sharpening augers

[smojo]

Picked up some old scotch eye augers on car boot sale. Cutting tips not too badly worn. I have tried to sharpen them using small files and keeping to original angles got the edges pretty sharp. Tried them on some scrap sycamore but they still rip the grain as they cut across. Anyvtips/suggestions to get them cutting clean?

 

[Dave Budd]

what style of tip is it? There are quite a few tip formats and they all need different treatments

If it is the most common and modern style, then you will have a cutter and a nicker. The cutter is the horizontal blade that removes the wood and is sharpened on the screw side only. The nicker cuts the outside circumference of the hole allowing the cutter to sever a disc (well, spiral) or wood; it is sharpened on the inside of the auger only and only really the leading face/tip

You could use a diamond file instead of a file, but a smooth or second cut file is normally fine enough

 

[Robson Valley]

Paint the bevels with black felt marker first = reliable indicator of your sharpening activity/bevel angles. . . . . .

 

[Fraxinus]

This video might help, I thought I'd find one for you that shows how I was taught to do it, except for the valve grinding paste idea that's a new one on me so thanks for asking the question.

[video]https://youtu.be/MSbN5bhKVAw[/video]

Rob.

 

[smojo]

Thanks guys. They are the cutter and nicker style as you described Dave. Pretty much followed what the guy is doing already. Maybe I just need to sharpen a bit more. Will have another go and see if any better.

 

[Dave Budd]

maybe show us a picture of what you've done, so we can help work out why it's not sharp

 

[smojo]

I was wrong about the cutting style. Its not like modern ones. I'll try get some photos on. Would love to get them cutting cleanly

 

[smojo]

Some photos. I tried it on some semi seasoned hawthorn and it cut through OK but the edges or the hole were ragged and ripped suggesting that the nicker part of the bit wasn't doing its job well enough even though it's pretty sharp. I'm guessing that the edge that cuts the meat of the wood out might need to be filed so that the edge line is a slight concave rather than straight so that the corner of nicker part (where they meet at right angles) cuts into the wood first to score a circle. At the moment it is pretty straight. The other thing I guess is that the actual cutting bevel needs to be as flat as possible (like a wood chisel) (not rounded) although by nature it tends to be rounded as it spirals up the drill shank. So far I have removed very little metal as it wasn't badly chipped and still reasonably sharp. Suggestions on correct sharpening of this type welcome please. Ta

 

[mrcharly]

It could be a trick of the light, but those edges don't look sharp at all. A sharp edge doesn't have a line of light reflecting off it.

 

[wattsy]

is there an existing bevel on the horizontal cutters? it looks like you've sharpened the bottom of them when there's usually a bevel on the top

 

[Fraxinus]

Don't quote me on it but... that looks like a version of a gedge or scotch pattern auger, which are designed for rough work or end grain. The upward pointing wings are designed to slice off splinters rather than prevent them (not that downward wings do a great job of it every time btw ) but need to be sharpened on the inside face and the main cutting edges are sharpened as per the video I linked to before.

Rob.

 

[smojo]

Thanks everyone

It could be a trick of the light, but those edges don't look sharp at all. A sharp edge doesn't have a line of light reflecting off it.

well they're not razor sharp like a knife but I didn't want to take too much off till I knew what I was doing

is there an existing bevel on the horizontal cutters? it looks like you've sharpened the bottom of them when there's usually a bevel on the top

No bevel on the bottom, it just follows the natural curve. It looks that way because I just took a small amount off to remove the surface rust but didn't carry it on very far. Most of what I took off (and that wasn't much) was on the inside.

Don't quote me on it but... that looks like a version of a gedge or scotch pattern auger, which are designed for rough work or end grain. The upward pointing wings are designed to slice off splinters rather than prevent them (not that downward wings do a great job of it every time btw ) but need to be sharpened on the inside face and the main cutting edges are sharpened as per the video I linked to before.

I just did quote you didn't I? Thanks for the info I'll see what Mr Google has to say about Gedge. Ah I found this link. http://www.theluddite.com/auger_bits.html

The gedge pattern (first in the link picture) has curved over cutters and is mainly for end grain but mine isn't that pattern, it looks like the second to last described as a Scotch pattern. So it seems it's meant for rough work on hardwood and probably never gives a particularly clean entry hole. I think I need to do a bit more sharpening on the inside edges and see how that goes.