My 1st successful hollow form.

[Old Croc]

This is my 1st successful hollow form from a piece of Queensland Maple, approx 200mm/8inches tall, 150mm/6inches in diameter, done through a 32mm/ 1 1/4 inch hole. I have various factory and home made hollowing tools, but I have had no end of failures with the hand held variety. 2 years ago someone had a Simon Hope articulated hollower at the Prossie Turnout and MKPenturner set it up and gave it a run. I was hooked and decided I had to get one like it. Well I searched the world, looked at products from Hope, Monster, Gizmo, Harrison, Trent Bosch and Vermec. I liked features from all the different versions but the actual tools from Trent Bosch appeared to be the best to suit the figured timbers I work with. So I decided to make my own using the TB tools. Special thanks to Paul39 for collecting the tools for me in the US.
I added the 2 handles to make it easier to steer and it took a bit of refining to eliminate some slop I had with the end thrust bearings it pivots on, but it is as smooth as silk now, does not bite in as the lower part of the tool under the TC tip controls the feed rate.
Following on from Ruru's questions last night, I decided to try and make a bowl with it to see if it would be any help for people with disabilities. The bowl is still on the lathe in the photo, it went OK, but I think it would need a scraper to get a more even finish on the outside. You can see the laser dot on the bowl as I was still working on the inside when the photo was taken.
I have done several other hollow forms, up to 325mm/13 inches deep, but I cant show them until our show competition is over.
Rgds,
Crocy.

[powderpost]

Looks good Richard, how thick did the walls end up?

Jim

[Paul39]

Beautiful piece. I'm as impressed with the tooling you built as the piece. Nice work.

[Christos]

Very nice looking form.

[Old Croc]

Looks good Richard, how thick did the walls end up?

Jim

Between 4 and 6mm Jim. Using the laser guide makes it so easy
Rgds,
Crocy.

[tony_A]

Thats a nice looking vase you have turned there Crocy, but I do like the look of the hollower. Top marks for the build. How did you make the articulated joints to keep them tight.
I started hollowing a vase yesterday using a Munro hollower in half dry blackwood and by the time I was about 200 mm deep vibration was becoming difficult to manage. You've got me thinking.

Tony

[artme]

Good one- or should I say good two - Crocy.

Very brave of you to make your own set up!!

The efficacy of the unit is shown in that beautiful first effort vase.

[Old Croc]

Thats a nice looking vase you have turned there Crocy, but I do like the look of the hollower. Top marks for the build. How did you make the articulated joints to keep them tight.
I started hollowing a vase yesterday using a Munro hollower in half dry blackwood and by the time I was about 200 mm deep vibration was becoming difficult to manage. You've got me thinking.

Tony

Hope this all works Tony. I added a few extra photos in case you want to build one from scratch.
The main pivot post was a billet of 4140 High tensile 50mm/2inch diameter to get the primary bearing surface. The conrod was also a billet of 50mm/2inch 1045 Medium tensile and I milled the flats and bored it with a 20mm / 3/4inch endmill all in one go to have it aligned then turned the middle down in the lathe to reduce its weight. Each pivot point has a bronze bush machined, frozen, pressed in then reamed out to get a precise fit. They all move on End thrust bearings like the one in the photo. I added O rings to try to keep the dust out. The parallel bars were 50X12mm, 2 X 1/2inch Bright steel. I am in the process of making up a height adjuster to fit between the primary bearing surface and the top of the RHS endpost. It will be a male/female threaded bits with knurled ends to make it easier to turn.
I found that sometimes I have to lift the height of the cutter to make it work on small diameters due to the afore mentioned rubbing of the bottom of the tool.
Hope this helps.
Rgds,
Crocy.

[tony_A]

Thanks for the description Crocy, doesn't sound overly complicated if you have the necessary metal working machinery, and the skills to use them. Unfortunately that rules me out on both counts.
Tony