BAD Blow out

[Nicholas Briggs]

Making some Desert Ironwood Statesmen pens for my groomsman in my wedding. When drilling the blanks I'm getting horrible blow out. It happens on both the bit 15/32, and the massive 37/64 bit. I did a Cigar pen 3 days ago, and had no problem with the 10mm bit. First blow out was at 1600 RPM, second blow out (pictured) was at 500 RPM. Any suggestions?

http://i70.photobucket.com/albums/i95/nethowler/DSC_0049crop.jpg

[Nicholas Briggs]

One more question. I already filled the gaps as best I could with CA. Will this blank still be usable for a Statesman? How noticeable will these cracks be after the pen finished?

[Keith Christopher]

Here is what I found out, when drilling blanks I have my press set to the lowest speed, and I keep constant even speed when lowering the bit. Raise the bit often and clear it out. This happens when the edges of the bit grab rather than cut. usually means forcing the bit into the blank.

slow and steady wins the race.


Hope this helps.

[Nicholas Briggs]

Hmm... Thanks Keith. Seems like with Ironwood I am constantly forcing it. Like the bit won't cut unless I apply lost of pressure. Unless the drill press is on a higher speed, in which case less pressure is needed.

I'm beginning to wonder if what is under the blank when drilling makes a difference. I use a pen drilling vice, and when drilling ironwood the bit pushes the blank down further into the vice. This worries me because I don't want my bit to hit the metal. So with these blanks I had a piece of scrap underneath the pen blank. Wonder if this made the difference.

[Bob Hallowell]

I always expect a little tear out but not that much. I leave the bit at 900rpm. And I raise it up to clear chips about 5 or 6 times and once right before I go through.

Bob

[Tim Brooks]

I have had more luck with these larger bits by stepping up to them. Start with a much smaller bit and work your way up to the larger drill bits. This has yielded good results for me. Might take more time but it is better than wasting blanks... I have not tried playing with the drill speeds so I cannot speak intelligently about that.

As far as your concerns about the cracks, you will not be able to notice them on the finished product. CA is a beautiful thing. Just as caulk is a carpenter's friend; CA is a wood turner’s friend. :D


Good luck with it...

[William Bachtel]

:)I do not make pens, that said, heres what I wood do. I wood use the lathe to drill the holes, or is this not done by pen turners.

[Benjamin Dahl]

I find that some wood has more blow out than others and while I have not used desert ironwood I think this should still work. On difficult wood I cut the blank a little longer than needed and do not drill all the way through. I then trim the blank on my bandsaw to the correct length. My experience with pen blank blow out has usually been at the end when the drill bit cuts through the bottom of the blank. it's an extra step but only takes a little bit of time.
Ben

[Tim Brooks]

I find that some wood has more blow out than others and while I have not used desert ironwood I think this should still work. On difficult wood I cut the blank a little longer than needed and do not drill all the way through. I then trim the blank on my bandsaw to the correct length. My experience with pen blank blow out has usually been at the end when the drill bit cuts through the bottom of the blank. it's an extra step but only takes a little bit of time.
Ben

This works well too... Forgot to mention this option.

[Barry Elder]

What type of bit are you drilling with and how sharp is it? Could it be tearing instead of cutting? Have read on different forums that this wood tends to chip and split without extra care. Had a blank split like yours and rather than waste it, I applied some medium super glue and put a hose clamp around it to save it. Worked great! Good Luck.

[Keith Beck]

I've never turned Ironwood, but I've had the same problem with Snakewood. For a while, I was losing just about every other blank. :( I've found that going slow and clearing the bit often is the best remedy.

Keith

[Nicholas Briggs]

Thanks for the tips everyone. I tried another today, going very very slow and even drooping a bit of BLO in the blank right before the end. This seemed to work very well. I read on another forum that BLO can act like a lubricant, it seemed to do it's job. These blanks are a bit longer than needed, so if the problem persists I will try what Ben suggested by not drilling all the way through and cutting off the end.

Thanks again every one!

[Bernie Weishapl]

Benjamin I leave my blanks about 1/4" longer than the blank actual size. I then set my drill press to drill so it will be short 1/4". Then take them to the small bandsaw and cut to length. Never have had a blow out since. As all the others have said on some woods, corian, plastics, etc. it is especially important to keep the chips out there.

[Larry Marley]

Hey Benjamin,
I was taught to do as Bernie describes when I made my first pen 10 years ago and I have never had a blow out.
The key is to not drill all the way through, then trim off the end and you are good to go. I use the table saw with a sled to trim the end.

Larry

[Jerry Lawrence]

Instead of leaving the blank long and cutting the ends off, I drill just over half-way through my blank, then flip it over and complete the hole from the other side. Then i ream the blank with a drill press mounted reaming bit to make sure the holes meet cleanly in the center. Of course this works best if your blank is dead center when you're drilling the holes. I have drilled literally thousands of blanks for pens, keychains, etc. using this method for the company where I work, and there is very little loss (less loss = more profit for the boss and a happier work environment..lol). Still, to echo previous responses...the most important advice would be clear the bit often and keep it sharp!
Just my two cents.

[Jon Lanier]

Go slow. Use a sharpened bit. Use a step up method. and when drilling, pull the bit out to clear shavings (up/down/up/down), shavings that have no where to go will split the wood.