Robert Sorby Hollowmaster issues

[Scott Austin]

Hello everyone,

I have recently aquired a sorby hollowmaster. Brand new. It really came with no instruction of any kind, and the only thing I can find on-line is a sales video in youtube. I have tried to use it on a few hollow forms with little success. The hollow forms were simple, beginner stuff as I have never really done hollow forms at all. It just seems to me that it is extremely slow at removing material. I have been playing with it trying different tool rest heights, different angles of approach, so on and so forth. Either it is barely cutting at all or it is catching. I can't seem to find a happy medium. I have tried it on end grain and face grain, even though I know it is more of an end grain tool, I thought it to be worth a shot. If you guys and gals have any infinite wisdom you would like to pass along I am all ears. Thanks in advance.

Scott

 

[Bill Boehme]

Did you view the movie clip on the Robert Sorby web site? If not click on this link -- Sorby Hollowmaster.

There are two different tools -- a straight shank tool and a swan neck tool. Each has several different cutters. For rough hollowing, use the small narrow tip and use the round and elliptical scrapers for smoothing.

The two different tools are used in the same manner -- perfectly level and with the cutter exactly on centerline. The tip used for roughing is sharpened like any other scraper. The round and curved cutters need to be honed on the top surface to remove the bur after sharpening. When using the swan neck tool, never put the curved part on the tool rest -- always the straight part. The video covers most of this stuff pretty well.

Hollowing is best done by starting off drilling a center hole with a Forstner bit (about 1 to 1.5 inches diameter). Then starting at the top, use pulling cuts to remove the wood. Check the wall thickness as you go because things do work so well when the inside diameter is larger than the outside diameter.

Run your lathe at a slow speed when hollowing -- if you can slow it down to about 200 RPM, then use that, otherwise whatever is the slowest speed.

The reason that you are getting catches is most likely because you are letting the cutting tip droop below the center line. If the tip is too high above center then you will just be making some dust, but no shavings. Center line ±0.0001 inch is the sweet spot -- OK, maybe ±0.1 inch, but the point is that the closer to centerline the better the results.

Until you get some hands-on instruction, you will be behind the power curve for quite a while because it is simply not feasible to write down all that you need to know without writing a book (and video).

 

[MichaelMouse]

Add one more "gotcha" to the list. Don't press the broad scrapers. They can build up a LOT of heat when you think you're making great progress. Then you start to hear a bit of crackle as the thinnest endgrain portion checks. :mad: It's especially musical when you're turning something like eastern red cedar (aromatic), which rings almost like a bell as it self-destructs.

See if you can't get some of the carbide metal-working cutters with the ground-in "burr." http://www.woodcraft.com/product/2005931/18220/hunter-4-hunter-tool-replacement-cabide-cutter.aspx You'll have to shop hole size and contour, but my machine shop buddy gave me several that fit mine. Those you'll want to use as you would a burr cutter, not a burrless.

 

[Rob Wallace]

Practice hollowing bowls first......!!!

Hi Scott!

When suggesting technique to beginning "vessel hollowers", I recommend first getting acquainted with your new hollowing tools by turning a simple bowl shape with a tenon, reversing it on the lathe in your chuck, drilling a center access and "depth" hole as Bill suggested, and then use your new hollowing tool to hollow the center of the bowl using the drilled hole while you can see (and feel) what is going on. At the same time you will get a sense for how the tool works on the inside of your form, what optimal tool rest height should be, how hard (or not) you should be applying the cutter to the wood, and related "tweaks" in your technique to make the cutters work efficiently. Once you have mastered a couple of test/practice bowls, you can then start-in on a true hollow form where most of your hollowing will be done "blind", and by feel through a small hole. The experience you get from hollowing out the bowls will make you a better user of the hollowing tools. It also will allow you to learn more quickly when practicing on bowls because the shavings you generate will fall away from a bowl, as opposed to being trapped inside the hollow form. Knowing when or how often to clean out the shavings is also a big part of learning how to hollow, since shaving accumulation can drastically effect the performance of the cutter.

Keep your turning speed down, use sharp bits, clean out often (compressed air really helps), and make sure the ID is always less than the OD!

Rob Wallace

 

[Scott Austin]

Thanks everyone for your advice. I have turned a couple bowls and a hollowform with my shiny new hollowmaster. I figured out that I was running way way too fast. Thanks again

Scott

 

[Curt Fuller]

Scott, just in case you're like me and you have to try to make something work to the point of almost total frustration before you ever break down and read the instructions, I'll mention what gave me fits with the swan neck sorby hollowmaster. With most tools you want to keep the tool from hanging over the tool rest as much as possible. I had a terrible time with the hollowmaster because I was trying to put the curved (swan neck) part of the tool on the rest. So in case you're doing the same, the tool must rest back where the tool is straight. That puts you about 5 1/2" over the rest and I was taught never do that with any hand held tool. But that's just how the swan neck works and how it keeps from torquing the tool out of the control of your hands.