Drilling birds eye maple

[vbatwork]

I have cracked two pen blanks (all 4 pieces) while drilling due to heat. BEM seems to be producing the most heat during drilling of any wood I’ve used including Pink Ivory. It cracks straight up the side right when the drill is getting close to exiting the blank. My wood is dry and stabilized (by BB). So far I have tried drilling just a few millimeters at a time before allowing five minutes or so to cool down the blank and bit but I always have the same result. I have searched the forum and will next try the 1/4in stopped hole technique. I also read about using a vacuum to draw cool air over the bit, but wonder if that would be enough? I also intend to try drilling on the lathe to see if that works for me. My bit is new, and sharp, but large (31/64). Anyone have any other cooling tips to try?

 

[Dario]

How fast is your drill speed setting?

While I never worked with stabilized wood...I've drilled a lot of BE Maple Burl and none of them ever cracked. So I find your experience a bit odd.

 

[vbatwork]

Hmmm, good thought. I'll check my speed tonight. Its probably still set pretty high. Its an old Delta radial head drill press. The other night I cracked my nogin on it hard enough to see stars, and also knock the head out of alignment with the table! [xx(]Probably explains the failure to check speed. Thanks Dario.

 

[Paul in OKC]

Also more important to clear chips more often wit the larger bit, IMO. I clear chips every 1/8". Sometimes seems like I'm just pecking my way through, but better than the alternative[]

 

[vbatwork]

Yeah, I was clearing chips each time I stopped. Every 1/8th seems excessive but I'll give it a shot. Otherwise, I'll never get to see the finished product except in someone elses pics. I was concerned the deeper the bit went in the blank that I could hear a slight screech indicating friction that isn't there with other blanks. Thanks Paul!

 

[DWK5150]

The screech a lot of times is from heat. What is your speed you drill it?

 

[KenV]

New bit does not equal sharp bit nor center ground bit. There are numerous reports of import bits that are ground with the center point not being in the center. If you have one of the norseman bits from BB, that is not the problem. (I have one in that size and it is dead on!!) If you have a close relationship with Harbor Freight or similar check the bit closely, watching the center while it is turning will show gross error. Little Machine Shop is selling a dial indicator with magnetic base on special that will allow you to really check the bit for runout and see if the center is centered.

Drill Doctor works for many for getting bits resharpened. I also have an old video from FWW where Jim Cummins shows in simple terms how to get a bit resharpend by hand on a grinder that will work too. Finding a retired tool and die maker is another approach to learning/getting sharp bits. I think Paul Hoffman also sharpens drill bits.

Also check your table for square and your vise for sitting square with the table. I use an XY vise and had to futz a bit to get the vise to square up.

I drill, turn, etc alot of maple (pens, bowls, etc) and if the tools are sharp and the cuts controlled, it is a fine material to work with. Stabalized maple is a bit more brittle in my experience but have been turning dyed, stabalized maple burl without problems (except measurement errors).

 

[vbatwork]

Don, I'll check that speed which I am sure is way too high and try another on low.

Ken, my bit is a new Norseman from BB. I check for sq fairly often because of that radial head, and table that simply holds the column with a hand screw (no lock). I also am tinkering with my vise setup constantly which is far from ideal. I'm on Paul's list for the next batch which will help.

Thanks guys!

 

[Paul Russell]

... It cracks straight up the side right when the drill is getting close to exiting the blank...

I never drill all the way through. I cut my blank longer than I need, drill to the depth of the brass tube and cut off the excess on the band saw. I used to crack many blanks especially those needing big drill bits. Since I started the new way I haven't cracked a one.

 

[chigdon]

Paul's method is probably the safest, the next safest being BB's method of using a waste block under the blank. I don't use either method however. I USED TO have this problem a lot more when I drilled at a speed of about 800. Now I drill about 2500 and almost never have any problems now. I do use a fair amount of stabilized wood and a lot of dense fragile exotics. Basically I am not sure why it is happening to you but in my experience slowing down the drill isn't it.

 

[GBusardo]

I have never had a problem with BEM cracking, I would try another drill bit. Now watch, I was planning on turning a couple of BEM pens this weekend. Any bets on whats going to happen? [!]

 

[Russb]

I use bullet point bits to drill stabilized woods,not so much because of heat but to keep the bit drilling straight...

 

[gerryr]

I don't even own a drill press, although I am going to need one. I drill all my blanks on the lathe at 500rpm. I use both brad point bits and Harbor Freight Ti coated bits. The only blanks I've ever had blow out were PSI Mica Swirl. Drilling horizontally helps the chips exit better than vertically, I think.

 

[Ryan]

When I first started making the Statesman pens I got the big bit and wanted to see how small of a blank I could drill it through. I had a lot of scrap maple so that is what I used for my test pieces. I cut 5 3/4" blanks and 4 of the 5 split vertical just like you have said.

I have not had that happen on any other blank. The only maple I have been using since the test pieces is maple burl. If you are using 3/4" blanks that may be the reason. Try a larger blank and see if that helps.

Ryan

 

[Paul in OKC]

I also do the support block under the blank, and recomend that you use it with my vise as well.

 

[Rudy Vey]

Use high speed!! Faster drilling - less heat generated, less prone to crack! I think this is a misconception that one should drill slowly, I do so when I use large Forstnerbits.
Cleaning out the chips is important, do it often. I use parabolic drill bits that already cleaning chips out very good. Be very carefull when you approach the bottom end of the blank, I clean out, as Paul said, about every 1/8".

 

[reed43]

Why don/t you drill a pilot hole about one quarter or even three eights inch prior to your larger bit.

 

[stilgar]

how do you hold your blanks on the lathe for drilling. I am without a drill press for now and been having some success but I would like to use the lathe until I get my press back.

 

[gerryr]

You need a 4 jaw chuck like a Nova or Talon or something of that sort. Or you can turn the blank round between centers and then use a Beall collet chuck.

 

[stilgar]

I have an aussie made one that I use for bowls. It does not go small enough for some of my blanks. I may have to come up with a quick "jig" to hold those.

 

[Randy_]

I just took a look at the manual for my drill press. There is a chart with suggested drilling speeds for wood and other materials. The recommended wood speeds vary depending on the bit size from 3600 RPMs for a 3/8" bit to 250 RPMs for a 2" bit. For a half inch bit the speed should be around 3100 RPMs.

And while doing this research, an idea came to me.....don't know if it has any validity. Seems like the chips might be a lot smaller if the bit is turning at high speed and that it would be easier to clear small chips than big ones?? What do you think??

 

[vbatwork]

Well, my drill press was set to 1560 RPM which was slower than I thought I had set it. I managed to get a quick test in at slower speed of 940 and 580 with a lesser amount of screech than before. The blanks didn't split anyway and I produced less heat overall. I'll try the higher RPM tonight Randy and see how that goes. Paul, I always use a backer board with my setup. The problem is with my little drill press vise holding a homemade jig to keep the blank supported, I have to cut these little square backerboards to fit. I like the way your vise has that open base to slide a board beneath the work as you need to. Its much handier looking to me.

 

[Dario]

Originally posted by Randy_
<br />I just took a look at the manual for my drill press. There is a chart with suggested drilling speeds for wood and other materials. The recommended wood speeds vary depending on the bit size from 3600 RPMs for a 3/8" bit to 250 RPMs for a 2" bit. For a half inch bit the speed should be around 3100 RPMs.

And while doing this research, an idea came to me.....don't know if it has any validity. Seems like the chips might be a lot smaller if the bit is turning at high speed and that it would be easier to clear small chips than big ones?? What do you think??

My thought it just the opposite Randy. Though I agree that higher speed produce finer shavings...it is more difficult to clear because they pack better.

Not sure if you experirnced this but, the shavings can easily turn into pellet like substance which exerts force outward toward the holes wall that may cause cracking and definitely heat build up too.

Just my observation.

 

[Rifleman1776]

Originally posted by Rudy Vey
<br />Use high speed!! Faster drilling - less heat generated, less prone to crack! I think this is a misconception that one should drill slowly, I do so when I use large Forstnerbits.
Cleaning out the chips is important, do it often. I use parabolic drill bits that already cleaning chips out very good. Be very carefull when you approach the bottom end of the blank, I clean out, as Paul said, about every 1/8".

Heartily (and respectfully) disagree. That high speed equals cooler stuff is just that IMHO, stuff and nonsense. Slower is cooler. I'm sure tests could be set up to prove it. Logically, the slowest you can go is zero. No heat at all. A little movement will produce a little heat, a lot of movement will produce a lot of heat. I do 90% of all my drilling at about 600 rpm. Delicate woods like birds eye maple does require much care and clearing of chips. Brad points work best for me.

 

[ccarse]

I totally agree with ya Frank. All my drilling is done at the slowest speed on my DP and I never have any problems except with really soft stuff like spalted stuff then I will up the speed a bit.

 

[Dario]

I am with Frank on this 100%.

I too drill at the slowest setting (or the 2nd one) and drilled hundreds of blanks. None cracked on me yet (knock on wood).

If you feel a wood may tear out/crack at exit...try treating that (exit) end with thin CA before drilling. It may help.

If I lost any wood while drilling it is because of drill bit drift caused by bad drill press, bad clamp, probably bad drill bit and mostly operator error [][}]. Most are remedied by buying a new Drill Press, PaulH vise and bits from AS/BB.

 

[vbatwork]

Honey do list complete and I finally got a chance this morning to get back to this. I was unsuccessful at the highest speed. The screech and heat began to build the moment the bit touched the blank as many of you said. For me drilling on the lowest speed was the best, coupled with frequent chip clearing. I ended up drilling at 540 rpm and the bit was cool enough to touch at the end of the blank. Thank you to all who responded! I really appreciate the advice.

- John

 

[Rudy Vey]

Quote:"The screech and heat began to build the moment the bit touched the blank as many of you said"

Maybe you are using a dull bit. Check it out again with a sharp bit. There are worlds in between a dull and a perfectly sharpened bit. I do a lot of Dymondwood, and had my drill bit sharpened professionally by Paul Hufman: what a difference!!

BTW, drill speed: if you check the yahoo site, do a search since this comes up every so often. Rich Kleinhenz, who is, in my opinion, the Grandmaster of all penturning, recommends also the fast speed drilling.
It works for me, may not work for others and for them slow speed works fine. So be it.

 

[bradh]

I agree with keeping the drill speed high, but advance the bit into the material slowly and pull out to clear chips often. For woods that stick in the flutes, tap the bit with a scrap of wood to help clear the bit. I also like to keep a dust pick-up near the bit to get a little extra cooling air flow over the bit each time it is pulled out.
Brad
hardingpens.com

 

[Joe Melton]

I think heat is a consequence, not a cause. Heat is created because of friction, indicating rubbing of the sides of the drill on the walls of the wood. If the friction is too great, pressure is exerted outward radially by the pen and material inside the flutes of the drill, thus breaking the wood.
Some woods seem to swell when you cut, and the hole you are drilling actually gets smaller in diameter. Since the drill cuts only on its point, not on its sides, you need to retract the drill (and clean the flutes) so when it re-enters the hole, it trims off the sides that have crept in. Obviously, if your drill bit is not sharp, it will do a poorer job of this trimming.
A second problem in drilling blanks is blowout. This occurs when the drill tip exits the end of the blank. The end of the drill is pressing downward on the wood, and when the point has emerged, there is less supporting wood to press back against the force of the drill bit. Adding a block of wood to support the blank helps to alleviate this; not letting the drill bit exit the wood is obviously better if the particular wood tends to blow out.
Some woods blow out much more often than other woods.
I agree that if the point of the drill is not in the center of the drill bit, this could cause the drill to "wobble", thus putting undue force on the sides of the blank. This would also cause heat buildup, since as the drill turns, it is being actually forced against the sides of the blank since the tip is rotating eccentrically.
Given the loss of money associated with loss of blanks, and also the loss of time involved, it makes sense to me to invest in quality bits. You only need a few sizes, and the investment is not that great.
Just my opinion.
Joe

 

[vbatwork]

Hi Brad and Joe,
Thanks for the input. I was using a brand new bit to drill with. The nice Norsemans that Bill Baumbeck has been selling. My problem did seem to be friction related. The screech I encountered was as the bit was (cleaned) re-entering the blank. It hadn't yet contacted the bottom of the hole. I was also using birdseye maple, stabilized, from AZ as the blank material. The slowest speed on my drill press seemed to stop the screech and resulting heat for me. Well, that and clearing the chips about every 1/8th inch as was suggested here.

- John