I learned something

[SceneryMaker]

that everybody else probably knows but I thought I would share, just in case.

I needed to bore a 2" hole in a green turning and my biggest forstner bit is 35 mm (1.38") so I tried a trick. After boring the 35 mm hole normally, I turned the headstock back a little so that the bit was only cutting on one side, much like a boring bar. Rinse and repeat until the hole was big enough. Yes, the resulting hole was a bit tapered, but for the inside of a vase, it was close enough.

[iclark]

After boring the 35 mm hole normally, I turned the headstock back a little so that the bit was only cutting on one side, much like a boring bar. 

My brain is being a bit slow tonight. It took me a while to figure out that you were talking about swiveling the headstock.


That sounds like it should work fine with a good Forstner bit as long as you are not too aggressive. If you get aggressive and have a catch, the bit may get bent. I would not try it with a hole saw.

An alternative for those  whose headstock does not rswivel is to use the Forstner bit and then use a skew flat on the tool rest as a drop-nose scraper to enlarge the hole to whatever size you want.

[SceneryMaker]

I tried reaching in there with my skew but felt it was too deep for good control. It was chattering and I don't know how to stop it.

My general rule around power tools is "If it feels bad, figure out another way before it bites you".

So I did.

What I should have done is go buy a hollowing system. Good excuses don't come along all that often..

[Herebrooks]

Another trick, which wouldn't apply in this case, is to grind one side of the spur on  a spade bit to get a slightly bigger hole. Of course you sacrifice the spade bit.

[vernonator]

I tried reaching in there with my skew but felt it was too deep for good control.  It was chattering and I don't know how to stop it.  

My general rule around power tools is "If it feels bad, figure out another way before it bites you".

So I did.

What I should have done is go buy a hollowing system.  Good excuses don't come along all that often..

That's a GREAT rule and I have the same one. If I feel uncomfortable doing it I figure some other way....

[iclark]

I tried reaching in there with my skew but felt it was too deep for good control.  It was chattering and I don't know how to stop it.  

My general rule around power tools is "If it feels bad, figure out another way before it bites you".

So I did.

What I should have done is go buy a hollowing system.  Good excuses don't come along all that often..

That's a GREAT rule and I have the same one. If I feel uncomfortable doing it I figure some other way....

+1 on the good safety rule.

That is why I have been too chicken to use the Scorpion hollowing tool that I bought 2nd hand. I bought the Monster Tools articulated hollowing system and am very happy with it. The founder of the Monster Tools was a member here until his death. The next generation has impressed me with their efforts to follow in their father's footsteps.

I have also been privileged to try a couple of captive rigs like Lyle Jamison's (sp). Lyle's system is also a good one and he is a very good man.

There are also some specialty toolrests that can support tool deeper into a vessel/bowl.

You also get less bounce/chatter with a thicker scraper. Alan Lacer's large skew, Glenn Lucas' dropnose scraper, and Doug Thompon's largest skew are all well made examples. If you go with the one from Doug, there is some tuning at the grinder that can be done to make it much easier to control and much friendlier to your toolrest surface.

I should also point out that I should have said that the slew that I was recommending was a traditional one and not an oval skew. An oval skew will just get you in trouble as a dropnose scraper.

[MichaelMouse]

You can use the point of the skew as a scraper, but you have to take gentle bites.  You can use other scrapers as well, and the same advice works.  Makes no difference how thick the metal part is, what counts is how long the handle, and the resulting mechanical advantage.  If you have a toolrest that will swing to allow closer support, or project, as some specialty rests do, you improve MA.  It chatters because the drag exceeds the force you can exert against it with small MA.

http://s35.photobucket.com/user/GoodOnes...rt=3&o=383

http://s35.photobucket.com/user/GoodOnes...rt=3&o=382

If you have a cheap deep gouge to spare, make a "pointy gouge" for hollowing side to side.  You can see the shavings rolling out in the second picture.

http://s35.photobucket.com/user/GoodOnes...rt=3&o=381

Works rapidly, because it's cutting more than scraping.