Damn, now you're gonna make me spend money.
Not gonna use that on my carbide tipped gun drill though.
But, the parting tools, drills and lathe bits could use some sharpenin'.
Haha, my bad
Damn, now you're gonna make me spend money.
Not gonna use that on my carbide tipped gun drill though.
But, the parting tools, drills and lathe bits could use some sharpenin'.
Whoa!
That would save a lot of money.
& make a great youtube video. :thumbup:
One of the best T & C guys i knew in early daze did some backing off that way. You too? Or the whole grind?????
I need crutches. Cincy #2 & fixtures; or one of the surface grinders here + same.
smt
JoeyInCali
I need a video tutorial
I've ground buckets full of moulding knives to profile by hand.
Still grind most twist drills that way, up to 1" dia. Can't see the really small ones anymore. Lathe bits as a matter of course, HSS & carbide.
Gun drills are new to me though. If there's a specific grind for wood, i'll try it with fixtures. & diamonds.
I was not careful of dust/fumes/solvents in early years. Taking better care these days and avoiding most. Carbide is pernicious & one that would be nice to avoid but it is too useful. So coolant, & chemical respirator.
Green wheels under the right circumstances can get the job done. I ran a Fitchburg cylindrical with a 20" green wheel in a buddy's shop, nights for a while, spinning port tools in. But the truth of the matter is that green does not really grind the carbide, it erodes the binder around the particles so they fall away. The edge is not as good as when honed with diamonds.
These days new diamond wheels seem about as cheap as any other abrasive substrate at least on ebay..
smt
you will want to drill/bore about an inch deep in the backside. Otherwise, as the gun drill comes through the other side, it may catch, grab, and can wreak havoc.
etiquette question.
Some have asked where i buy gun drills surplus.
Short answer is i went on eBay, researched and bought an order. Next time made a point of searching for vendors that might be close, and found one, turns out i've bought machine tooling from online for at least a 1/2 dozen years, that was close enough to drive to.
Bob's focus as a dealer is machine tools and tooling. But he says he sells a lot of gun drills to cue makers, flute makers, bagpipe, etc. Bob says it's fine with him to post link. He might or might not have sizes or lengths that suit woodworkers at any given time. Points and condition are what they are, though all of mine are sharp/recent regrinds so far.
No connection to those who asked back channel, so would prefer to mention source in the open so it (maybe, possibly) benefits those who have helped me if anyone. It might or might not help anyone let alone Bob, depending on nuisance factor. It's not a big deal.
Should i post business name and town?
smt
If you'll go back to the title page for this section and look at the topmost subject (it's called a "sticky") you'll see the rules for this forum - the short answer is "No", links to vendors and sources are to be given through PM's and not published
What kind of air pressure do you use in a gun drill?
They are made to take hundreds, if not a thousand PSI hydraulic for drilling metal, is let's say 100 - 120 psi air enough for wood?
Also, do you rotate the drill and the work, or just the work?
What kind of rpms?
Thanks!
smt
I will try not to make this reply too long, but feel compelled to say something since I spent more than 30 years in the deep hole drilling business before I retired. I designed, sold, and serviced gun drilling machines that produced extremely accurate bores in many different types of steel.
The most accurate way of reducing drill drift is to start the drill using a close tolerance drill bushing and rotate both the drill and the work. This is called counter-rotation. Forces tending to make the drill stray (drift) from the center line will counter act each other and, with the right set-up, counter rotating gundrilling machines can produce run-out accuracy of (T.I.R.) of 001" inch per foot.
Counter rotation gundrilling machines use a rotary union attached to the rotating tailstock to induce coolant (or air in the case of drilling wood, graphite, plastics, etc.) to the gundrilling tool.
The total rpm's can be split however you like between the work and the tool. Often 50/50. But, the advantages of counter rotation will still be evident even at a 90/10 ratio.
I would be happy to try to answer any questions you might have, including giving you some names of used machines that can probably be picked up pretty cheap at used machinery dealers. Some manufacturers also sold just the rotating tool tailstocks to those who wanted to make their own machines.