Thread: WIP: deep hollowing

Ah ... thanks.

Yes, tried to use the new jacobs chuck for this but was out of bed length. The new one looks to have better gearing. Many thanks again for it.

Need to make a bigger steady; that'll free up some length.

Ern,

Maybe you already do this but I find it useful to blast with compressed air to help clear the shavings when drilling, seems to cool the drilling process too.

Peter

Thanks Peter.

Don't have a compressor (apart from the lungs). The dust is irritating enough and in those concentrations it was a pox. Couldn't wear the filtered visor and blow at the same time. Had the 'big gulp' as close as I could get it.

Good point about heat. I've discoloured hard woods this way.

While I procrastinate chk out the vid at

http://www.philironswoodturning.co.uk/woodcut.htm

Just as well Woodcut aren't a casting agency.

Ern that is a very old video and they still use it today on the DVD they supply with their tools.

Ken is no longer the owner of the company , you may have met Peter Hewitt when he was over here last year at the woodsho in Melbourne.

He is coming over next week for the Sydney show , I will get into his ear and see if they can get some new videos done.

A bit more progress to report.

Pic 1: opening up the mouth. Alternating between the Proforme slightly bent and seriously bent shafts mounted in a toolgate. Using the seriously bent shaft to undercut the shoulder. Running at c. 500 - 750 rpm; faster than usual since the diameter is not great.

Staying hand-held cos that's what I know and it's easy to see and feel the line. Stopping every half minute or so to vac out the shavings.

With the seriously bent shaft the short straight between the head and shaft provides restricted travel when mounted in the gate and that's a useful limiter on the extent of cut.

Getting a deal of vibration at the tool head. Could be flex in the piece, or could be variation in the material: voids, wood, knots and epoxy. Makes me uneasy.

The initial drilling out has popped some wood in the bead. The 1:1 epoxy/coffee grounds mix turns well but hasn't been tested with a micrometer ;-} It's holding well so far (knock on wood) but the real test is yet to come.

Now down about 75mm. The line is good but there's some corduroy. If I were more confident I'd just go in with one clean smooth pass rubbing the bevel.

Pic 2: cleaned up the inside shoulder with this tool, the scraper produced by Woodcut to fit the Proforme shaft. The spigot has no flat so you can rotate it to shear-scrape.

Worked well. Results (as far as I can picture them) in pic 3. Got some thrumming so it was just as well to do it now.

Checking is appearing at the shoulder as well as a crack running between each of the two top knots and the rim. Filled the cracks as well as some of the bark inside with CA and sanding dust. Running at about 250 rpm with 80 grit paper so as to blend the mismatching lines from the outside shaping and remounting for hollowing. Doesn't look too obvious.

Ern ,
a quick question , is your toolrest brass ?

Nope.

Plate is brass coloured but some kind of plated steel; the gate some other kind of plating.

PS It's an Irons toolgate; made over your side of the Southern Ocean by Woodcut.

quick question , is your toolrest brass

Passivated zinc

http://www.bstsa.org.uk/tech/zinc_pl.../page_3/p3.htm

Ok , thanks guys

One for the brains trust ...

The form was out of round relative to the spindle steady.

Could be the wood, could be the chuck.

The effect is that the steady wheels when lightly pushed in don't contact all the way round.

With the initial hollowing I pushed them in hard. Also got a deal of vibration ... that could have been the wheels pushing the form around; could just be the extent of overhang and the piece flexing. Dunno.

What would you do? Persist, or back off on the wheels?

There's not much shoulder on the tenon, and the form tapers to a diameter well under its anyway.

Can you get it to sit truer in the chuck?

I would try backing off the chuck a crack & bumping the piece to centre it better & then do the chuck up again.

Yep, thanks Cliff, that's an option.

Would lose a bit of tenon shoulder support but maybe that won't matter.

Yup, it won't matter if it is running true in the steady again.