Straight side on a bowl blank?

[Alie Barnes]

Ive got lots of chunks of wood which i have roughly shaped with a c/saw to roundish.

I dont have access to a bandsaw as yet, the problem im having is this.

Im attaching a faceplate to a piece of wood for making a bowl, the surface isnt 100% smooth.

after roughing it out If i make a spiggot? for the chuck, i attach it to chuck but the piece is wobbly as in ive turned it round but becuase the faceplace surface wasnt flat it slightly wobbly so while its in the chuck i then have to true it round again.

Is this clear for anyone? so my question is this (other than use a bandsaw) what other ways are there so i dont have to true it twice and lose a lot of wood?

Thank You

 

[cornucopia]

Hi alie, i think your getting two things muddled up. just as an example it doesnt matter how uneven your wood is for your faceplate as long as its on securely and is unable to be moved- once its on like that on a face plate you are turning on one axis and only one- so every circle you cut be it a dovetail or a bead will be on that axis and will be concentric.
the wobble you refer to when you re-mount your wood onto a chuck is normally down to soft wood/overtightening or poor fit for your jaws. theres an article on this subject in the last woodturning magazine- your jaws have a optimum point where are most concentric and grip evenly and the strongest.
I like you dont have a bandsaw and all of my wood starts of on a faceplate on a chainsaw cut surface.
it takes a bit of pratice but its worth taking extra time making sure your dovetail mounting is good.

 

[Paul.J]

Alie.
What i do,and i know you're not supposed to,i think, is,
if the blank as a really uneven surface i try and make the faceplate fit as even as i can.
I place the FP on the blank where it as got to be fitted put a screw in on the highest point,then the next screw opposite that one then the other two.
If one of the screws starts to pull the FP down so it is not even i put a small packing piece in under the FP.
It is all a bit of trial and error but you must try and keep the FP as even and level as possible.Using longer screws if needed.
Then when you are happy that you have good fixings put it on the lathe and just turn the face flat at a slow speed,put your spigot,tenon,dovetail on,then mount it in your chuck then round it all off.
Ideally it is best to get the surface as flat as possible to start with,with the chainsaw.
You can also use an electric planer to flatten the surface.

 

[cornucopia]

Alie.
What i do,and i know you're not supposed to,i think, is,
if the blank as a really uneven surface i try and make the faceplate fit as even as i can.
I place the FP on the blank where it as got to be fitted put a screw in on the highest point,then the next screw opposite that one then the other two.
If one of the screws starts to pull the FP down so it is not even i put a small packing piece in under the FP.
It is all a bit of trial and error but you must try and keep the FP as even and level as possible.Using longer screws if needed.
Then when you are happy that you have good fixings put it on the lathe and just turn the face flat at a slow speed,put your spigot,tenon,dovetail on,then mount it in your chuck then round it all off.
Ideally it is best to get the surface as flat as possible to start with,with the chainsaw.
You can also use an electric planer to flatten the surface.

i agree with what pauls saying but its irelevant to your problem alie- as long as the faceplate is on tight -an uneven surface will not make a wobbly bowl when reveserd onto the chuck.

 

[Paul.J]

Cornucopia wrote

an uneven surface will not make a wobbly bowl when reveserd onto the chuck.

Well i seem to get the same problem George when i reverse it onto the chuck.Which is why i try and keep the plate as level and even as i can.
Is it something i/we are doing wrong :?

 

[cornucopia]

hello paul- think about it step by step paul- if the faceplate is attachd firmly all turning done on that fixing will be on the same axis and will all be concentric to that axis- it wouldint matter if you screwed your faceplate to a couratgated surface once its on and if its on firmly you will only be turning on one axis. any wobble once reversed into the chuck is down to other factors which i listed above.

 

[Mark Hancock]

Alie

Cornucopia mentioned possible causes:

the wobble you refer to when you re-mount your wood onto a chuck is normally down to soft wood/overtightening or poor fit for your jaws

It's for these reasons I would suggest you don't worry about the initial wobble you get when you put the piece in the chuck but simply true it up and carry on. That is the way I work. The first holding of the piece, be it on a faceplate, screw chuck or between centres, is purely to get a rough idea of the shape and a method of holding it in the chuck. Once in the chuck the piece is trued up and the form/shape is refined.

 

[cornucopia]

hello mark- everyone works diffrently and for me i turn and finsih the bottom/base of a platter or bowl on he first mount then turn and finish the inside before finally removing the chuck recess.
if its a tiny bit out of true i dont mind as after all we are working with wood- but if its worse than that i know its my chuck recess and i re-cut it until its right.
I use a diffrent method on roughed out bowls and a diffent method on thin walled green bowls/forms- just to make life more intresting

 

[Mark Hancock]

Hi George

Your method is the way I was taught but I use to get really frustrated when turning thin walled vessels when they didn't run true in the chuck :roll: I even use to try the Bert Marsh remedy, a flick of the finger, to get the piece running true but it never worked for me. Hence the method I now work which I find quick and easy. The process is also speeded up because I don't tend to use recesses for chucking but a parallel spigot which I 'eyeball' for diameter so I've no measuring and cutting of dovetails to worry. Never been very good at measuring things :lol:

As you say we all work in different ways and it's just a case of finding what suits each individual. At the end of the day it's the finished piece and it's visual appeal that is the most important thing.

 

[duncanh]

When I want to attach a chuck ring/face plate to a very uneven surface I go over the surface several times with a hand held electric planer.

If the piece is not true in the chuck after turning the chuck point and bottom surface and reversing the piece, I often find that slackening the jaws, rotating the piece approx 90 degrees in the jaws and tightening again will correct the eccentricity. If it does not I repeat until it's the best I can get.

Duncan

 

[robo hippy]

There are a few tricks to getting a flat surface with a chainsaw. Mostly it is a matter of practice. I used to draw a pencil line down the center end grain of the log I was cutting. This helps you to see a straight line. As soon as you start to rock the saw back and forth (up and down) to make the cut, you start to leave bumps and dips. Cut through from one position as far as you can with the front part of the blade, then lower the back part down through the rest of the cut.

I do keep a small sharp hand axe for some leveling.

If you have a drill press with a depth stop, and some forstner bits, You can level out a place for a face plate as well. Drill once for the center, and a few times around the center, and you have a flat spot. I do this a lot for natural edge bowls.

Mostly for me, I use a recess on the top rather than a face plate. Again, a forstner bit the size of your chuck jaws, drill in about 1/4 inch or slightly more (you don't want the face of your chuck to seat on the wood, but you do want the jaws to bottom out in the recess), and expand into the recess. Turn the bottom, then reverse by using a recess or tenon, whichever you prefer. For me, this works especially well for my bowls because I core everything, and using this method, each core has a center (I take the biggest ones first), and the chuck never has to come off the lathe.

robo hippy