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Hollowing

L

LANKFORD

Joined
Mar 21, 2006
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Location
Vienna, Virginia
For a vase, or other tall container, turned with grain inline with the vase, do you guys with the experience resort to drilling say a 1" hole on a drill press before starting the hollowing on the lathe? If not, how do you start? I'm getting the jitters just thinking about the task. Any tips would be helpful.
 
I haven't done any "tall" vases, but the short ones that I have done were drilled on the lathe. It would not be wise to drill the center off the lathe because when you remount it, the hole will be off axis.

Before you start roughing the exterior, you could drill a shallow hole about a half inch deep on each end so that a catch will not cause the piece to come off the lathe. Make the diameter large enough that the spur drive and the live center point/cup fit into the holes. If the vase is "tall" then you will need a steady rest or a very solid faceplate arrangement.

Bill
 
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I am with mike on this use your lathe to drill the hole. Rather than for starting the piece which is easy enough with a gouge our scraper I drill mine for depth marking. Depening on the piece I use my lamp auger or a 24" hss drill bit in a handle mount through the tailstock and hollow center. Other times I use a forstner bit in the drill chuck.
 
Try the big brad-point bits over a Forstner. They haul dust out of the piece more effectively, and are cheaper. Chinese quality is good enough, because they're easily sharpened. Additional benefit in the greater length, which requires no extension to bore deep enough for a test tube, which is all, in my opinion, a vase needs. Anything hollowed becomes a looker, rather than a user. Can't even effectively use a turner-pleasing "hollowform" effectively for dry arrangements, because it doesn't have enough weight to counter the load.

Remember with either bit that the outside cuts a circle below what you feel or see as the bottom. If you don't allow for it, you have a tendency to rediscover it when tapering the outside.
 
I like to drill a hole first - on the lathe. It gives me a space for chips and it also give me a depth for the inside bottom. I like "taper shank" drill bits. They come with a Morse taper and fit in the tail stock. If they are not long enough, I use the taper shank drill first and then go to a hand held extra long drill. Then I use the hollowing tools to widen the hole. The bigger the hole the more chips/sawdust it will hold before cleanout is needed.
Hugh
 
I do alot of hollow forms and, yup, I drill them out. I use forstner bits when available and will often start with a regular twist drill bit then run the forstner. This lets me set depth and helps alot with the shavings clearing and ease of penetration.

I used to use primarilly spade bits but they exert a very strong and somewhat uneven force on the piece, pulling it off the lathe sometimes.

If you don't have one already, make a steady rest to use on any piece longer than 6". Makes a huge difference in vibration and difficulty of hollowing.

And, finally, I usually hollow much more than just drilling. It makes a big difference in the feel of the vase, changing it from feeling like a block of wood to feeling more like a sculpted form. I usually taper the hollow towards the bottom, leaving a nice, solid, bottom heavy feel to the vase. Not too light, not too heavy. If it feels like the vase could be light ceramic, I've hit it about right. This also helps alot with dry arraingements not tipping.


Dietrich

P.S.(if you haven't discovered single flute metal milling bits for use with deep hollowing rigs, you're missing out. Find them at a machine shop supplier)
 
LANKFORD said:
For a vase, or other tall container, turned with grain inline with the vase, do you guys with the experience resort to drilling say a 1" hole on a drill press before starting the hollowing on the lathe? If not, how do you start? I'm getting the jitters just thinking about the task. Any tips would be helpful.
Click to expand...
The drill press will only allow for maybe 4" or so of depth, and the mounting off center thing too. Use the lathe for the drilling, depending on the depth of the form, if you have a bit long enough, mark the bit somehow and drill to that depth. No need for jitters, it is a practice thing, like everything else you have already done.

How deep?


dkulze said:
P.S.(if you haven't discovered single flute metal milling bits for use with deep hollowing rigs, you're missing out. Find them at a machine shop supplier)
Click to expand...
Single flute? Can you show me an example?
 
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If you use a forstner bit make sure to back it out often. It could get stuck when shavings pile up behind it. DAMHIKT

I have also done a lot of hollow forms. Another technique to get the central hole is to just drive a detail gouge in to the depth you need. It act like a good drill bit and you don't have to worry about which angle it is at.
 
drilling weed pots

I also use auger bits . I don't think you need to clean out the hole as you go as often as with the others, and it "saves" the forestner drills. But they don't have the right sized auger (? 1 1/16"?-am at work and can't check my cheat sheet)(at least in some of the catelogs I have) to fit easily fit the 1 inch glass inserts and the lip of the glass doesn't sink below.
So I predrill with the correct forestner for an inch or so (to prevent wandering for redrilling with the forestner), haul out the major wood hole with the auger, and then use the correct size forestner on an extender and drill to depth.(6 inches or so). Not sure all these steps needed, but what I have worked out. As Michael M alluded, you can blast thru this hole from the side while being "creative" and "artistic". Early in woodworking I used a drill press first, put on lathe and had this nice hole in the side of the vase neck. Many people asked "How did you do that neat thing!!!" :D
My problem has been parting off and finding the drill hole staring me in the face from the bottom. Needed a piece of wood 1/4 inch longer!!!That is an "artistic " creation to assist glass removal for cleaning, in case the wood swells it tight!! ;)
Again, like Michael ( maybe I'm beginning to understand you!!!) I don't see much use in hollowing out, at least for the smaller vases. I have Jamieson's set up, but have never used it. Waiting to get bored with all the pretty woods that are out there. Don't want to take the time to learn it now. Gretch
 
Interesting P.S.

dkulze said:
I do alot of hollow forms and, yup, I drill them out. I use forstner bits when available and will often start with a regular twist drill bit then run the forstner. This lets me set depth and helps alot with the shavings clearing and ease of penetration.

I used to use primarilly spade bits but they exert a very strong and somewhat uneven force on the piece, pulling it off the lathe sometimes.

If you don't have one already, make a steady rest to use on any piece longer than 6". Makes a huge difference in vibration and difficulty of hollowing.

And, finally, I usually hollow much more than just drilling. It makes a big difference in the feel of the vase, changing it from feeling like a block of wood to feeling more like a sculpted form. I usually taper the hollow towards the bottom, leaving a nice, solid, bottom heavy feel to the vase. Not too light, not too heavy. If it feels like the vase could be light ceramic, I've hit it about right. This also helps alot with dry arraingements not tipping.


Dietrich

P.S.(if you haven't discovered single flute metal milling bits for use with deep hollowing rigs, you're missing out. Find them at a machine shop supplier)
Click to expand...
Dietrich, Could you take a moment and explain this comment about milling bits for deep hollowing? In my adventures of learning how to hollow this sounds like a very useful idea that I need to explore. Thanks, Phil
 
Most hollowing tools use some type of tip or bit attached to the main body of the tool. A good example of this is the Sorby Hollowmaster (my favorite), which has several interchangable tips held on by small pressure plate and set screw. The cutting bits are made from a variety of materials ranging from heat treated steel rods to tungsten steel variations.

Now most folks who get into hollowing end up improvising tools at some point. The most common of these improvisations comes when it's 8pm, the local woodcraft is closed, and you've just realized you can't find the little half round hollowing bit. At this point, pretty much any small, hard steel item becomes a potential bit. Most folks just hit the grinder with an old drill bit, flatten one side of the shank, and mount it right up on the tool.

For those of us who get a bit more experimental, there is an almost infinite variety of milling bits available through machine shop supply companies. These come in square, round, oval, diamond, and other shaft shapes of pretty much any length or dimmention and can be purchased with shapes already ground into the ends or as unshaped stock to grind to spec.

Most folks, when they purchase such stock, get the basic, unshaped or flat ended stock of some type of tungsten steel. These are hard and durable but soft enough to grind without totally destroying your grinder (though it will still take alot off your wheel). But, turns out, you can also buy bits designed for milling machines that are preground and are increadably hard, even diamond coated. Bits such as this come with a variety of cutting flanges and look like fancy drill bits. A drill, by the way, would have two flanges. The milling bits may have as many as 16.

Turns out, if you get a single flange bit, you are basically getting a round shaft with a half round end on it. Perfect for using in a hollowing rig. You can even get them this way on both ends. If you're willing to spend a bit, you can get a bit that will, basically, stay sharp for a long time and be thrown out when it dulls. The bits designed for milling tool steel and such would be good examples of this. For the lesser bits, you can get one designed for milling aluminium, soft steel, and iron that is 1/4" diameter and single flanged for about $5-7. Just slap this puppy into the attachment point on pretty much any rig and you're set to go.

And that's what I was talking about.

Dietrich :D
 
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