Vintage Axe Reprofiling

E

electricfax

Joined
May 19, 2013
Messages
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Hey guys, I wanted to ask for your opinions.. and maybe some pictures from more experienced members on axe bit profiles. I dont have any gauges or anyway to measure my angles. Ive just been going at it by eye and trial. These two axes seem to work for me, but im curious if theres anything im missing or could do better.(Mainly im looking for approval or criticism to make sure im doing this correctly) Im not very knowledgeable in the field but i like to use the vintage axes i restore. The top pic is of a kelly Ct pattern and the bottom an e&s mfg co. Ct pattern. Let me know what you think and maybe post up some pictures of your axes? I appreciate guys

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Download this: http://www.fhwa.dot.gov/environment...lications/fs_publications/pdf/pdf99232823.pdf

Print off page 29 (the one with the gauge template). Make sure to set your printer scaling to "none" or "100%" so that its to size. Setting it to "grayscale" and "print as image" might speed things up if you have an older printer like me. Then just find something like cardboard or really thick paper and just glue that sucker on there:
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Use a really sharp, thin bladed knife (exacto or the tiny blade of a swiss army) to cut the inner portion of the gauge itself. The outside I just did quickly with a pair of scissors since they're not as critical. And there we are!
20140522_1633551_zps121a1e32.jpg


Anyways, I'll post up in awhile with how it fits on my favorite user axe (a 3 lb Keen Kutter Jersey) as well as on my newly acquired and refurbished 3.5lb Kelly Flint Edge CT :thumbup:
 
Hope this isn't hijacking the thread, but I've been meaning to ask a couple of questions re the banana grind specifically.

1) does the banana grind eliminate the advantage of a high centre line? I feel like it probably doesn't, but I don't quite understand.
2) how the heck do you file this grind without the file making contact with the cheek farther back towards the poll?

thanks
 
Wdmn- That's why I don't use full banana grinds. My thoughts exactly on both points, but I know someone here can answer better.
 
Killa, awesome! And thankyou. Ive been searching and seen photos of the profile gauges but was unsure of which ones were still being used and wether or not they were scaled or not
 
My suggestion would be to get a digital caliper. I recently did and even though the display on it don't work (will be getting a new one as soon as possible) it is still a great sharpening tool as it basically takes the guess work out of it.

Close to being filed flat

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I tried to catch a top view, but my camera won't quite let me

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wdmn said:
Hope this isn't hijacking the thread, but I've been meaning to ask a couple of questions re the banana grind specifically.

1) does the banana grind eliminate the advantage of a high centre line? I feel like it probably doesn't, but I don't quite understand.
2) how the heck do you file this grind without the file making contact with the cheek farther back towards the poll?

thanks
Click to expand...

1) The point where an axe binds is beyond the banana grind. Shallow cuts don't have a problem with binding.
2) If the file makes contact further back then let it - remove some more material. But double check that you're angle isn't too shallow.

I like the banana grind to continue about 3/4" to 1-1/4" back from the edge.

Here's one on a vintage Plumb rafter which I really like. Of course I had to touch this one up but it came with this very nice shape.

3-Banana%20grind.jpg


Here's one I recently did for a buddy.

2-Banana%20grind.jpg
 
wdmn said:
1) does the banana grind eliminate the advantage of a high centre line? I feel like it probably doesn't, but I don't quite understand.
2) how the heck do you file this grind without the file making contact with the cheek farther back towards the poll?
Click to expand...


No. Compared to a radially sharpened axe with a high centerline, for example. The high centerline doesn't accomplish anything if the axe doesn't bite deep enough for it to do it's job. An axe with a well done "banana grind" wouldn't make a very good splitting axe, but for biting deep and still throwing a chip it will function on a bell curve much farther than most people here seem to go before becoming problematic.

A lot of times my filing scuffs up the upper part of the axe. If you're filing an unhung head, so you file off at an angle with success, but I find that harder with there is a handle in the way.
 
Does anyone file the "banana" profile with the file running toe to heel? Filing along the bit as opposed to perpendicular?

I do not claim to be good at the banana but for my version of thinning, this work easier to me.

Bill
 
Thanks for the helpful answers. I will worry less about taking material off of the cheek/poll, and also reassess the angle I'm filing at in case it's too shallow... thanks to killa_concept for the directions on creating a gage, which will help with that.
 
lmalterna said:
Does anyone file the "banana" profile with the file running toe to heel? Filing along the bit as opposed to perpendicular?

I do not claim to be good at the banana but for my version of thinning, this work easier to me.

Bill
Click to expand...

Not a banana grinder myself, but I do use a technique similar to draw filing on the edge, I.e. running a single cut file along the edge at a 45 degree angle (NOT the bevel angle). Leaves a nice smooth finish.
 
lmalterna said:
Does anyone file the "banana" profile with the file running toe to heel? Filing along the bit as opposed to perpendicular?
Click to expand...

I don't. I think the proper filing stroke is with the filing pointing at an imaginary point near the poll that would be the center of the radius of the arc of the bit.

Confusing enough? Let me put it another way. Aim the file near a point at the back of the eye halfway up the poll. Clear as mud now? :D


Also, change the angle of your filing stroke near the corners of the bit to create a wider angled edge bevel at the corners (the heel and toe of the bit). The heel and toe are the weakest points on the axe since the steel is supported from only one side whereas a point in the center of the bit is supported on both sides. The heels and toes can easily be dulled, chipped or rolled on a hard knot. A more robust (thicker) edge angle helps protects against this.
 
When I file I start at the heel, pushing the file straight in to the point on it and then working myself towards the toe while keeping the angle. When one side is done I flip it over and do the same thing, while switching hands on the file.

marcuspics111_zps964132db.jpg


That is a smaller head than I'm used to so I scratched it pretty badly, but you can clearly see how its filed.

The bevel is very uneven, but it is not difficult to make a reasonably straight and even edge. I just fixed that one up quickly for my son to try out. The first thing he did was hit a rock.

If you keep a constant angle and the cheek is convex at all, the bevel will form an arch. Idk if that is what is meant by "banana grind", but this is what it looks like.

marcuspics034_zps79bb136b.jpg

(excuse the knife)

And I never make an effort to make the heel and toe thicker, simply because I have never been able to damage an axe beyond the secondary bevel except when hitting rocks and then the edge will get pushed in regardless of how thick it is, if it is thin enough to cut wood. So for me it is not worth it to sacrifice any cutting ability.
 
KingKoma said:
..... I have never been able to damage an axe beyond the secondary bevel except when hitting rocks and then the edge will get pushed in regardless of how thick it is, if it is thin enough to cut wood. So for me it is not worth it to sacrifice any cutting ability.
Click to expand...


Be thankful that you don't have to deal with hemlock knots. An axe should be tuned for the expected cutting conditions.

http://www.fs.fed.us/t-d/pubs/pdfpubs/pdf99232823/pdf99232823Pdpi72pt06.pdf

"A word should be said about hemlock knots. These knots are very hard, especially on dead limbs. It is sometimes better to break off small limbs with the poll of the ax than to try to chop them. It is easy to take a huge nick out of the ax bit by swinging too hard at right angles to a hemlock limb. This is more likely to happen in cold weather, when the ax is more brittle. In such cases, warm the ax bit before using it on such limbs. If possible, use an ax with a blunter taper than you would for ordinary chopping. As a final precaution, chop lightly at an angle to, or with, the grain, and do not attempt to twist out the chips."
Click to expand...

Western Red Cedar knots can be equally hard. For me it's not a sacrifice but rather a necessity to keep an axe in good cutting condition.
 
Square_peg said:
Be thankful that you don't have to deal with hemlock knots. An axe should be tuned for the expected cutting conditions
Click to expand...

I don't think I ever will be thankful for that, missing all those awesome tree species is one of the few drawbacks of living where I do.

But yes, it's a good idea to profile your axe for the work you plan on doing with it. I do that equally across the length of the bit, because the most damage I have ever done to an axe is on rocks and when that happens I haven't noticed much difference if I have filed it thin or left it thick. So for me it makes sense to get as much penetration as possible and not worry (much) about durability.

If you have an axe that you plan on limbing hemlock with, do you leave the heel and toe thick and grind the rest thin?
 
wdmn said:
Hope this isn't hijacking the thread, but I've been meaning to ask a couple of questions re the banana grind specifically.

1) does the banana grind eliminate the advantage of a high centre line? I feel like it probably doesn't, but I don't quite understand.
2) how the heck do you file this grind without the file making contact with the cheek farther back towards the poll?

thanks
Click to expand...

1) From my experience, I'd have to say no. When I swing a properly reprofiled axe, the bit tends to penetrate well past the grind point. And it's mostly the back-most portion of what's going into the wood which causes binding or chip throwing. On my axes, the banana grind doesn't extend much more than 1.5" - on my main user, it only extends about 1". If you're keeping the bit reasonably thin (that's where the gauge comes in), you should easily be getting that much penetration into the wood. Also, just because it's being banana ground, doesn't mean that it's making the bit flat there. On almost all of my axes, the banana ground area still maintains some level of convexity/high centre line.

2) I do occasionally end up scraping the back portion while filing. If this ends up being the case and the bit isn't reasonably thin enough for my tastes, I'll start filing at an angle. You can see the 45 degree stroke marks on the Kelly Jersey Perfect in this photo:
20140202_211739_zps46416cd5.jpg


In all honesty when it comes to penetration, the type of grind isn't really as important as how thick the bit is at certain points from the edge. If you follow the gauge I linked above, it's essentially saying that 3/4" back from the edge, the axe shouldn't be thicker than 1/4". I think that's a perfectly reasonable suggestion for a felling or general purpose axe. With worn down axes, you'll generally have to do more filing to adhere to this rule of thumb. That's why my 3 lb Keen Kutter Jersey (which seemed almost unused when I got it) only has a grind line that extends 1" while my 3.5 lb Kelly Perfect Jersey (which was a bit worn down) has a grind line that extends about 1.5-1.75".

Grind lines become more aggressive the more you have to compensate for the worn down state of a tool. This idea is just as applicable to knives as it is to axes. If we say that (fig 1) is the optimal thickness a certain distance behind the edge, then when the tool wears down from use (fig 2), we have to regrind fairly far back to establish the same optimal thickness and shape (fig 3). A lot of material ends up having to be removed from the cheeks on a worn down axe if you want it to perform closer to its original state. A lot of times I hear people talk about adding a relief angle to a worn down edge and that's pretty much the same concept.
Reliefedge_zps17179fe1.png
 
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KingKoma said:
If you have an axe that you plan on limbing hemlock with, do you leave the heel and toe thick and grind the rest thin?
Click to expand...

Exactly. And they're not really 'thick' they're just filed at a little steeper angle. You don't even notice the difference when chopping. My old Stiletto double bit has one entire bit sharpened for durability rather than maximum penetration. That's my go to limber. It might be the toughest axe I have.

My Pulaski is always sharpened as described above (thick heel, toe) as it may encounter limbing work at any time. OTOH, my bucking axes are sharpened for penetration the entire length of the bit with just a minute thickening at the heel and toe. With those I just avoid large hard knots. When juggling a timber if I have to cut through a hard knot I just make sure to use the center of the bit and never the heel or toe.
 
Thank you k_c.

One other question though I know this has been talked about before so i'll direct the question to k_c and square_peg specifically: for larger reshaping jobs when you have to remove a lot of material do you use a double cut file?

thanks
 
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