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I picked up a rougher/core drill....

LVLAaron

LVLAaron

Gold $$ Contributor
I do mostly 308 chambers... so in my last order of reamers I got a JGS spiral core drill (rougher)

I'm... shocked at how well and fast it removes material. I know it's an expensive drill bit for a home-gamer. I'll have to play with some barrel stubs and see if it's working with my dialing method and a floating holder.
 
That’s on my list to start looking at getting. I think you can buy core drills from MSC too.
 
Core drills are the best cutting drills. The ones I have need a pilot hole because they dont cut in the center of the drill. They do cut like butter.
 
Been planning to invest in 22 cal spiral fluted carbide roughers in a few cals, like 222, ppc, '06 and "243, as well as some magnums...just haven't for most yet. It's been working for 22 years, or whatever it's been but those roughers would speed things up considerably. Especially when you get the occasional big caliber, like 338 Lapua or 50 bmg.
Dial it in with a flush system and hog it out pretty fast, then go back with the appropriate finish reamer, vs pre boring stuff. The reamer will follow the hole. Not much we can do to change that in a good way. I indicate where the throat will be and judge where I stop with a rougher based on runout behind the throat area. Might have a problem child like 1 in 50 bbls or so that needs more attention but a rougher that is about .010 under finish should speed the process exponentially. Another "to do list" item.
 
^^^
Performs the same function as a drill bit. If you've indicated the throat area, you would obviously still need to lightly bore it to get it true to the throat you indicated. Any piloted form cutter will follow the bore, it can't do anything else. If you indicated the breech (or are working in the steady), it works just like a roughing reamer
 
Yeah... I know it needs to be pre-bored and aligned to the area I want dialed in. Just going at it with a reamer isn't going to get me there. Perhaps just a quick pre-bore after dialing... hit it with the core drill... perfect fit for the reamer.
 
These "core drills" are specialized for chambering barrels. Core drills in the machine shop have been around forever. They are a carry-over from manual machining, as a hole can be enlarged quit quickly with a carbide inserted boring bar in a CNC machine, not that a core drill couldn't be used in a CNC. It's just more economical to use that inserted boring bar. Materials can be bought in the form of thick walled tubing. That is what the core drill was used for, to make that hole bigger, so a boing bar could be used to go to finished size. The traditional core drill has 4 flutes and 4 cutting edges. A regular jobber drill has a 59 deg point, the core drill almost always has a steeper angle. If you have ever tried to enlarge an existing hole with a 2 flute drill bit you are aware of the chatter that can take place, especially before the diameter of the drill is yet to be "in the hole". You have to go slow. That's hard on drill bits. The core drill is the 'cure'. With the steeper angle and 4 flutes chatter is reduced greatly. Speeds and feeds increase, also, because of the 4 cutting edges, and the 4 flutes stabilize the tool. In production shops, they are all but a thing of the past. In repair shops they can still be useful. The problem arises with resharpening. Not that it it can't be done or is hard to do, but it is expensive when compared to inserts which are so common today. The 'tool man', who can make and recondition (sharpen) tooling is getting more rare as the day, weeks, months and years go by. The 'time' to sharpen a tool is expensive. It is a specialized skill that machinists of the past used multiple times daily. The tool grinder and the accessories used with them are expensive, also. many of the grinding fixtures I used in the past were shop made in the tool room for their specific task. Others, like for sharpening chasers for self opening die heads, where purchased. The days of HS tooling. It still has its place, as it is tough even though it's not as fast and dulls more quickly then carbide.
 
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Thanks shortgrass, you’re right.…when Aaron posted the picture, I realized…that’s piloted and not at all what I was referring to at MSC. I had not seen the piloted JGS version.
 
DaveTooley said:
This is the first time I've used my 3 jaw since I got my Haas. Tailings from 30 chambers roughed in with a caliber specific core drill.


View attachment 1409771
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Are those chucks good? I'm sure they are or you wouldn't be using one but they appear to be a less expensive option vs a Bison or Buck adjust tru. Just wondering your thoughts on it as I'm gonna buy an adjust tru for a little Heavy 10 that I've had around here for a while, soon. The machine itself is exceptional but the 3 jaw is junk. Been using the 4 jaw or collets for what little bit I've used it for. It's been handy, having a second manual lathe in the shop for odds and ends but for most of what I'll use it for, I think I want a set tru type 3 jaw
 
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gunsandgunsmithing said:
Are those chucks good? I'm sure they are or you wouldn't be using one but they appear to be a less expensive option vs a Bison or Buck adjust tru. Just wondering your thoughts on it as I'm gonna buy an adjust tru for a little Heavy 10 that I've had around here for a while, soon. The machine itself is exceptional but the 3 jaw is junk. Been using the 4 jaw or collets for what little bit I've used it for. It's been handy, having a second manual lathe in the shop for odds and ends but for most of what I'll use it for, I think I want a set tru type 3 jaw
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Isnt that just a scroll chuck not a set-tru? Im in the same boat needing a set tru. I like the gator as of right now
 
Dusty Stevens said:
Isnt that just a scroll chuck not a set-tru? Im in the same boat needing a set tru. I like the gator as of right now
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You're probably right. After a second look, I don't see adjusters on it but they make one for about half the price of a Buck chuck. That's why I was wanting to know more about them.
 
Dusty Stevens said:
Yes thats true. I have a buck but wouldnt buy a new one just because of the price. I use a bison daily and it works very well
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There may be a better place to buy but here's one. You'll have to see if they have what you need or not.
www.lighttoolsupply.com

BTC Zero-Set Precision .0005 T.I.R. Fine Adjustment Lathe Chuck Cast Steel - 1063R

Find the best deals on the web here at Light Tool Supply for all your precision measuring and metalworking tools & machinery.
www.lighttoolsupply.com www.lighttoolsupply.com
 
I made one years ago from a regular scroll chuck and back plate when I was working in a tool and die shop. I don't remember the details but I remember it took a ton of time, even with all the right tools at my disposal. I'm thinking 10 hours machining time for some reason. It's been a long time ago. I thought about doing it again but I had a print to work from then and that's a lot of time and money to scrap something out vs just paying the $800 plus a semi finished back plate.
 
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