Newbie best way to get rid Of end grain tear Out after Turning A bowl

[thebowlerhattedturner]

Hello Bill,
            on re-reading my comments earlier on this post I realised my fingers were typing quicker than my brain was thinking, I wrote:-

 I think your problem is you are rubbing the bevel during the cut,you may have your tool ground at the wrong angle to achieve this on this design of bowl. Bevel rubbing is very important.

It should read:- I think your problem is you are not rubbing the bevel during the cut etc .etc.
Regards
John

[arcos]

My 'speed table' is in my head... It's called fear! 

I have started turning at higher speeds as my confidence has grown BUT still keep to mid range speeds (my comfort zone) even when I know that I could run  little higher speed.

I have an issue with some wood that is very 'seasoned' and has started rot in places. It turns really nicely and is solid enough but the end grain even with sharp tools, light cuts still results in tear out.

I turned two bowls and had the exact same problem on both. I have yet to experiment in ways to try and stabilise or harden the end grain prior to taking final cuts but there are some interesting ideas on this thread, thanks!

[Mark Sanger]

I have put a link in the Web site, videos section, but here is one from the same site that may be of use and goes through the problems.

http://www.woodturningvideosplus.com/torn-grain.html

[woodndesign]

As with Andy's reply, I'd like to thank both Marks and Nick as well for their valid knowledge and for their time to post on what is a grey area of speed (lathe that is) for some this is the only place of contact, for others it can be passed onto them by someome, I learnt this or I do such, then it could just be from a book, for some we have set 3, 4, 5, upto 10 speed ranges, with VS what 0-3000 upto 4000+ rpm on some. 

Yes given a piece maybe 6" dia or any other dia. to that regard, doesn't take into acount the piece could be anything from 2" to 6"+ in thickness, we can find, read and hear all kinds of formulae and tables, but it is what your safe and comfortable with that is important at all times.

My question with Bill was what speed he used, was more as a consideration to the many factors involed, just as it is that he was using Elm, so is speed relevant to tear out, I'd not considered it to be as such.

And Bill your important to us all, where are you, keep posting.

Cheers   David

[Mark Sanger]

David

yes speed can be directly related to tear out depending upon the wood/chip formation of the species, how dry it is, interlocking grain etc etc.

All materials have a speed by which they like to be cut. So on top of tool presentation and sharpness as already mentioned then feed of the tool and speed can also be an issue.

Even with the sharpest of tools and correct presentation if traversing the tool is too rapid for the wood beyond the point of efficient chip formation then the fibres can tear out.

So it comes down to geometry, sharpness, speed and feed, this is in turn dependant on wood species and the respective chip formation which in turn can alter the geometry of the tool use.

IE a soft wood cuts easily with an acute angle whereas a very dense timber or alternative material will chip better with an obtuse angle and at time negative rake.

Even the shape of a bowl can make a difference to finish with some woods.

This is why the charts as mentioned are of little real purpose.

The point I am hoping to get across is there is no simple answer   and while yes forums are useful there are many in depth answers and solutions that only a book, DVD or tuition with in depth explanations and practical application can answer.

Often (certainly with me) these books have to be read/ referred back to more than once for it to sink in,  such explanations are difficult and lengthy to clarify in a forum and often answers only confuse, are not presented in a concise clear way/especially without diagrams to be of use, and end up being another hurdle ( although they are posted with good intention and much knowledge) some things have to be shown.

So in short yes speed can have an effect on tear out if it is considered along with with feed rate, material/wood species, tool geometry for the material/species etc.

There is a very good book that ( yes I know it is a book)   that goes into this in much depth and after reading it several times made me realise that we have to fully understand the substrate we are cutting (wood) to know how to present tools/cut it etc.

http://www.amazon.co.uk/Understanding-Wood-Craftsmans-Guide-Technology/dp/1561583588/ref=sr_1_1?s=books&ie=UTF8&qid=1366991150&sr=1-1&keywords=understanding+wood+technology

it was one of the best investments I ever made. In fact I would say probably the best investment in my development as a woodturner as once we really understand about wood then we can start to understand how to get the best out of it with our tools. Without this knowledge it is like trying to bake a cake in the dark without a recipe.

 

[woodndesign]

David

yes speed can be directly related to tear out depending upon the wood/chip formation of the species, how dry it is, interlocking grain etc etc.

All materials have a speed by which they like to be cut. So on top of tool presentation and sharpness as already mentioned then feed of the tool and speed can also be an issue.

Even with the sharpest of tools and correct presentation if traversing the tool is too rapid for the wood beyond the point of efficient chip formation then the fibres can tear out.

So it comes down to geometry, sharpness, speed and feed, this is in turn dependant on wood species and the respective chip formation which in turn can alter the geometry of the tool use.

IE a soft wood cuts easily with an acute angle whereas a very dense timber or alternative material will chip better with an obtuse angle and at time negative rake.

Even the shape of a bowl can make a difference to finish with some woods.

This is why the charts as mentioned are of little real purpose.

The point I am hoping to get across is there is no simple answer   and while yes forums are useful there are many in depth answers and solutions that only a book, DVD or tuition with in depth explanations and practical application can answer.

Often (certainly with me) these books have to be read/ referred back to more than once for it to sink in,  such explanations are difficult and lengthy to clarify in a forum and often answers only confuse, are not presented in a concise clear way/especially without diagrams to be of use, and end up being another hurdle ( although they are posted with good intention and much knowledge) some things have to be shown.

So in short yes speed can have an effect on tear out if it is considered along with with feed rate, material/wood species, tool geometry for the material/species etc.

There is a very good book that ( yes I know it is a book)   that goes into this in much depth and after reading it several times made me realise that we have to fully understand the substrate we are cutting (wood) to know how to present tools/cut it etc.

http://www.amazon.co.uk/Understanding-Wood-Craftsmans-Guide-Technology/dp/1561583588/ref=sr_1_1?s=books&ie=UTF8&qid=1366991150&sr=1-1&keywords=understanding+wood+technology

it was one of the best investments I ever made. In fact I would say probably the best investment in my development as a woodturner as once we really understand about wood then we can start to understand how to get the best out of it with our tools. Without this knowledge it is like trying to bake a cake in the dark without a recipe.

 

Mark your a gentleman, an of many valid words, you expess it but than I was coming across, it is a factor, it was with metal turning a fast feed on to slow a speed riped the metal, the opposite happens with faster speed.

Thank you for the link, get it before demand puts the price up ...    ..

David

[arcos]

I think that there can be no substitution for taking some tuition...

Unfortunately some are not in position to take advantage of this so stupid questions have to be asked from this side of the channel on forums where the experts can give some guidance/opinions.

For my tear out problem, mostly with some very dry, aged, rotted acacia it has to be trial and error.

I have two bowls turned, both have end grain tear out. I believe, from reading comments and ggl'ing that it may be the softness of the wood combined with my tooling (I don't have any tear out issues with other woods now).

Having such a vast amount of acacia I really want to try and find a solution to this as the wood is fantastic and takes a finish really well.

I have left the bowls with quite a fat belly so that I can apply waxes/glues etc in an attempt to stabilise/harden the the wood

[EnErY]

Hello Bill,
            on re-reading my comments earlier on this post I realised my fingers were typing quicker than my brain was thinking, I wrote:-

 I think your problem is you are rubbing the bevel during the cut,you may have your tool ground at the wrong angle to achieve this on this design of bowl. Bevel rubbing is very important.

It should read:- I think your problem is you are not rubbing the bevel during the cut etc .etc.
Regards
John

Hi John
Thank You For Taking Time out To rectify your Post. I since Made a natural edged cherry bowl which I am very Happy with It has also raised some good comments on another forum reading all that has been posted here on the subject I think I might have got rid of it with cherry question cherry vs elm is there a difference in the plan of attack being different timbers?
Regards
Bill

[woodndesign]

Hi all.

I know I drone on about this but in my opinion there is no substitute for tuition from a good tutor.
When I started out 12 years ago I went to Don White  http://www.don-white-woodturning.co.uk/ for tuition and one of the first things he said to me was George I am going to save you 25 years.When I said how are you going to do that Don he answered I am going to teach you not to make the same mistakes I have made in the last 25 years.
I think the small cost of tuition is the best investment you could make in woodturning.
You can have the best lathe and tools in the world but if you don't know how to use them properly you will always struggle.

Regards George

That be true ...  but honestly there is nout better than getting off on the right foot at all times...  Of the very things that are involed today with any hobby alone, is cost .. I know as do many others and £130 ever in 1996 for 2 days with Oliver Plant looked like a lot on top of and not considering the almost £1000 spent on lathe, tools, grinder...  well all the basics to get under way ...  as for the lessons, well you learnt all the right basics, mastered some and having loved the whole thing go away happy, if not bitten by the bug .. a turner I'll be ..  ..  bad habits you start yourself ..  ... maybe be not knowingly and hard to break if you take lessons later on. Then for some it's location that limits being able to get tuition, thankfully theres internet access and a strong band of helpful fellow turners ..  .. who will share their advice to help.

The best .. like everything there are lathes and I've seen and used tools that don't induce the best results, I know ... the man who blames his tools, but be fair the tools are out there, they work, they cut, but the form and profile are cr..  I'll not name or shame.  Adds another element to the list of why things can go wrong.

Cheers   David

[thebowlerhattedturner]

Hello Bill,
           yes there will be a difference between Elm and Cherry, there is also a difference between different types of Cherry.
 I would suggest that when you get near to the bottom of the bowl just turn the lathe by hand slowly and with a freshly sharpened chisel follow the cut through(go through the motions) Look to see if the bevel will rub all the way through the cut as some bowl gouges are ground to different angles.Observe which part of the tool is doing the cutting, you may need to regrind to a different angle. The flute should be pointing to the 2 o'clock-ish position and should arc across the bowl. You may find it easier to cut a bowl with a nice even curve to it rather that one with a dramatic change of curve.Cut towards the middle of the bowl.  Something that may help when you sand is to spray a fine mist of water over it and let it dry and then sand. This will raise the grain slightly and make it easier for your abrasive to cut any offending fibres, try this at each subsequent grit.
Good luck.
Regards
John BHT

[woodndesign]

Hi David.

I appreciate there is a cost to tuition but I believe woodturning is still a cheap hobby even with the cost of tuition.
Our local Golf club charges £800  00 per year for membership at least with woodturning you only pay once and if you get good enough you can sell your work for decent money.

Regards George

Someone has to pay for cutting all that grass ...    And I've never understood the want to hit a little ball that you could so easily loss .. then again the famous names can make big money ... more than a bowl of mine ..

See you on the T''

Cheers  David