Bumbling forward into the unknown.
Whatever bit you select, keep in mind that a Bridgeport knee mill will allow you to use the full quill travel, plus the vertical travel of the knee. Combined, it should eliminate the need to disassemble. I've seen machinists reach into seemingly impossible places with a well thought out setup. - - Hope it helps.
Can you bore the hole as deep without the extension.
Then use an extension to drill a smaller diameter hole through to final depth.
Finally, attach your original bit to the extension and ream out the hole to final width.
I use this method when drilling dog holes in my bench - not because I'm afraid of deflection, but because it makes it SO easy and resistance-less to drill to deep depths. The reduction in resistance might (my theory) reduce the desire of the bit to deflect.
Malcolm, I'll continue to keep that in mind, as I have for the past 14 years that I've worked with this machine.
Fixturing to the machine is not the issue. I was looking for specific types of woodworking bits best known to minimize deflection and maximize chip evacuation. I assumed Forster but was looking to double check unless there was something significantly better.
Maximum underhead is 16" and the piece will likely end up at 10-12"~. Which is why I expected to need to cut then drop the longer bit in to finish the cut.
Last edited by Brian Holcombe; 04-05-2017 at 9:13 AM.
Bumbling forward into the unknown.
I have come to know you as 'The SMC Neander Guy'; had no clue of your metallic skill set. I'll shut up now.
...and don't try to school him on scotch either, Malcolm
Hahaha! Ok, we may as well steer this one well off the rails. I'm an Islay man and I like long walks on the beach (the second part is a lie )
Bunnahabhain 18 and Lagavulin 16 are my go-to's.
Bumbling forward into the unknown.
We're all allowed some claim to fame...
Ian.jpg
...my cousin. And not a sassenach.
Anybody else?
And anybody who likes the Lagavulin is welcome in my home ... with a bottle in his pocket!!
Last edited by Malcolm McLeod; 04-05-2017 at 9:43 AM. Reason: can't be all bad
Awesome! That's got to have some good benefits. Also, good to know that I'm in good company on this board.
Bumbling forward into the unknown.
I've read that flute makers use gun drills for deep, straight bores.Would that work for you?
Grant
Ottawa ON
To be on point with the O.P. and the derailment, consider the Scotch eyed tee auger, still available from the UK.
As a former timber framer, I would layout drawbored peg holes and drilled the holes before cutting the joints. I used several bit types and achieved predictable results, namely twin spurred solid center Irwin bits, single spur ship auger bits from various sources and triple spur Wood Owl bits. Lengths from 12 to 18 inches. Sharp spurs are, imo, one absolute key getting a clean bore. Other key are directional control and boring through perpendicular to tangential grain. I used drill frames of two types and several jigs to focus the bit. The simplest is a block five or six inches thick with a perfect bore through the block. Layout the bore on both sides and center punch. Insert bit through the bore in the block, find the centered punch hole with the feed screw and clamp the block to the workpiece. Drill halfway through and flip the stock and repeat process. Accuracy depends on crisp layout and regular surfaces. Or one could just bore through with a block clamped of the side where the bit comes through. to prevent blow out.
Last edited by Roger Nair; 04-05-2017 at 1:56 PM. Reason: typos
https://www.mcmaster.com/#standard-drill-bits/=172fyd9
?
Not sure if a drill bit on your mill would be good enough.
Thanks for the insights.
Bumbling forward into the unknown.