Linear Float Chuck?

================== Have you considered using step drills? This will eliminate a secondary operation.

You can also add a chamfer cutter to a drill or reamer.

You may want to include something like a drill stop, possibly in combination with a chamfer device on the drill.

Unka' George [George McDuffee] ============ Merchants have no country. The mere spot they stand on does not constitute so strong an attachment as that from which they draw their gains.

Thomas Jefferson (1743-1826), U.S. president. Letter, 17 March 1814.

-Hmmm. Howzabout sticking the shank of the countersink in a Tapmatic and cranking up the torque?

Hehehe... The very first thing I thought of. 15+ spindles later, that's a lot of tapmatics! Probably cost prohibitive. :)

Regards, Joe Agro, Jr. (800) 871-5022

Used to run CNC machining centers along time ago, in a tractor factory far, far away. Taps were held in a collect type (DA if I remember correctly) holder with a straight shank that was spring loaded both ways, this in turn was held in a standard ER collet tool holder. In use a feed slightly higher than the tap lead was programmed both in and out, thus the spring pressure pushed and pulled the tap in and out of the hole. Possibly something like this, maybe with a somewhat lighter spring, might work for counter sinking. I never new their correct name or who made them.

For chamfers on holes to be tapped subland drills were used to eliminate the chamfering tool, on radial drill operations 'burr bits' were used on the tap itself.

I think what you need is out there, off the shelf, you'll just have to track it down.

Regards Paul

Same issue... Drillign through a product there aren't many worries about overstroke unless you hit the table below or run out of drill... With the deburr-via-countersink, he needs to hold depth quite accurately.

Bingo! Exactly what someone handed me about 10 minutes ago. Just got off the phone with them and while I thought the "Counter-bit" would be perfect, they claim it doesn't float in the way that I need it to...

Regards, Joe Agro, Jr. (800) 871-5022

"Joe AutoDrill" wrote in news:RcC3j.26540$XT.905@trnddc01:

There is a company that makes spindles that float like this just for deburring/chamfering. They have both axial compliant models and angular compliant models.

Interesting. Inquiry sent off to them. Seems high-end, but ya never know!

You know -- I've just realized that I have something similar to your original need statement -- except in size. It is a sensitive drill chuck -- a 1/8" Albrecht chuck in a 1/2" shank with a spring-retracted sliding inner shank keyed to the outer shank -- and a ball-bearing mounted ring just above the chuck for allowing you to pull it down by hand.

I would suggest getting one of these and taking it apart to see how it is made, then just making your own. You could add a spring to push down on the ball bearing ring just a bit to make it self-adjusting and make sure that it is not bottomed by the interior spring at rest.

Enjoy, DoN.

Might just work for my customer's application since it is a simple deburr... But doesn't the accuracy of said chuck suffer for critical applications?

Well ... I have used mine with solid carbide drill bits down to #70 (and steel ones down to #80), and as long as the chuck which is holding the shank has little runout, so does the carbide bit. Since the solid carbide bits are *very* brittle, I would know if there were problems with this.

IIRC, the construction is a sliding drill rod in a reamed hole, with a keyway milled into the side of the drill rod, and the edge of a Woodruff key held in to engage it through a slot milled in the outer shank by a spring ring in a groove turned into the outer shank (so it does not project above the OD of the shank). So -- it is up to how concentric the hole is in the outer shank, and how concentric the inner shank is with the Jacobs taper on the end of the inner shank. (Oh yes, and the match of OD of the inner shank and ID of the outer shank, of course.)

Good Luck, DoN.