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advice on mounting a blank

3K views 65 replies 8 participants last post by  Nubsnstubs 
#1 · (Edited by Moderator)
I have a bowl blank I am not sure how to mount. the part that would be the logical bottom has a serious crack in it, its not long but it is deep. I have laid out the circle on the large side but the other side is flatter and will work smoother on the circle jig, how do you judge where to place your center on the small side, the billet was cut from the side of the log. the billet is about 3 inches thick. any help is appreciated thank mike

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#27 ·
Hmmmm, now, start at the top of the crack and keep removing material until that crack is gone. Look at your foot. The crack looks to be about 1/4" from the inside of the foot. Remove all that wood until the crack disappears. While causing the crack to disappear, you should end up with an elevated foot, about 1 1/2" tall. Shape the outside bottom to make that ogee you are trying to make. Do that next, and show another of your progress. I'm going out and start my bowl, and will take pictures of what I was trying to get you to understand in my other posts…... Jerry (in Tucson)
 
#29 · (Edited by Moderator)
Okie dokie Mikie, here is a tutorial from the start after rounding the blank. It is right now 5:03 pm. I started this about 4:15pm. It's taken me about 15 minutes to get the pictures downloaded and then resized for Lumberjocks to accept them.
This first pic shows the half log that has been rounded. It also has a couple dowels in it, but they will disappear.
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The next 2 pics shows the contour of the log. If you notice, my Chuck Plate is what's holding it in at the headstock, and my live center is keeping it between centers. I call both the LC and CP "My" because I made both. I did some cutting on the face of the bowl as I wanted to see what kind of depth there would be for the bowl, and how tall the foot would be.
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The next 2 pictures should show where the bowl ends, and the foot begins. Notice the area where bark used to be. That will be removed when I start the cut from the middle towards the foot.
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Just for S&G's, I tried to make it look somewhat like yours did at the beginning. The foot is starting to get down to dimension. That's what I was trying to have you arrive at when I kept saying to remove the crack. Of course, there is much more to be done to refine all this.

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The bulge has been removed, and now it's time to start defining the bottom contour of the bowl. Just turn up to the foot and stop. Repeat until you think the contour is right.

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I don't know if you can see the pencil marf at the ftenon area. The tenon and foot OD has been determined, and will get that done.
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Next is to refine the foot and make the tenon.
Foot is turned to the bottom edge.

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Foot is now refined

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Tenon recess is made. Tenon is 2 1/4" OD, and recess is large enough to have the chuck jaws fit flush at the bottom of the bowl.

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Blank is mounted into the chuck, ready to remove the innards.
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The blanks is now faced, and will remove the innards at a later date, possibly tomorrow.
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This is as close to a step by step as I could come up with. I know it's short on detail, but you have been turning over 2 years now, and some of this should just be a refresher course in turning. Maybe it doesn't make sense to some, but that's the way I approach most half log blanks, unless it has some nice crotch feather, then I go from the bark inward.

Also, I'm not hijacking Mike's thread as I'm just trying to give him instruction…........ Jerry (in Tucson)
 

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#30 · (Edited by Moderator)
heres where I am at so far.the crack where there is no glue is about 1/8 deep put a machinist rule in it. What is happening and why I quit foe the knight is when I started taking down the bulge more the bowl started to straighten out. I'll tell ya I am having a real struggle to keep that from being just another flared bowl. I can't see a 1.5" foot unless I am not taking off enough. I did have a nice smooth surface with very little roughness now its like a wash board. accidently closed the form heres the pics
 
#32 ·
Hi Jerry I didn't respond to your pics because I was responding to your request for an update and didn't see it till much later. That is an impressive piece you have to work with. i studied the picture sequence and i can see how the bowl developed. That is a great help. I have learned more from this bowl than any other i have done. The main reason is because I am forcing my self to do something different. My usual way is to mount a piece and start turning and see what comes out. on this one I am trying to do something different. I am not good at seeing the obvious. Thank you for everything I will post pics when I get it done Mike
 
#38 ·
thats what I thought when I saw the first picture of the fully turned outside. Is that light of mesquite uncommon. From the couple pieces you sent I love that wood. Ok I broke the foot, well chipped the crap out of it and there is not much to work with and the crack runs right through it, its doweled and stuffed with epoxy but its can still move take s look
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#39 · (Edited by Moderator)
Mike, I'm back, like a nightmare…... this first 2 pictures in this batch is a close up of the dowels. I managed to remove all traces of them.
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I've started removing the innards, trying to keep the same contour as the outside. Notice that big a$$ catch I got on the rim at about 1 o'clock. I was between centers, so not a big issue there. If possible when hogging out the innards, always keep your tailstock as support until yopu are almost done.
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The innards are removed, and am now ready for sanding. Look closely at the very center. A nub remnant should be visible. I don't have a lot of luck at getting them smooth when cutting them, so I leave them proud and sand them off with my right angle pneumatic sander when sanding the insides.
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After sanding both outside/inside, I decided I would revise the foot pedestal. Notice the Ogee on the foot.
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The Chuck plate I use with my Rim Chuck is mounted into the chuck
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and the proper size Rim Chuck is ready to set up.
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It fits.I make my rim grooves the same size as the bowl rim. It's an interference fit, which I have to get creative sometimes to remove the bowl for bottom checking and just taking it off the Rim Chuck.
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Next is mounting it between centers to remove the tenon and hog out the innards of the foot.

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The tenon is now history. I want to make a finial with the remnants of the nub.
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The nub.
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Oh,oh!. It disappeared. About 2 seconds after making tool contact, it broke off. Notice I am using my Tail Stock Steady and the Chuck Plate. Without them, a lot of the stuff I do couldn't be done. Anyway, I was still able to put a feature on the bottom.
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the bowl is done, and sitting on my ways.Total time was about 1 1/2 hours. Bowl is 7 1/2" round at the rim, and 3 1/4" tall. The foot OD is 4" and 1 1/4" from table surface to outside bowl bottom…......

You now have some type of tutorial for your next piece. You can also make any change you like, but if you choose to make an Ogee, this is a start. might not be the PROPER way to do it, but it's how I do it. It's also a good way to utilize the full height of a half log blank.

If the blank was a crotch piece, I would have started with the bark up against the headstock, make the tenon, reverse it and work towards the pith to expose the feather. That's another lesson for another day. .......... Jerry (in Tucson)
 

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#40 ·
Looks like ya'll got that cake baked. Nice.

I don't know if this will be put back to finish drying or finish turning now.
Maybe I won't be the "too many" cooks in the kitchen.
For the icing…
I drew a line on your bowl and the curve looks very nice. Will just need to tuck the bottom curve in at the base when you finish it.
The other pic is from http://turnawoodbowl.com. Lots of good info and you may want to visit there a while as time permits. Your bowl looks very close.

Lyle Jamieson has a nice short (8 minute) video on designing/layout of the foot. Works for either recess or tenon.


Only a suggestion but you can decrease the diameter of the foot, shorten it just a little, and leave maybe a 1/4" bead for the bowl to rest on. That will get rid of the torn grain and maybe a lot of the crack.

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#41 ·
thanks Jerry the bowl is beautiful i will try to save it for future reference.I appreciate all the work you have gone to to record it.
thats ok Lee you are a contributing cook. your ideas are good. I had planed to straighten the foot but then I chipped itand don't know what to do with that. The foot is narrow about 5/8 wide so if I narrow it it will be more likely to break of in my face. I think the crack is about 1/8th deep. I was thinking lengthen the foot a tad and turn down the surface of the foot but that will weaken the the recess. what ever I do I want to keep a gentle ogee shape. I am try to turn something that I haven't done before. It seems that my bowls turn out be classic bowl shape or flared
 
#42 ·
I went down to touch up the bowl, I very slightly undercut the foot and straightened the side. I gentled the cure and reduced the hight of the foot, the recess was deep enough to do that, do i dare undercut the foot and still have it hold when I turn the inside. I'll have to get some more epoxy in that crack

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#43 ·
I would not mess with the foot at all now. I meant for the last of the very last turning, you want as much meat on the bone as possible to turn the inside and to remount if you are going to set it back to dry before a final turning.
If you have to let it dry you will probably lose just a little when you re-true it.
I would not do anything else with the foot until both the inside and outside are finished complete.
I would mark the center now of the recess for ease of aligning later.
 
#45 · (Edited by Moderator)
Mike, I didn't show the pic of the bowl on the ways, so here it tis. .

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Now that I see a better view of the extent of the crack, you sould keep cutting away at the bowl OD and foot height until you can't see the crack on the bowl bottom. That would also allow you to refine the shape you have now. It's close. Look at what Lee just posted. His line goes right through the foot you have and it's pretty close to what you should end up with.

I would leave the OD of the foot alone until you are done turning the inside to the finished thickness. Since you use recesses and normally don't re-chuck your pieces for any refinements that might be needed, on this one I would suggest you make up a Rim Chuck attached to your face plate. It's no more than a piece of 3/4" plywood or a piece of MDF. I like to double up on mine with 2 pieces making up my thickness 1 1/2". After you have it made up, turn a groove in it that matches the OD of your piece. Doesn't need to be more that 3/8"' deep. It should be a snug fit. Mount the piece in the groove and bring up the tailstock. You really shouldn't need the mark/dimple that Lee suggested, and I agreed to, but it would indicate if you're not totally aligned. Start working on the foot being careful to not remove any from the outside bottom of the bowl. With good tool control, remove the OD of the foot until it's about 1/4" wide. If the crack is disappearing quicker than you expected, and the foot rim is thicker, GOOD. If you reach the 1/4" thickness, and the crack is still there, fill it with super glue cuz it's going to be negligible.

The bottom picture you posted in post 37 looks like taking out the crack will leave you with a quarter inch rim for the foot. That's plenty for a foot. You just need the confidence to do it. So far, you've shown that you are capable of doing it. You just need to take the plunge.

Go ahead and put a pencil mark at the center of the bottom. Then if you make the Rim Chuck I suggested, when you put your piece into the Rim Chuck, put a small piece of wood between your live center and the bottom of the bowl. Apply tension, and turn on the lathe slowly. If the piece is pretty much centered, leave the piece of wood in and turn the outside of the foot to try to remove the crack. Put a bead on it or a cove. Decorate it to make it look like some thought went into your bowl instead of just having a plain old bowl…..... If you aren't already done by now, Good Luck. If you are done, show the pictures. ........... Jerry (in Tucson)
 

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#48 ·
I would turn the screw holes out….unless they are too deep.

As far as the crack goes I would fill it with fine sawdust form the turning blank, then in quick succession, saturate the sawdust with thin CA glue followed by medium or thick CA glue. The thin glue quickly wicks in to the sawdust and than draws the thicker glue in behind it. Keep adding the thicker glue until no more will go in or it starts to set up. You could treat the screw holes the same way.

You can treat the open spaces around those knots the same way and also use the thin CA to firm up those tear out spots before further turning.

If you have a lathe chuck there is a much easier way to mount a blank like that. Check out my blog on the subject if your are interested.
 
#49 ·
Mike, now that you've raised the bowl bottom above the crack, you have a couple options. One would be to remove the foot past the crack. The other option is to leave the crack and fill it. Leave it alone after filling it if you choose that route.

After filling the crack, attack the lower portion of the shape you have and make it a reverse of the upper portion coming from then lip. It does not matter if you cut into the foot portion to make the bowl bottom more appealing. Remember, if you are going for the height of the foot, you have plenty of solid wood to keep this piece intact. You are a long way from losing it. Go back and look at my pictures of the foot. You can remove at least 2 inches of it right at the bowl bottom without sacrificing the strength of the foot. While taking off some of the extra wood, make the contour a clean look. When you have that turned down to your satisfaction, start the innards.

Turn the inside out until you like the thickness of the bowl, about 1/4 - 3/8" maximum. Make up your rim Chuck, and then measure for the groove you need for the rim OD. Measure across the grain, and with the grain. If there is a difference, try splitting the difference and make the groove fit the rim. It should be a snug fit, but not something you have to force the bowl into. Turn the groove while starting/stopping to check progress until you have a good snug fit.

There are two ways to approach this. Mount the bowl between centers and start removing the outside of the foot taking it down to that 1/4" thickness I've mentioned numerous times between the recess and the outside. Stick with that option by starting to trim the height down to remove the dowels. That will give you a short foot with a still good looking bowl. just keep removing wood until you reach what looks good to you. For me, that would be about a 1/4" high foot with a bead, or a small cove at the transition between the foot and bowl. Remove all wood until yopu have a small nub. If your Rim Chuck is a good snug fit, pull the tailstock back and remove the nub while still in the Rim Chuck always cutting towards the headstock. Very light cuts, and comfortable speed. Since I invented the Tail Stock Steady in 2012, I don't really know how to approach it the way I described. Physics indicates if it's snug, and you always cut towards the headstock, it will stay in place until you remove it. Stuart Batty uses jam chucks, which are not too much different than the snug fit I just described using the face plate and Rm Chuck.

The second option would be to leave the foot as long as it is and trim it towards the recess, leaving the 1/4" thickness I described above. After you achieve that, then start cutting in towards the center of the pedestal to give it some flow, rather than having a straight foot/pedestal. f you choose to go for height. Leave the OD at the recess about 4" if you have that much to work with, and then start tapering the pedestal towards the bowl bottom. When you get it to 3" round, that's as far as you need to go. Start hollowing out the foot to remove excess wood, leaving the nub in place. When you get the depth where the bowl bottom is now 1/4 -3/8' thick, sop and remove the nub. Piece of cake.
The tools I use for the foot shaping and hollowing is usually Easywood CI5 which is the small round tool. It will allow me to get rounded inside corners, plus it's just so easy to use. ......... Jerry (in Tucson)
 
#50 ·
Hi me again. I have a finished form. Not quite the smooth lines I wanted. but its ok. one dowel disapesared and another partially I sanded it to 1000 grit then wiped it down with paint thinner, that is what I want in a finish. I wish the wood would dry that color.

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