Flex

Re: Flex

Hi Barbara

When I am turning a big bowl, I usually finish turn it in stages. In other words, after getting the shape i want on the outside, I will turn the (inside) rim and a little down the side to finish thickness before moving to a lower part of the bowl, and so on down to the bottom. This allows me to have support from thicker wood as I go down towards the bottom. The disadvantage is that it commits you to the final shape as you go, and you have to be careful not to get ridges between "sections".

Another alternative for thin walled bowls is to use a steady rest. I just came into possession of a very nice one, but I haven't had a chance to "take it for a spin" yet.

It can help as well to true up the tenon before you start to finish the bowl. I just stick the bowl over the chuck and use the tailstock center to center it. This creates a friction drive with enough force to turn the tenon true again.

Bill

Re: Flex

Thanks Bill; as usual, a great answer.

Re: Flex

Good Morning,

I'm glad to see I'm not the only one up this early checking turning sites.

I have had the same problems with maple, elm and sycamore. Wish you were closer I'd give you some mesquite or pecan for large bowls. The mesquite stays real stable even fresh cut and some pecan I turned stayed running so smooth that when I stopped the lathe to check thickness I stuck my finger through it. I also turn the outside first and then hollow to finish in steps of 1/2" to 1", A slight ridge at these steps is easy to power sand if the opening allows access. My lathe is variable speed and I also slow the lathe down enough to keep the tool going in and out with the warp of the piece. this is slow go but helps on some woods. I also on platters and more open bowls when I feel safe doing it, will slide the tool rest out of the way, put a fresh edge on a curved scraper, lathe speed slow and with one hand on the outside of the bowl for support, the tool handle tucked firmly between my side and my arm, scrape the inside to remove the ridges. this will also leave an easly sanded finish. If it is a real fresh piece of wood I will also sit it back in water or wrap a wet towel arould it so it will usually run true for a few more passes. I don't mind sanding, since most of the wood I turn is green I let them dry for at least a week and hand sand anyway.

Have fun turning and good luck.

Larry

Re: Flex

Thanks Larry, between you and Bill I will do it better next time.

Re: Flex

I read your response to Barbara's question with great interest. Now I have a question in regard to that. (I hope this doesn't sound too stupid but let's remember I am a novice at turning) You say you "slow the lathe down enough to keep the tool going in and out with the warp of the piece." Here is the way I interpret that. If you have turned a bowl using green wood and then leave it sit, it usually develops a warp. Do you mean to say that when you turn to the final finish that you leave the warping in place? I thought you were supposed to turn the piece enough to eliminate the warp. The reason I am posing this question is that about six weeks ago I rough turned about a half dozen osage orange bowls (I don't know how to spell "bodark") and they warped fairly severely and two of them checked badly. We just came back from a trip and I was going to finish turning these pieces and when I looked at them I was aghast. I really didn't know what I was supposed to do. Do I use the split ones for firewood or patch with inlace/epoxy ? Do I try to true up the warped ones (is it possible) or finish them with the warp in place ? Many thanks. (I answered your e-mail a few minutes ago)

Wolf

Re: Flex

Wolf even kiln dried slabs of wood can develope a warp depending on the species, say in the case of a 8/4 hard maple platter 12" or 14" in diameter. I don't turn very fast rpm around 1200 to 1600 at most but cutting a hard will generate while cutting, the removal of material relieves internal stresses that will let the wood distort slightl, orientation of grain in the blank(quarter sawn probably wouldn't warp), excessive sanding will generate heat and can cause not only distortion but cause the thickness to start varing all over the surface. there are probably several other factors that cause warping I'm not aware of or exactly why the change takes place but we can adapt and allow for these changes by adapting a different technique to get a easily sandable finish from the tool. In the maple platter shape the outside profile first then remove the material in steps from largest to smallest diameter, I take it to 1/4" or 3/16" thickness throughout. small ridge can develope,sometimes on opposite sides of the platter as the edges of the blank try to curl inward and not all the way around, a slight warp is not real noticable and if the ridges are slight I will sand instead of trying to further clean up with tool. If this was mahogany it would probably stay true and you could take one continiouscut from edge to center for a clean surface. In the case of rough turning to return when dry, you should leave a thickness of 1/2" to 1" thickness depending on the size of the bowl and allow 3 to 4 months at least if the drying is going to be un assisted, don't keep in a heated area or the moisture can be removed too quickly and unevenly, because of end and face grain exposed in one piece. coat the wood with wax to slow drying, put in a paper bag, microwave to speed up drying, there are countless methods to the same end.I like to turn my pieces at one time and let the wood move where it wants to, later truing the bottom and finishing. as long as you turn the entire piece under about 1/4" thickness and don't leave the bottom real thick cracking is usually not a problem. woods like mesquite will stay nearly perfect and persimmon, It shrinks about 1/5 th in size, will look like a football. Experience with different woods and shapes will help to develope a cooperation between you and the wood to produce pleasing forms. Remember that wood is a living material even after cut, always breathing and moving with the changing climate.

Good luck and safe turning

Larry Hancock