Hi all
I am new to the Tormek community having recently plunged for a T-4 Bushcraft. The free Gransfors Axe pushed me over the edge! My main interests (in wood terms) revolve around greenwood working. I am part of a small charity in southwest London that promotes these activities (amongst other things) within the community.
So far I have managed to successfully sharpen up some old chisels I bought off ebay for the very job of practicing and even managed a gouge.
My questions will be myriad, no doubt, and I will try to ensure that I sure the search function first.
Next job is to to sharpen up the Gransfors. The single, convex bevel looks like it might not last if I use the axe jig...
Ian
Welcome to the forum, Ian. You have come to the right place.
How long will the edge last on your ax? I don't know; however, here is a thought:
This thought started with thinking about truing my grinding wheel. I think it can apply just as well to ax edges. Please cut me some slack with the math portion; it has been over fifty years since my high school math classes.
Imagine a two axis graph. The vertical Y axis represents grinding wheel trueness or edge sharpness. The horizontal X axis represents usage time. Start with fresh truing or sharpening, 100% on the Y axis. The X axis starts at zero usage time. Record sharpness points at consistent usage periods. Do this long enough to record several sharpenings. Tally up all the sharpness points to calculate the average sharpness.
Each time you sharpen, the vertical point returns to 100%. Frequent, light "touch up" sharpenings will translate into a higher average sharpness. For a non math person like me, that means easier, more pleasant cutting.
That's my not very scientific idea (which might actually work). Your Tormek is the ideal tool for controllable, repeatable sharpening. You need sharp tools. Try the program. Tormek and Gransfors are both respected companies; the program might work.
Keep us posted.
Ken
I think that the OP is concerned with losing the convex bevel as the wheel will give a slightly hollow grind. I really don't think that the small amount of concavity will make any significant difference.
Willym,
I understand what you are saying. However, I think the grind issue for axes is a more complicated issue. Axes, like chisels have several designs for different functions. I would want a more substantial (convex) edge for a full size ax with a heavy head being used to chop down trees and/or split wood.
The Gransfors hand ax (hatchet) sometimes used as a promotion with Tormek is designed for lighter work. The head is lighter and the handle shorter. It does not have the power of a full size ax. It is better suited for light trimming, carpentry, or spoon carving. The ax jig is discussed at the end of this online class:
https://youtu.be/QlScXCdisAo
Ken
Thanks both.
Willym is correct in that I meant that I will lose the convex shape when sharpening with the Tormek. It's a pleasing shape but one I may need to sacrifice for the sake of sharpness.
Anyhoo - looking forward to trying out the various jigs I have bought and getting the best for my tools.
Quote from: IanO on October 14, 2021, 05:50:07 PM
...snip...
It's a pleasing shape but one I may need to sacrifice for the sake of sharpness.
...snip...
Its been a while since I worked on any axes/hatchets. I wonder if you can't preserve most of the convexity, using a file, and only put the concavity, using your Tormek, into a narrow margin/bevel right at the apex in order to achieve the sharpness. That probably means a larger angle, but it isn't a knife bevel.
Rick
I think one of the issues we face is that the majority of illustrations we see showing concavity are greatly exaggerated so the viewer can easily see what is being described. It has been my experience sharpening a few axes that not much material is removed and it will take many sessions over a very long time before you notice anything. I would watch the Tormek video on axe sharpening.
https://www.youtube.com/watch?v=QlScXCdisAo&t=2185s
Welcome to the forum.
Very good post, John. I had to be up most of last night. To help pass the time, I studied several of the online class videos, including the ax video. There is much to be learned from that video.
A well prepared Tormek sharpener who sharpens axes needs to know about more than using the jig. Axes come in various sizes and have various functions. Believing that all axes should have a convex edge is an oversimplification.
Knowledge is power.
Like you, I find the exaggerated diagrams annoying. Six inch grinders went out with three speed vehicle transmissions. Using them to illustrate (concave) hollow grinding is deceptive. When I was testing CBN wheels with eight and ten inch Tormeks years ago, I ground a lot of chisels bevels. (I have a dozen Irwin Blue Chip 3/4" chisels for testing and practice.) I had trouble finding much concavity in the chisel bevels.
I have probably sharpened as many axes as some of the the concavity versus convexity "experts", and I have never sharpened an ax. I debated whether or not to buy the ax jig for ten years before I finally broke down and purchased one. I have never used it. Don't take my word for it. Base your decision on your own sharpening and actual use.
Ken
Various methods can be used.
Do you have a belt sander or a buddy with one? The "slack" portion can put a convex shape on your axe then as stated above the edge can be done by other means.
Here is a link to a PDF download of "An Ax To Grind" by Bernie Weisgerber and developed by the USDA Forest Service. I have found it to very informative and helpful. The discussion of sharpening begins on about page 27 of the booklet.
https://www.google.com/url?q=https://www.fs.fed.us/t-d/pubs/pdfpubs/pdf99232823/pdf99232823Pdpi300.pdf&sa=U&ved=2ahUKEwj-qcPnscvzAhUynOAKHffSAH4QFnoECAsQAg&usg=AOvVaw3WA8YCZpFecsmmWJi-Ou3j
Quote from: Elden on October 15, 2021, 04:09:27 AM
Various methods can be used.
Do you have a belt sander or a buddy with one? The "slack" portion can put a convex shape on your axe then as stated above the edge can be done by other means.
...
https://youtu.be/1Gt_J9PXa-U?t=105 (https://youtu.be/1Gt_J9PXa-U?t=105)
Elden & CB,
Great info. Having been reminded of the belt sander, I would definitely do it that way, over the Tormek. The OP, however, probably doesn't have one.
I saw a video a couple years ago, that I think Ken S. posted about, that went into great detail about the different kinds of axes and their uses. I don't do many axes, but found it very interesting and entertaining.
Rick
Just out of curiosity..........
Has anyone determined, based on actual hands on sharpening, that the combination of the Tormek and SG-200 is not capable of producing a long lasting edge with the small Gransfors ax?
Ken
Ian,
I believe this is the model of the Gransfors ax included with your T4 Bushcraft:
https://www.boundarywaterscatalog.com/gransfors-bruks-inc/gransfors-bruks-hand-hatchet-5775
This looks like a very practical ax for many purposes, perhaps more practical for most people than a full size ax.
I hope you get a lot of happy use with it. As with any edge tool, your best use will be from light resharpening before it really gets dull.
Enjoy and keep us posted.
Ken
Thanks for all the tips and info everyone.
@Ken - yes, that is one of the axes I have. I also bought a couple of old axes from ebay to practice sharpening with. Going well so far.
Ian
Ian,
You have the tools you need to move forward. At this point, increasing your knowledge base will assist your experience. I recommend two resources highly:
The Complete Guide to Sharpening is one of my longtime sharpening library staples. The author, the late Leonard Lee,
was the founder of Lee Valley/Veritas. He grew up on a farm and was no stranger to using axes. It has been my go to reference for over twenty years.
The second source is the Tormek online classes. The entire series is well worth studying. I especially recommend the T4 Bushcraft class and the Scissors/Axes classes. Wolfgang Hess does an outstanding job of demonstrating using the Tormek for both concave and convex grinds. Highly recommended.
Keep sharpening!
Ken
Starting at 1:02:00 there is a good demonstration/ discussion of concave and convex grinding.
https://youtu.be/7eCDSZ2PHU0
Ken