a box?
Depends somewhat on where you live, how humid, how hot, kind of wood, etc. In CO, I anchorseal the complete bowl inside and out, then sit it as low to the ground as I can (no higher than a couple feet) for several months before moving it up higher on the shelf. Some highly figured woods or crotch wood is more prone to cracking, so for those pieces I will Anchorseal them and then put them in a brown paper bag or box for a few months to slow down moisture loss even more.

9) I left the roughed out bowls with wall thickness at 10% of the diameter like Grumbine did and left the bottom wall thinner. Is this correct? He says this is done to reduce chance of cracking as they dry out.
Yes this is correct, 10% is a good rule. Others say make sure the wall thickness is consistent throughout - which is also good. What some forget to take into account is including the thickness of the tenon. So when measuring 10% or measuring for consistent thickness, don't forget the tenon. This is why you'll hear to make it thinner on the bottom. The walls will distort more than the bottom which is why you leave more mass at the top than bottom. For a 10" bowl, if the walls are 1" (10%), and the tenon is 1/4" thick, then the bottom should be 3/4". You'll get cracking in the sidewalls if the bottom is thicker than the walls. The walls will try and move as the wood dries, but the bottom is so thick it won't let the walls move, so they crack.

One last comment, be careful about some of the YouTube videos! There are a lot of guys out there posting videos that show a lot of bad techniques and unsafe practices. Good luck and above all be safe.

[Bruce Pratt]

Additional 2 cents worth. I know I will probably catch a lot of flack on this, but I don't think that the Tormek can do a true Ellsworth grind - not enough axes (axis pl.) of rotation to get the long side wings. You will need to use a Wolverine jig/Ellsworth jig to achieve the full profile.

[Thom Sturgill]

I try a few items.
A convex curve on the edge can be from spending to much time grinding the end. Dave at D-Way has a good video on fixing grinds. On the other hand, if the edge were too straight you would have too much cutting edge presented when using the edge. This is part of the reason for parabolic flutes rather than straight flutes, or so the argument goes.

You were given the formula for speed, but this is not based on the size of the bowl, but the radius of the cut. as you work inside the bowl, and its weight becomes more balanced you can increase the speed because the working radius keeps getting smaller. One hint as to speed is to turn at the fastest you are comfortable with, and don't worry too much about a formula. Note that sometimes increasing the speed will quieten those harmonic vibrations.

[Mike Goetzke]

With help from the forum I made an improvement to the grind. I thought with the sharpener you rolled the tool till it cleaned up the new shape. Now I know there is a lot of user input required beyond that. As suggested by Mike C. I spent more time on the wings:

http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0006_zpsfcda82f6.jpg

[Mike Cruz]

That's a major change from the profile you had before, Mike. Whether that grind you have now is one that you will like/love or not is still to be seen, but you HAVE to like it better than the dipped tip that you had before.

[Reed Gray]

One other thing to do to the grind is to take off about half or slightly more of the heel on the bevel. This makes it a lot easier to go through the transition and any concave surface. It keeps the cutting edge closer to the bevel rubbing spot. This makes it a lot easier to remove those concentric rings you see on the inside of your bowl. The sharp heel can also bruise the wood making marks that won't sand out. Most bowl turners have at least 2 gouge grinds they use. One has a bevel angle of about 40 to 45 degrees, which is great for convex surfaces/outside of the bowl/down the inside of the bowl. The other has a bevel angle of about 60 or more degrees which is used mostly for going through the transition and across the bottom. The sharper bevel angle can not do this except on very shallow bowls and plate forms.

Wing design is more for personal taste, and they can be ground on anything from the Sorby belt sander to the Tormek. How much wing you have depends on how far to the side you roll the tool. Some like a convex wing, some like straight, but I don't think any one likes a concave wing (it can be used as long as the concave part isn't too deep, but not really a good shape for anything). Some love a very long wing, some prefer the short wings. The longer wings can be used for getting a lot of steel into the wood at one time for heavy stock removal. It works best with a dropped handle. It is also used for a 'shear scrape' which is not a bevel rubbing cut, but one to take fine whisker shavings and clean up tool marks so hopefully you have less sanding to do. This cut is difficult to do on the inside of a bowl because the tool rest, ways of the lathe, and bowl rim get in the way, especially if you are turning on a long bed lathe without the headstock being pivoted or a sliding headstock where it is on the end of the lathe. Here, mostly I will hold the tools level, and use a more open flute design for the finish cuts. For shear scraping cuts, I prefer scrapers.

robo hippy

[Mike Goetzke]

Took 4 bowls but I think I got it (or at least I'm getting closer). Changed a few things I was doing wrong after re-watching Grumbine videos and a video on line by Steve Fulgoni (and the help here and mentoring from Mike Cruz). The curlies were as abundant as in the videos! My first bowl too about 4-hours and this one only one hour. I can see how this can become addictive. Only thing I need to do now is think about how to weigh down the lathe a bit (or get a bigger machine :D):


http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0002_zps4424dcd7.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0002_zps4424dcd7.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Projects/Cherry%20Bowls/IMG_0003_zps793340db.jpg (http://smg.photobucket.com/user/mbg/media/Projects/Cherry%20Bowls/IMG_0003_zps793340db.jpg.html)




Mike

[Mike Cruz]

Ahhh, the vortex is pulling you in! And now the "new lathe" search begins!!!!!!!

Hey, thanks for those pics, Mike. I think there really is some curl in that cherry. I wasn't sure, but I'm seeing some "fun" in it. ;)

And nice "product placement", too. :D

[Mike Goetzke]

Ahhh, the vortex is pulling you in! And now the "new lathe" search begins!!!!!!!

Hey, thanks for those pics, Mike. I think there really is some curl in that cherry. I wasn't sure, but I'm seeing some "fun" in it. ;)

And nice "product placement", too. :D

You caught that...the grain on this one is especially nice. This wood is so green it would temporally turn darker as I turned it. The photos above also show wet/dry areas.

Ahhh....only 6 more bowls left then I wait. Will need to find more wood!


Mike

[Mike Cruz]

I wonder where you could get more? :rolleyes: :D

[Marc Himes]

You have had lots of good advice Mike and it looks like you are making progress. Turning green wood is a great way to learn the basics and the more shavings you make the more you learn. Though it is great to get a finished piece at the end, while you are learning you don't need a finished product, just turn to get the cuts right and you will do well. Be safe.

[Mike Goetzke]

You have had lots of good advice Mike and it looks like you are making progress. Turning green wood is a great way to learn the basics and the more shavings you make the more you learn. Though it is great to get a finished piece at the end, while you are learning you don't need a finished product, just turn to get the cuts right and you will do well. Be safe.

Couldn't believe how a relatively small change in the tool positioning made such a large change in the cutting control. The help I got here helped me get there. Now I need to work on the shape;).


Mike

[Bob Bergstrom]

Looks like you're getting the hang of it. Nice job. Looks like you are getting sucked into the vortex quickly. Enjoy it. It is a great, but very addictive venture.

[Bernie Weishapl]

Mike you gotten some good answers so will tell you that I don't wrap my bowls after sealing with anchorseal. I talked with Mike Mahoney about this at one of his demo's. He said no need to wrap.

[Thomas Canfield]

I try a few items.
You were given the formula for speed, but this is not based on the size of the bowl, but the radius of the cut. as you work inside the bowl, and its weight becomes more balanced you can increase the speed because the working radius keeps getting smaller. One hint as to speed is to turn at the fastest you are comfortable with, and don't worry too much about a formula. Note that sometimes increasing the speed will quieten those harmonic vibrations.

Thom,

I take exception to your statement. The speed calculation should be base on the maximum diameter/radius. If you think it through, you could have a very large diameter piece turning way too fast when you got down the smaller foot dimension using your logic. The speed range does account for roughing at slower speed and then increasing to higher speed when balanced and finer cuts are required. Centrifugal force and wood less than solid can cause major damage when they come apart.

[robert baccus]

A minor thing after this great advice is to wax the rim to the inside a bit, double wax the rim and any wild grain. Good luck--I vote for a big lathe.

[Reed Gray]

I would suggest wrapping the rim, only if you are turning to final thickness rather than the twice turned method. With the once turned bowls, you can't put anchor seal on them because you will not be turning it off. Do round over your rims. Oh, and Mike dries his bowls in his wine cellar, constant humidity and temperature. The DNA soakers (denatured alcohol) do wrap the outside, but I don't see any reason why you couldn't let the alcohol evaporate out and then anchorseal. Never tried the twice turned method though. I just like the warped bowls.

robo hippy