Hollowing tool help

[DaveO]

A while ago I bought a Sorby swan-neck hollowing tool in hopes that I could start working on some open-form bowls and undercut rims.

I can't make this thing cut worth a dang. Despite the instructions telling not to sharpen to a burr (because you don't want it to cut to aggressively) I have tried that and I still am having no luck. I get a bunch of chatter, and sometimes a little dust. But nothing like I would expect from a scraping tool. Am I just not driving it right, or holding my head the right way. I have seen videos of similar tools in use and they seem to make pretty quick work of the job. At the rate that mine is cutting I could sand the bowl hollow faster :--(


Any tips, help or suggestions would be greatly appreciated. I have a special bowl blank that I have been saving for a nice open form, but I have to be able to use this thingy before I can try to turn that bowl :BangHead:

TIA,
Dave

 

[NZAPP1]

Sorry Dave I can not help I have this one and it works very well. I also did buy the small one like you have but have not given it a try yet. I hope to finish my power and use my lathe today:eusa_danc if the LOML will let me get away early from her plans:BangHead::BangHead::crybaby2:

 

[froglips]

Dave, in the land of irony, I'd be the court jester's gopher.

I don't know nutt'n bout hollow turning, but a lot about hollow turning tools. I built one for my father last year for xmas.

I sharpened the cutters razor shap and they cut like butter. I mention this, as many of his fellow turners tried my tool and were amazed.

While I like to think I'm that good, its really about a sharp cutter IMHO.

http://www.aroundthewoods.com/brace.shtml

And here is how I did the cutters:
http://www.aroundthewoods.com/hooktool.shtml

I made up about 10 cutters, right and left hooks.

Another tip, I did the final honing in my drill press. I took a 1/4" bit of dowel and coated it with some crazy automotive rubbing compound. That seemed to do the trick.

Cutters and scrapers may be different animals, but a hook seems like something you'd want.

If you'd like, I'd be happy to whip up a few cutters for you to try. I'm sure they would fit in your Sorby. They cost about $0.00003 for the nail and $3,000,000.49 for me to be labor.

Good luck!

Jim

 

[DaveO]

That's very similar to what I have, mines cheaper:cry:. But the principle is the same. If you get an opportunity to try your other one out, and have successful results with it, I would really appreciate a picture of your technique. Tool rest height, angle of approach, if you changed the grind on it, etc.
Thanks for your reply

Dave

 

[dino drosas]

Hi Dave,

Go to this site http://www.robert-sorby.co.uk/ Firstclick on the movie clips and then to the "Hollow Master" clip. I am not much of a turner but have found these vediod very helpfull and imformative. Good luck and Happy New Year.

 

[Wildwood]

DaveO, have a real old set on Sorby mini hollowing tools with home made handles. This set doesn’t come with replaceable tips. Not sure they even sell this set anymore. Have always sharpen these tools with a cabinet scrapper burnisher. Had a heck of a time figuring out how to hold the tool.

So moved the tool rest as close as possible, removed as much material with a gouge. Then slowed the lathe speed down and practiced letting the bevel to rub before twisting tool slightly. That’s how learned to get shavings or chips. Even with lathe speed up still proceed slowly, moving in kind of an arc working my way to the bottom and clearing chip constantly.

Your tool doesn’t look like it has much of a bevel on the cutter. So would think you have go slow and take super light cuts till you find the sweet spot and still maintain control. You’ll know when you find that sweet spot, cause will have to stop and clear waste.

If you have any scrap wood you can mount on a face plate to practice on might help. That way can see and control what’s happening at the cutter end of the tool. It's all about tool rest placement, lathe speed, body movement, and learning to do it the same way every time without seeing what's going on.

 

[froglips]

I talked with my dad. He said it was a lot like learning how to use a yo-yo, only with more accesories and a motor

He echoed wildwoods comments.

He kept adjusting height and rolling the tool till suddenly he got the feel for it. Now he can start and roll the tool till he gets that "feel" and it cuts.

None of the bevels I ground were the same. Given it is a round tool, round cutter head and the universe I rent space in is far from perfect, it was easier to just get close and let the operator feel for the sweet spots.

He empathized with your plight and did mention it was quite frustrating for a while.

One "trick" he mentioned was to practice with the tool on the outside of a turning or even a normal bowl.

Hope this helps.
Jim

 

[NZAPP1]

That's very similar to what I have, mines cheaper:cry:. But the principle is the same. If you get an opportunity to try your other one out, and have successful results with it, I would really appreciate a picture of your technique. Tool rest height, angle of approach, if you changed the grind on it, etc.
Thanks for your reply

Dave

Dave here is how I have the larger tool set when turning hope it helps

 

[Wildwood]

Quite a while back, folks used dull HSS planer blades to make cutters for their hollowing tools. They would grind the profile, drill a hole for the hex screw, then cut off new cutter with a dremel tool. Some how vise grip pliers, for grinding, and snapping off new cutter held in a vise after scoring with dremel cutter involved.

I've never done it, but have a buddy that spent a day making new cutters from old planer blades. They did work better than one that came with tool.

Others would order HSS bar stock from various machine shop suppliers like ENCO or others and do the same thing. Think now most of the wood turning suppliers or Grizzly will sell you HSS stock pretty cheap. Packard has them on page 16, as "HSS Boring Bar Cutters." Grizzly has them on page 648, as HSS Square Tool Bits. If you take a picture of these bad boys, to any machine shop in the area, just may have some laying around they can sell you. One of those item shipping cost more than actual item.

Might be worth a try! If the cutter you have now not working.