Thread: WIP: deep hollowing

What depth of hollow are you hoping to get Ern?

Also what sorta hollow are you planning. Are you hoping for a thin wall or are you just going to remove 2/3 the inside timber?

I saw a couple of presentations at the Bris WW show one by Bruce Bell of Vicmarc and his idea was that these vessels are mainly for holding dried flowers or such and no need to aim for thin wall hollow form - but I suppose if you are after something for handling and appreciation of turners then you will have other ideas.

I also saw on the Vermec stand a hollowing tool on my "can't live without" addition to the lathe a wonderful hollowing tool and support but I think it's maximum hollowing depth (from memory) was not much over 300mm. You have a 500mm long object - so my curiousity is to what depth you intend to go.

TJ, with the tenon and the turning away of the shoulder I had to do the total height is now 39cm.

As for the machismo of wall thickness at this stage I don't know. Conservative is prob. wise given the knots and my skill level. And Joe's point is important: too light and it'll easily blow or be knocked over.

Yeah, IIRC Cliff has the Vermec and can comment on how it goes. Least you getting some cutting tools thrown in compared with the VM support. On the other hand the VM allows you to fit varying kinds of tools, and shafts up to 3/4" in diameter. Seems most guys doing this kind of thing mount a HSS scraper tip in a mild steel shaft.

Well Cypress is an interesting timber to finish

Using std power sanding techniques deep scratches were left that subsequent grits wouldn't remove. Sounds a bit like Huon.

It took three tries from scratch (ahem) to sort this out.

One problem was using Sunmight velcro paper from a local supplier ... crap paper.

So it's now sanded down to 800 grit and has half a dozen coats of weak shellac sanding sealer (Ubeaut White dewaxed shellac that had gone off, diluted 1:3 with meths). Chose this to get just a bit of darkening to blend in the CA/dust filled checks. Not dark enough as it happens.

Will knock this back with hand-held fine wet and dry and hopefully it'll be ready for drilling the depth hole with a sawtooth bit and extension.

It's a bit nerve-wracking having a virtual audience leaning over the shoulder! And the hard part hasn't started yet.

such is the price of fame...

LoL.

Or infamy.

The lump stares back at me in silent reproach every time I go out to the shed for an illicit fag.

Lost my sense of playfulness in turning a piece.

Come on Ern where's the pics

I know i'm impatient but waiting for the big curly things and photos - its like getting a new bandsaw or thicknesser and reading the instructions and watching the video instead of bolt it together, get a lump of wood and put through it to try it out.

The tension Ern, the tension, it getting to me

cant wait

Well, it's your kindly donated piece Calm, so ...

Remounted it in the chuck adding the spindle steady which sits about half way down.

More out of round than I expected which will make a clean opening more challenging than I wanted.

Tightened up the Titan and Powergrips hard (like with multi-grips) since I didn't want the shoulder of the tenon broken off.

Turning off the stub revealed major voids at the top (pic 1).

I like depth holes and so used my procedure for hollowing pepper grinders. Was aiming for a 340mm hole. Opened up the first bit with a 2" saw tooth bit in a Jacobs chuck.

Then did the depth drilling with a 1" saw tooth bit in a MT extension (pic 2).

Measured repeatedly, and had to mark the quill rather than the extension. Kept withdrawing and blowing the shavings out with a rubber tube. Took it gently, esp. the withdrawing, mindful of 's warning of Jacob chucks coming out of the tailstock. As it happened that occurred with the extension but only on the home stretch so I hit the mushroom switch, removed the tailstock and was able to wiggle the extension and bit out by hand.

Sure took some time. Expect after the 20th it'll be easier

For the old hands, what could I have done better/quicker?

Sure sounds like "fun", Ern. Especially coaxing the bit out when it's clogged with shavings. My Jacobs chuck shank has Jacobs taper into the chuck and Morse taper into the tailstock. Even more "fun" when they both loosen at the same time. I guess the MT extension reduces the "fun" to only one adventure.

I've abandoned Forstner/sawtooth bits for end-grain drilling in favour of Irwin/Speedbor augers. They have a lead screw, but in most timbers the screw just fills with dust and doesn't pull too hard into the timber. For some hardwoods, it may be advisable to grind down the lead screw, but we have softer wood around here. Their three flutes still clog a bit, so frequent extraction and blowout is still the way to go.

The Irwin bits have been available here at Lowes and Home Depot for a while; probably in stock at Bunnings and such. Irwin also has 6- and 12-inch extensions that snap onto the bit shank without the need for grub screws.

Cheers,
Joe

Thanks for the tip Joe. Augurs prob. be a bit easier to sharpen too.

Yeah, if the bit had come out of the extension there would have been some cursing.

[Thanks for the tip Joe. Augurs prob. be a bit easier to sharpen

Ern
Also you can modify the cutting end fairly easy if needs be. Sometimes I like to shorten the point down some to reduce the over depth..nothing like a pin hole in the bowl bottom............................. and flatten out the cutting points as well. This gives me a flatter hole and much better depth control

yeah, if the bit had come out of the extension there would have been some cursing

.....just another opportunity to excell..........

if it happens frequently or if its a hairy situation , try grinding a small angular flat for the locking screw to anchor on. Angled it back like a hook or incline, so as to prevent the bit being pulled out should the locking screw loosen off a little.

If the bit has a hex on the end as some do, grind it on that, or chop it off seeing you have an extension.

My extension has a double locking screw so I grind two recesses with the corner of the grinding wheel, to date no dramas. But from time to time I do split the side out of the grub screw so I keep a few spares around.

Ern you are nearly there.

Ern is there a reason not to open the hole up a bit as you go.

Drill 4 inches open up 3 inches a bit with your hollowing tool, drill another 3 or 4 and open up the next bit. That way it gives a bit of relief for the chips to come out. So long as you leave the last bit of hole the drill should start straight again.

I think

cheers

I use saw tooth or forstner bits on end grain. When doing a deep hollow job, that's what I do, bore about 75mm or so and open the hole a bit and bore deeper and so on.
Jim

Yeah could do but there'd be a deal of faffing around swapping tailstock and hollowing rig.

Hughie, thanks for those tips. My biggest prob has been the round shank of the 2" s/t bit turning in the (old) Jacobs chuck, even going gently and tightening the three sides.