Weekly discussion topic - Week 2 - hollow forms made simple!

[SVB]

Wow. Last week's discussion on airbrushing was great and generated some good advice, tips and of course, allowed Dal boy to once again share his excellent remembrance piece.

So this week the hollow forms topic came out of the hat.

There were a number of Qs on hollow form on how to simply make them without loads of specialist tools to the steps in finished deep or narrow forms:

(From the 'topic hat'):

* Simple ways to construct deep hollow forms that don't require specialist or expensive hollowing tools.
* Sanding and finishing internals of deep forms
* Sanding and finishing internals of small diameter hollow forms (with entry lips)

So, away we go. Take these as a start but it is all our forum so we'll see where you want the topic to go!

What say you this week?

Best regards

Simon

 

[Dalboy]

I will start off with a simple way of making a hollow form and this is something I picked up from Mark Sanger and that is to make the piece in two parts this allows the use of the basic tools. The join can then be hidden using lines around the piece or my texturing over the join line like in these two pieces.
The join on this piece is the centre of the pattern

The join is hidden in amongst the texture on this one

To finish the inside of deep forms you can either make a stick up with sandpaper on the end of if you have a sanding system like the Hope one as long as you can get it in comfortably

If the form ha a small hole then I tend to get the best finish that I can from the tool and go over with a tear drop shaped scraper but will only sand as far as you can possibly reach as there is a good chance if you can't reach into it then no one else can. You could again use the sandpaper on a small stick. I am in the process of making a kind of flap wheel for sanding further into small openings but will have to try it before showing on any forum.

I am sure there are many question to be answered on this subject.

Special tools for doing hollow forms are varied I have the crown Revolution system with a 1/2" and 3/8" shaft I also have the Midi Revolution which is for smaller forms. I find the very good and am sure others will have their preference.

A good book is Mark Sanger's "Turning Hollow Forms" very informative

 

[CHJ]

If I really want an internal finish to rival the external I follow Derek's system of splitting the piece into multiple sections.


I did this initially some 9 yrs or so ago when using small offcuts to make deeper items and got into the habit of working with this easier principle rather than going down the deep hollowing route.

I also still use the simple technique shown here for vases, hopefully with a little more finesse in the actual turning these days but still using the same tools.

On the sanding front I often use the velcrow pads and abrasive cut in oversize squares as a crude flap wheel inside deep hollows using hex bit extension rods.

 

[Honest John]

Splitting the job into 2 or even 3 pieces makes total sense, and is the way to go. Sure it’s posible to turn an elegant tall piece through a tiny hole on the top but why would you even want to do that if there are easier ways to produce the shape. In my book you don’t earn extra brownie points by producing something by a more difficult means, that’s just silly.
I generally use normal bowl gouges, both long “Ellsworth” and conventional grinds but I also use the Crown Revolution hollowing system with their ring cutter. I have never thus far used the crown revolution scrapper type bits.
I also like the Sorby K200? Hollowing device and tear drop shear scraper.
I do own and occasionally use carbide cutters (Sorby). I don’t really like these, but I use them mostly when roughing out my segmented builds that have a significant amount of glue in n them. The carbide deals very effectively with the abrasive effects of the glue, but I always finish on the conventional tools.
Sometimes an adaptable tooltrest that enables support nearer to the cuting surface, box tool rest or curved bowl rest, can be of more importance than any special laser guided gizmo. I guess it all depends on the depth over the rest that you are working to, but spliting 5he job into two parts should always be the first consideration.

 

[Dalboy]

Another way of hollowing a piece if a join line is not required but a small neck is part of the design is to hollow through a larger hole in the bottom of a piece. This means that a chucking point is needed around the neck which can be turned off by reverse mounting the piece this can be a complete subject by itself.
There are times when hollowing that the neck allows a good access to the inside It can be done using conventional tools as long as there are no deep undercuts at the top. If deep undercuts are required then special tools are part of the norm.
With nearly all hollow form turning the outside shape is needed to be able to work out the inside shape and how much is needed to be removed, Just like you would a bowl.

 

[CHJ]

Following on from Derek's comments larger hollow forms can be constructed using smaller stock, does not need to be segmented to use this technique

Anyone use small Drum Sanders, are they effective in vases etc. I haven't tried because I've not found a reasonably priced source for the abrasive tubes which I suspect would be rather short lived used this way.

 

[Robbo3]

Anyone use small Drum Sanders, are they effective in vases etc. I haven't tried because I've not found a reasonably priced source for the abrasive tubes which I suspect would be rather short lived used this way.

These drum sanders from APTC are sleeveless
- https://www.axminster.co.uk/axminster-s ... s-ax896201

 

[Lazurus]

I use the Lyle JAMIESON deep hollowing rig, if anyone is interested in getting a rig I can thoroughly recommend this one it is literally fingertip control and very accurate.

I did have a selection of deep hollowing tools but now I just use this and a Hamlet big brother which I get on well with. Befor this I like above made segmented hollow forms and these can be done with more modest tools to great effect. I have recently been using resin / burr hybrid forms and this can produce some stunning results.

 

[Chris152]

Nice works, Derek.
I think that for these weekly discussions to work we need to see more of what people are making - pics, I mean.
I've never done any deep hollow forms so have nothing to offer, and the thought of doing it frightens me. But I'd really like to see the possibilities, and hear about the struggles to create them.
I quite like Ellsworth's pieces, very much based on 1960s/ 70s ceramics from what I can see. How on earth does he get in under the rim with those bent gouges to hollow sideways without getting catches/ the tool tipping? To my mind, wood-turned hollow forms are generally more interesting than ceramic ones on account of the medium, but is woodturning just chasing ceramics when it comes to hollow forms?

 

[CHJ]

How on earth does he get in under the rim with those bent gouges to hollow sideways without getting catches/ the tool tipping?

The Swan Neck tools aim to keep the cutter in line with the tool centre line to reduce any twisting loads on the cutter.

But hollow forms of that nature are rarely "Finished" inside beyond what can be felt with the fingers.

 

[CHJ]

Anybody make their own flap wheels for internal finishing?

Disc or Drum format?

How do you assemble them.

 

[Lazurus]

I find with the Lyle JAMIESON rig no sanding is required

 

[Dalboy]

Anybody make their own flap wheels for internal finishing?

Disc or Drum format?

How do you assemble them.

https://youtu.be/UFHPbZff9Eo

https://youtu.be/wAHsLzB6ayE

View attachment flap sander.pdf

 

[CHJ]

Thanks for the links Derek, more grist to the mill as they say, some variations on the theme, I think I'll forgo the glued/moulded versions though, I'd spend more time making replacements than using them I fear.

 

[Dalboy]

i am thinking of having a go at the one in the PDF when I get chance.

 

[Paul Hannaby]

As long as the undercut beneath the hole isn't too steep, you can hollow a hollow form with a gouge that has a fingernail profile on it. So it follows that for deeper hollow forms, a longer gouge would work so a decent sized bowl gouge could hollow an 8" deep vessel.

Simple swan neck hollowers with scraper tips are fairly cheap in comparison to some of the other tools available and to be honest, although I have several hollowing tools, I often find myself going back to the basic ones because they just work better!