Thread: accurate countersinking SS

What type of Countersink bit are you using.

haven't decided as yet - any advice is most welcome

From your first post it appeared that you had allready tried .
If you havent as yet bought your bit I would suggest a Cross Hole countersink bit.
Run your drill as slow as you can.
Apply a heavy cutting force to the bit,dont let it rub (it will work harden the stainless).
Use a good quality cutting compound.

A good quality bit is the important thing here, not the machine. Even an old hand crank drill will do a nice job with the right bit. I like the zero flute countersinks, get a good one (IE. German, American, Japanese) Keep the speed slow, stainless work hardens easily and will eat your bit if your not careful. these bits have a size range get one that is sized appropriately. Good luck
Darrell

Have done a lot of SS flush countersinking with a drill press and cross hole (no flute) countersink. Things like exposed legs for multi thousand dollar lounge and dining furniture where the cs screw had to be exactly flush with the surface of the bar or a $300 part gets rejected. No problem to set it up with the drill press provided that the unit has a decent depth stop arrangement. I always made up jigs to use for setting fences and stops to position the hole locations (our components had to match other components made 50 km away so we had master jigs at each site).

I also made a depth stop setting jig from matching material so that I could quickly setup when required. To get that spot on, I set the depth stop at an arbitary positition shallower than required and made a test cut to check, checked it, and elevated the jig material with a sheet of paper between the press table and work and made another test cut etc till the cs was spot on.

Then used the depth stop jig on a single sheet of paper on table to reset the depth stop for production work. Sheet of paper was to provide consistant and replaceable surface protection as these workpieces were prepolished prior to bending drilling and countersinking.

This method worked well for materials from 4mm to 12mm thick. Beware of thin material wanting to spin when drilling and countersinking, much harder to stop this and more likely to slice flesh if it can occur.

"A good quality bit is the important thing here, not the machine. Even an old hand crank drill will do a nice job with the right bit. I like the zero flute countersinks, get a good one (IE. German, American, Japanese) Keep the speed slow, stainless work hardens easily and will eat your bit if your not careful. these bits have a size range get one that is sized appropriately. Good luck
Darrell"

Just realized my reply didn't really speak to your question (missed the accurate part) my apologies. Accurate depth countersinking on a machine without good provision for it can be a frustration. manufactures of drill presses have for the most part not put a lot of effort into this point. there are probablee a few exceptions ( I believe southbend may have had a decent setup on the drill press they made, but they made some of the best machine tools so why wouldn't they have solved this small problem. I have never seen one of there drill presses in the flesh but from photos they look well made. All of the drill presses I have ever used have either had the two nuts on the side for depth or the clumsy lock on the lever arm. A small milling machine would certainly give you a numerical way of repeating your depth but may not have any provision for a mechanical stop (which I think would be preferable) you cold also make a setup with a dial indicator on your own machine but again without some sort of positive stop there is risk of something getting knocked and messing things up. Although this may not be of much help to you I came across a solution to the problem of accurately countersink in holes by hand with a drill when I came across something used in the aircraft building industry for countersinking for the rivets used in building planes, lots of rivets done by hand makes sense they would have solved it. Its a roller bearing adjustable depth assembly with a carbide tipped counter sink. Could be used in a drill press.
Darrell

that looks pretty intresting
any idea what its called?
any idea where i might get such a tool?

I believe its called an aircraft countersink. A goggle search will work to find some suppliers. There are usually some on ebay as well. Get extra ends for it if you get one.
Darrell