captive v articulated arm

[Harvey M. Taylor]

Isnt it also true that you can do small hollowing turnings with a captive system, but you cant do large hollowing turnings with an articulated arm system. Please help me make a decision. Max

[Steve Harder]

I have a homemade elbo articulated arm - I have successfully hollowed 14" deep with it - FWIW. This was with a vessel opening that was large enough to accept a 1" bar with cutter on end of it. So vessel opening was probably 2 1/2 " diameter or so.

When hollowing that deep, the work goes slowly, no matter what system you can't take a lot of wood in a single pass.

[David DeCristoforo]

The "real limitation" is the 3/4" boring bar. It seems massive until you have it hanging ten inches over the tool rest. The articulated system is much more maneuverable, "lighter on it's feet" as it were. The captured system is "better" for deep hollowing. But there is a lot of "crossover" and different people use the two in different ways. I really like the articulated rig for cleanup cuts and for hollowing smaller forms. The captured setup is my "big gun" but while it might bring down a moose, you would probably not want to go elephant hunting with it! If you got the hand held piece with your system, You will find that very useful too.

[David E Keller]

I ended up ordering them both, but I've yet to use the captured system. I love the articulated system, but I tend to turn forms under 10". I agree that the limiting factor is the size of the bar not the method of holding it.

I doubt that you are disappointed in either system, but I've only used the articulated system thus far.

[Ken Fitzgerald]

I've only got the captured system. It's limitation is the bar. I am a rather large guy so operating the captured system really isn't a problem for me.

[Reed Gray]

The articulated systems make hollowing a lot easier, especially on smaller pieces. I have the Monster system, and it takes finger tip pressure to core. Bar size has some thing to do with how far you can reach out with your tool, obviously, the bigger the bar, the farther you can reach. The articulated systems do have some flex in the articulated part, so that is as much of a limiting factor as the bar size is. Larger pieces are more of a specialty item if you are looking to sell them.

robo hippy

[Bernie Weishapl]

Harvey I have both systems. Both have there places and I agree with the rest the bar is the limitation on both systems. I have went 12" with the articulating arm system with light cuts and it has did fine. Most of the time with this system I go 8" to 10" deep. I have also did some 12" to 14" with the captured system but again light cuts are in order. I think if I had a 1" bar I could go much deeper with either one of these units. I don't think you can go wrong with either system. If I could only have one it would be the articulating arm system because I rarely go much deeper than 12".

[Steve Schlumpf]

Max - I have both of Randy's systems and the captured system is my go-to system when roughing out hollow forms. I can get some seriously clean surfaces using it but find the articulated system excels at finish work because it is so easy to control.

No matter which system you decide on - with a little time using it - you will be amazed at the difference it can make with your turning!

Have fun! Looking forward to seeing your gloat!

[Ken Glass]

Harvey,
I have Randy's Monster System and I love it. I can get about 12-1/2' before it becomes less controllable to use. It makes HF's a dream to hollow and with some special bits it can get a great finish on the inside.

[Roger Chandler]

I most likely will get Randy's monster articulated system in the not to far distant future..........now I have a question related to the overhang past the tool rest:

If one used one of the tool rests that are inserted inside a form, and extend the support of the bar thereby, would that allow for a deeper form with the 3/4" boring bar? :confused:

I suppose one would have to keep the opening sufficient to allow a rest to be inserted, which might not allow for as narrow an opening as one had hoped, or either a collar might need to be added to narrow the opening after hollowing is done.

[Don Geiger]

I've got two of the Kobra systems. Because of the lack of marketing, there aren't as many of them out there. I've been turning a long time and I can't imagine anything better for hollowing than a Kobra.

Don Geiger

[David DeCristoforo]

"If one used one of the tool rests that are inserted inside a form, and extend the support of the bar thereby, would that allow for a deeper form with the 3/4" boring bar?"

You answered that question with your next line...

"...one would have to keep the opening sufficient to allow a rest to be inserted..."

The opening would have to be large enough to allow both the tool rest and the hollowing bar to be inside the form, keeping in mind that the cutting edge needs to be "on center".

[Mike Stephens]

I've got two of the Kobra systems. Because of the lack of marketing, there aren't as many of them out there. I've been turning a long time and I can't imagine anything better for hollowing than a Kobra.

Don Geiger

I saw his video on the youtubes. It looks like an amazing system. Is it still on the market?

[Don Geiger]

Yes it is. Contact Jerry Arnold at: 765-534-4437 or jatooling@yahoo.com

They don't have a web site and don't advertise. The company was started by three former GM machinists that also enjoy woodturning. The system works as smoothly (and without vibration) as anything I've seen or used. They have a lot of standard features and several options. Great stuff!!!

They will be demonstrating a Kobra system at Indyfest in September.

Please tell Jerry I sent you to him. He has been very kind to me and very supportive of my pursuits in woodturning. I was on a five-city/four-state woodturning tour a while back and stayed at his home for two nights. I got to see their impressive machine shop in detail.


Don Geiger



I saw his video on the youtubes. It looks like an amazing system. Is it still on the market?