Drilling with shopbot desktop

[stumpgrinder]

Another newbie question here. I plan on making a bunch of parts that have holes of different sizes drilled into them. What do you guys use to hold the drill bits on the router/spindle? At the moment we used an end mill that was slightly smaller than the hole diameter and used the cut a pocket feature in partworks, but that took far too long. Thanks.

[adrianm]

I use these - http://www.wealdentool.com/acatalog/Router_Drills_25.html

[dana_swift]

Lauri- do you really need to use drills?

Almost always I use a router bit smaller than the smallest hole, then create pockets the size of the holes I want in PW (or Aspire). Then one bit makes all the holes and does it in a single toolpath.

When holes get really big, I use an inside profile toolpath on PW. Tabs may be needed to keep the bot from throwing the center scrap out into the room.

Carpet tape can hold the scrap without tabs.. consider that an option too, but only when the holes are big enough that it is obvious where to put the tape before you put the material on the table.

I have "drilled" a zillion holes of all kinds of sizes and did it all with the bot.

One of the reasons I love having CNC.

D

[Gary Campbell]

Lauri...
The answer would be different for a router or a spindle.

A Router has a more limited RPM range and you will need to use an endmill or bit rated for that range. Most drill bits are NOT made for that rpm range. So my suggestion would be to use a spiral down, inside profile toolpath. Hopefully, your required holes are not so varied in diameter that multiple bits are needed. Use of a bit that is over half the hole diameter results in no center plug to fling. (or use tabs as per Dana above)

With a spindle the above option is still available, but you will have the option of reducing the RPM and reducing possible burning. This will increase bit life. You also have the option to add a 10mm collet and bore with carbide tipped brad point boring bits. These bits will give the best holes and lowest hole cycle time. RPM on these will usually be 6000 rpm or lower.

[dlcw]

Lauri,

This thread has a lot of info on drilling with the Shopbot:

http://www.talkshopbot.com/forum/showthread.php?t=13631