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I bought this Sorby hollowing tool (I just looked it up 2 years ago!) and I've never figured out how to use the dang thing.
enter image description here

There wasn't ANY instructions that came with it, not even how to put the different pieces together (though that wasn't terribly hard to figure out). However, the tool that is supposed to be for creating an even thickness (the big semi-circle and touching the wood in the picture) does not seem to be as 'simple' to use as you would think. The first problem is the end of that wire is sharp and will mark up the outside of the surface. I generally finish one side then work on the other of a piece.

If anyone can give me step-by-step instructions on how this is expected to work I would be grateful. I spent a lot of money and a so far worthless tool.

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    "Full instructions provided for all aspects of useage and sharpening" says their web page, I think you got a bum deal :p robert-sorby.co.uk/hollowtool.htm It looks like 851H/854H. Maybe you could e-mail them and get the instructions? sales@robert-sorby.co.uk – Daniel B. Mar 24 '15 at 15:02
  • @DanielBall I'm going to have to look again, but I'm pretty sure the little piece of paper that they sent was only for the pieces that were obvious in their use. Otherwise, yes, I'll have to see if I can get them to send me the instructions they promise. – bowlturner Mar 24 '15 at 15:06
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    @guitarthrower The first one was for different tool (I have that one too and it works great!) the second one has no instructions for the 'guide' at all, it was next to worthless, since by the time you start using a tool like that you should know those basic instructions. But Thanks for pointing it out. – bowlturner Mar 24 '15 at 15:27
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    Wait. With a name like @bowlturner, you're supposed to be the expert at the lathe! My world has shattered! – FreeMan Mar 25 '15 at 12:34
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    @FreeMan No one knows everything. Learn this lesson well grasshopper. ;) – bowlturner Mar 25 '15 at 12:37
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+50

I am generally good at research but I have no hands on experience with turning. I am honored at even the attempt to try and help you with your plight. I contacted the tool's manufacturer Robert Sorby to try and see what they could offer. One of their agents provided me with a PDF that I don't think is hosted on their site.

I have the best I could muster for the official instructions on how to use the tools you have pictured. However they don't cover your concern about the surface scratching but I have some ideas about that.

Boring Bar and Depth Stop

The tool in the middle is the boring bar and depth stop. Depth stop appears to be an adjustable collar. Pretty simple to figure that one out but here is the content of the document all the same:

The boring tool is used to remove the centre of the hollow vessel or bowl to an accurate depth. The depth stop limits the depth of cut to prevent the risk of cutting through the bottom of the project. The tool should be presented to the work horizontally and cut on centre line. The boring bar is sharpened by rubbing a diamond file on the two cutting edges.

Hollowing Tools

The bottom tool picture is a fixed edge swan-necked hollowing tool which is designed for general cutting and hollowing. The tool above and on top is just the same except the cutting head is adjustable making it more versatile for more complex cuts and better geared for smaller sizes of work as well.

These tools cut on the centre line of the work. Throughout which the tools are held horizontal. For a more gentle cut rotate the tool until the tip trails around the 8 o'clock position. Make a series of light cuts starting from the top of the work and working towards the bottom. We recommend that these tools are honed with a diamond file on the bevel. If the tip is severely damaged it may be necessary to re-profile the tip on a bench grinder.

The following notes are also present

  • Cutting occurs on centre.
  • For a gentler cut rotate the tool until the tip trails up to 15° off horizontal.
  • Tool must be horizontal at all times.

Wall Thickness Gauge

More of your issue comes from the Wall Thickness Gauge which is supposed to make it so you don't cut through the wood completely. It is expected that the external shape of the work is completed before these tools are used. The following is the instruction for setting the gauge which I am sure you figured out:

  1. Lock on to ferrule with 'T' knob (A).
  2. Slacken screw (B) with allen key provided.
  3. Holding the finger loop in contact with the handle, set to the required gap and retighten the screw

I don't know if this part is just obvious but based on what I read (it does not say itself) the bar will move while you work obviously. You will know you hit your desired depth once the bar comes to rest and is not under tension. Not the most fool proof system (assuming I understand right) but you are cutting blind so it is better than nothing.

Some notes also compliment the gauge:

This can now be left in position whilst turning if required, and can be swung in and out to check the wall thickness as you tum. If the project is made from an open grained wood such as a burr, it is best to check the wall thickness when the work is stationary.

N.B. The wall gauge can be bent if required for any difficult areas. This is sometimes necessary on deep necked hollow vessels.

The last note has the following accompanying photo

Setting correct gap

Scratching outer contours

Does the bar scratch all of the work or just the tighter inside contours? Perhaps you need to bend the bar more for part of the cuts? Also I cannot tell from any photos what the end of the gauge looks like. Mostly wanted to know if it had a flat or rounded end. I would have assumed the latter but it is possible either way that you have a manufacture defect?

My suggestion would be make sure that the end is rounded as much as possible. Rotary tool and using a few different heads should help. Polish that baby and that should hopefully prevent scratches.

Only other suggestion which you are probably already doing is make the outer surface slightly uniformly wider than the intended finished product and clean once you are done hollowing on the inside.


For completeness there is a warning both in this document and almost every video I watched on the subject.

All swan necked hollowing tools should be used with the straight section of the shank on the tool rest. At no time should the swan necked section of the tool come into contact with the rest.

The markup from the document was also underlined. Clearly set to stress the message

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  • Hopefully this helps a little. – Matt Mar 2 '16 at 16:33
  • I thought I was going to have to let the bounty run out! Thanks, while it wasn't what I wanted to hear, it did 'click' how I was thinking about it incorrectly. – bowlturner Mar 2 '16 at 16:50
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This video isn't of exactly the same tool, but it might give you some insight:

Hollowing TOOL Review:woodturning with Sam

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    Hi Lewis, welcome to Woodworking. Indeed, the link to this video is helpful. However, you can still improve this answer by describing the techniques shown in the video. A proper answer will stand on its own and not rely on content linked to another site. We strive to do this for every answer so that they will all be just as useful even if the link becomes broken (e.g. if the author of the video were to remove it from youtube). Thanks and welcome again to our site! – drs Apr 20 '15 at 15:07
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    It was a helpful video, and gave me ideas, but it is still different from the one I have. Feel free to put in some of the highlights of the video in your answer. we like to have the gist of a link here in case the link disappears. – bowlturner Apr 20 '15 at 15:07
  • Sorry about that. I was afraid the written description would be too long. Guess I'm a visual learner. – Lewis Kauffman Apr 20 '15 at 17:13

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