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Hollowing tool size

Discussion in 'Woodturning Discussion Forum' started by Fadi Zeidan, Dec 25, 2017.

  1. Fadi Zeidan

    Fadi Zeidan

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    hey guys,

    I ordered Trent Bosch’s 3/4 hollowing bars because I wanted to do few deeper hollow forms, done one 10” and one I believe 11”. They are great for deep hollowing, but I found the bars to bee too thick for smaller openings.

    Now I’m debating getting smaller size and torn between the 1/2 and 5/8th and if I should try other hollowing tool shapes, for example hope’s or Ellsworth. I know hunter makes great ones too but they tend to be more expensive and not sure if the extra cost comes with an advantage.

    One of the challenges I found was hollowing around the neck of the vessel. Oh and I did go through the bottom of couple of them :) this one is 4” wide, not sure of the height off hand, under 3 I believe.
     

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  2. Larry Copas

    Larry Copas

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    Ellsworth uses 9/16" for the heavy work and cleans up with 1/2". They are shop made and described in his book.

    I made copies and used them as he does by riding the lathe. After a while I got comfortable using them, but never attempted anything over I guess 8" deep.
     
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  3. john lucas

    john lucas

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    The cutter is also a consideration. I find smaller cutters like 3/16HSS work better especially with smaller bars. They will cut very aggresively if pushed but on deep forms with thin bars a light cut is much better. I re read David's book last year and realized I had missed something. Hollowing by cutting down hill with the grain instead of into the grain reduces chatter a lot. I would suggest using the largest bars you can simply because it reduces the chatter a lot when going deep.
     
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  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    If your goal is pieces with smaller holes I would suggest the 1/2” tools these work nicely through 3/4” hole
    The 1/2” tools will work the same as your larger tools - what you learn with one set will work with With the other set.

    I like the Bosch tools. I have used the 3/4” Bosch tools with the jamieson handle over 15 years with a home built laser. I added then Bosch visualizer to the jamieson handle 3 years ago.

    About a year ago I got the Simon Hope hollowing jig. It holds the Bosch bars nicely and i moved the Bosch visualizer to it. at this point I like Simon Hope and Jamison both about equal. The Hope is a bit quicker to set up
    so I use it all the time now.

    If you decide to get a HOPE Jig both sets of the Bosch tools will fit it. You will need to use an adapter sleeve with the 1/2”tools.
     
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  5. Fadi Zeidan

    Fadi Zeidan

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    I am using the Hope hollowing system with Bosch 3/4 bars. My thinking is that I could get Bosch 1/2” for small vessels and do it without a jig since Hope’s doesn’t take 1/2”. I can also use the 1/2” near the rim areas of bigger ones before switching to the 3/4 for the deeper areas. But then I wonder if it would make a big difference between the 1/2 and the 5/8 where as the 5/8 would fit Simon Hope jig.

    I have Ellsworth’s hollowing and tools videos and his book. His cutter appear to reach under the rim due to it being angled. Simon Hope has similar concept with carbide cutter, but appear to be little thick. If they are same as swan neck, then no need to bother with off center cutter.
     
  6. George Guadiane

    George Guadiane

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    Not a mathematician, neither do I know much about physics, but there are basically four factors that dictate success and/or failure when deep hollowing. Other than your own human strength or the strength of the hollowing system and/or jig you use, they are:
    Opening diameter: The opening size limits the diameter of the tool you can put through it. The smaller the diameter, the shorter depth you can go because the tool will begin to flex and stutter, even in an articulated hollowing system. It also limits the size and shape of which cutters you can use
    Tool diameter: The larger the tool diameter, the deeper you can hollow without the chatter and flex.
    Tool length: Too short and you can't hollow deeply enough. Too long and you're tempted to go beyond the limits of the diameter and end up with that flexing and catching
    Overhang over the tool rest: You need to keep enough of the tool (and handle) behind the tool rest in order to have adequate control.
    Tool articulation: I have only really used the Rolly Munro hollowing tools. BECAUSE I can get the shape I need for virtually any shape. If/when I need more articulation, I can add a link. I picked that one because it has the smallest cutting head, making it easiest to get through small openings. Amy/all of the other tools available will work within their limits once you get them through the opening. Your ability to get an articulated cutter through the opening if you are using a lathe mounted hollowing attachment can be limited, so sometimes, especially near the opening can be better managed with hand held tools.

    So you either need a lot of tool options or deal with the fact that you have limitations when hollowing through a small opening.
    One demonstration I saw, more than a decade ago showed us how to cut a portion of the top of the hollow form off, hollow the "vase" part and the "lid part separately, fit them together, kind of like a box then make some beads to hide the joint. I'm just throwing that out there in case someone would like to give it a try. I never made one, and I've got to say, every time I see beads on a hollowform, I REALLY inspect it to see if it's "one of those."
     
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  7. William Rogers

    William Rogers

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    Fadi, I also have the Hope hollowing system with his camera. I just bought the whole system from Hope. I also bought his 5/8'bar and also the bent cutter attachment. This would be similar to the Bosch 5/8 bent, but not the extreme bent. The Hope 5/8 only uses the Hunter style cutters, no method to attach scrapers. I would not be able to get under the rim very well with the Hope bent cutter, however I do have several previously bought hand hollowing tool I could. I don't think I will ever get a 1/2 bar for the reasons of chatter as posted above. I have seen some hollow forms where a contrasting wood was use with a small opening at the top as George described above rather than hide it. I have thought about hollowing from a larger hole in the bottom and then making a pedestal to hide the hole and having a small opening at the top. Is that "cheating"? I'm guessing that has been done. I also thought about encapsulating something in resin or even gluing a silver coin or something else in the bottom to cover the hole Just random thoughts.
     
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  8. Fadi Zeidan

    Fadi Zeidan

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    Thanks William,

    I’ll go with the 5/8 Trent Bosch set with straight and bent scrapers.
     
  9. hockenbery

    hockenbery AAW Advisor Staff Member

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    You can always add an adapter so it fits the Hope socket.

    The wonnderful world of trade offs
    Hollow through a Small hole -small tool
    Hollow deep - large tool

    This little seed jar form is 7” diameter about 3” high opening is about 3/8”
    All the turning was done with a gouge turning two pieces and gluing them together
    C21775C7-0CB0-4EE3-B5BB-9C2B3BBC4BD5.jpeg
     
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  10. Gerald Lawrence

    Gerald Lawrence

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    There is another way to cover a larger opening. Use a larger hole to hollow and then create a collar to cover the hole and make a small opening. This allows embellishment and a hole too small to get a finger into.
     
  11. Richard Coers

    Richard Coers

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    I prefer a pivoting cutter for small openings. It allows cutting parallel to the bar on the back side. For flatter forms, you can even bring the cutter back further. I grind back the holding disk to allow a smaller entry hole. The bar is an S bend and is an old Stewart tool. Looks like I need a new bolt!
    hollowingbar.jpg
     
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  12. Fadi Zeidan

    Fadi Zeidan

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    Lyle Lamieson have double bar, straight and 45degree, with optional swivel for a good price but it comes in 1/2 or jumbo size. I’ll look into it some more.
     
  13. Richard Coers

    Richard Coers

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    I have everything from a 1/2" bar, to a 1 1/4" bar. Doing small opening forms requires changes of tooling as you progress down the form. You have to stay pretty small to be able to work the shoulder just inside the opening, then larger to get the depth. I suggest you work up an optical system if you've been going through the bottom.
     
  14. hockenbery

    hockenbery AAW Advisor Staff Member

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    I have the Stewart tools which I mostly keep teardrop scrapers on.
    I like the zero clearance of the Bosch tools. The holders tend get in my way more than they help.
    I also have a couple of bar CA Savoy made for me that do a nice job under the lip and a tighter radius Bosch tool
    It looks like your holder has had a session on the grinder to get some of it out of the way.
     
  15. Richard Coers

    Richard Coers

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    Sure did. Pretty hot on finger tips! I made a stack of those blade holding washers before grinding this one up. But it works so well, I still have the stack for the future. I also prefer an articulated system so I can rotate the cutter and holder into the opening. I usually start cutting as I feed it in.
     
  16. charlie knighton

    charlie knighton

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    well....I think the biggest consideration on types of tools should be the size/space for display for you and your customer base.....6 inch high is plenty to fit on mantle or side table.....usually fancy/exotic woods are offered in smaller blanks....Michael Mocho comes to mind....Jacques Vesery another ...Mark Gardner does some beautiful work.....there are many others including John Lucas's doll house turnings.....I apologize for leaving others out.....I get these brain _arts
     
  17. Fadi Zeidan

    Fadi Zeidan

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    My limit is what will fit in the kitchen cabinet :) I turn for fun, so my wife picks what she likes and the rest gets stacked in a cabinet above the fridge.
     
  18. Mike Johnson

    Mike Johnson

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    An artistic piece turned on a lathe is a one of kind work of art, you can always find a new wife. :)
     
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  19. Fadi Zeidan

    Fadi Zeidan

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    I showed your reply to my wife and she said she IS work of art! :p
     
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