Drilling pen blanks

[Gizmo3k]

Recently I have lost a few pen blanks because they split, and I am wondering if it is my technique.

If I am drilling a fairly large hole (for example an Omega cap) which won't leave much wood thickness left, is it worth drilling a smaller pilot hole first? I have been drilling the full size straight away, albeit slowly, with plenty backing out to clear out the drill bit. I am wondering if taking out a smaller amount of wood first would help.

As far as I can tell, my drill bit is nice and sharp, and I don't think I have been going too quickly (although I may be wrong there! )

Any advice gratefully received as always!

Alan

 

[Vic Perrin]

Are you drilling them on your lathe or a drill press

Vic

 

[Woody]

In some woods a pilot hole is the best way also I always cut my blanks to long then if there is any damage from the drill exiting the wood then it gets cut of another way is again cut the blank to long mark the drill bit with a bit of tape as a depth stop and don't exit then cut the end of I always listen when drilling and the sound changes as the drill starts to exit then go slower and softer good luck

 

[Penpal]

Alan drilling blanks is a very elementary process in the needed preparation of a blank two things have to come together to achieve this. Firstly suitable drills and suitable methods of drilling. Having conquered these the knowledge needed to determine how to learn the characteristics of the timber or otherwise material you wish to drill. The internet abounds on U Tube with practical methods and instruction in these matters. Helpful advice can be had first hand through a convenient Wood Club or Association in your case are there members of this forum within reach of you that could help you. I found out the correct alignment strong methods of holding the blank are vital for repeatable success I strongly support the things Woody has said like the Irishman said to be sure.

Trust you find a way to practice and apply methods to give you success.

Peter.

 

[chas_41_uk]

I'd advise always drill smaller holes and work your way up, unless it's a 7mm hole. Say your want a 10.5mm hole, start with a 7mm drill bit (or even a 5mm), then an 8mm one and finally the 10.5mm

 

[Gizmo3k]

Generally, the blank isn't blowing out at the end, the whole thing is splitting along its length. Mostly on spalted timber, which could be a contributing factor.

I did try wrapping one piece in duct tape which worked ok, although I managed to take a chunk of it off the tube while turning!

 

[Vic Perrin]

If it's splitting along a spalting line for the whole length of the blank I would suspect that it might be the spalting causing the problem. I have had this happen on a few occasions when turning bowls a whole piece has come away during turning. To get away with this on some other pieces I had from the same tree i drizzled thin CA into the suspect area and got away with it.

Vic

 

[Grump]

It's only spalting cos it's rotten, stabilise it before drilling if possible.
If not drill a smaller hole and fill it with thin ca and let it soak through from inside.
Do same again with a larger hole until you reach the final diameter.

 

[brody2123]

I use masking tape on fragile blanks. I also usually start by using a centre drill for metal which, gives a good straight starting point for the drill bit. A bit overkill maybe but I got tired of blowing the sides of blanks out because the drill bit was wondering. Works for me

 

[paulm]

I give mine a good soaking of super thin ca first if there is a risk of the blank breaking. I always seal the ends after trimming them with super thin ca as well and have now got into the habit of doing this on all blanks.

 

[Terry]

All of the answers are good but I would go along with Chas and use a few drills to get to the required size. This stops the swarf from compacting in the drill flutes which can cause internal pressure on the inside of the blank !!!

 

[Woody]

Now you have mentioned spalted thin CA has to be your answer to stabilise the wood

 

[Buckeye]

Drill in several steps to get to your final size and if the wood is spalted use lots of CA from inside as well. Drill slowly and use sharp bits if your bit is too hot to touch it is not cutting properly, let it cool down.

Peter

 

[Gizmo3k]

Thanks for all the advice! Will give it shot!

 

[Neil]

If it is going to split without CA then chuck it out, its not worth the hassle.

Other thing not mentioned is you need to clear the drill bit by withdrawing it, perhaps you need to do this more frequently, this will slow down the build up of heat and allow the drill to work properly.

If you are using a pen blank drilling device you could be overtightening the vice?

Could be exiting the blank too quickly, try putting a sacrificial off cut under the blank.

 

[Buckeye]

If it is going to split without CA then chuck it out, its not worth the hassle.

Some of the most beautiful woods need CA or stabilising, if it gorgeous it worth the time, just send all your most beautiful blanks to me

Could be exiting the blank too quickly, try putting a sacrificial off cut under the blank.

I read that as, exciting the blank too quickly, and thought I never talk dirty to them

Peter