Problems with breakage

Discussion in 'Open-Segment Turnings Forum' started by rjkssmith, Jan 14, 2017.

  1. rjkssmith

    rjkssmith PRO Member

    I have done quite a bit of segmented work, both open and closed. I have been using Woodturner Pro for a couple years and have recently purchased Segmented Pro. They both work great. I also have been using the 18-4 Seg-Easy with no problems. I recently bought the 48-2 Seg-Easy and that is when my problems began. I am having trouble with the bottom two or three rows breaking out when I try turning the bowl. The glue is holding, in most cases, but the pieces are breaking. I have been taking very light cuts with very sharp tools. I have had the same result with a bowl gouge and a large scrapper. The wood I am using is primarily padouk in the first couple of rows. I have not seen anyone else comment on this problem in the forum and all the videos I have seen just show how to construct the bowl, but not much on the turning. How do you all keep the first couple of rows from breaking when making a 48 open segment bowl?
     
  2. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    I'll be interested in hearing the comments of others, but here are a couple things...
    Padauk is a hardwood, but it is one of the softer hardwoods and does have a propencity to chip and break. I know it is more expensive, but bloodwood would be a much better alternative.

    Next, you didn't mention what tool you are using to do the turning, but it needs to be something that can be presented in a shear cut. If using a gouge, in addition to it being very sharp, it has to be presented to the wood in a way where the wood fibers are being shear cut. That means that if you are cutting the inside with the tip, the angle of the presentation needs to be very great. Any angle that would cause the cutting surface to be parallel to the wood needs to be avoided because it is a very aggressive presentation.

    I still like to use a gouge, but another option is an Eliminator or an Easy Wood tool that has a round carbide disk as the cutting head. A carbide cutter is typically used in a scraper approach which should absolutely be avoided. The circular cutter head has a raised edge around its perimeter which when presented correctly to the wood is a knive that slices the fibers and this would be an excellent choice.
     
  3. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    rjkssmith That is one of the problems. The pieces are very small and fragile, I have two post you might want to go through in this section of the forum Title: {title] and Title: {title] .
    I'll rough turn the bottom 3 or 4 row after they are good and dry before adding more. You have more access and movability. I normally use a 1/4" detail gouge down in the bottom. Ride the bevel as mush as you can and take VERY light cuts. I'm normally turning here at about 1200 - 1800 RPM
     
  4. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    Don't use a scraper or negative rake scraper, way to much pressure on the wood. Keep your tool handle as LOW as you can this will give you a shearing cut. Then cut as slow as you can then slow it down some more. You are not in any kind of a race here.

    Here you can see some rough turning before adding more rows Title: {title]
     
    Last edited: Jan 14, 2017
  5. Tom Lohman

    Tom Lohman Tom Lohman

    Well sounds like I have been doing it wrong because all I ever use are the Easy Tool with round carbide disk. The way I get around the breakage issue is to sand the bowl before your tools are used to remove the vulnerable small tips of wood that are sticking out without much support. I also keep the blade at an angle and take light cuts.
     
  6. stuart johnson

    stuart johnson Super Moderator Staff Member

    Tom, sanding first is a great tip. Small processes like that are the probably the most overlooked tips. They are so routine to the user they don't get mentioned until there is a very specific question. Thanks for sharing.
     
  7. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    Thanks Tom remember seeing that on one of your videos.
     
  8. Brent Dalrymple

    Brent Dalrymple PRO Member

    I've used gouges of various types, skews, and Easy Tools--and still do as necessary--but what has worked well for me most of the time is my Sorby multi-tip hollowing tool with the little round tip (see photo). I can take heavy or very light cuts and have never gotten a catch or a "chip out". I have lots of replacement tips, keep them sharp, and change them frequently. I use this tool, followed up with the multi-tool shear scraper tip (+- sanding) for the final finish for nearly all of my bowl work, inside and out.
     

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  9. Mike Goldfine

    Mike Goldfine Member

    This is an old thread, but I want to get my two cents worth in anyway. My only open segmented bowl was in pine and I turned the walls down to 2mm, slightly more than 1/16" thick. I used a hollowing tool with a small round tip I ground from an HSS drill bit. This sounds pretty much like what Brent (comments above) uses. It worked really well and I felt I had full control even though the whole thing was glued up before turning. I did the final smoothing with a regular round nosed scraper. I have seen some other open segmented turners on Youtube who also swear by this type of cutting tip, although I'm sure there are several equally good alternatives as noted above.
     

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