Countersink Hole

[samseksek]

Hello,
I'm new in this filed and need help.
I have solid works 2009 and BobCAD V21 with Fagor CNC Mill 8055.
My question is how can I make countersink as in picture on CNC 8055?
Thanks

[frankee]

I don't know .... this sounds like a trick question ... but have you considered using a countersink bit? If that hole is for a standard screw head it's probably a 82 degree countersink which you can buy at most tool suppliers.

I have a side business manufacturing front panels for electronic enclosures (Protoplates), and after having made many panels for many different customers, and a lot of grief, I'll share with you something that I have learned the hard way: the fastest and most cost effective way to make countersink holes is to drill the through-holes with your CNC, then take the part to a drill press which has a drill stop and make the countersinks manually ... unless of course you are manufacturing something in very large quantities, or something that is a regular production part.

Why? If you're countersinking on a CNC it becomes very critical to mount the material flat and horizontally true, otherwise even a small height variance along the part will affect the resulting size of the countersink holes on the part. Even if you mount your part very flat, the burr created by drilling a hole can lift the part just enough to affect the countersinks. While for most screw heads it doesn't really matter if the hole is a bit too big, your, or your customer's eyes can really pick up on the small changes and if you have more then a few countersinks on a part it doesn't look very professional ... or at least that has been my experience .. not sure if this applies to your application.

By the way .... good look with BobCAD V21. I sold my copy right here on this forum to another member for, I think, about 25 cents on the dollar, and I was happy to get rid of it.

[samseksek]

Thanks a lot for quick respond.
I have to make at least 64 of countersunk hole. Can I use one program for drill through all and countersunk with or without change tools?
If yes, can you tell me how I do countersunk draw and G-code?
Thanks again for your help.
Picture for countersunk M8 hex soket screw

[frankee]

Hi Samseksek,

The link to the picture didn't work; you may want to edit your post and fix that.

You can drill and countersink in one operation if you purchase a combined drill/countersink bit. This is one supplier, Dormer, search down this document until you find part number A217, you probably would buy the size 8 bit ... Dormer Catalog

Personally, not knowing exactly what you're trying to do, I would still probably drill the hole for the 64 8mm screws using your CNC, then take the part to a drill press to make the countersinks manually: even if they take 10 seconds each to make you would be done in a couple of minutes which is a lot faster then the time it would take to make sure your part is sitting completely flat for the CNC... again ... that's my experience and I appreciate your situation may be different.

PS. I'm headed out for the remainder of the day and may not see your response till later.