Blanks breaking at end of tube

[martin.pearson]

Had this happen a few times now & running out of comfort pen rubber bits lol I did try searching the forums but anyone that knows me will tell you I am rubbish at searching forums.

Apart from a couple of Burs which I was half expecting because my method of stabalising consists of trying to fill them with very runny superglue this has only happened with cross cut or diagonally cut blanks, in this case a 45 degree cut piece of Yew & always at the right hand end if your facing the lathe.
My first thought was that it might be a glue problem but why always just the one end & why only on cross cut blanks?

Any help would be much appriciated so I don't have to but more comfort pens just for the rubber bits lol

 

[yorkshireman]

It could be a few things Martin. The main issue is probably gluing. With cross cut blanks you are in effect gluing your tubes into end grain which doesn’t have the same grip as if the grain was running the length of the tube if you get what I mean. This will be weaker at the ends. If your tools aren’t sharp or your taking off too much at once the glue will sheer as you’ve experienced. The answer is to ensure plenty of glue around the tube, sharp tools and very light cuts. A skew chisel will help if you’ve got the experience and confidence to use one.
No doubt others will be along with further advice.

 

[Phil Dart]

What cutting tool are you using Martin?

 

[wm460]

I only use Epoxy, I spread the Epoxy around the inside of the blank from both ends, then put a bit more Epoxy on the tube and twist the tube as I push it in.
I had the same problem as you when I was using CA.

 

[Penpal]

I saturate both the brass and inside the blank. Messy but no failures. Turning by starting at the each end helps.

Peter.

 

[Frederick]

Hi all

I sympathise and empathise here. Once the tube is fitted, I place some thin CA on the ends of the tube making sure that some permeates between the tube and the blank. I always pay particular attention to cleaning and roughing the tube ends as well. If some goes in the tube then it isn't the end of the world and can be cleaned out. Of course you cam always sacrifice a potato or apple to prevent this. I just think you are having some bad luck. I would just check to see if your tools are very sharp as well. I use a scraper most of the time and I am always honing it. I think it pays off well in the end.

I am no expert by far, but have been there more times than then I care to remember. Employing the above seems to have stopped my problem and I hope I am not teaching you to suck eggs.
Please let us know how you get on and what the remedy is.

Cheers,

 

[Bammer]

Hi Martin, could be a combination of three things

1. Glue Looks like not enough glue and looks like you are using CA. Stop using CA to glue your tubes in, especially X cut. The wood will absorb it into the grain but the too far and not create the bond you need. When it dries on hard surfaces it is Brittle, (not like when it dries on fingers) Use a polyurethane glue such as Gorilla Glue, the stuff sticks like the the proverbial "S**t to a blanket" it will also expand and fill any drill wobble. Let it cure, at least 8 hours, preferably over night. I always rough my tubes up, some say it isn't required some say it's better, who really knows.

2. X cut wood. It is weak, far more so than a piece with the grain, we all know that. So it's going to re-act differently when you are working it. So when you cut it, light cuts with sharp tools. I mean sharpen them before you start work on this piece, not use a tool that you sharpened in the morning and have done another 10 blanks before this one.

3. Technique No idea what tool you are using. But x cut is more difficult, again light cuts and sharp is best, be patient and don't try to take to much off. If you saw the x cut Cocobolo I posted well that stuff is quite tough, but the x cut still makes it weak so care has to be taken. I use a 3/8 spindle gouge for all my wood pens.

The combination of all these 3 will cause your problem, Glue, The material and Technique. get all those right and you'll "crack" it ... no pun intended

PS, a good tip for you. Once you got it round, cover it in Thin CA, the thinnest you can get, this will soak in and help hold it together. Spray with activator and carrying on turning. Can do it as many times as you want. When you get close to your finished size, do it again. Then carry on with gentle light cuts. The object is not to do it as quick as you can, but to get a finished piece that's intact.

Hope this helps

Brad

 

[Steve68]

I may be WAY out here as I am nowhere near as clever or experienced as you and my forum colleagues.

I kept experiencing a similar issue. I thought I was trimming the blank right down to the tube but I must have been just shy. Obviously when I tightened the tail stock the bushes were not putting pressure on the tube, but only on the blank. Only by 100th of a gnats todger, but enough to fail when pressure from the bushings and the tool cutting the blank came together.

As I said I expect I'm way out but a forum lurker new to the hobby may be able to benefit from my fumblings in the shed

 

[martin.pearson]

Thanks for the replies people, glue wise yes I have been using CA, actually started with thin CA as I have that from other things I do, didn't like that because it dried to quickly for me & yes I know it doesn't have any gap filling properties, moved on to Epoxy which worked ok but if I had a few blanks to glue up I was rushing to try & get them done before the adhesive started to cure so wasn't iseal for me. I use mitre bond for some things & the activator always runs out way before the CA does so I gave some of that a try with it being a thicker CA & slower curing I thought it would be better than the other stuff I had tried. Seemed to work OK for me so carried on using it. I used what I had available to me rather than buy something that may have been better suited to what I was doing, will have to buy some polyurethane & see how that goes. I always rough up the tubes & pay particular attention to the ends so don't think that is part of the problem, tool wise I use a gouge, I believe it is a spindle gouge although not really sure what the differences are with some of them lol, 20 years in the RN as an engineer, trained as a fitter turner OK working with metals rather than wood but the point is I know the importance or sharp tools but I may not be keeping it quite sharp enough, will pay more attention to that.
technique may well be a problem, being quite new to turning & not having been trained properly for this sort of thing. Confidence certainly isn't a problem, be quite happy to use a skew but I don't have the experience, I don't fear any toolong or equipment, I have a very healthy respect for it but my engineering knowledge & experience has taught me well.

Rather than start a new post since sharp tools has been mentioned a couple of times can I ask how you people manage this side of things, I have a wetstone sharpening machine, its the lower end of the market, the likes of tormek were just to pricey for me as a machine but I did buy tormek jigs which has made it very easy to keep tools sharp without removing half the tool trying to get the angles right lol, (lack of experience thing again).
One thing I have found is that cross cut wood takes the edge off the tool far quicker so have spent more time sharpening/honing the tool & as gouges have a curved tip the grinding wheel isn't going to stay flat which means it is going to need dressed much more frequently I would have thought. So just wondering what the best solution might be, harder stone or maybe a seperate machine for gouges ?
Since I intend to cut most of my blanks cross cut from now on this is something I probably need to think about.

 

[Steve68]

Thanks for the replies people, glue wise yes I have been using CA, actually started with thin CA as I have that from other things I do, didn't like that because it dried to quickly for me & yes I know it doesn't have any gap filling properties, moved on to Epoxy which worked ok but if I had a few blanks to glue up I was rushing to try & get them done before the adhesive started to cure so wasn't iseal for me. I use mitre bond for some things & the activator always runs out way before the CA does so I gave some of that a try with it being a thicker CA & slower curing I thought it would be better than the other stuff I had tried. Seemed to work OK for me so carried on using it. I used what I had available to me rather than buy something that may have been better suited to what I was doing, will have to buy some polyurethane & see how that goes. I always rough up the tubes & pay particular attention to the ends so don't think that is part of the problem, tool wise I use a gouge, I believe it is a spindle gouge although not really sure what the differences are with some of them lol, 20 years in the RN as an engineer, trained as a fitter turner OK working with metals rather than wood but the point is I know the importance or sharp tools but I may not be keeping it quite sharp enough, will pay more attention to that.
technique may well be a problem, being quite new to turning & not having been trained properly for this sort of thing. Confidence certainly isn't a problem, be quite happy to use a skew but I don't have the experience, I don't fear any toolong or equipment, I have a very healthy respect for it but my engineering knowledge & experience has taught me well.

Rather than start a new post since sharp tools has been mentioned a couple of times can I ask how you people manage this side of things, I have a wetstone sharpening machine, its the lower end of the market, the likes of tormek were just to pricey for me as a machine but I did buy tormek jigs which has made it very easy to keep tools sharp without removing half the tool trying to get the angles right lol, (lack of experience thing again).
One thing I have found is that cross cut wood takes the edge off the tool far quicker so have spent more time sharpening/honing the tool & as gouges have a curved tip the grinding wheel isn't going to stay flat which means it is going to need dressed much more frequently I would have thought. So just wondering what the best solution might be, harder stone or maybe a seperate machine for gouges ?
Since I intend to cut most of my blanks cross cut from now on this is something I probably need to think about.

I was recommended, by many on here, a Sorby Pro Edge. Not cheap but WOW!!!

 

[yorkshireman]

Quite a lot on here use the proedge Martin, it’s very quick and very good.
You will blunt the tools quicker when using cross cut blanks as you are cutting in to end grain. To lessen the amount of sharpening make sure that you cut with every bit of the gouge and not just the middle.

 

[Pierre]

Using your system with the tormek guides will be enough, if you are happier with a gouge rather than a skew then take the widest you have and put long sides on it, I use this ie the top one, (the bottom one is its replacement about to be educated into long sides).



Its a Martin Pidgeon all-rounder with a change to lengthen the sides ie tormek bowl gouge 45 degree setting 2 middle distance (65) . I can then use the sides as you would a skew and the round part as a detail gouge all the time. And this is the most important element which has not been mentioned you MUST rub the bevel ie get the bevel onto the wood and then lift the back hand until it starts cutting then don't raise it any more to take light cuts. If you dig in you will break the wood. Add this to the rest above and you will succeed.

PG

 

[Bill Mooney]

There's a lot of good advice there Martin. When I make x cut pens I cut from the ends of the blank towards the middle, if you cut towards the ends you run the risk of pushing the timber off the tube thus broken grain at the ends. As previously said, sharp tools. light cuts & high RPM.

 

[martin.pearson]

Thanks for the replies People, with the amount of hand turning I can do a sharpening system like that isn't going to happen anytime soon unless I win the lottery lol, I don't mind spending money on quality tools if I have it but I have Chronic fatigue syndrome as well as a bit of a physical disability which means the time I can spend doing anything is limited.
I have a second CNC machine that I need to fix & convert to a rotary axis when I can get the money together & that is a high priority just now to just about any other equipment.

For now I will stick with what I have, dressing the wheel a bit more often if I have to seems to be my best option just now, will change the adhesive I use & also take note of the other advice given & see how things go, will report back any findings in the hope it helps others.

 

[Dibbs]

Using your system with the tormek guides will be enough, if you are happier with a gouge rather than a skew then take the widest you have and put long sides on it, I use this ie the top one, (the bottom one is its replacement about to be educated into long sides).
...

It's interesting that you made the wings concave. Everything I've ever seen say that is to be avoided so I've never tried it. I imagined it could cause catches on broad coves.

 

[Phil Dart]

All been said, but the most important aspect for x cut, apart from sharp tools of course, is as Bill says, cut in towards the middle from the ends.

In the same way as you wouldn't plane off of the edged of an end grain on a plank of wood for instance, so you shouldn't cut off of the end on an end grain blank. The gluing thing - enough or not enough- only means than when you knock off the end of the unsupported end grain with your gouge, which I think is exactly what's happening, if you have enough glue, you'll get some left stuck to the tube, and if you haven't it'll just break off without leaving any behind. In other words, irrespective of your gluing technique, it's destined to break off in any event, unless you cut from the edge towards the middle.

 

[martin.pearson]

Ordered the polyurethane adhesive which should be here soon but decided not to wait for it to arrive so glued up some blanks using the same CA I have been using, once the CA had time to dry I trimmed them as usual but then I used a little bit of thin CA around the ends as someone had suggested. Roughed a few today & as suggested cut from the ends inwards, haven't had any problems yet but as I said in the original post it is a bit random so it might just be that I wasn't going to have any problems anyway lol
I had thought about possibility of me pushing the wood off the end of the tube before I asked the question but thought it unlikely as it only ever happened at the one end & I was cutting in both directions so would have expected at least some of the failures to be at the other end. Having thought about that a bit more there are a couple of things that I hadn't considered previously. I am quite new to hand turning so lack experience, it may be that I am taking a deeper cut moving left to right than I am moving right to left, in the same way the tool angle may be slightly different or the speed I am feeding at may be different or even a combination of them all lol.
Once I have the new adhesive I will just start using that for all of them plus any other kits that need tubes glueing in place.
I will also make sure I keep the tool well sharpened, actually had a bit of a pratice with the skew on some of those I did today, most of the pens I will make will be cross cut, since I lack experience & can't make pens like some of the experts do I am trying to concentrate more on making sure the wood is the best it can be lol

 

[Bammer]

You Ordered it ? Screwfix, B&Q, Honebase, Tool station etc etc all stock it ...

 

[martin.pearson]

You Ordered it ? Screwfix, B&Q, Honebase, Tool station etc etc all stock it ...

Yes I was ordering other things as well so just got them all from the same place, don't think we have tool station in Scotland, the others we do but I haven't been in B&Q or Homebase in years, way to expensive for most things I use lol, Screwfix I have used on the odd occassion but wouldn't have thought of them. They don't stock most of the things I use generally.