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-   -   What do YOU use... (https://www.woodworkingtalk.com/f6/what-do-you-use-24998/)

HS_Woodsman 03-29-2011 09:11 PM

What do YOU use...
 
...to attach your platter/bowl to the lathe? Faceplate? 3 or 4 jaw chuck?

The reason I ask is I'm in the middle of my first bowl. I started with it between centers and turned it round, then made a 1/2" tennon to be used with a 4 jaw chuck. I got it tightened down in the chuck, on the lathe, and when I started turning the piece it flew out of the chuck and across the shop! :wallbash: Mr. ShopTeacher wasn't to happy about that. :laughing::laughing:

Do you think my tennon was too short? Now it's got a faceplate screwed directly into it - not going anywhere (knock on wood!)

Thanks,
Logan

john lucas 03-29-2011 09:26 PM

Well first of all, did you turn a shoulder on the tenon. The 4 jaw chucks won't hold a bowl very well just grabbing a tenon. The wood compresses and as you turn you create vibrations which worsen the compression and next thing you know the bowl rocks it's way out.
If your jaws are say 1/2" deep. Make your tenon shorter than this. Leave a square shoulder so this part sits on top of the jaws with the tenon inside. This gives your chuck 2 points of reference. the shoulder keeps the bowl from rocking and the tenon is gripped.
Use the tailstock as long as you can and anytime you can. That also helps keep things from flying. re-tighten the jaws periodically. Wood compresses and you need to check the tightness very often.
That being said I did alot of bowls using a faceplate. You have to allow for the depth of the screws but there is nothing more solid than a faceplate. If your wood isn't thick enough glue a wasteblock onto the bowl blank and then mount this to the faceplate.

robert421960 03-29-2011 09:34 PM

listen to john he knows what he is doing
i use a faceplate on the inside of the bowl side for turning the outside then i make a tenon or mostly make a recess to insert the jaws in and like john said i use my tailstock till i cant anymore
Robert

duncsuss 03-29-2011 11:09 PM

If you are using the tenon in a 4-jaw chuck method, don't fall into the trap of thinking "bigger is better".

Too large a diameter makes it so that only the tips of the chuck jaws actually contact the tenon.

Better is to make the tenon diameter just a bit larger than the inside diameter of the jaws when closed all the way down. This leaves most of the jaw surface gripping the tenon.

txpaulie 03-30-2011 09:09 AM

1 Attachment(s)
I'm really new to this, so take anything I say with a chunk of salt...:yes:

I've found that I have better luck holding on to a bowl by turning a recess, as opposed to a tenon, as pictured...
p

HS_Woodsman 03-30-2011 04:36 PM

John - I can't quite picture what you mean by a shoulder. The only thing that comes to mind would be like the picture above.

john lucas 03-30-2011 04:44 PM

think of the shoulder like the Letter T. The chuck grips the lower part and the upper crossbar sits on top of the jaws. the shoulder would be the upper crossbar of the T. I would have to take a photo to show you better but I'm going to a club meeting tonight and won't be home to do it.
Mounting the chuck into a recess like above works fine however you need enough wood on the outside of the recess to keep from breaking when you tighten the jaws.
both methods are viable and Use both. I mostly use recess's for platters and ball shaped hollow vessels. I use tenon's for most other things because I can cut it off and completely change the shape of the bowl foot if I want to. sometimes when turning a bowl there is problem or some interesting detail that needs to be changed and that may alter my plans for that bowl. With the tenon I am free to change things. with a recess I'm kind of stuck.

fischer18 03-30-2011 09:36 PM

King of new to turning also, but what I have noticed is put the bowl in the jaws and push on the opposite end firmly to make sure it is as deep as it will go and then slighly turn the bowl while pressing still. This I also noticed to help center the bowl instead of having to go back again to get the bowl perfectly round. If you cannot acheive this, just to be sure that your speed is low enough until you do get it round to also ensure it will not fly off.

doug1980 03-30-2011 11:50 PM

Well when I am going to rough a bowl I use a 4" faceplate that I screw on the side that will be hollowed out. After it is roughed and I have made my tenon I remove the faceplate, turn the piece over and use my chuck. When finishing a bowl I use the chuck until I am ready to remove the tenon from the bottom of my bowl. I then attach my jumbo flat jaws on my chuck and rotate the bowl so I can remove the tenon. Makes it so much easier with all the right tools.

john lucas 03-31-2011 09:14 AM

This PDF shows the shoulder at the top of a tenon for bowl turning. Maybe that will explain it.
http://www.google.com/search?q=chuck...aafe62ca039844

robert421960 03-31-2011 09:05 PM

Quote:

Originally Posted by john lucas (Post 201033)
This PDF shows the shoulder at the top of a tenon for bowl turning. Maybe that will explain it.
http://www.google.com/search?q=chuck...aafe62ca039844

that is an impressive tutorial:thumbsup::thumbsup:


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