Dodd's Pattern Shell Augers

[xy mosian]

A recent thread about of Jimi's, about Gouge Bits, drifted over to mention shell Augers. This reminded me of mine. I do not often come across people who think these mildly interesting so I'll show them here.

I was looking for one of a particular size many years ago and came across this bunch at a very reasonable price. As I knew there were basically none to be had I bought the lot, including some duplicates. I have used the 1 1/8" and the 1 3/4", sorry 28mm and 44mm for you younger folk, both through a hollow tailstock on a lathe. I suspect some of the others have never been used.

The list:-
2", 50mm, Brades Co. x2
1 3/4", 44mm, Brades Co. x1
1 3/8", 35mm, Brades Co. x1
1 1/8", 28mm, I. Sorby x1
3/4", 19mm, I. Sorby x1
3/4", 19mm, Wingfield x1
5/8", 16mm, I. Sorby x2

Interestingly the two 5/8" Sorby's use a different size of marking punches, but are otherwise very similar.

xy

 

[Alf]

Oo, very nice, XY. I can't believe many folk have a range of shell augers at their disposal; you may be on a Slope all your own! Does my boring heart good to see them; thank you.

 

[AndyT]

There was some loose talk on here a while back about re-enacting the scenes in "The Village Carpenter" where they bore out elm trunks to make water pipes and pumps. I reckon with a collection like that you could make a good start on the smaller sizes!

 

[toolsntat]

There was some loose talk on here a while back about re-enacting the scenes in "The Village Carpenter" where they bore out elm trunks to make water pipes and pumps. I reckon with a collection like that you could make a good start on the smaller sizes!

Mmmmm, loose was as far as it got :lol:
village-pump-auger-set-up-wanted-please-t50974.html

And yes , nice set of augers indeed 8)

Andy

 

[xy mosian]

Thanks all.
I've read Rose as well and I must admit to fleeting thoughts of making a pump for the water butt. As with so many thoughts nothing came of them. One of the snags of using shell augers, as with flatbits and twist augers, is that it is not possible to creep up on the required diameter. No chance of using increasingly large diameters of bit. I have tried out that 2" bit but it takes some long handles to use it, for me at least. If I recall Rose mentions adjustable augers which rather shave the outside of the hole they are in rather than the end cutting action of these shell augers. I must look up that chapter again. I cannot imagine my needing to use any of these again but I am lothe to get rid of them.
xy

 

[Richard T]

Lovely bunch there.

How do (did) you start them Xy? And how was the bite? The cut on my 1 - 1/4" looks like about 1/16" and that is over more than half the circumference. That's why I thought they were probably best for green wood - Ican't imagine mine cutting into anything hard very easily.

 

[xy mosian]

Hi Richard.
Starting, I have only used mine through a hollow tailstock, on a lathe, so I suppose the 'hole' was partly defined. A shallow gouged hollow or a shallow flatbit hole would do as well I suppose.
Bite - Cut. I am not one hundred percent sure exactly what you mean, but the offset of the cutting edge to the trailing edge is 5-6mm on the 2" and 4-5mmm on the 5/8" if that's what you are after.

I think you may well be right about the green wood. Or, I can say they work very well in end grain Central American Mahogany. I have not checked, yet, but I think they would chew up long grain badly.

When I bought them I was appalled that Record had just stopped listing them, believing that meant the only ones to be had, new, would have to be blacksmith made. Taking development back substantially. The more I think about the use, as above, the less use I can find for them. Other than water pipes, wheel hubs and long holes in columns. My use was a thirty inch long hole in a music stand column. Since then I have come across a chap who brazes a bar to the back of jobbers series twist drills for long holes. I have not done a comparison but I suspect his long holes have a poorer finish.

xy

 

[jimi43]

Ooooo errrrr XY...how fantastic.

As ALF suggests...I doubt many have one let alone a set!!

How does one sharpen them? #-o

Jim

 

[AndyT]

How does one sharpen them? #-o

Jim

Very gingerly, on the turned over end that does the initial cutting, with a fine file or slipstone. The disadvantage of this design was that they could not be sharpened very many times without reducing the available metal at the end. However, file it away entirely and you are left with a shell bit, which is still serviceable - that could be why shell bits are commoner than nose bits.

 

[Richard T]

xy wrote: "Bite - Cut. I am not one hundred percent sure exactly what you mean, but the offset of the cutting edge to the trailing edge is 5-6mm on the 2" and 4-5mmm on the 5/8" if that's what you are after."

Just the depth of slice really - the angle of aggression. I've struggled with big lead screw bits with very aggressive threads and cutting angles in big mortices and my first thought about these was that no screw = less bite, but thinking about it, it's still a screw .. though a very shallow one, it's a much wider one... like a very slow helter skelter.

Anyway, I should sharpen mine up and find out for myself.

But how to ... Jim, I'm tempted to cut a tapered sliver of wood and stick some emery to it to get down into that tricky cleavage; a slip stone is good for the majority of that edge but the last bit disappears to nothing and a very thin thingy is needed.

Andy, you're right. I reckon mine is about half way through its life as a nose bit and half way to retirement as a shell. This must be the same for spoons too? Long live the shell/gouge - (literally) you can sharpen them down to the nubbin.

 

[xy mosian]

Sorry for the tardy response folks. Here is a link to a tip from Robert Sorby:- http://www.robert-sorby.co.uk/tip.htm
A quote from that site:-
"Use and Care of the Lamp Standard Shell Auger
Unlike regular augur bits which have a screw nose which pulls itself through the wood, Lamp Standard Shell Augers have a lip and flat cutting face to ensure that they cut straight and true. As a result it has to be pushed into the wood by the turner. The curve of the lip ensures that the auger runs centrally and is unaffected by either the grain or texture of the wood being turned. The leading edge of the shell serves to start the hole and is relieved on the outside to prevent binding. The form of the nose then allows the Augur to cut into the wood under steady pressure.
Great care should be taken when using a Lamp Standard Shell Auger. It is particularly important to avoid running the Auger through the wood and into the drive centre. You should avoid potential damage to the nose by preventing contact between the Auger and the long hole boring attachment in the tailstock.
You should frequently withdraw the Auger and remove waste wood. Failure to do so will lead to a build-up of wood in the hole which prevents the Auger from cutting and causes the wood to burn. This may in turn lead to drawing the temper in the nose of the Auger thereby causing permanent damage.
Sharpening of the Auger should be carried out with a degree of care to avoid removing too much metal from the nose. You only have a small amount of material to work with. Therefore you should never sharpen your Auger on a bench grinder.
With the Auger held vertically, use a flat diamond hone on the bevel of the nose. A few strokes should suffice. For the inside of the flute use a suitable slip stone or diamond hone. When sharpening move the slipstone to the left so that the leading edge is honed. Do not try to sharpen the outside of the Augur as clearance may be lost causing the Auger to bind in your wood."

For those not familiar with the shape of these augers, some more images, these of the 1 1/8" Sorby.

Best of luck with the mortices Richard, I look forward to hearing of your experiences.

xy