What went wrong!

[Martynbez]

Well it was going to happen sooner or later. Can anyone see if it was something I did wrong?

 

[Phil Dart]

You're not the first Martyn, and you won't be the last. We've all been there I assure you.

Half the problem in your photo though, is your glue distribution I'm afraid. If you have the tube glued in well, when you get a catch or a dig-in with the tool, it generally just stalls the lathe or the blank just spins in the mandrel. When the glue is uneven or absent though, there is a tendency for the wood to break away, which is what it looks like has happened in your piccie unfortaunately.

Have a read of this, which you may find helpful - it was written to deal with polyurethane glue, and it looks like you're using CA, but the method for inserting the tube and getting a good coverage of glue applies equally to both
Preventing pen tubes from moving with Gorilla Glue

 

[Martynbez]

I see what you mean and you are right it might not have got as good a coating as it should. Such a small stage in the process can have such a large impact on the project.

 

[AllenN]

I am sure Phil is correct. Personally I prefer epoxy glue but just the same good distribution is key.

 

[Gadget-UK]

Over the years I have had FAR to many of those Martyn
Phil is spot on with his assessment and I now make preperation time just as important (if not more so) as Turning Time.

I still get the odd one that decides to split on me BUT I just put it down to a learning curve (6 years and still heading upwards )

Clean off the wood, clean up the tube and start again

 

[flexi]

We've all been there!!
We all have our own glueing regime.... Mine is drilling tight fitting holes, I use callipers and both metric and imperial drills. I use Gorilla pu glue, applied to the tube which I insert with a twisting motion.... I push flush with a mastic/ silicon gun nozzel.... Then probably most important I leave over night and turn the next day.
I have tried CA and had more half inserted stuck tubes than I cared for, I have also tried epoxy two part glue and got tired of trying to find something to mix it on, never a problem finding it with your hand with half set sticky glue on it....
As I say you'll find a preference

 

[Pierre]

As well as what Phil said which is perfectly valid, I note a couple of other things, on your photo I can see a step on the left of the photo just at the sheer point of the split this indicates to me a fairly deep cut into a wood with a clearly defined diagonal grain, had you been cutting in the opposite direction it probably would not have happened. I also note that you seem to be cutting in from the flat end face, I would recommend that for both ends you cut from the middle to the end then your gouge wont lift the grain and help the split. Finally I dont know how you use your tooling but just in case, for every tool you should rub the bevel first then lift the cutting edge into the wood and the slide angle of the cutting edge should be about 45 degrees, creating a slicing 'V'. For some people this will be an automatic movement for others it may take a second or 2.

All is not lost though, use some CA glue on the tube and the face of the sheered parts and clamp it for 24 hours (make sure its a nice snug fit) then finish the pens for your self and carry it with you all the time to remind you of the problem what a cheap workshop pen!!

 

[Bill Mooney]

I agree with Phil. It’s a shame though.

 

[Phil Dart]

on your photo I can see a step on the left of the photo just at the sheer point of the split this indicates to me a fairly deep cut into a wood with a clearly defined diagonal grain, had you been cutting in the opposite direction it probably would not have happened.

Huh??

I think it's fair to assume that the lathe was switched on Pierre

....which means that you're going to be working against diagonal grain every 180 degrees, not matter which end you start.

#justsaying

 

[Pierre]

Huh??

I think it's fair to assume that the lathe was switched on Pierre

....which means that you're going to be working against diagonal grain every 180 degrees, not matter which end you start.

#justsaying

Erm nope that's a specious argument, if you work from the middle out with the bevel applied and slide towards the open end of the grain then you are always pushing down the wood cells and no matter the spin of the lathe you are constantly slicing rather than lifting: and you know exactly what I mean despite me losing the English words for it!!

 

[Phil Dart]

Erm nope that's a specious argument, if you work from the middle out with the bevel applied and slide towards the open end of the grain then you are always pushing down the wood cells and no matter the spin of the lathe you are constantly slicing rather than lifting: and you know exactly what I mean despite me losing the English words for it!!

I agree that best practice is to work from the middle towards the ends and ensure that the tool bevel is rubbing the work piece, but you will still have end grain at an oblique angle winking at you several times a second, no matter in which direction the tool is travelling.

It's a problem that bowl turners face twice in every revolution, as I appreciate you already know, but all I'm suggesting, given that your original statement was "had you been cutting in the opposite direction it probably would not have happened" is that the method won't necessarily make the problem go away - working from the middle towards the ends may or may not have prevented Martyn's blowout since he would still be working against the grain once in every revolution, irrespective of tool feed, and irrespective of his tool handling skills, albeit that good tool skills and best practice, as you have subsequently said, will do a lot to mitigate the problem.

 

[Penpal]

My practice with Gorilla glue,using it for yrs before most anyone on this forum is to coat inside the blank from either end and liberally half way on the leading end of the brass ,following a brass moved twice on me in hundreds of hundreds I still run a rubber band around the glued ends and use a potato in one ,ie the leading end of the brass at insertion and poke it out with a chopstick when in position.I have used at least ten differing glues since the 1980,s but am happiest with the Gorilla Poly Glue. Just finished glueing 32 Slims.

Peter.

 

[Tiny James]

I would like to add as this has just happened to me on acrylic pen blank (HEAT) will warm up your blank and this will act as a shrink wrap effect and if there is any unevenness in the glue IT will show up on your pen.

so be careful when sanding and polishing that you don't get the acrylic hot it happened to me while polishing with a cutting agent and a paper towel

James