Pin drilling reloaded

making work easy

Oliver Dreher
Master Dental Technician


Pin drilling may be only a small stage in fabricating a precision model, but it is a very important one. This is because if the hole is too large, the pin moves and can loosen at a later stage. If it is too small, the pin can only be inserted with difficulty and tilts or jams before full insertion. This is quite apart from breaking dental arches or corrosive plaster dust in the chuck as a ‘precision killer’. In brief: Anyone who ignores such points during drilling will not be able to retrieve the situation or only retrieve it with great difficulty.


I have used the Top spin drilling machine since 2001, because for me in a certain way it also embodies traditional values of the craft: it is solid, good and ‘made in Germany’. A machine of this quality class only has to be purchased once in the life of a dental technician. So I was skeptical as Renfert introduced its new model. I therefore checked it thoroughly when it was brought to me in the laboratory for testing:


Drilling accuracy of ≤ 0.01 mm

The forerunner model was previously the most precise on the market, even though it was now showing its age. The latter showed itself in the direct comparison of the two machines. I was all the more pleased to discover that with the new model Renfert had achieved not only the same, but also even higher precision. Renfert guarantees a drilling accuracy of ≤ 0.01 mm thanks to a special motor and new shaft bearing. The optimum drill concentricity impressed me, Renfert had not promised too much!


Process reliability

I was also impressed by the excellent combination of a new drill geometry and uniform drilling table resistance, with which I can dispense and control the force selectively during drilling. Even delicate dental arches do not fracture any more. Thanks to the adaptation of the drill geometry and the lower speed I can drill easier and more reliably. The coordination of speed and cutting head geometry has been very successful. The sentence: less is sometimes more, is fitting in relation to the number of revolutions, which was previously 16,000 and is now 8,000 rpm!



The properties described above certainly also contribute to a longer operational capacity of the machine. In addition, there is also the new plaster collection drawer with filling level display, which in my opinion is also a ›longevity advantage‹. If the dust collects in the motor housing, it affects the drilling accuracy of the motor. Any plaster now falls directly in the drawer, which can be easily emptied.


Pin drills

To date I have drilled several hundred holes using the new pin drills and I am highly satisfied with their drilling capacity. They seem much more superior and more stable than the previous models. The lower loading is not only an advantage for the dental arch but also the motor – and of course also the wallet due to less cash outlay.
The new pin drilling machine is available in three versions: S, M and L. If a laboratory buys pins from another manufacturer, this option is certainly practical.


The new Top spin also excels due to the removable dust collector and the contact-free switch-on function



Renfert has adopted the good properties of the forerunner model – fortunately. For example, that the base can be rotated and the machine tilted. The grip options, which are used to fix the dental arch securely in position during drilling, are also thankfully retained. A new addition is the contact-free switch-on function. This prevents any fine dust collecting around or in the switch. Cleaning is also easier.


Top Spin pin drill


Potential errors

The majority of inaccuracies and errors during pin drilling occur, if the table is pressed down and this procedure is too stiff or the drill offers too much resistance. The model or dental arch is then raised and slips or is drilled at the wrong angle, resulting in excessively large drill holes. Renfert has reduced this problem to a minimum, because the new drill geometry is intended to reduce the force during insertion into the plaster by up to 50 percent. And it is a fact: In combination with the uniform table resistance there is now a subjective ›butter soft‹ drilling sensation, even with high-strength dental stone dental arches, which have fully hardened over the Weekend …



In my opinion the new Top spin represents a new generation of drilling machines. The excellent properties from the previous units have been retained and it has been greatly improved in terms of precision and process reliability. If the previous model was the benchmark of pin drilling machines, the new model will again set new standards for the future.“