Hollowing systems revisited

[David Reed]

I am seriously looking at buying or making a hollowing system to ease the strain on my rapidly wearing out hands and shoulder.
What are the pros and cons of the articulated system (Monster or similar) vs the captive system (Jamieson or similar).
For comparison purposes, using the 3/4" boring bar, what is the useful hollowing depth beyond the tool rest of the individual systems?
Is there a significant difference in finesse and control of the cutter/scraper or in the final interior finish (considering vibration etc)?
What about access to hollowing up under the rim?
The captive systems appear to be readily upgradable to larger boring bars. Is this also true of the articulated system? (I do not see this as an option on the Monster website).
Thanks for your thoughts
David

[Tim Rinehart]

I have not used an articulated system, however, since you mention use of a 3/4" boring bar I will say that I've not heard anyone talk about using articulated types on really deep hollowing using a 3/4" bar. Can it be done, probably...perhaps someone will respond.

As to depth for a 3/4" boring bar, I suspect somewhere in the range of 10-12 inches comfortably before vibration starts becoming a factor, and you would need to use much lighter cuts with smaller cutting tips.

Up under the rim, I still use my hand held cutters (Sorby multitool) or Hunter swan neck, but I have used captive system there too with a Sorby swan neck from Soveriegn system. Either system will allow the work on the shoulder, provided the tool isn't too long. The articulated systems that mount to the tail stock may have less flexibility to move around that area than the ones mounted on plates that can swing a bit.

I'm sure you'll get alot of info to digest...I made my captive system using info from Lyle Jamieson's site. If you have any questions on build, let me know. I'm very happy with it and it's very flexible in what it can use, and it cost less than $75 to build...including a remote switch and batteries for the laser similar to the Monster system.

[Bernie Weishapl]

David I have both the Monster articulating arm and his captured unit. I like Randy's system as when you buy you don't have to add this and that. The articulating arm system with what is supplied can go 10" deep pretty well. I use the captured system for deeper bigger HF's. I would give Randy a call and talk to him. He is great to work with and will give you some sound advice.

[Reed Gray]

I also have a Monster system, and a larger home made captured system. Going 6 inches deep is simple, and I would keep forms no deeper than that till you get the hang of it. Going deeper takes a little more experience. I prefer to do the rough hollowing with my Kelton hollowers (I have all the adapters and the whole Kelton set of hollowers), and then use the carbide discs to finish cut. The articulated systems are disgustingly easy to use (especially with a laser), and really take finger tip pressure to operate. The Kobra articulated system looks to be beefier than the Monster, which means you can reach out farther off the tool rest with it.

robo hippy

[Don Geiger]

Dear Fellow woodturners:

As a general rule of thumb with a solid steel round bar, you can expect to be able to go a maximum of 15 times the diameter in beyond the tool rest. Theoretically, if you have a 3/4" bar, you should be able to extend approximately 11.25" past the tool rest. Of course this depends on how sturdy your support system is behind the tool rest is. If it is flimsy then the distance would be shorter. Also, anytime you get to the limits of a system you'll need to use more finesse to make your cuts and use less aggressive bits.

I have a Red Kobra that came with a 1" diameter bar and I have adapters for 3/4", 5/8" and 1/2" bars. The Kobra is very sturdily built and I can go 15 times the diameter past the tool rest. Jerry Arnold, at Kobra, told me he has recently built a 1.5" diameter bar and can go 22" with it. I believe the Kobra is capable of supporting the 1.5" bar at that distance since I get no discernable chatter or vibration when the 1" bar is fully extended.

I also have an original Sudol system with a 1.5" diameter X 6' long bar that weigh 40 lbs. It too is capable of going 22".

Sincerely,
Don Geiger

[David Reed]

Thank you all for the input. I think I will concentrate on a captured system. I have some plans for some fairly deep hollowing on the horizon. I will likely build the system and buy the inserts with cutting/scraping tools. I like the looks of the carbide cup cutter for interior finish. Currently I am using the Sorby swan neck hollowing tool with the strait and round scrapers. I am intrigued by the hook tools but they really scare me off. I can cut on the bevel outside but interior is just too spooky.
thanks again
David

[Richard A. Rivera, M.D.]

I have used a couple of hollowing systems and the same proublem with most is in controlling the torque on the tool and the size of the tool. I now have a flat tool rest made by Don Derry (see Derrytool.com )with a top on the tool rest to act to reduce the torque. The tools are of square materal instead of round. With a round tool the greatest strength is at the maxium diameter an tapers to the edges, with a square "rod" the max strength is spread through the entire width. For my tips. I use 5% cobalt 3/16 square cutters which I gring to shape and are mounted using the holder from Packard (part #105809) attached to 1/2 in 1080 square steel bar and for larger forms I have built one with 3/4 in. steel, with this one I have done an 18 in vase.

Think square ....not round......Richard

[Greg Bender]

including a remote switch and batteries for the laser similar to the Monster system.[/QUOTE]from Tim

Tim,
tell me about the remote switch and laser you were talking about in the post from Dec2.I bought a laser pointer by mistake on fleabay.Come on ,spill the beans.Talk to you later,
Greg

[David Reed]

The tools are of square materal instead of round. With a round tool the greatest strength is at the maxium diameter an tapers to the edges, with a square "rod" the max strength is spread through the entire width. For my tips. I use 5% cobalt 3/16 square cutters which I gring to shape and are mounted using the holder from Packard (part #105809) attached to 1/2 in 1080 square steel bar and for larger forms I have built one with 3/4 in. steel, with this one I have done an 18 in vase.

Think square ....not round......Richard

I was also thinking square for it's rigidity but 18" deep with 3/4" bar - impressive! I was considering square tube to maintain lots of strength but reduce the weight over a solid square. Need to check engineering tables for the difference in bending and rotational moment.


including a remote switch and batteries for the laser similar to the Monster system.from Tim

Tim,
tell me about the remote switch and laser you were talking about in the post from Dec2.I bought a laser pointer by mistake on fleabay.Come on ,spill the beans.Talk to you later,
Greg[/QUOTE]

Yes, I would like that info as well.
Thanks

[Tim Rinehart]

Digi-Key (www.digikey.com (http://www.digikey.com/))
Laser- P/N : VLM-650-03-LPT-ND (~$ 9.00)

Battery Holder with Switch-
P/N : SBH-321AS-ND (< $ 1.00)

After getting these two pieces, I used some plastic tubing to run the wires thru...not necessary, but helps keep things neat.

if you need anything else...just PM me. Good luck, it's a pretty nice way to do this and avoids possible expensive batteries with some cheap lasers. I'll go get a pic to attach...self-explanatory on how I mounted it..or at least easier with a pic to go along.
here's the pic...
169446

Tim

including a remote switch and batteries for the laser similar to the Monster system.from Tim

Tim,
tell me about the remote switch and laser you were talking about in the post from Dec2.I bought a laser pointer by mistake on fleabay.Come on ,spill the beans.Talk to you later,
Greg[/QUOTE]

[Greg Bender]

Tim,
Thanx for the reply,ordered it this morning.Also found some speaker crossover components I needed.Talk to you later,
Greg

[pat miller1]

Thanks for the info on the laser and battery holder- just ordered-
--pat

[Wally Dickerman]

If you want to do really deep HF's, check out Brian McEvoy's system. He does HF's of 30 inches or more. He has plans to make your own.

I'm not sure, can I post his url?

onegoodturn.ca

[robert baccus]

If you enjoy peeling 5/8 curls at 20" deep with no chance of grabbing simply pick up the Woodcut promaster powerhead with safety guage on top which limits cut depth cut. mount on any deep boring device. It will peel(as in cut) out a gallon sized vase in much less than an hour. Is there a challenger??

[John Keeton]

Robert, the concept appears similar to the Munro system.

[Joe Meirhaeghe]

If you enjoy peeling 5/8 curls at 20" deep with no chance of grabbing simply pick up the Woodcut promaster powerhead with safety guage on top which limits cut depth cut. mount on any deep boring device. It will peel(as in cut) out a gallon sized in much less than an hour. Is there a challenger??
Yes there is a challenger. The Rolly Munro will do the same thing. I've been using one for years. It's a excellent choice too.

[robert baccus]

Just to look at you are right John. However I think the Woodcut has 2 advantages. It is really a very heavy hook tool and is open in the back for chip ejection. You cannot break the things--several of mine are 10-15 years old. No cutters to buy and easily sharpened with a diamond tapered tool or dremel. They survive dry oak burls ect. It essentially never clogs--maybe on full wet aspen or sweetgum. Dry it out for a week and they cut fine. My Jamison shop built tool also accepts all the square and teardrop cutters for special shapes. The tip cuts a smallish round cut but the side of the oval cutter takes out a 5/8" wide, deep curl. I usually use it with a 1.5 to 2" pilot hole and the side of the cutter does most of the work. Monroes are cool but these are much heavier duty IMUO.