Aircraft Drill Bits? I Need Long Bits For The Lathe

strantor

strantor

Active User
Registered
Joined
Oct 29, 2012
Messages
1,328
What are "Aircraft drill bits"? I'm looking for a set of drill bits 1/16-1/2", 12"+ long. This looks like a match.
But I'd prefer they be fluted much further down. I have two bits like that currently, and when I'm drilling out a long piece of stock, once I get past the end of the flutes, it's a time-intensive routine of moving the tailstock base up and down the ways to clear the chips.

In my search for extended bits, I keep coming across these "aircraft" bits. What are they exactly? From what I read, they were designed for the aircraft industry, and that's all the info that I can find. I guess that means they weren't designed for boring out stock on a lathe, and my experience says they aren't a great match for that task either. Are they even meant for drilling metal? Where can I get more ideal bits for this task?
 
Really HIGH speed steel? Enco and many others sell them.

Bruce
 
Yes, they are designed for aircraft work primarily. Give a hint as to what you are drilling, the depth and the number of times and it's possible to come up with something better and easier to use. Depending on material and quantity of holes, you may be better off using gun drilling bits.
 
cvairwerks said:
Yes, they are designed for aircraft work primarily. Give a hint as to what you are drilling, the depth and the number of times and it's possible to come up with something better and easier to use. Depending on material and quantity of holes, you may be better off using gun drilling bits.
Click to expand...
My immediate need is to drill out a 1/2" of aluminum round stock 10" deep. But I'd like to be able to do similar things in the future with the same bits in mild steel.

As for number of times, I don't know what's reasonable. I never considered drill bits to have finite number of uses; in my mind, you just keep using them until you break them or until you've resharpened enough times that there's no usable length left - if you take care of them, they should last a lifetime. I probably have that idea in my head because I'm not a machinist. I guess if you're using the same drill bit for a repetitive task for 12 hour shifts, they might not last a week even with the gentlest care.
 
You should be able to find extra longt bits with short and long flute length although you may not find the long flute drills in full fractional sets. A short flute length provides more rigidity which is usually a desirable feature. For longer flute length, check "extra long length drills". Enco and Travers both sell them with longer flute lengths. As you have stated, short flutes tend to jam chips in the flutes more easily but, if you are drilling deep holes with any hope of maintaining straightness, you should be using a pecking routine anyway.
 
Ok, that's a lot of help. 10" depth and both Al and steel gives some better insight. For drilling at that depth, you need to be looking at gun drills. Standard for Al and probably carbide for steel. You are not going to like the pricing on them from a regular source, so I would start crawling ebay like crazy to find what you need. New, bits are going to set you back anywhere from$95 to $250 each, depending on material and overall length and you can find good or new bits on ebay for less. In addition you are going to need a coolant feed adapter, as at that depth, chip clearance is going to be a big requirement to keep from binding the bit and breaking it off.
 
Wholesale tool has 12" long bits and it looks like the flutes are long not like the bits you have.
 
I do a recurring job, 7/16" hole through a 12 1/2" 440C stainless round, I use an 18" X 12" flute length 118° HSS twist drill easily available from many different suppliers. The first google hit was Travers Tool but I have no experience with them and the manufacturers name is unknown to me, (imported in house brand I suspect, TTC) so be cautious, they sell them in sets up to 1/2" for less then $400.00

McMaster also has them with the 18" length starting at 1/4" diameter. You will not like the prices however.
 
You must log in or register to reply here.
Back
Top