General Category > General Discussion
Newbie best way to get rid Of end grain tear Out after Turning A bowl
John D Smith:
Hello Bill, I hope you have not decided to leave the Forum I was looking to see if you had made any further comments on this thread and maybe taken George up on his offer. Regards John
Andy Coates:
I thought I try and do an honest and hopefully constructive critique of this bowl in an effort to redress some of the hurt the various misunderstandings have caused. But you may not appreciate it anyway...
Ok. First impressions?
I don't like it. The main reason I don't like it is the shape. It's a shape commonly produced by novices which I call "the dog bowl". The outer shape (IMHO) is one produced by the geometry of the tool rather than the maker's design.
The wall is probably an exact copy of the angle of the bevel under the flute of the tool. The reason the bowl ends up this shape is not by design but because upon taking the first shaping cuts the turner produces a shaving, and judging this to be a good thing allows the tool to continue to cut in the same direction. The result is a sheer-sided 45 degree(ish) bowl shape.
As turners we should be aiming to dictate our design on the wood, not allowing the tool to do the designing for us. So how do you put "intentional shape" into your work?
Imagine the same bowl blank mounted on your lathe. You've roughed it to a cylinder and are about to begin shaping it (I will assume you have either already cut the chuck holding or are happy to accommodate it later). Convention has it that you begin at the foot and turn towards the rim. The reasons for this are sound...cutting with the grain...cutting "downhill", but try from the rim towards the foot.
As the cut begins you are holding the bowl gouge close in to your body, supporting it at the toolrest with either an under or overhand grip, but your grip is light and the tool is form in to your side. The flute is at about the 1-2 o'clock position if the clock is in front of you. As the cut begins your job is to slowly swing your body to the right, feeding the tool through your fingers at an appropriate pace relative to the speed of the wood and size of the blank. In doing this you apply (gentle) pressure to the bevel which cause it to drive the cutting edge in the direction YOIU wish it to travel. Correctly done this will produce a variation on a "classic" bowl shape. Ive attached and example of the shape on an old bowl of my own. Ignore the after lathe work and concentrate on the shape.
So to the inside of the bowl...
steep sided and flat bottomed....another dog bowl shape.
The shape here can be the result of two things: a) see above - same applies and b) a wish to echo the outside for want of any other idea.
More often than not it's a result of option a. The problem then arises when the maker realises that the base of the blank is fast approaching and fears going through the bottom and so makes a 90 degree change in direction which produces a flat bottom and a sharp corner. Another result is often a heavy base as the change of direction was far too early anyway.
The remedy is to use the same principles as detailed for the outside of the bowl but where the tool position is appropriate for the interior of a typical bowl shape...
facing the bowl as if it's face is the clock the flute is at about 2. The tool is held against the body if possible, if the lathe bed won't allow then the tool handle is under the forearm and firmly supported on the rest. Assuming you have turned the outside as previously detailed your job is to copy the same shape on the inside. Let's assume a 6mm wall thickness at the rim. Follow the shape by slowly pulling your body backwards as you feed the tool through your fingers to give it the necessary depth. Repeat until the wall is 6mm all the way down and follows the shape of the outside. If your wall thickness is even you CANNOT go through the base. Another problem removed.
By choosing this simple shape you will remove the problem of the steep sides, the tool will cut cleaner leaving less torn grain, the shape will be more pleasing. Once you've mastered this you can then start to change the shape of subsequent bowls for something more adventurous with the knowledge acquired during the process.
If you still like the dog bowl shape and want to make another you'll at least be in a better position to make a cleaner-cut version.
Finish is your own preference but the rules of thumb are - good quality abrasive, start at an appropriate grit (if the tooling is poor then 80g) if better 120g Etc. Work though the grits to (we are encouraged) 400g (a utility bowl doesn't require such a fine finish IMHO). Abrade slowly without undue pressure applied. Keep the abrasive moving constantly to avoid marks. Only start the 2nd grit when ALL the tooling marks are removed. The following grits remove the abrasive marks of each subsequent grit. Seal as preferred and final finish of oil, wax Etc.
None of this is cast in stone but will help. 1 to 1 is the best way of learning. But in the absence of 1 to 1 you can use a good book, DVD, or YouTube (but knowing what's good on there is another problem). Ask for recommendations on here. Mark Sanger has some good vids on youtube, and I have some, and there are others.
I hope you don't feel offended by this. You can only get help with a constructive critique and I believe this is constructive.
thebowlerhattedturner:
Andy, I think this is a fair and considered reply.
Bill it was probably me that took your £16 at Yandles. you must be fairly local to me so get in touch at:- swrep@awgb.co.uk and I am sure something can be worked out.
Best regards
John BHT
EnErY:
--- Quote from: Andy Coates on April 21, 2013, 08:54:22 PM ---I thought I try and do an honest and hopefully constructive critique of this bowl in an effort to redress some of the hurt the various misunderstandings have caused. But you may not appreciate it anyway...
Ok. First impressions?
I don't like it. The main reason I don't like it is the shape. It's a shape commonly produced by novices which I call "the dog bowl". The outer shape (IMHO) is one produced by the geometry of the tool rather than the maker's design.
The wall is probably an exact copy of the angle of the bevel under the flute of the tool. The reason the bowl ends up this shape is not by design but because upon taking the first shaping cuts the turner produces a shaving, and judging this to be a good thing allows the tool to continue to cut in the same direction. The result is a sheer-sided 45 degree(ish) bowl shape.
As turners we should be aiming to dictate our design on the wood, not allowing the tool to do the designing for us. So how do you put "intentional shape" into your work?
Imagine the same bowl blank mounted on your lathe. You've roughed it to a cylinder and are about to begin shaping it (I will assume you have either already cut the chuck holding or are happy to accommodate it later). Convention has it that you begin at the foot and turn towards the rim. The reasons for this are sound...cutting with the grain...cutting "downhill", but try from the rim towards the foot.
As the cut begins you are holding the bowl gouge close in to your body, supporting it at the toolrest with either an under or overhand grip, but your grip is light and the tool is form in to your side. The flute is at about the 1-2 o'clock position if the clock is in front of you. As the cut begins your job is to slowly swing your body to the right, feeding the tool through your fingers at an appropriate pace relative to the speed of the wood and size of the blank. In doing this you apply (gentle) pressure to the bevel which cause it to drive the cutting edge in the direction YOIU wish it to travel. Correctly done this will produce a variation on a "classic" bowl shape. Ive attached and example of the shape on an old bowl of my own. Ignore the after lathe work and concentrate on the shape.
So to the inside of the bowl...
steep sided and flat bottomed....another dog bowl shape.
The shape here can be the result of two things: a) see above - same applies and b) a wish to echo the outside for want of any other idea.
More often than not it's a result of option a. The problem then arises when the maker realises that the base of the blank is fast approaching and fears going through the bottom and so makes a 90 degree change in direction which produces a flat bottom and a sharp corner. Another result is often a heavy base as the change of direction was far too early anyway.
The remedy is to use the same principles as detailed for the outside of the bowl but where the tool position is appropriate for the interior of a typical bowl shape...
facing the bowl as if it's face is the clock the flute is at about 2. The tool is held against the body if possible, if the lathe bed won't allow then the tool handle is under the forearm and firmly supported on the rest. Assuming you have turned the outside as previously detailed your job is to copy the same shape on the inside. Let's assume a 6mm wall thickness at the rim. Follow the shape by slowly pulling your body backwards as you feed the tool through your fingers to give it the necessary depth. Repeat until the wall is 6mm all the way down and follows the shape of the outside. If your wall thickness is even you CANNOT go through the base. Another problem removed.
By choosing this simple shape you will remove the problem of the steep sides, the tool will cut cleaner leaving less torn grain, the shape will be more pleasing. Once you've mastered this you can then start to change the shape of subsequent bowls for something more adventurous with the knowledge acquired during the process.
If you still like the dog bowl shape and want to make another you'll at least be in a better position to make a cleaner-cut version.
Finish is your own preference but the rules of thumb are - good quality abrasive, start at an appropriate grit (if the tooling is poor then 80g) if better 120g Etc. Work though the grits to (we are encouraged) 400g (a utility bowl doesn't require such a fine finish IMHO). Abrade slowly without undue pressure applied. Keep the abrasive moving constantly to avoid marks. Only start the 2nd grit when ALL the tooling marks are removed. The following grits remove the abrasive marks of each subsequent grit. Seal as preferred and final finish of oil, wax Etc.
None of this is cast in stone but will help. 1 to 1 is the best way of learning. But in the absence of 1 to 1 you can use a good book, DVD, or YouTube (but knowing what's good on there is another problem). Ask for recommendations on here. Mark Sanger has some good vids on youtube, and I have some, and there are others.
I hope you don't feel offended by this. You can only get help with a constructive critique and I believe this is constructive.
--- End quote ---
Thank You Andy This is The Sort Of critic I was looking for it Is both helpful informative and not scathing this is the sort of ideal information im looking for not to be given a hauling over the coals for selling the item
Kind regards
Bill
Andy Coates:
Good. Glad that's what you wanted..
Now if we can make that the last time we mention the other thing we can all get along better and people can stop sending me post reports and taking up time I can not afford to waste.
safe turning
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