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UKTony

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First attempt last night at making a goblet, after limited succes with a couple of bowls used a pieced of timber 6-7 inches long turned it between centres and got a very nice finish, did as the video suggested and cut a spigot(if thats what its called) about 6mm long and 30 mm wide for attaching to the chuck, put it on tightened as much as i can and trued it up again - so far so good but as soon as i started to work on the end grain to hollow it out the wood came loose and flew off, i tried this 3 times before i gave up am i missing something or am i just not getting it tight enough

Any ideas, in the end i put the wood back between centres and turned it into an "Appear" (was supposed to be an apple then a pear and in the end came out looking like a bit of both"

Tony
 

mudman

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Tony,


What chuck are you using?
Check your lathe speed. The Supanova manual says that you shouldn't exceed 850rpm.
Also, if you're using Supanova with the standard 50mm jaws, your spigot needs to be a minimum of 40mm so it seems likely that the jaws weren't providing the best grip.

But then, if you're not using the Supanova chuck, it must be something else. :?
 

UKTony

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Thanks for that, im using a Supernova - sounds like you may be right, will have another go this evening

T
 

Taffy Turner

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Tony,

Did you cut the spigot straight, or did you cut it on a dovetail?

The dovetail will give you a much better grip than a straight one. (Make sure the angle matches the one on the jaws of the chuck)

Regards

Gary
 

UKTony

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Im using C Jaws, i cut it straight no idea how you cut a dovetail?
 

Taffy Turner

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I am not familiar with that chuck, so don't know what a C jaw is.

However, if you look on the inside of the jaw (the bit that actually grips the wood), you will notice that it isn't parallel with the lathe axis, but that it is undercut. When you cut a spigot for gripping on, try to match the angle on your spigot with the angle on the chuck jaw - I have found the easiest way to do this is by using my skew chisel flat on the rest as a scraper.

If you cut your spigot as described, you will find that you have to have a MAJOR catch to pull the wood out of the chuck (it can still be done though - trust me!).

Similarly, if you are cutting a recess in a bowl bottom for internal gripping, you also have to undercut it so that the external part of the chuck jaw can seat in properly.

Hope that this helps.

Gary
 

mudman

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Bit confused now. :? The C jawsare an Axminster designation for their own proprietary chuck and not the Supanova. I'd be nervous of using the wrong jaws on a chuck.
If you are using the 50mm jaws then your spigot is too small and needs to be larger, check the link to the jaws manual in the other Supanova thread.
If you are using the spigot jaws, then the diameter is correct but far too short, it needs to be about 30mm long I think. (Can't check right now as the manual has stopped working for me.)
 

mudman

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Taffy Turner":1pqshf3c said:
I am not familiar with that chuck, so don't know what a C jaw is.

However, if you look on the inside of the jaw (the bit that actually grips the wood), you will notice that it isn't parallel with the lathe axis, but that it is undercut. When you cut a spigot for gripping on, try to match the angle on your spigot with the angle on the chuck jaw - I have found the easiest way to do this is by using my skew chisel flat on the rest as a scraper.

If you cut your spigot as described, you will find that you have to have a MAJOR catch to pull the wood out of the chuck (it can still be done though - trust me!).

Similarly, if you are cutting a recess in a bowl bottom for internal gripping, you also have to undercut it so that the external part of the chuck jaw can seat in properly.

Hope that this helps.

Gary
The Supernova manual makes a point that you shouldn't do this with the 50mm jaws as it will reduce grip.
 

Taffy Turner

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Just looked at the SuperNova manual on their website.

The Supernova chuck has a lip designed to bite into the wood, so does not require a dovetail spigot - sorry for the confusion. :oops:

I had naively assumed that the jaw design was similar to my Record chuck (which does require a dovetail spigot, and consequently provides a very strong grip).

However, looking at the C Jaws on the Axminster website, they do look like they require a dovetail spigot, so I think we need to establish exactly which jaws Tony is using.

I would agree that using Axminster jaws on a Supernova chuck may be a little unwise to say the least!
 

UKTony

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mudman":2ax1j1xn said:
Bit confused now. :? The C jawsare an Axminster designation for their own proprietary chuck and not the Supanova.
Sorry used the designation C as an indication of the shape, mu understanding fro the videos ive seen were the spigot is the depth of the indentation on the jaw. Are you sugesting that its cut with a notch and then longer so it goes into the jaws further

Sorry if im confusing anyone
 

Adam

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UKTony":nu9g8y8h said:
mudman":nu9g8y8h said:
Bit confused now. :? The C jawsare an Axminster designation for their own proprietary chuck and not the Supanova.
Sorry used the designation C as an indication of the shape, mu understanding fro the videos ive seen were the spigot is the depth of the indentation on the jaw. Are you sugesting that its cut with a notch and then longer so it goes into the jaws further

Sorry if im confusing anyone
Time to get your digital camera out me-thinks!! :wink:

Adam
 

UKTony

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Top ones, im making my spigot the depth of the first recess which i think is about 6 mm down

Many thanks

Tony
 

mudman

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Okay, then I think the problem is with the size of spigot that you've made. The manual says:
SPIGOT SIZE: Standard jaws will grip a round spigot between 45mm (1 49/64 inches) to 65mm
(2 9/16 inches) approx. Square timber between 40mm (1 37/64 inches) to 50mm square approx.
(Note: EUROPE/UK: Maximum size is 6mm (1/4”) less).
Doesn't say how long the spigot should be but 6mm does seem a little short.

The troubleshooting section also says:
10. Wooden spigot shifts
during turning
Check that the spigot area is made correctly for jaws to grip. Check that
the spigot is not oversize. See spigot operation instructions Page 11.
Use careful chisel techniques that do not exert too much pressure.
Irregular rough wood blanks need to be checked to see whether there is
enough jaw contact.
Edit: Just checked the jaws manual, spigot size should be a minimum of 16mm so that is probably your problem.
 

mudman

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Just had a thought when you say spigot, you do mean a bit for the jaws to grip around and not a recess for the jaws to go into don't you.

Only asking 'cos I kept calling a recess a spigot until I was put right. :oops:
 

UKTony

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Its a spigot...i should revert to my IT background and use terms like a "Male" connector :)

This woodturning bug has completely taken over my life, i have not touched in anger a new Thicknesser and Planer that arrived this week and am about to now start looking for a new Bandsaw for Blank cutting, I was in the workshop last night completely redesigning the garages to accommodate the Lathe until 2 am....at least the wife will never have to buy a salad bowl again :)



 

mudman

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UKTony":27si20be said:
Its a spigot...i should revert to my IT background and use terms like a "Male" connector :)

This woodturning bug has completely taken over my life, i have not touched in anger a new Thicknesser and Planer that arrived this week and am about to now start looking for a new Bandsaw for Blank cutting, I was in the workshop last night completely redesigning the garages to accommodate the Lathe until 2 am....at least the wife will never have to buy a salad bowl again :)
Phew, thought it would be safer to be sure, you know how these things happen.

I know what you mean about that bug, bit me a while back as well. Trouble is that I can't get to anything in my workshop at the moment. It's full of plasterboard and furniture. :evil:
Not happy. Especially as I have a nice new Sorby RS2000 hollowing system to try out. :cry:
 

UKTony

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mudman Especially as I have a nice new Sorby RS2000 hollowing system to try out. :cry:[/quote said:
Ive brought one of those too, stupid really considering i cant use a spindle gouge yet, just spent another 80 quid on a sharpening Jig from Sorby after watching there free demo CD and reading some of the other posts.

No complaints from the wife yet - ive given up smoking and as part of my rehabilitation im getting to spend my £70.00 a week saving on tools for as long as i can drag it out 8)
 
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