Nose augers (aka Shell augers)

Nose augers are an old-style boring tool that are no longer available. They are notable for the fact that you can bore long straight holes (ie little or no deviation associated with a bit following the grain [following the path of least resistance through the lower density earlywood and away from the more dense latewood]).

I need to bore accurately sized holes 0.75" and 1.00" in diameter to depths of 18 to 20+ inches in the end grain of relatively narrow turning billets.

Rather than attempting to have a blacksmith attempt to forge such tooling from tool steel, I am considering tipping (with HSS) a piece of machined steel.

I would appreciate recommendations concerning necessary rake, sharpness and clearance angles given I will be boring woods with a density range of 0.35 to 0.70. Any other comments on tool design suggestions would be greatly appreciated. For example how much slope is recommended between the center and outer cutting edges; and most importantly, will this tool design concept actually work. I've never seen such a tool and have been depending on pictures and text from Mercer's book entitled "Ancient Carpenter Tools".

Thanks . . .

boring a 3/4 inch hole and a 1 inch hole will be fairly straight unless you hit a knot or other hard spot in the wood, can you rout a groove in 2 pieces of wood and glue the wood together ?

You might try asking this question on the WoodenBoat Forum. This question comes up when ever someone needs to the deadwood on their boat for a propeller shaft.

Lee,

I have done some searching for nose, lamp, and shell augers and gun drills since we spoke the other day. One of the more interesting search results brought up Bob Strawn on this forum. Here is a link to a thread he was involved in; http://www.sawmillcreek.org/showthre...end-of-a-dowel and here is another link you might find interest in; http://toolmakingart.com/2009/01/05/...ot-me-started/

I have also read the papers that you let me copy and have some ideas to play with when I get a chance.

Jerrimy Snook

Thanks Ray . . .

I have already attempted the boring in straight grained knot free material (wood I actually split to minimize grain angle) and the resultant holes all end up off-center. I've made fixtures with guides and still cannot keep the various tools I've tried to run straight. Even a small variation in angle over 18 inches creates a noticable problem.

Yes, it has been suggested that I machine an "half-bore" in two pieces and then use an adhesive to bond the two surfaces. I am trying to avoid this approach because of the high probability of misalignment (by even several thousandths of an inch) and the problem of removing the inevitable squeeze out on the interior surface. Additionally, given some forty-plus years of observation, I have yet to find an adhesive that at some point in time does not fail. I am not a religious person but for some applications I prefer god's glue (ie the wood's ligno-cellulosic matrix) to man-made stuff.

And if nose augers do bore straight, then I would like to use some highly figured Bigleaf maple. A glue joint in such would be visible because the grain patterns would never match.

As I am new to this forum, I am also wondering if I should not have posted this thread in the Metalworking forum ?

Lee, you mention turning billets, can we assume you have a lathe, and are these through holes or blind? I have no problem drilling 9" depth end grain for pepper mills with good forstner bits + extensions. If I had this task for through holes, I would just drill in 9" from each end on the lathe. The end holes would be centered and the meeting point at the center would be very close.

Quote:

---

Originally Posted by Lee Niemiec

Thanks Ray . . .

. Even a small variation in angle over 18 inches creates a noticable problem.

Y

And if nose augers do bore straight, then I would like to use some highly figured Bigleaf maple. A glue joint in such would be visible because the grain patterns would never match.

As I am new to this forum, I am also wondering if I should not have posted this thread in the Metalworking forum ?

---

I do not know what you are drilling this for but one other method involve drill the hole end to end and then machine the blank to true the hole to the outside of the blank

What Ray means is to make the outside diameter grossly over size,drill the hole,then turn the flute between centers (centered on the hole) to get the outside perfectly aligned with the bore.

I detailed a fairly simple to maintain and make shell auger in the second half of this rather long blog entry, How to Make an Octagonal Handle, Shell Auger and Straight Drilling Guide.

http://toolmakingart.com/images/Shel...er%20divot.JPG

http://toolmakingart.com/images/Shel...er%20point.JPG

With the concave part just touching the center of the rod, and the bevel sloping away from the leading edge caused by the bevel and concavity, this shape is easy enough to file sharp and restore angle to.

Since I wrote that article, I have put a point like this on a few nicely fluted long drills so that they deal with shavings better while cutting straight holes. I still need to clear chips constantly to prevent drift, but not quite as constantly. If straight matters, then chips need to be removed well before they pack.

As far as angle goes, this version is practically a scraper. Not fast, but it does cut fast enough to make me feel like I am constantly clearing chips, so a more aggressive bit would do me no good. This bit not only leaves a straight hole, it also leaves a burnished smooth hole. If I were in production, then perhaps a more aggressive edge might be called for.

Bob

Ted: The hole(s) are blind which is the problem; especially so because I need to bore from both ends and have the axis of each hole aligned.
(I would have used the term "axes" to indicate the plural of "axis" but that was too confusing for even me.)

Bob: More or less I have created something similar for boring long holes in lamp blanks (going through the head stock of an old Rockwell lathe). It is almost certain that your tool design is superior to mine. With the tools I've made (and I have made at least four different variations on the same theme) I still get drift such that (with the lamps) the holes from each end are misaligned. These holes for lamp blanks need to be approximately 0.415" in diameter to accomodate the lamp rod/pipe which, as a hole, is considerably smaller than 0.75" or 1.00".

With the larger holes, it will be impossible to bore through the headstock of the lathe. The fixture I made with guides allows me to use a 1/2" chuck portable drill which I may or may not be able to use with a nose auger. It is entirely possible I will need to use muscle power with this tool (hense my interest in best tool cutting angles) because overfeeding (too great a bite) would almost certainly damage the tool and the frictional forces lead to metal expansion and that results in machine burn.

One of the key features of a nose auger is that it only has its cutting edge on its end and has no ability to do any side cutting -- the barrel of the bit acts as its own guide once the hole is started.

I have been attempting to resolve this issue for some thirty years. It started with any early book I purchased on turning ("The Practical Wood Turner" by F. Pain [published 1979]). In Chapter 11 entitled Boring Holes, he shows the detail of a boring auger (a line drawing) and states: "Now the following is the quickest and best way of boring long straight holes that I know of. A judge, some prisoners, several ladies, and lots of boys have been sucessful at their first attempt. One boy at an exhibition does it blindfolded. . . . The boys put five holes down a 1.25" square thirty inches long, and three down a broom-stick, so it must be easy to bore one hole."

Quote:

---

Originally Posted by Bob Strawn

I detailed a fairly simple to maintain and make shell auger in the second half of this rather long blog entry,

http://toolmakingart.com/images/Shel...er%20point.JPG



Bob

---

If you was drilling a hole in a length of wood 18 " or longer, is the distance between the 3 boards keep the same ? your drill bit and the drilling board are a good idea

Quote:

---

Originally Posted by george wilson

What Ray means is to make the outside diameter grossly over size,drill the hole,then turn the flute between centers (centered on the hole) to get the outside perfectly aligned with the bore.

---

thanks you George

Quote:

---

Originally Posted by ray hampton

If you was drilling a hole in a length of wood 18 " or longer, is the distance between the 3 boards keep the same ? your drill bit and the drilling board are a good idea

---

The distances between the boards can and should be altered by the application. The space between the center hole and the target divot needs to be large enough to accommodate the item being drilled. The space between the hole at the chuck end of the drill and the middle hole provide an accurate reference.

There are a few lamp augers available, such as these. I have a few, but prefer my hand made ones as they are much easier to sharpen. The designs normally sold for use on a lathe, cannot be sharpened much before they are ruined. If you have to fix a ding in the cutting edge, you probably need to get a new one. The design I show is easy to sharpen and can be sharpened over and over.

Peter Child has a better guide for using one on a lathe, but it would be even better if the hole were elongated and a live center could spin on the end of it.

To make a nice big hole, first you make a small hole and use a pilot to guide a larger counter bore.

For example, if I had a 5/16" lamp auger and wanted to make a nice 3/4" hole, first I would drill the 5/16" hole. Then I would use a counterbore with an interchangable pilot. Enco's 368-1048 counterbore with a 368-3320 pilot would probably do the trick. Going slow and cleaning the tool and the hole regularly is required. Keeping all the tools and the wood being drilled cool is also a very good idea. heat and steam can distort wood, so taking time and letting things cool off as you work is a very good idea. You will also need to come up with an extension on the counterbore since the hole needs to be deep.

Bob