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GBusardo

GBusardo

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Dec 8, 2005
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Beachwood, NJ, USA.
I am having a hard time believing I am having this problem. I just bought two new drill bits from one of the regular suppliers. They are regular twists with black coating. Whenever I just get to exit the blank, the bit grabs and either stalls my small press or blows up the blank. I do use a little backer and after the first time, I made sure that during the last 1/4 to 1/2 inch of blank the bit and hole are cleaned out. I am running at about 600 rpms and I was going real slow with the feed. At first, I thought it was the wood, but after the second, third and fourth blanks of different kinds of wood, I am guessing it's the bits. Any ideas? The bits are sharp as they go through the wood pretty good.
Thanks
 
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Cut your blank a little long, drill short (do not exit) and then cut the blank exposing the drilled hole. Be sure to leave the blank long enough to square the ends as you normally do.
Do a good turn daily!
Don
Originally posted by GBusardo
<br />I am having a hard time believing I am having this problem. I just bought two new drill bits from one of the regular suppliers. They are regular twists with black coating. Whenever I just get to exit the blank, the bit grabs and either stalls my small press or blows up the blank. I do use a little backer and after the first time, I made sure that during the last 1/4 to 1/2 inch of blank the bit and hole are cleaned out. I am running at about 600 rpms and I was going real slow with the feed. At first, I thought it was the wood, but after the second, third and fourth blanks of different kinds of wood, I am guessing it's the bits. Any ideas? The bits are sharp as they go through the wood pretty good.
Thanks
Click to expand...
 
It could be a number of things. Are you backing the bit out a couple of times while drilling and clearing the flukes, is the bit 'hot' to the touch, are you sure you are not being to aggressive towards the end of the drilling, do you have your blanks in a vise and is it bolted to the drill press table, is the wood wet or freshly cut? These come to my mind right away. Other folks will ask more... [:D]
 
Too slow a speed in my opinion. Slow speed grabs on many woods. While your bits may be new bits, not all new bits are sharpened equally. The sharper the bit, the slower you can go and not have it grab. I have bought new bits and they felt sharp; then I buy another bit and it literally cuts my finger like razor when I feel it. That is what I call sharp. These are less likely to catch/grab and cause blowouts. By the way, I find more HSS bits to be sharper than the so called Titanium and most black coating bits also.

Some woods are more prone to this than others; Good drill blank holders will help some too but not always in all cases.

All of this is dependent on drilling feed rate too.
Here is a picture of drill speed and the smoothness as it relates to speed. This does not DIRECTLY apply here in this situation, but it does give indications of cutting versus tearing at different speeds. Yes, Pen blanks are rarely soft pine, but a correlations can be drawn from this.

( double click for a larger view.)
tn_drillspeed.jpg
 
There could be any number of reasons why you are having a problem and without all of the facts, it is difficult to accurately diagnose the problem. I fully agree with Hank that 600 RPMs is much too slow if you are drilling wood and the holes are in the 7mm range.

You could spend a lot of time experimenting and tearing up blanks to find why you are having the problem; but following Don's advice is the easy out and will save a lot of ruined blanks!!
 
I have found the best way for me is to drill my blanks at a farily high speed, back out to clear chips often, and use really sharp bits. Most of the time I automatically sharpen the brand new bits, as I don't trust them to be totally sharp to begin with, just like I will not use a new gouge or skew without sharpening/honing first. One other thing I found that helped me, I put a little pressure on the blank downward to make sure it is seated fairly tight against the backing board before drilling. This seems to eliminate samll gaps that can start a tear out before it happens. This works for me, but Don's advice is definetly fool proof[;)]

Rob
 
What are you holding your blanks with?

I had that problem when I was drilling with a hand clamp. The blanks would "jump" when they got to the end.

I bought a PH vise, clamped it down and I haven't had that happen again.
 
You didn't state supplier. But, I have gotten "black" bits from CS that were pitiful to the extreme and performed just as you described. Lousy. In my experience, their bits need professional sharpening, or with a Drill Doctor, before use. BTW, 90% of all my drilling, on the drill press, is at about 600 rpm. Works fine and doesn't generate the heat of higher speeds. And that is with bits from 1/8" to 1" in all kinds of (non-metallic) materials.
 
Thanks for all the feedback.

I did think of doing what Don suggested, but dismissed it because I really don't like not knowing exactly where I need to cut.

Fred, after the second blow out, I made sure to clean the flutes and empty the hole often. and I took it real slow.

Lee, The drill bits I was using were the 27/64 and 31/64. Kinda hefty for high speeds. The woods I was using were Desert Ironwood, BOW, and two Blackwoods. A lot of good wood down the tubes [V]

Randy, I used to set my drill press at 1500ish rpm for almost everything. On my first JR Gent, I slowed down to 600 and was amazed on how much better the drilling went. I usually speed it up when I am drilling 8mm and slimmer.

Scott, My birthday is coming up. I think I will print that ad and slap it on the fridge :-)

Rob, I do press down on the blank so its seats firmly on the backer. made sure after the first blow out.

Mark, I have one of those blank vises from Craft Supplies. I never had this problem before. The only thing I don't like about it is I wish it would open a little wider.

Frank, I felt uneasy naming names when the problem could very well be my fault.I am begging to think its the bits though and somehow will have to get the Drill Dr. I took you advise on how to sharpen brad points and it is working out fine, but those two sizes in the brad points seem to have a little runout and I wanted to replace them.

Thanks again to everyone
 
Measure the tube and transfer it to the blank and mark a little long(maybe 1/8 inch); lay the tube on the blank and mark(an eigth inch longer) then set your drill press to drill the same depth. Drill to past the mark and cut leaving the mark. It works great and no more drilling problems as the bit exits the blank.
Do a good turn daily!
Don
Originally posted by GBusardo
<br />Thanks for all the feedback.

I did think of doing what Don suggested, but dismissed it because I really don't like not knowing exactly where I need to cut.
Click to expand...
 
Gary said, in part: "Frank, I felt uneasy naming names when the problem could very well be my fault."
I understand that and respect it.
When something is obvious, I don't mind naming the supplier. Most of my purchases come from CS, they aren't the enemy but there are times they need problems brought to their attention. I'm kinda [:(!] with their China made bits, at $7.00 to $12.00 eash, performing so lousy. Especially when a Harbor Freight set of many bits can be bought where the per-bit cost is about half a dollar and they perform beautifully.
 
For what it is worth I use parabolic fluted bits available at most any tool supply place. These were actually developed for deep drilling in soft metal such as aluminum.
In wood and acrylic and most other I usually drill at about 1200 RPM's. The Norsemen bits that AZ sells are also superb bits. (super sharp) and worth the money.

Ron

www.woodfan.com
 
Don, Thanks for the tip. I didn't think of marking the blank. Probably because my small drill press only has a two inch throw. I have learned to make due. In case anyone is wondering. I drill a hole in the blank about 1 1/2 inches, then put the bit into the hole and slip a piece of particle board under the vise, then resume drilling.
Yes, a new drill press is also on the list of "must have someday". [:)]
 
I'm going to be controversial again, but please bear me out.
I have a very cheap drill press and have had similar problems.
The problem could be backlash. Normally the handle drives the quill down via gears between the two. On a cheap drill press or even a very old good one, there is a gap between these two gears. Gently turn your handle and see how much movement you have before the quill starts to move. This difference is the backlash. While you are pressing down, you have good contact between the gears. Now, as a drill bit acts a bit like a screw it wants to bite in and do its job. The problem comes just as the drill starts to come out of the end of the blank. With not much resistance left, the bit will pull itself through the half-drilled hole and take up the backlash. This of course will cause the 'blowout' at the end of the hole. It is more often noticed when drilling sheet plastic.

If you think I'm talking %^&*$ again, go to your shop and try it out.[;)][:D]

But I do like Don's trick.[:D]
 
Could be Skiprat, that drill of mine was bought in 1982! I am going to check it out, I am wondering though, why it doesn't happen with my other bits.
 
Originally posted by GBusardo
<br />Could be Skiprat, that drill of mine was bought in 1982! I am going to check it out, I am wondering though, why it doesn't happen with my other bits.
Click to expand...

Maybe the new drills are sharper than your old ones. A sharp bit will tend to bite more if the quill can move down a bit to take up the backlash. When I need to drill holes in trafolite labels, I dull the drill bit first[;)]
 
I may have to go Don's way after all! I could mark the bit with a piece of tape for the depth of the hole. i'll have to start checking the prices on a new press. [V]
 
Gary,

I have used Don's method for years. Haven't blown out even ONE blank that way. When I get really cocky and try to drill through, it works MOST of the time - but not always. So, I stick to "cut off the end" unless the blank is just too short!

Your mileage may vary.[:D][:D]
 
Originally posted by skiprat
<br />
Originally posted by GBusardo
<br />.....Maybe the new drills are sharper than your old ones. A sharp bit will tend to bite more if the quill can move down a bit to take up the backlash. When I need to drill holes in trafolite labels, I dull the drill bit first[;)]
Click to expand...

OK, I'll bite. What the heck is trafolite??

But I do agree with your basic premise. An old machinist friend once told me that it was common practice to dull tools a bit when drilling or turning "grabby" metals. Can't remember for sure; but as I recall he was talking about brass or aluminum or maybe both. I think it may also have applied top Plexiglas??

I can't see any reason why the same might not apply to some woods.
Click to expand...
 
Originally posted by skiprat
<br />I'm going to be controversial again, but please bear me out.
I have a very cheap drill press and have had similar problems.
The problem could be backlash. Normally the handle drives the quill down via gears between the two. On a cheap drill press or even a very old good one, there is a gap between these two gears. Gently turn your handle and see how much movement you have before the quill starts to move. This difference is the backlash. While you are pressing down, you have good contact between the gears. Now, as a drill bit acts a bit like a screw it wants to bite in and do its job. The problem comes just as the drill starts to come out of the end of the blank. With not much resistance left, the bit will pull itself through the half-drilled hole and take up the backlash. This of course will cause the 'blowout' at the end of the hole. It is more often noticed when drilling sheet plastic.

If you think I'm talking %^&*$ again, go to your shop and try it out.[;)][:D]

But I do like Don's trick.[:D]
Click to expand...

Exactly! Well explained, there. I have tried to explain this tosome folks as well, just didn't word it as well.
 
Randy, trofolite ( spelling may be wrong ) is the same stuff as pickgaurd basically. Normally two or three layers of different colours. We get labels engraved through the first colour to show the middle colour. We have to drill small holes near the corners, if the bit is too sharp it often grabs. You can sharpen a bit to avoid this grabbing, but it is simpler to dull it with a quick touch on a concrete floor and re-sharpen it later.[:D]
 
They are to sharp, lol. I realize this sounds crazy , but I have found that some brand new bits grab with a hand drill. I guess this should not happen with a drill press and something holding the blank? Skiprat has it it so sharp it bites and pulls through. a brad point would not do the same thing. Quetion for you does your older slightly dull bits of the same type do this brake out the end or just more the new very sharp bits ??? Good Luck Sir, Victor
 
Victor, I checked my drill for "backlash" and i don't have that problem. I drilled out blanks for a cigar pen tonight with an older hand sharpened brad point bit and did not have that problem. You think the bit can be too sharp?? Maybe, it does feel very sharp. If the bit is too sharp, I guess getting a Drill DR would not help my problem. Jeez. all I want to do is drill a hole!!! After all these pens, that was the one area I thought I had down pat. This hobby is enough to make you bang your head against the wall. Talk about being humbled..
 
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