Not scared of dig-ins any more

[graduate_owner]

Really,truly, because I'm getting very used to it happening now, so I'm not scared but I am getting very pi$$ed off with it happening.

I'm sure it must be my tool sharpening technique and I'm working on that. I haven't invested in professional sharpening jigs yet - may have to it seems.

I currently have a log on the lathe with grain running along the direction of the axis of the bed, have turned the outside to get it in balance (no problem there). But as soon as I try hollowing out - well everything goes to pot. I'm not actually making anything special, just getting some practice in. This is similar to making a box, except the log has a diameter of about 6" which I thought would be easier to hollow out. Hah !! Some hopes.

So there it goes, dig in after dig in, catch after catch. The gouge went across the workshop twice (no, not in anger, just another two catches). If I get fed up with it then I reach for the scrapers, but I have to say I'm envious of those turners I see in videos where the shavings come away thick and fast. I just love it when it happens, but it only happens for me when turning the outside of the work.

K

 

[Dalboy]

What tool are you using to hollow out with and how deep are you trying to hollow. these may help so that someone can point you in the right direction

 

[graduate_owner]

Hi Dalboy,
and thanks for replying.
I'm using a 3/8" Henry Taylor Superflute and I'm less than 1/2 " into the hollowing process. There's a long way to go yet !! I've also tried a spindle gouge but it's not so sturdy as the superflute as it has a shallower flute. Also I'm not getting decent shavings, just thin strings of shavings. Judder, judder, judder.

K

 

[tekno.mage]

When I hollow out end grain I normally use a 3/8" spindle gouge (not a bowl gouge) and I start by drilling a depth hole down the centre of the piece for two reasons, it makes the hollowing go easier and it tells me when to stop I normally hollow end grain by starting with the gouge in the centre of the piece and cutting/scraping outwards (rather than cutting in toward the centre as it susual with hollowing a bowl) .

If I get a lot of juddering and vibration it normally means one of three things - my gouge is blunt (most likely!), or I'm trying to take too deep a cut for the hardness of the wood and/or type of lathe, or I'm not paying attention and approaching the cut at the wrong angle. You may not get long strings of decent shavings when end grain hollowing, it depends on the type and wetness of the wood!

You say your log is 6"' in diameter - this could also cause the juddering if you try and take deep cuts near the edge of the diameter of the piece as this is putting more strain on everything and if you have a small lathe with some types of bearings it may complain and judder. Cut more lightly from the centre outwards and things should go more easily. I know I can hollow more aggressively and with deeper cuts on a small Vicmarc lathe (which has long taper bearings) than on a small Axminster lathe (which doesn't) before I start getting vibration and juddering.

 

[finneyb]

With the lathe off. Place the gouge in contact with the wood as if were going to hollow. Rotate the lathe by hand and look what the edge is doing. If its digging in rotate the tool until it cuts but doesn't dig in. That is the angle to stop the catches. I would reduce the rpm and go lightly with the cuts until you have got the hang of it.

Try http://www.youtube.com/watch?v=3XR4cLethvM - there are many on Youtube


Brian

 

[nev]

Hi K
I too use a superflute and I do not get the same issues, so if you fancy calling in if you are ever passing Cross Hands (Foelgastell), come and have a try of mine and see if you have the same problem - I am sure we could work out whats going wrong between us.
I don't have a proper job so I am here most of the time, just drop us a PM if you fancy it. (you can bring the custard creams )

 

[Dalboy]

When I hollow out end grain I normally use a 3/8" spindle gouge (not a bowl gouge) and I start by drilling a depth hole down the centre of the piece for two reasons, it makes the hollowing go easier and it tells me when to stop I normally hollow end grain by starting with the gouge in the centre of the piece and cutting/scraping outwards (rather than cutting in toward the centre as it susual with hollowing a bowl) .

If I get a lot of juddering and vibration it normally means one of three things - my gouge is blunt (most likely!), or I'm trying to take too deep a cut for the hardness of the wood and/or type of lathe, or I'm not paying attention and approaching the cut at the wrong angle. You may not get long strings of decent shavings when end grain hollowing, it depends on the type and wetness of the wood!

You say your log is 6"' in diameter - this could also cause the juddering if you try and take deep cuts near the edge of the diameter of the piece as this is putting more strain on everything and if you have a small lathe with some types of bearings it may complain and judder. Cut more lightly from the centre outwards and things should go more easily. I know I can hollow more aggressively and with deeper cuts on a small Vicmarc lathe (which has long taper bearings) than on a small Axminster lathe (which doesn't) before I start getting vibration and juddering.

This is how I hollow but I use the bowl gouge or my crown revolution hollower especially if it is end grain

 

[woodfarmer]

How long is this blank? I wonder if it might be better to use a centre to support it then use a flat drill to remove the centre. I had a hell of a time trying to turn a bit of wet willow. The wood would flow around the cutting edge It was like trying to turn a balloon with a sausage so what wood are you using?

Basically if a gouge catches you are not on the bevel. So check with the power off that the cutting edge is presented correctly. If boring down the inside I have found running the gouge on its side is fine, but run slightly above centre until you get to the bottom. Turn the corner by levering on the bevel as you get to the bottom. To get a bit more room dip the handle a bit more. once Once you have enough room to swing the handle out to run on the bevel horizontally you can then face off the bottom. A steep bevel angle needs less handle movement and helps on deep steep sided hollows.

Wood that has soft and hard areas seem to present more problems to me because when the tool is not sharp enough instead of cutting a true circle will cut deeper in the soft stuff and leave the hard stuff proud. the tool will then judder and bounce and can make controlling it much more difficult.

Ideally the bevel should only have one face, straight or slightly hollow never convex. (there are a few exceptions but these are specialist tools)

Hope that helps and is correct.

 

[OldWood]

Woodfarmer has given the answer I would give you - the bevel is not rubbing when you are cutting.

I know that this is challenging the fates, but since I finally got that into my head, I've not had a dig-in ! And I find that my turning is clean and requires far less cleaning up after cutting.

Rob

 

[Spindle]

Hi

As above - almost certainly caused by loss of bevel contact. I'd suggest grinding your hollowing gouge to a greater angle, around 60 degrees, this will allow you to maintain bevel contact much easier when hollowing.

Regards Mick

 

[graduate_owner]

Once again, thanks to everyone for their invaluable and knowledgeable advice. I shall try regrinding one of my spindle gouges to a steeper angle to see if that has any effect. And thanks also to Nev for the offer. You're only just over 25 miles away so that's quite a realistic proposition. Custard creams - no problem. I'll bring my superflute too.

The lathe I'm using is a union graduate on lowest speed, so should be solid enough. It's second hand (or third / fourth/whatever) but I think the bearings are OK because the outside turning seems fine. Must be the gouge sharpness / angle - or more probably the ham-fisted user, but I'm not giving up !!

K

 

[woodfarmer]

I have re read all of this and it occurred to me that it might be that the "ears" of the gouge are fouling the wood. This is more likely if they protrude forwards and are proud of the bottom of the U of the gouge. I mention this because you say you are freehand grinding.

It may be entirely wrong of course, but I have no idea what you do and don't know so please accept this as a helpful (maybe) idea.

 

[Richard Findley]

To help, we need to see your grind on the tool first. Could be the wings need grinding away more... Or less...

Are you cutting into the end grain or drawing it out?

How have you mounted the timber? Could be a lot of vibration.

When are the catches happening... At the edge? Half way down? Across the bottom?

Might be better to start with, say, a small box blank rather than a big log?

More info then I'm sure you'll be awash with answers.

Cheers

Richard

 

[Tazmaniandevil]

When I first started out, with only books and youtube for guidance, I spent hours with green stuff on the lathe just finding the bevel and allowing it to rub. This probably sounds very basic, and may come across as patronising. I really don't intend to offend anyone, but as a beginner I didn't understand what people meant by rubbing the bevel.
We were given lessons at school, and my uncle was a keen turner, but no-one really explained why it was so important for the cutting edge to be supported by the bevel. I liken it to too much of a plane iron protruding through the sole. It can't help but dig in to the wood because the iron is not being supported at the correct angle or height.

Like I say, I'm not trying to teach my granny to suck eggs. Many folks who have been turning for a while though, may not realise how many of us beginners have such little understanding of basic terms.
Like many aspiring hobby turners I tried to run before I could walk, and as a result ended up with a huge pile of firewood & shavings and a lot of frustration. I got hold of a few old scaffold boards which I cut into squares and mounted on a faceplate one after the other. I then practised over and over getting the bevel to rub. It was scrap timber, so did not matter one jot if I destroyed it. I then followed one of Cap'n Eddie's videos on slicing cuts, slowly allowing the gouge edge to take very fine cuts before building up the confidence to take deeper cuts.

Feel free to tell me to bolt, I will not be offended.

 

[OldWood]

When I first started out, with only books and youtube for guidance, I spent hours with green stuff on the lathe just finding the bevel and allowing it to rub. This probably sounds very basic, and may come across as patronising. I really don't intend to offend anyone, but as a beginner I didn't understand what people meant by rubbing the bevel.
We were given lessons at school, and my uncle was a keen turner, but no-one really explained why it was so important for the cutting edge to be supported by the bevel. I liken it to too much of a plane iron protruding through the sole. It can't help but dig in to the wood because the iron is not being supported at the correct angle or height.

Like I say, I'm not trying to teach my granny to suck eggs. Many folks who have been turning for a while though, may not realise how many of us beginners have such little understanding of basic terms.
Like many aspiring hobby turners I tried to run before I could walk, and as a result ended up with a huge pile of firewood & shavings and a lot of frustration. I got hold of a few old scaffold boards which I cut into squares and mounted on a faceplate one after the other. I then practised over and over getting the bevel to rub. It was scrap timber, so did not matter one jot if I destroyed it. I then followed one of Cap'n Eddie's videos on slicing cuts, slowly allowing the gouge edge to take very fine cuts before building up the confidence to take deeper cuts.

Feel free to tell me to bolt, I will not be offended.

I hold a lot of respect for people who can have the dedication to the art of learning that they can put the time to practicing in the manner Tasmaniandevil has done - well done. My practice I'm afraid was mainly for the benefit of the log burning stove, getting dig-ins and all the rest until, like my violin learning daughter, suddenly getting to the point where I learnt the key.

I did have the pleasure recently of getting my own back on the wood-burner in finding that some of the delivered logs were spalted beech - a dozen or so selected bits during the stacking have produced some nicely patterned items.

Rob

 

[woodfarmer]

Hah! last week I nobbled 3 cherry logs from the woodpile about 4" diameter. thinking they were dry I spindle turned some candlesticks, the next day they all had split to (insert epithet here) so they ended up in the logburner

Maybe the next cherry I will plank out because so far everything I have turned with it has split hopelessly.

 

[graduate_owner]

I've been raiding the wood store too, but just for practice material. I need plenty of practice.

K

 

[graduate_owner]

Right, so I put a chunk from the firewood pile onto a faceplate, with grain running across as in normal bowl turning. I started facing off and there they were- - shavings. Ankle deep in nice curly shavings. When trying to hollow out with the grain running along the axis of the bed however, that's a different story as I said previously. Snatch snatch snatch. I haven't changed the angle of the gouge yet though.

K

 

[Spindle]

Hi

So with the lathe off, offer up the gouge to the work and look at the angle between it and the gouge. Now try to replicate this angle when hollowing - doubtless the gouge will either contact the lathe bed or the periphery of the work before the angle can be replicated resulting in an unsupported bevel - grinding a greater angle to your hollowing tool will allow presentation without fouling the bed / work.

The other thing to watch is where the wings of the gouge are, you should be rolling the gouge so as the wings will not contact the work, (grinding them back if they aren't already will also reduce the risk of them catching).

Regards Mick

 

[Richard Findley]

There are a few differences between hollowing end grain and hollowing a bowl that make the process quite different. Firstly, you won't get shavings like hollowing a bowl, when hollowing end grain because you are always cutting down directly into the end grain. This makes the process much harder.

For hollowing end grain it is much easier to push into the centre, either with a drill or by using a correctly ground gouge as a drill, then using the lower wing of the tool, flute facing around 10 o'clock, and drawing the shaving out. This way you are working with the grain, rather than against it.

Personally I use a bowl gouge ground at 60 degrees for bowl work and a spindle gouge ground around 35 degrees for spindle and hollowing work. When I say hollowing, I refer to goblets and boxes, rather than larger hollow forms.

Hope this helps

Richard