Odd problem drilling blanks... Please HELP!

[ThinkBlot]

Last week I ordered some new supplies for a few pen kits. I am making a Roman Harvest, and ordered one of the Olympian Elite kits from PSI that includes the appropriate brad point bits required (which are the same for both kits; 31/64" and 33/64").

I got out a few of my blanks (a bloodwood and a zebrawood) sectioned them, and drilled the 33/64" hole. Both turned out too large. There's about an extra 1/32" of an inch the whole way around the brass tube insert, yielding ruined blanks.

I mounted up a scrap piece of pine and drilled it. The bushing fits perfectly. Bizarre. Tried a piece of bubinga. Hole is too big. Tried to remount the drill bit once again. Still too big. Tried a different drill press. Too big. No matter what I try, the hole is always too big in any of my blanks, but in some soft scrap pine, it is fine.

Unfortunately I don't have a second 33/64" bit around here to try. I did mount up a 1/2" bit, and tried again with some of the previous materials, and the 1/2" bit was right on... and too small for the brass tube. However, if I drill the entire blank with the 1/2" bit, and then remount the 33/64" bit, and try to redrill through the hole I made with the 1/2" bit, then the brass fits fine.

I am so confused! Has anyone ever experienced anything like this?! The only thing I could possibly think of, is if the 33/64" bit is flexing a little bit under the force against the point/flank face?! (but only on woods harder than pine). I am drilling at a slow pace, with frequent pull-outs to dispense the shavings. The wood seems to be cutting easily with no rubbing, heating up or burning. The bit is a PSI HSS brad point bit.

Any ideas? Better yet, know how to fix it? Or am I doomed to requiring a new bit? I certainly can't double drill all my blanks... too easy to get off center and weaken the blank. Thanks in advance!

 

[longbeard]

I may be misunderstanding. Are you saying once you drill the holes in your blanks, the bushings dont fit? Are you gluing the tubes in your blank? The bushings are made to fit the tubes not the hole in the blank.


Harry

 

[ThinkBlot]

Sorry... let me clarify, it is the brass tube insert that does not fit inside the holes drilled in the blanks. So much so, that the gap is way beyond anything that could even be glued (as I said in my first post, I am estimating about 1/32" too big all the way around; or about 1/16" inch total) Obviously I am not trying to glue the bushings into anything. Haha. Sorry for the confusion (that's what happens when you try to post to a forum when the misses is beckoning you for dinner).

 

[randyrls]

Do you have calipers? measure the drill bit. Then lay it down on a flat surface and roll it to see if it is bent.

Lastly; I always drill the first hole on a new pen kit undersize and then sneak up on the correct size bit. About 50% of the time the bit that gives me the best fit *IS NOT* the one on the instructions. I have full sets of Fractional, Number, Letter, and Metric bits. There are several good drill bit charts in the Library.

 

[ThinkBlot]

Do you have calipers? measure the drill bit. Then lay it down on a flat surface and roll it to see if it is bent.

Lastly; I always drill the first hole on a new pen kit undersize and then sneak up on the correct size bit. About 50% of the time the bit that gives me the best fit *IS NOT* the one on the instructions. I have full sets of Fractional, Number, Letter, and Metric bits. There are several good drill bit charts in the Library.

Thanks Randy. I'll have to measure and roll the bit tomorrow when I get a chance... but I didn't suspect the bit to be bent as the hole in the blank was the proper size if I underdrill it first.

That's a great idea to underdrill and work your way up on a new kit. However, as I said, if I underdrill, and then step-up to the size specified in the instructions, then the bit seems to be the right size. Weird huh? After you undersize and drill up, I would assume that you document that final size, and jump straight to that size in the future (eliminating the need to drill up anymore). For some reason, that isn't working for me?! If I don't drill up, the hole is too big.

 

[IowaBob]

One thing I may suggest. Make sure you clean the bit often.I only drill about 1/4" back it out and make sure it is clean and then proceed. I have had a problem with the waste building up and with softer wood , the hole tends to gets bigger due to the waste not exiting the drill. I have done several Olympian pens and not had any problems.

 

[frank123]

Your drill bit could be ground improperly.

If you have a bit sharpener try using it, if not try a different bit.

 

[monophoto]

In the interest of ruling all possibilities, have you measured the diameter of the drill bit?

 

[Krash]

I had a weird problem with a brad point bit that may be causing your problem.

The point of my brad point bit was off center. So, when drilling, the point sets and if the wood is a hard wood, the bit will flex a little causing a larger hole. If you are drilling a soft wood. The point will cut more of the wood and the bit won't flex. If you pre-drill a hole, the point is out of the picture. If you drill with a twist bit, no problem.

Does your blank or vice vibrate a lot when drilling? That may be the dead give away that your point is off.

 

[ThinkBlot]

Thanks for the help and responses everyone.

One thing I may suggest. Make sure you clean the bit often.I only drill about 1/4" back it out and make sure it is clean and then proceed. I have had a problem with the waste building up and with softer wood , the hole tends to gets bigger due to the waste not exiting the drill. I have done several Olympian pens and not had any problems.

IowaBob, I am cleaning the bit very frequently. I tend to back out every 1/4" to 1/2" as well. Made no difference with this bit.

Your drill bit could be ground improperly.
If you have a bit sharpener try using it, if not try a different bit.

I have not tried sharpening the bit, but the tip did seem sharp when I checked. I will most likely be switching to (aka forced to buy) a new bit tomorrow to see if it makes any difference.

In the interest of ruling all possibilities, have you measured the diameter of the drill bit?

I have not measured the diameter of the drill bit yet, but will be doing that tomorrow when I head back over to my shop. Like I said though, I don't think it's the diameter because when I drilled through a slightly undersized hole and in soft woods, the final hole is appropriately sized.

I had a weird problem with a brad point bit that may be causing your problem.

The point of my brad point bit was off center. So, when drilling, the point sets and if the wood is a hard wood, the bit will flex a little causing a larger hole. If you are drilling a soft wood. The point will cut more of the wood and the bit won't flex. If you pre-drill a hole, the point is out of the picture. If you drill with a twist bit, no problem.

Does your blank or vice vibrate a lot when drilling? That may be the dead give away that your point is off.

Wow Krash! This may be the key post to this topic! I have never even considered an off-center point, but with what you describe, it makes a LOT of sense. I did notice while drilling that there was a little bit more vibration than usual, but I haven't used the drill press in awhile and I mount my blanks in a jig that I made, so without any tactile feedback as to how much vibration I had sort of just shrugged it off (as evidence by the fact that I hadn't even thought it important enough to mention when describing the problem).

Perhaps tomorrow when I head back over to the shop, in addition to measuring the bit, I think I will try to drill a few all the way through with a small pilot hole (just slightly larger than the brad tip), and then follow it up with the bit in question to see if that fixes the problem. It'll be very interesting to see what turns up... but an off-center point seems like the strongest contender.

Thanks so much for all the help and suggestions everyone! I'll be sure to keep you posted.

 

[cjn]

The vibration (regardless of where it came from) is likely the problem. You might want to try clamping your jig to the drill press so that it can't vibrate.
I had a hole that came out large and one that came out oval before I started clamping the jig.

 

[ThinkBlot]

The vibration (regardless of where it came from) is likely the problem. You might want to try clamping your jig to the drill press so that it can't vibrate.
I had a hole that came out large and one that came out oval before I started clamping the jig.

Thanks for the suggestion cjn. The drill press is equipped with a milling vice, so all of my work (and my jigs) get clamped in already. This odd problem was happening with the work already clamped in.

 

[ThinkBlot]

Well, wanted to give you all a quick update.

Caliper measures on the bit diameter turned out to be fine, and the bit appeared to be flat when rolled across a machined cast iron surface. Drilling through with a smaller bit first definitely helped, but still didn't seem "perfect." Finally sucked it up and drove 25 miles (each way) over to the closest brick and mortar woodworking store to buy a new bit. Got back, and the new bit worked like a champ.

Then, I went to drill the pen body sections. The 31/64" Bit is straight and correct diameter. Try to drill and it won't even cut through a piece of brazilian rosewood... brand new... straight out of the package. It just sits on top of the wood, spins, and starts burning/smoking. I even tried to sharpen the bit; works a little better, but still drills like garbage. Lovely... another 50 mile drive to buy a second bit so that I can get this pen done on time.

So... this was my first order from PSI. It included 2 pen kits, a sleeve for my trimmer, and 2 drill bits. Both bits were bad... not just bad, but horrible. Ruined a lot of nice blanks with them, cost me 100 miles of driving, and I ended up having to pay over twice as much to buy replacement bits from a "local" shop anyhow. I'm pretty upset about it, and can't imagine that I will ever order from PSI again. Has anyone else had bad experiences with them?? I'm really shocked after seeing how often their company name i thrown around on various forums. Sorry for the rant.

 

[JohnGreco]

You need a Drill Dr. I don't even bother using new bits until I sharpen them on that first.

You are drilling Pine perfectly...because the bit is dull and Pine is soft, but the hard, dense woods are making the bit wander around as it tries to bite into the wood.

Best of luck.

 

[jsolie]

You need a Drill Dr. I don't even bother using new bits until I sharpen them on that first.

He was using brad points, and I don't think the Drill Dr. works very well with those. With twist bits, the Drill Dr. is amazing.

 

[chrisk]

A rule of thumb that works for me:
the diameter of the tube + 0,3 millimeters (0.012") = the appropriate drill bit.

For example, if the lower tube of a JrGent II is 10,2mm, the appropriate drill bit is 10,5mm.

For plastic (i.e. PR) back painted blanks, sometimes it's better to add 0,4mm (0.016").

 

[JTisher]

He was using brad points, and I don't think the Drill Dr. works very well with those. With twist bits, the Drill Dr. is amazing.[/quote]


It makes them into a perfectly fine twist drill.:wink:

Joe

 

[Tom T]

I have he the same issue with all of my PSI bits. Kits are fine drill bits not so much. I have. Been using a set of colts for several years and they have never had to be sharpened.
7mm has drilled over 100 pens.
I really need that drill dr. I was looking at the 750 model.

 

[Smitty37]

Well, I sell drill bits, if you want one I'll sell it to you. If you ask my advice I'll tell you to go to your local hardware store and buy it there, you'll get it cheaper and odds are pretty good it will be a better bit. I sell USA made when I can get them but can't always get all the sizes at a reasonable price.

 

[Tom T]

There is nothing sweeter than a sharp drill bit. I do not know why every one wants to sell cheap. We're are the quality bits.