Drilling Corian Blanks – Step 2

Introduction and Rationale

In a previous post, I wrote about many of the general characteristics of working with Corian as a pen making material. That post came about as a result of a project in which I decided to make a batch of 36 pens using Corian blanks and Slimline pen kits from two vendors: Woodcraft and Craft Supply USA. The kits were essentially identical, although there was an extremely slight difference in the length of the brass tubes. This difference had no effect in the assembly of the pens however as the blanks were mixed by accident although I had kept the blanks for each manufacturer separate initially. So goes one of the risks of a shared shop space. My motive in making this batch of pens was simply to use the kits. I had purchased them years before and as I had the kits and I had the Corian I went with it. I don’t have any more Slimline pen kits but I still have a great deal of Corian, so mission partially accomplished. In what will be a series of 9 consecutive posts, I intend to discuss in detail each discrete step in the process of making this batch of Corian pens. I hope you enjoy this in-depth look at the pen making process in general, and the use of Corian as a material in specific.

Drill Bit Sizes

Drilling the center of the cut to size pen blanks is often, for me, the single most frustrating and difficult part of the entire pen making process. Every pen kit will include some form of instructions that will tell you what size of drill bit, or bits, you require. Some pen kits use a single blank, some use two blanks. Some pen kits with two blanks required will use the same size drill bit on both blanks whereas some pen kits will require two different sizes of bit with each blank being drilled to a different size. In practical terms, what this means is that if you work with multiple different pen kits you will quite quickly amass a wide range of drill bit sizes. Always read the product descriptions of any pen kit you wish to try to determine which bits you will need and then make sure you have them on hand, or order them if you don’t at the same time you purchase the pen kits. You cannot use a bit that is “close” to the right size. The proper size bore is essential to the success of the pen making process.

You Get What You Paid For

As is always true with tools, there are the cheap entry level items and the much better quality, and usually much higher priced, good quality tools, and this includes drill bits. It is easy and cheap to buy pen makers sets of drill bits from the same retailers who sell the pen kits, but a word of caution is that if you intend to make very many pens over time you will be much better served by investing a bit more in good quality bits that will last a long time and run true and clean. A low quality bit will result in endless frustration and even wasted materials. It is very often true that you get what you pay for.

Small Blank, Small Drill, Colt to the Rescue

In the case of these Slimline type pens, a 7mm drill bit was required for both of the two blanks. Given that Corian pen blanks are 12mm squares a Slimline design is the only realistic option of a pen to make with Corian blanks. And even with a Slimline bit requirement of only 7mm, drilling that size bore straight through leaves very little margin for error. A good quality bit becomes essential as does one that is easily long enough to complete the entire bore in one operation. It is not highly likely that you will have the bores match up exactly evenly if you try to reverse the blank and drill from both ends. I really don’t recommend even trying. For drilling a range of common pen bore sizes, including the 7mm, I use Colt drill bits. Colt is a German company that has introduced a line of drill bits specifically sized to meet the needs of many of the most common of the pen kits. The marketing claims that the bits are high enough quality to drill straight through even the toughest of materials, including acrylics and other plastics, with a single pass, eliminating the need for the common practice of pulling back every ½ inch or so to be sure that the debris is being cleared. If debris is not being cleared, the drill bit can jam into the blank and you may never be able to retrieve your bit!

I have used the Colt 7mm drill bit a great deal, obviously, given the sheer number of Corian pens I was making and I was pleased with its performance. I never had the bit travel off center to the degree that a blank was busted or drilled so close to the edge that I could use it to turn a finished piece. The Colt 7mm drill bit is a generous 15mm in length so one can drill even the longest of pen blanks without having to try the usually ill-fated move of reversing the blank and drilling from both ends, hoping to meet perfectly in the center. You can get away with that when drilling out pepper and salt mills because the interior chambers only hold the pepper or the salt, not mechanical parts with limited tolerances. Pen kits are highly specific and will only work if the bore is true and even. This is almost impossible to achieve when drilling from both ends, so a bit that is long enough to do the job is essentially required.

Colt 7mm by 15mm Drill Bit

Colt 7mm by 15mm Drill Bit

As has been discussed, Corian is essentially an acrylic product. I did find that the Colt drill bit could drill the entire blank without repeated withdrawing, however, as I have noted before but I think it bears repeating, this is only true if you are drilling only one blank. If you are drilling multiple blanks one after the other, I wouldn’t trust this practice. The reason is that simple physics and experience will tell you that friction, such as is generated when drilling any material and especially a hard material such as acrylic, will generate a great deal of energy in the form of heat. Corian in particular is designed to withstand heat but if it gets hot enough it will melt. A drill bit, no matter of what quality, melted into a pen blank is only useful, if at all, as a piece of modern art highlight what NOT to do in the future.

Keeping Your Cool

Therefore, I exercised caution to prevent excessive heat through several methods. First, I adjusted the drilling speed down to no more than 600 RPM at the absolute maximum and there are experts who recommend even much slower speeds or down to as little as 300 RPM, especially when drilling acrylic or when drilling very large bores. I was very careful to catch the drill debris in my hand during the drilling process to have some immediate sense of the degree of heat being generated and I carefully monitored the flow of debris to ensure that it was flowing constantly and consistently. If the debris stops flowing, immediately stop drilling and withdraw the bit so that you can clear the bore with a blast of compressed air or through another means.

I noted that after ever bore, even these of relatively short length, that the drill bit was quite hot to the touch. The bit must be allowed to cool before starting the next bore. That cooling could be accomplished through air cooling but you would have to wait a good bit of time between bores and with 72 blanks to be drilled, two for each of 36 pens, time was not in huge supply. Instead of air cooling, I dampened a towel in water and stored it in the refrigerator until it was quite cold. After every bore, I would wrap the drill bit in this cold towel to quickly cool the bit before the next bore. To further reduce heat, I also stored the Corian blanks in the freezer overnight before drilling them. I know it sounds ridiculous but it really did make an appreciable difference. I also utilized a frozen “cold-pack” such as you might use in an ice chest to keep a picnic cold to help cool the drill bit between bores. By doing this, I managed to avoid the potential for the bit to “travel” off center and bust the blank and I prevented overheating which could have melted the blank debris, which would jam the bit perhaps permanently in the blank or which could cause the blank to break due to heat. Pre-cooling, cooling during the drilling process, slow speed, and patience were all essential in allowing me to core such a high number of blanks in one run.

For reasons that are just not clear to me, I also noticed that the darker the color of the Corian the hotter it seemed to drill. I don’t know if the additional pigments, or the pigment types, made a difference but it was quite discernable over time.

Smells and Ventilation

I should also mention that Corian creates a distinct odor when being drilled that some could consider unpleasant. I don’t have any reason to believe that the odor was in any way toxic or otherwise potentially harmful but I did increase the air circulation in the my rather enclosed shop by turning on a circular fan that was facing away from the lathe, thus drawing the smell away and outdoors. Good ventilation if always advised regardless of whether odors are present or not, especially in pen making where adhesives and finishes both might create potentially hazardous vapors. Also, dust should be controlled to prevent potential lung or eye irritation. A good air filter can help with that as well, such as the Air Tech HP by JDS Tools that is installed in my shop.

Drilling Equipment – Drill Press

What I have avoided mentioning thus far is the equipment I used to drill the pen blanks and I will specifically address that now.

Ever since I started making pens years ago I have been on the search for the best way to hold the blank for drilling. At first, as a low cost solution, I used a Jorgensen wooden clamp to hold the blank on the table of a drill press. As was true of my first bandsaw, my first drill press was a tabletop model purchased from one of the “big box” stores, probably Lowe’s. It was possible, at that time, to buy one for less than $100 and while it worked most of the time, it had severe limitations. The most significant drawback was that the range of the “travel,” how deep one could drill with any given full pass of the machine was limited. This meant that I would have to make an initial bore, then turn off the machine, raise the table such that the drill bit was now lodged inside the blank, turn the machine back on and complete the bore. This not only required a great deal more time it also greatly increased the heat from friction. I realized I needed an upgrade, but as I had discovered with the bandsaw prices went from low to very high quite quickly with almost nothing in between. I simply didn’t need a floor model drill press, nor did I have a place to put one anyway, since I wasn’t going to be using it for heavy duty daily use. In the end, I found the same solution as I did with the bandsaw; I bought a Grizzly drill press.

Grizzly Drill Press

Grizzly Drill Press

Now, as I have noted about the bandsaw, I quite realize that Grizzly is not a good choice for someone who needs to use their machine daily for industrial use but for a hobbyist who needs something better than the toys that the big boxes sell but not an industrial machine, Grizzly fills the need. In this case, the drill press was a very generous gift from my Dad. It is the G7943 12-speed heavy duty bench top model, currently on sale for $295, a quite reasonable price for a decent machine. The travel range of the drill head is a full 3 ¼ inches which means it can easily drill most any pen blank without a table adjustment. The speeds are changed by adjusting the drive belts on the top of the machine and that process is reasonably easy, although speed changes are not usually needed for most of what I use it for. The only problem I have ever had with the machine was that the drill head would fall off of the mounting with some regularity but the application of a good deal of pressure has solved that problem years ago coupled with roughening the mounting pin with some sandpaper to create better adhesion.

Holding the Pen Blank for Drilling

Now that I had a decent drilling machine, the question still remained of how to best hold and stabilize the blanks. Several of the retailers that sell pen kits and pen blanks sold variations of a theme of a clamp mounted pen blank vise that would install on the table of a drill press. The marketing promised these devices were the ultimate solution and that once set they would require not adjustment and hundreds of pen blanks could be drilled without adjustment. Models sold by Woodcraft and Rockler are viewable on-line.

Hmmmmm. I should know that when it sounds too good to be true it probably is. While the claims MIGHT be true if every pen blank you wanted to drill was exactly the same size, any pen maker knows that just isn’t the case and forget about these devices working at all with blanks that are anything other than the commercially sold and sized ones. I often use off cuts from other projects to best utilize as much good wood as possible and these odd sizes simply didn’t work in these clamps. Also, they usually required a sacrificial blank of impossibly small size to help prevent break out of the blank when the drill came through the end. These were difficult to make, ridiculously expensive to buy, and hard to place.

Some pen makers use a method of drilling where they don’t drill all the way through but instead drill as deep as the kit requires in a pen blank cut intentionally longer than needed. Then, they cut off the un-drilled end on the bandsaw thus preventing any break out. I’ve tried that, but I find that it takes more work and estimating size and drill depth than I am comfortable with.

Lathe Drilling Solution

Over time, the solution I came to is to use the lathe itself to drill out the bore in the center of the pen blanks. To use the lathe for this process you need two pieces of equipment. First, you must have a lathe mountable drill chuck, either keyed or keyless, it doesn’t matter. These chucks are mounted on a spindle of the appropriate size, in my case a Morse Taper number 2. They can be mounted in either the head or tail stock although I always use mine mounted in the tail stock. These chucks are readily available from various vendors. This is one available from Woodcraft very similar to the one I use to this day which was purchased concurrently with my very first lathe many years ago now. I have replaced the taper with a model from Harbor Freight but the chuck is the same.

The drill chuck will hold the drill bit you need to use in the tail stock. If you have never drilled this way before it may strike you as odd because set up this way the drill remains stationary while the blank spins. The drill bit is slowly advanced into the spinning blank material through the use of the turning handle on the tailstock assembly. The lathe speed should be adjusted for the material being drilled.

Dedicated Pen Drilling Chucks – Penn State Industries Version

Penn State Pen Drilling Chuck and Drill Bit Chuck

Penn State Pen Drilling Chuck and Drill Bit Chuck

The other item you will need is a chuck mountable to the headstock on the lathe that will hold the blank for drilling. I use two different chucks from different manufacturers for this purpose. The first such device I purchased was the Dedicated Pen Blank Drilling Chuck, Item #: CSCPENCHK, from Penn State Industries. It isn’t cheap but it was cheaper when I bought it years ago than it currently is. Prices have really skyrocketed! This chuck is quite good for drilling relatively small blanks but great caution must be used with blanks that exceed 1 inch maximum. The problem that I ran into with this chuck is that if it runs out too far you will never get it aligned properly again and it is useless once that happens. In fact, I had to return and replace the first one I bought for this reason. One other problem with the chuck itself is that it is only available in a 1 x 8tpi headstock size and my new lathe is a 1-1/4″ x 8 TPI. Thankfully, Craft Supply USA offered an adapter that would fit a head stock of the larger size while fitting chucks of the smaller size. The HUGE advantage here is that if, as was my case, you start with a smaller size lathe and buy several chucks and then upgrade you could end up with lots of very expensive chucks that are now useless. This one tool resolves that problem and save hundreds if not thousands of dollars in retooling costs. I love mine and use it with several different chucks, including this Penn State Industries Pen Blank Drilling Chuck. Craft Supply USA no longer sells exactly the model I have but these are exactly the same, just not made in the same size I use, whereas this model is the size I use but the design is slightly modified, for the better I might add since it includes indents to accommodate a wrench for removal, a necessity I wish mine featured.

Penn State Pen Drill Chuck With Blank and Drill

Penn State Pen Drill Chuck With Blank and Drill

Caution against Penn State Industries

I hate to have to say this, but I think forewarned is fair in all things. While I like the performance of the Penn State Dedicated Pen Drilling Chuck, I am always very reluctant to purchase anything from Penn State. I don’t find their shipping policies to be reasonable when comparted to their competitors, especially not compared to Craft Supply USA. Penn State requires up to 2-3 days for “order processing.” I’m not sure what that means but I work with a company that ships daily and we ship most orders the very next day without fail on in-stock items, and Craft Supply offers same day shipping up to a generous cut-off time, especially advantageous for those of us on Eastern time as they are on Mountain, giving us two more hours to order in general. Penn State shipping is slow whereas Craft Supply USA uses either 2-day Priority Mail by the USPS which reliably reaches me in very rural Georgia on time, or FedEx which is a bit slower, oddly given the name, taking about 3 days to arrive. More often than not, Penn State won’t have shipped yet in those time frames whereas with Craft Supply USA I already have my items. And, my experiences of Penn State customer service were not positive when I have had to call them. They are not friendly, are reluctant to be helpful, and the processing time for a refund was literally over a month after they had the return. When I asked, they told me that my return was “on the pile” and they were just now getting to it. On the rare occasion I have had an issue with an item from Craft Supply USA they were beyond pleasant on the phone, didn’t require me to return the item, and issued immediate replacements or credits to my credit card account. Customer service really factors large into my decision about where to buy and I won’t buy from Penn State Industries unless there is simply no other choice for an item I deem essential. The only item to fall into that category in almost 10 years has been the Dedicated Pen Drilling Chuck.

Dedicated Pen Drilling Chucks – Teknatool Nova Version

Recently, I received as a gift the Nova Pen Plus Jaws by Teknatool, out of New Zealand but sold all over the United States, that fit onto a range of Nova Chucks also manufactured by Teknatool. As one would expect from Teknatool and the Nova line, this is a very high quality heavy duty item. One great advantage is that these jaws do not require a dedicated, good for nothing else, chuck option as is the case with the Penn State version. These jaws can be put on and taken off an existing Nova Chuck with only 4 screws, or the jaws can also be used for other purposes including the mounting of small bowls or other spindle projects. That versatility just can’t be matched by the Penn State version. This is an excellent addition to the Nova Chuck line, in my opinion, and I ended up using both pen drilling chucks during this project.

Nova Brand Pen Drilling Chuck and Drill Chuck

Nova Brand Pen Drilling Chuck and Drill Chuck

I started with the Nova version because I had not tested it before and I was curious to see how it would perform. For the most part, it was excellent but in the end I switched back and stayed with the Penn State version. Given my commentary above, that probably seems confusing and contradictory but really it isn’t. When working with such small pen blank stock the Penn State version has the advantage because it is very specifically designed to work with small stock. While the Nova version will hold the extremely small size of the Corian stock, it is closed so tightly that if there is any travel at all of the bit, which does happen despite the quality of the Colt bits, you find yourself drilling into the heads of the bolts that hold the jaws onto the chuck because they protrude somewhat because of the limited thickness of the Nova pen jaws. I didn’t want to risk permanently damaging the jaws or the screws so I quit using it for this job, BUT for a job where I would be using larger stock, which I commonly do when working with cut offs and other “rescued” pieces I am using as pen blanks, the Nova version wins hands down because the Penn State version can’t expand that far at all, and if you go much beyond about ¾ inch at all you run the risk of misalignment that I mentioned above.

Nova Brand Pen Drilling Chuck and Drill Chuck in Use

Nova Brand Pen Drilling Chuck and Drill Chuck in Use

Which Dedicated Pen Drilling Chuck to Buy?

My conclusion and my advice for pen turners regarding which pen chuck to buy is simple: if you can afford it, buy both and use them for their respective strengths. For very small stock, provided you have a spindle adapter if needed, use the Penn State version. When working with larger stock, above ¾ inch, use the Nova version. If you absolutely have to choose one and live with it, hands down, choose the Nova version and just exercise care when drilling smaller stock. Without question, the Nova version is a better tool, better made, much heavier and stronger, and it is adaptable for other turning projects in ways that the Penn State version simply isn’t.

With the addition of these pen drilling chucks I no longer use the drill press at all for drilling pen blanks. In fact, the drill press still lives in my shop for one purpose only, milling the ends of the drilled and glued pen blanks, a topic for a different post.

Final Words and Next Steps

With some degree of patience and by using a variety or combination of cooling methods, drilling Corian or any other pen material is relatively easy on the lathe because of the dedicated pen drilling chucks now available. I was able to drill all 72 required blanks, without mishaps of any type, in one afternoon. At that point, I would turn my attention to the brass inserts that would be glued into the drilled blanks.