hollow rig formats?

[Walt Caza]

Good Day to the Creek,
I wonder if anyone would be so kind, as to explain to me...
the advantages and benefits of an articulated arm VS a captive hollowing system?

Yes, I have searched the Creek archives...
but did not see this specific difference discussed.

I see that some systems offer one version or the other,
some systems offer both, and some systems offer both in the same combo package.

Not trying to stir up a brand loyalty kerfluffle...
but I would benefit to hear what you are using, what you like, and what you wish you had for a hollowing rig?

Any insight appreciated,
hope you get some lathe time,
Walt

[Ken Fitzgerald]

Walt,

I have a Jamieson....but..

Both really are captured systems as they don't rely on the turner to hold and withstand the forces while turning the interior of the HF.


The one advantange that I can see of an articulated system over say my Jamieson would be the amount of space it takes up. Other than that it might take less effort to use the articulated arm.

Those are the only two reason I can see and at least one of those is somewhat suspect IMHO.

[Steve Schlumpf]

Walt,

When I first started turning hollow forms, I was using a Sorby goose neck and the Sorby multi-tip tool. Both worked fine but the torque encountered and rotational forces I had to deal with while hollowing left me sore for days. Figured there had to be another way…

While there are a number of hollowing systems out there – I can only address the systems that I have as I have no experience with any of the others.

So, I did some research, saved my money and ordered the Monster captured system. The system was designed such that it absorbs the bulk of the rotational forces and prevented the cutting tip from rotating while inside the turning. In addition I picked up the laser system that went with it and no longer have to hollow blind.

The more hollowing I did, the more comfortable I became with the system. There was a noticeable improvement in my hollow forms and I wasn’t sore for days like before.

I eventually picked up the Monster Articulated system as well and really like using it also. The articulated system runs on bearings and operates unbelievably smooth. You have to be careful - really pay attention - when doing the finishing cuts as the arm moves effortlessly and it is real easy to apply to much pressure or move to fast and cause a catch. You get used to how easily the arm moves and can actually achieve finish cuts inside the form that makes sanding optional.

So, for me, what I found is that the captured system excels at rouging out the hollow forms and taking the form down to almost finished thickness. Then I switch over to the articulated system to do all the finishing cuts. Can you get by with one system or the other – absolutely. Is one system better than the other – no. Everything depends on the application, wood, your experience, time of day and wind direction. In all honestly – you would be happy with either style of hollowing system but these systems are expensive. If possible – get with someone who has a hollowing system and try it out first. See what the different style systems can do and which one works for you.

If you feel like a road trip – I have both systems.

[Richard Madison]

Steve,
Would you say that you can go a bit deeper with the "captured" rig versus the articulated rig?

[Bernie Weishapl]

I agree with Steve as I have both systems. Both have there places and as Steve said one or the other would work. I have also found the articulating arm unit is so easy to use you really have to pay attention.

Richard the one thing I did notice and I don't know if Steve has or not but with the Captured rig I am not afraid to do a deeper HF. I do about 6 to 8 inches with the articulating arm and have went 10 to 12 inches with the captured unit. Unless my boring bar was larger I wouldn't go any deeper.

[Richard Madison]

Thanks Bernie. I suspected that but did not know for sure. I have the articulated rig, and the going gets tough for me at about 6" deep. However, based on something Steve wrote recently I ground the end of a 3/16" bit to 1/8" wide and then ground usual rounded end on it. Trial run today was much better.

[Steve Schlumpf]

Richard - I find I can go deeper with the captured system as compared to the articulated. The captured seems to handle the rotational forces better than the articulated - probably because it is mostly a straight boring bar. I really like the articulated for finishing but it gets pretty grabby when using a straight cutter and going deeper than 6" to 8".

Glad to see the smaller bit is working for you. Takes a little longer but a whole lot less rotational forces come into play when using it.

[Jeff Nicol]

Well I think they both are great systems, but like Steve and Bernie have said the articulated arms will give a little at each joint and at deeper points you will notice that. That is why I think you will get catches if you take to heavy a cut while finishing. The bearings are nice but I think if there was more surface to surface contact at the joints it may take that away, the side torque put on the bearings on a heavy cut causes the flex. If they were a full thickess of the arms roller bearing and the bolt was perfect tolerence to the bearing that may get rid of it. So I think the captured rig is the heavy duty one and the articulated one is the finisher because of its smooth movements. So far I just use my homemade tools and hollow as deep as 20" so far, but like Steve posted after our visit, I use my "Harpoon" for the deep stuff! It is 1 1/4" steel with a maple handle about 6' long! I have added a side handle for a 2 handed grip to account for the torque.

So use them all and you can't go wrong!

Jeff

[Reed Gray]

Is there an echo here? I agree pretty much about the differences stated. You have 3 options for hollowing. There are hand held devices, captured systems, and articulate systems. I do tend to use hand held (McNaughton/Kelton) for roughing. I don't go beyond about 10 inches with them. If I am going deeper, I have a heavier captured system (1 1/2 inch bar). For the finish cuts, I prefer the articulated system (Monster).

I can hollow faster with the hand held than any of the other systems. No need to be dainty or neet, just get the rougage out of the way. If you spend a few hours doing it, you will get sore. It is a lot of work. If you do it all the time, you can get conditioned to it. Hard to put a laser on them, but it can be done. You can learn to do fine finish cuts with them, but there is a learning curve, and you really have to learn to 'feel' what you are doing.

The articulated system does only take fingertip pressure to cut, and I love the laser system with it. It really makes hollowing easier especially once you learn how to focus the laser and use it. The down side is the joints in the arm. They do make it much easier to move, but they will flex. This is why they don't work well for deeper than 6 to 8 inches. You can put a longer and heavier bar in them, but the levers are too long, and they will chatter. My 5/8 inch Kelton hollowers work fine but the 3/4 inch ones are just too long and will chatter no matter how dainty I am with even the lightest cuts.

Captured systems can be small and dainty to huge, depending on what you want to turn. Since they are in a form, or frame of some sort, the 'work' of holding them up and absorbing vibration is done by the frame work that has them captured. Okay for roughing cuts, finish cuts are pretty easy as well.

robo hippy