Fax: 01444 414813
Email: info@airstream.co.uk
by Peter Brett - November 2006
For more information call Christine
01444 440188
01444 440188
Good news for hard tiles
This edition it is the turn of Diamondjack Spot & Drill to be put through its paces, and they are subtly different in their market niche appeal. The Diamondjack product is very specifically aimed at users who want to drill holes in very hard products like quarry tiles, porcelain and granite. These are very demanding applications, and although some other products may be able to drill them, there are other questions raised, for example, how long do the drills last, how accurate are they and how easy are they to use?
The Diamondjack drills look very much like other diamond drills on the market, although their deep red colour differentiates them easily. They come in a limited range of sizes, namely 6,7 and 8mm, but since these sizes cover the most popular plug and hole diameters, this is not necessarily a marketing disadvantage.
The tips are the interesting part. Looked at with a magnifier, the ends are flat with a scattering of industrial diamonds across them. A slot cut into the shaft provides relief for cut particles to escape. The diamonds are also embedded into a portion of the shaft that extends about 10mm up, and from what I could see through the magnifier, they are quite liberally distributed. Experience with diamond disc cutters suggests that wear of the cutting surfaces will always take place, but it is the ability of the drill or disc to expose new diamond cutting surfaces that is important for determining how long it lasts.
Although these drills can be used dry, Diamondjack suggest that they will last longer and cut better, if water is used to lubricate the drilling area. To this end they have come up with idea of a localized water supply and drill guide in one. Other products have similar ideas of course so it is, to an extent, making a virtue out of necessity.
The Diamondjack solution comes in the form of a pack of self-adhesive drill guides. At a price of about £4.00 for 15, they are not extortionately priced, but they can really only be conveniently used once each.
The next part of course, is to try all this out on a set of materials that Diamondjack supplied to me namely, quarry tile, porcelain tile, marble and granite.
Setting out the position of the holes accurately is a priority. A cross-marked in waterproof marker is a good start, and the extended cross ends can be used to line up the middle of the hole with the edges of the hole guide. You then remove the cover from the self-adhesive drill guide and place it carefully over the centre of the marked cross. A squirt of water from a plastic bottle with a suitable spout will see you ready to start drilling.
Diamondjack suggest that a high speed of above 2,000 r.p.m. is used for best results. This may be a speed beyond some cordless drills, so a corded drill may be a necessity. Some users might find this a disadvantage.
I started with a piece of hard white granite tile about 12mm thick. It was nicely surfaced and polished, so attaching the drill guide/ water reservoir was quite easy, even following my cross guidelines. I then squirted in some water, the reservoir holding more than I thought it would. Then, using a speed of about 2,500 r.p.m. on a small corded drill I started. My first mistake became evident quite quickly. It is best to start gently, and probably at a slower speed until the hole is started and has a rim to follow, otherwise the drill guide could be moved or could possibly even come off. A variable speed drill is therefore a very good idea. Once going however, I was able to drill the first hole in less than a minute, which I thought was very good. The next hole was soon set up and avoiding the initial mistakes I was able to get going quickly.
As I drilled and increased the speed I became aware that the amount of heat generated is considerable.
This should not be unexpected as granite is pretty hard. The result was that some of the water was soon hissing away gently. Time to remove the drill bit, squirt in some more water and proceed. Because I was less gung-ho this time, the hole took over a minute to drill, but it was very controlled and accurate. The drill guide had not moved at all.
The more holes I drilled however, the more evident it became that the diamond tip had become glazed with the generated heat. Following the advice Diamondjack give, I drilled quickly into a bit of sandstone (or you could use something similarly soft and abrasive like breezeblock) and the diamond edges were restored, giving almost new performance again.
I spent the next hour drilling more and more holes, and a few things became clear to me. For example, the drill guides need careful preparation of the surface if they are not to move. Drilling holes close to each other usually results in a film of water and fine dust on the drilling surface, so it is important to have a pair of cloths nearby to clean and dry the surface before sticking the drill guide on.
I did get to know the wrinkles of the Diamondjack drills after a while, and in many ways they offer a unique product. From my limited experience of them, they would appear to offer a good service life drilling in very tough materials. They have to be used carefully, within the guidelines, and this care is repaid with many accurately bored holes. A comparative test could offer further insights into long-term performance, but my gut feeling is that these drill bits would acquit themselves well in comparison. They may not be the easiest to use and set up, but they are tough!
Independent Review by Peter Brett
Airstream Communications