The DBS-22 learning curve

[Jan]

Jan,

Ernie Conover did an excellent you tube for Fine Woodworking about using standard metal drill bits for precision drilling of wood. Ernie just uses the standard biy grind. However, following good machine shop practice, he first drills a considerably smaller pilot hole. Next he enlarges the pilot hole with a drill bit just slightly smaller than his final diameter. The third hole is drilled with the actual diameter bit. It removes very little wood, and can drill a very accurate hole.
Ken

Thank you Ken for your comment and reference to Ernie Conover. 
I usually use a two-step process, the pilot hole followed by the final diameter. The three-step procedure is surely better, but you spent more time swapping drill bits.

Jan

[Jan]

Drill bit geometry is very interesting and important topic. The MMS leaflet referenced by Elden is excellent reading. 

Let me set the drill bit geometry theory aside for a while. I would like to mention a real word example.

Recently I made decorative roof, above the door to the garden, of ¼" thick steel sheet, which required drilling several dozens of holes. All I needed for drilling the holes, were two conventional twist drill bits. One 1/8 " for the pilot hole and the other 1/4 " for the final diameter. Both drill bits are still usable.



The steel part of the roof was cut using the abrasive waterjet cutting technology.
Jan

[Elden]

That was a lot of drilling, Jan. I trust you were using a drill press.

[Jan]

Yes, Elden it was a lot of drilling. Fortunately I have a radial arm drill press. 

I have used drill bits designed for drilling holes for rivets. Those drill bits are very short and have flutes on both ends.



I always use suitable cutting fluid to cool and lubricate the drill bit.

Jan

[Dr Spin]

 

   It is possible to cause error to be introduced into the grinding due to improper pressure being placed on the attachment. If too much pressure is placed on the front of the drill bit holding fixture, flexing of the attachment can occur. Most is probably actually occurring in the slide areas. There may be a slight flexing of the USB as well.

Hi Everyone, I have just purchased a DBS-22 and have also noticed quite a lot of play between the attachment and the mounting plate. What seems to happen the rubber strips can be compressed on one side or another causing a change in angle of the drill bit. This becomes more noticeable the smaller the drill bit. As I'm sharpening I have to be very careful to keep the attachment stable as I go back and forth across the wheel.

Could Tormek replace the rubber with some ball bearings perhaps? (metal filings might be the reason they havent already?

Cheers John