AWGB Woodturning Forum
General Category => General Discussion => Topic started by: Haggy on June 08, 2015, 08:12:29 PM
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This 11 inch bowl was turned this weekend from a branch that had blown down in the wind. It was 'double turned' after being seasoned in the micro-wave oven.
To be honest, I was practising the turning method demonstrated in the 'Lets teach turning' DVD. The bit that puzzles me however is the scuffed grain (arrowed).
There was no tool bounce that I was aware of -I was aiming to finish the bowl with the gouge. The bowl wasn't warped either- it was running true. The grain behaved as if you were planing a knot ( end grain) on a flat board- smooth on one side and scuffed on the other, yet my problem occurred on side grain. Can anyone make sense of this?
Regards
Haggy
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The picture is actually not quite big enough to see the detail of the problem. Maybe you could take a real close-up and add it to the post?
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if that is walnut? then they are just the two points where you go against the grain and will tear rather than cut. there are very few woods that you can get away with finishing with the gouge and have zero tear out.
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It looks like the two areas marked are just before you get to the side grain sections and that's typically where you will see tearout. Try resharpening the gouge and taking light cuts (followed by very light cuts!) to finish. With difficult woods it often helps to adjust the way the gouge is presented to the wood to get more of a slicing cut.
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I am new to turning so spend far too many idle hours on Youtube looking at how the pro's do it - I do recall an American chap (Capt. Eddie Castelin ) explaining that when it happens to turn the speed up as your are getting such a fine 'bounce' you cant feel it and if you keep going over it at the same speed you will only make it worse. He also said to try cutting instead of scraping. Tried finding it to respost but he has hundreds up there
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You need to work on your tooling technique
Regards George
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looks like classic end grain tear out,what you need to sharpen your tool/tools on the final finishing cut/cuts even if it looks sharp and feels sharp and take cuts that give you that superfine spidersweb shavings,you might need to go back to the sharpener to keep the tool`s edge as it depends how deep the tear out is,I hope this helps,cheers,
Eric.
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Sorry Eric, but this cannot possibly the classic end grain tear out, as it is at a place where you are cutting with the grain and not against it.
Haggy: you don't say what wood this is. It looks to me like wild cherry or walnut. The strong contrast in colour between heartwood and sapwood probably also indicates a strong difference in hardness/density. In cases like this, if you put pressure of the tool against the work piece, then at those places where it comes off the dense heart wood, the tool will move into the softer sapwood, only to bounce back, and then you get these patches.
George is right: work on your tool technique. The only real pressure you should apply is to hold the tool down on the rest. Make sure your tool rest is as smooth as possible, the tool sharp as possible and then take fine cuts, without any pressure at all against the work piece, and try and present the tool so that it performs a slicing action.
You could also try to use a freshly ground scraper, the type with the rotating tool tip, and do a shear scrape. If you have a nice, even burr on that tip, it will actually perform a shear cut more than a scrape and that should do the trick.
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fuzzy,
your opinion is noted,but its still on end grain and it doesn`t matter wether its cutting with or against,its STILL cutting across end grain not side grain and this happens on some woods more often if they are going soft where they are spalted/rotten or green and soft before they are properly seasoned.
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Thank you for your help, particularly to 'fuzzyturns'. I have taken another close up of the problem and the tree as asked- I think it is wild cherry too.
I have kept another piece of of this wood and am now better equipped with knowledge to try again. The scuffed grain didn't reveal itself until I oiled the wood. Thanks for trying to find the video link z3eddie, I will try adjusting the lathe speed as well as my technique I have suffered with tool bounce in the past, but this problem is new to me.
Regards
Haggy
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Hmm, I cannot tell from the picture what tree this is. The bark doesn't look like cherry, but it could be walnut. OTOH, I can't see details of the leaves, so the old saying goes: I used to undecided, but now I am not so sure. If you want a better answer, let us see a close-up of a leaf.
It is often the case that when you start putting the finish on, then all the little problems become visible as they are exposed. I don't think you are alone in that (I certainly am very familiar with this). There is only really one thing you can do: back on the lathe, fine cuts or loads of sanding. Since you now have oil on the surface, you should be able to tell whether you are making progress. I personally would recommend to put some sanding sealer on first. That also exposes the flaws, but it helps in several ways:
a) It saves on oil (and generally sanding sealer is cheaper than oil)
b) It stabilizes the surface. It won't stabilize wood that has gone punky (you'll need something stronger for that), but it does help with sanding and cutting on very soft wood
c) It reduces the amount of breathing the wood will do. Unless your work piece was already at less than 10% moisture content, it will probably move. Not a big deal for a bowl, but it doesn't help when you want to do some more work on it.
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If you are using Oil as a finish don't put sanding sealer on it stops the oil from penetrating.
Regards George
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Thanks Fuzzyturns and George- I've posted a couple of images that may help identify the timber that has given
grief- I will take on board your advice and look to use a scraper if I can't get the desired finish. I can understand why you think it is end grain Eric, but if you look carefully it is side grain and that is why I have found this so intriguing. I now have plenty to go at when I come against a similar problem- thank you for your help.
Haggy
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Try taking a picture of a single leaf on a white background, I then should hopefully be able to tell you what wood it is for sure including the Latin species.
Happy turning
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The leaves look very much like a Victoria Plum tree I cut down yesterday.
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Your tree looks looks a species of Willow to me.
Have a look at these video's and in particular the one on 'Cutting into end grain and grain direction' on page 3
https://vimeo.com/woodturning/videos/page:1/sort:date
Andy
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I used the Leafsnap UK app and took a pic of it and it came back as Plum - Prunus Domestica
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Glad the app helped, I've been waiting for an app like Leafsnap to come out for ages, I must admit I'm amazed that 1)it's free and 2) how accurate it actually is, when I first downloaded it I thought it would be a "gimmick" so I was pleasantly surprised.
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That sounds reasonable. What I am surprised about is the size of the tree, to be honest. I have never seen a plum or damson or any other of the prunus species to grow to more than 10 inches diameter, with the exception of cherry.
It does however fit my theory that there is a big difference in hardness between heartwood and sapwood, especially when turned green, with all the consequences following from there.
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Plum or damson can grow a lot bigger than 10" diameter especially in some of the old orchards.
Pete
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when turned green,heart and sapwood of cherry,damson,greengage,plum etc;are all soft and easy to turn,with no noticeable difference between heart and sapwood,the only two things to watch is all the sap coming out,its like being in a shower its so wet and dead knots inside the trunk/branch that your turning can cause a wavy cut to set up which can be difficult for a novice to rectify,with this i find its easiest to cut from the opposite direction with fine well controlled cuts until the ridges set up by the wobble are cut away.
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I have just logged on to see if any one could shed any light on the type of wood, I am grateful for the replies.
There has never been any fruit on this tree in the 15 yrs we have lived here, when you turn it green, as Eric says you get wet, it doesn't smell very nice either- my son said it smelt like 'cat wee'. I will be surprised if it is plumb or Damson- although the leaves are similar. Tomorrow I will do as you say Ryan and post a close up of the leaf on a white background- I will include the size. My Dad thought the same as fuzzyturns, but wasn't sure either. The SB Videos You sent the link to are the best training ones I have seen Ryan- I own some made by Alan Batty but Stuart has taken the to another level.
Thank you for your interest - Haggy
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Leafsnap is only available for the Apple platform, had a look for android equivalents but nothing seems to be as good or useful. Shame. Hope they bring an android version out soon.
Pete
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the leaf is very like a blackthorn and it's definitely in the prunus genus but the bark is wrong for it to actually be blackthorn.
can you add a good picture of the bark too.
it would also help to know if the wood is very heavy, lightweight, hard, soft, ring porous or diffuse.
if it is one of the harder cherries then in theory it should be cracking like crazy.
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Thanks too for your help seventh devil - on the first page is a transverse sect. of the tree where I got the bowl blank- does this show the bark in enough detail? Can you do the app. Test on this Ryan? This piece of wood is starting to split badly just as you said Seventhdevil.
In reflection both Eric and Fuzzyturns have given me a deeper understanding of why the grain behaved in an odd manner - but it would be interesting to put a name to this tree- we can say for sure it isn't walnut!
Many thanks -Hags
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Well, the trunk looks more like a beech to me but the rest of the tree doesn't. The leaves don't look like your average European beech, either. Having said that, there are about a dozen different species with quite some differences in leaf shapes and sizes. You said it never carried fruit. Did it ever have any kind of flower or bloom? Beeches would have catkins, which are quite easy to recognize. And, in fact, your second picture above does show some fruit, albeit green and small. Hard to tell at this stage, what these would look like when fully grown. The mystery goes on...
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It flowered in late April, the flowers that formed were in small white clusters of petals that fell like snow onto the lawn. You were right to spot the 'fruits' that have subsequently formed Fuzzyturns- they are not catkins. Fingers crossed that Ryan and his app. can help.
Thank you for your interest.
Haggy
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the flowers just confirm it to be a prunus but as to which one i can't yet say. pick of the bark in the light will help but it won't necessarily be conclusive.
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I'm going to throw in Malus to the mix and Crab Apple, can be know not to fruit.
Cheers
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Checked and checked again, it should be an Apple (Malus Pumila). Hopefully this helps.
Regards.
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I had some Apricot wood a few years ago that looked similar to the tree in the picture bark wise,but the one I got was allot smaller,the leaves were similar to if memory serves correctly.
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Thanks for double checking Ryan- I take it this tree is a malus (apple) or some sort of prunus. When it flowers next season I will try again to confirm its identity. Meanwhile I feel a sense of pride that my tree has managed evade some very knowledgeable people.
Regards
Haggy
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the bark should settle it as they are quite different.
if you like you can send me a sample and i'll examine the endgrain for you.
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Barks are very similar on "same family" species but for your convenience Leafsnap also add pictures of the bark too.
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Are you going to the seminar seventhdevil? If you are I will slice a section off the branch and leave it at the desk where you collect your passes.
I have downloaded your app. Ryan but haven't had time to properly test it out. I didn't do very well with the leaf ID game .
Regards. Haggy
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The fruit shown in one of the earlier photos is definitely plum/damson/greengage family. Absolutely not apple of any sort. The leaves of malus and prunus are all very similar so I can see why the app might get confused, but the fruit is distinctly different. First image below is apple, pears are very similar. Second is damson, plum and greengage are virtually identical at this stage.
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Thanks for the pictures Chris - the second picture certainly appears the better match. I will bring a sample of the leaves and branch to the AWGB seminar as it is hard for people to study a photo. Once again I appreciate the help in ID, I didn't expect such a response.
Haggy
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having fiddled with the contrast and brightness on your image of the log i can now see the bark alot clearer and it's 100% a cherry but can't pin down the exact one.
after looking at some images of prunus species i'm leaning towards prunus padus, hackberry.
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I think you are right too seventhdevil- prunus padus seems to tick all the boxes. The wood is described as having a particularly nasty smell which my son commented at the time as smelling like 'cat's wee'. I don't remember it bearing small cherries, my wife thinks seed pods are formed but I will keep an eye on the tree this year. Thank you once again for going the extra mile seventhdevil, I really appreciate it.
Haggy