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Inner curve on a bowl?

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drillbit

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Sorry if this is a really stupid question...

I Have made a couple of attempts to make a small bowl with curved sides, a bit like a donut, and the inside to match the curve of the sides.

I can hollow out the bowl with the bowl gouge no problem up to the point where the hollowed area is parallel with the direction of the lathe bed. In fact, I have made several boxes now like this.

But as soon as I try to use the bowl gouge to cut a curve into the Walls of the bowl, however shallow, I just get dig in after dig in no matter what I do, until my bowl becomes a small plate.

Am I attempting the impossible by trying to use a gouge to do even the shallowest of hollowing tasks? Or am I missing something about how to hold the tool? Or am I just biting off more than I can chew?

I know there are specific hollowing tools, but does that mean there is just no way of accomplishing any interior curve with any other tool?

Thanks for anyone who can explain.
 

jumps

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it would help to understand how you are approaching this -

the smaller the diameter of the bowl the more difficult it is to get the proper tool angle
the smaller the bowl the more difficult it is to get an easy working angle on the inner face, even with a swivelling headstock and a good rest.
 

Paul Hannaby

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Once you get past that parallel section, you are probably losing bevel contact because the bowl rim will prevent you swinging the gouge to the correct angle because the tool will foul the rim. The loss of bevel contact is causing the catches.

Try a bowl gouge with a steeper bevel - maybe 60 degrees or more.
 

nev

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i use a small round scraper for the bottom and curve, but this does mean lots of sanding sometimes :oops:
also one cannot create a curve with a smaller radius than the tool.
i cant comment on the use of a bowl gouge cos i aint got one :(
up until last week i thought i did and could never get to grips with it no matter how i ground it. then i read through the sorby catalogue and found out it was a spindle gouge :oops:
in my defence i was told it was bowl gouge when i was given it #-o .
never mind, its my birthday this month, guess whats on the pressie list :mrgreen:
 

drillbit

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Thanks all.

Jumps - the sort of thing I am trying to do is like this



I wondered if I just should buy a hollowing tool, but I don't want to splash out more funds if this can be done with the tools I already have. I cant find any videos of someone doing an undercut bowl...
 

jumps

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drillbit

the thing to think about is the presentation angle of the gouge to make the cuts (with the bevel in contact!)

for bowls as above, scrapper angles are much easier to achieve, and obviously hollowing tools are designed to work in such areas.
 

Tazmaniandevil

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Like nev I use a round scraper for the inner bevel. I then go back and lightly smooth it with a small spindle gouge before starting sanding with 40 grit to remove the worst tool marks, then through the grits.
I have a coupme of silver steel rods in the garage which I was thinking about using to make a hollowing tool. I found a how-to a while back, but have lost the link. I'll need to have another look for it.
 

henton49er

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Drillbit,

I have a bowl gouge with a 60 degree bevel. It also has the heel of the bevel removed to reduce tool marks etc. With this I can get a bit of an "undercut" but not as much as in the picture you have shown.

I start the insides of my bowls with a long grind bowl gouge and finish with the 60 degree grind on a 1/4" gouge, always working from rim to centre, never from centre to rim. I am still learning to get a decent finish directly from the tool, and aften have to resort to heavy power sanding to get a smooth profile.

Mike.
 

drillbit

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Thanks for all the replies. I don't want to regrind my only bowl gouge, in case I never get it back again. So as a result I have decided to order...

..this



..and this..


I am really hoping the hollowing tool helps, but if not, I can try with the scraper like Nev, Taz and jumps mention.

What do you think? Will that hollowing tool do the job?
 

nev

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the one i use is a sorby 820H and ive managed eggcups to bowls, but the undercutting is limited and limited to larger bowls, although that might just be me :oops:

or if you prefer henry taylor in japanese :mrgreen:


i dont know but i would guess the hs47 you have listed will do a similar job but allow you to get more of an undercut?
 

jumps

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the Crown Cryo has huge versatility in the tips and, if I read the scale of the bowl you posted earlier, should do eactly what you want. The combination of the cutter and the scraper tips will enable both controlled cutting and finish scraping - enjoy.The other thing I like t it is that you can get a replacement set of cutter/scraper/scraper for £11 - nearer £30 for the Sorby equivilent bought individually :(
 

Weasel Howlett

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drillbit" [img:1tbndr6v said:
http://thumbnail.image.rakuten.co.jp/@0_mall/techno-ns/cabinet/techno_top/henry-taylor/hs47-1.jpg?_ex=266x266&s=2&r=1[/img]
Ive used a bigger, larger hooked, version of one of these beauties and have had great results. It'll do the job nicely i suspect.
 

drillbit

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Brilliant. Looks like the tools I've ordered are the ones for the job. Thanks to all. Nev I'll let you know how the scraper does..
 

skeetoids

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Hi,

It's likely if you intend doing more 'closed form' work then at some point a hollowing system will be needed.

I suggest you treat yourself to the new Revolution by Crown.

I use this tool, not extensively yet, but it is ideal for closed forms of this type and also deeper hollowing work should you want to go down that route.

It also has a range of tips, one is a key cutter tip and is great for getting into tight turns and corners, but does operate more as a scraper than a gouge.

Cheers,

Lee.
 

drillbit

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Skeetoids that looks like good value too, compared to the Sorby version. I think I will need to practice for a while before I am ready to move on to hollow forms, but that tool looks like it would do everything. Cheers
 

CHJ

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Although I use a couple of bowl gouges with differing front bevel angles for more open bowls if I have significant undercuts I must admit I tend to use freshly sharpened scrapers of one description or another on the sort of things I do, used above centre and well supported, catches are a rarety and any if additional sanding required is more than matched by the speed and ease of material removal.
I don't do enough closed form hollow turning for a need to go further than my homemade hollowing tools in the way of specialist tools.
 

drillbit

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Chas

OK...I know this is going to be a stupid question but....have you got your lathe in reverse?
 

CHJ

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drillbit":z4mlj4sj said:
Chas

....have you got your lathe in reverse?
Yes I have, gives a far better view and control of what you are trying to do.
You can stand upright instead of leaning over the lathe and tool support is better because you have the handle close to your body.
I often prefer doing it this way to swinging the head out far enough to reach with normal direction.
Have on occasions used a bowl gouge in reverse "left handed" mode for want of a better description, but that does take very careful concentration to avoid a catch as it's not my normal action.
 
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