Dear Tormek Forum members,
As per tradition we wanted to give you guys a little pre-information: Tomorrow on September 17 at 3 pm Swedish time we are saying goodbye to an old friend - the SVA-170 Axe Jig is retiring (finally, frankly) after a long and loyal service. We look forward to new and exciting things! Stay tuned ;D
/Hugo from Tormek
Thank you for posting, Hugo. We are eagerly awaiting online class #25 tomorrow
(Sept 17 at 9:30 EST).
I hope you can provide some history about the present SVA-170 jig, such as when it was first introduced and if it was the first Tormek Ax jig.
Ken
Can't wait! Axes is what brought me in to sharpening in the first place, and although some axes fits perfectly in the SVA-170, most doesn't.
Looking forward to what all the clever people at Tormek has come up with.
I'm guessing the new product launch email I just got is related to this.
I have sharpened many hatchets and an axe in my short time using the Tormek. One had about a 3 mm round over on the edge. This latter was being used by my son's neighbour who was wondering why it was not cutting. TBH I will not miss the old Axe jig. Not a huge fan.
In case anyone is having difficulty finding the new online class, here is a link:
https://www.youtube.com/live/5cll8S5zx8E?si=2NQs8P00naKRFO_6
Ken
I just watched the new online class. I am impressed with the new AX-40 axe jig!
Once again, the Tormek Development Team has cleverly built on innovations from previous other jigs to build a better product. Well done!
Ken
Quote from: Ken S on September 17, 2024, 04:54:05 PMOnce again, the Tormek Development Team has cleverly built ...
I agree. Just watching now and this will definitely be added to my jigs. Looks nice.
A review from Sharpening Supplies
https://youtu.be/b-q53A8-qBg?si=J-XZAVVJKV5acz2Y
Nice to see some familiar names mentioned from the chat.
Mine is on order!
This looks like a fine piece of hardware.
Still, I am as ever skeptical of the convexing ability of the dual-stop mechanism. For small bevels, I don't think it matters, but on large bevels such as axes or hatchets ?!? Removing the marker further up is no guarantee of convexity, and with the time spent grinding the edge in the first place, Sebastian for sure did not significantly change the geometry of the bevel.
If the material is hard it will take forever, and if the material is soft the result will be quite random.
I'm not even sure the result is guaranteed to be convex : To convex it properly in such a fashion, one would have to master the time spent at each angle and therefore at every point in between the stops. By going up/down/up/down, shlak/shlak/shlak/shlak, who says the end result is not something akin to the attached drawing ? Probably compounded with a less homogeneous finish along the edge axis...
Dimensions are obviously not to scale to increase curvatures, but I don't see a physical reason why it wouldn't end up like so. Or even something that remains concave, although to a lesser extent than when sharpening the edge only.
IMO, if convexity matters, a belt sander is the way to go.
Tgbto,
I respect your thoughts as an experienced. However, with the AX-40, I don't see where any of us have enough actual work time with it to offer more than initial impressions. I will look forward to reading your thoughts after hours of use. I will also anticipate your thoughts on flat grinding with the AX-40.
Ken
I have been mulling over TGBTO's comments on convexing. In my opinion, his ideas seem more applicable to the professional than to the home axe user. Just after sixteen minutes into the online class, Sebastien makes an interesting comment. He states that when he wants to use his axes for splitting instead of convexing the edge, he just makes the angle broader. We have seen this before when users were concerned about hollow grinding. To counteract the hollowing effect, they would just add three degrees to the bevel angle. With his axes, adding a few degrees to the bevel angle is not really the same as convexing; however, for occasional home and general use, it seems an adequate substitute.
Ken
Quote from: Ken S on September 20, 2024, 10:39:44 PMTgbto,
I respect your thoughts as an experienced. However, with the AX-40, I don't see where any of us have enough actual work time with it to offer more than initial impressions. I will look forward to reading your thoughts after hours of use.
Ken
Ken, physics don't care whether or not I have hours of use with the new jig. In the same way that I see, from a physics point of view, why the Tormek is very good at constant-angle grinding, I also see why this convexing stops thing will yield a random result, both in terms of actual convexity and variability of the result along the edge.
If you think of it in a dispassionate fashion for a few minutes, you will see that no matter how ideally you use the jig, the tip area of the edge will always be somewhat concave because the wheel is actually convex. I'm afraid Physics are more stubborn than either of us, and they know no such thing as first impressions.
That being said I have given a shot at "convexing" for several hours with the KJ jig, and it felt painful enough that I don't see the interest in trying it on a significantly more massive blade. I (convex) sharpen axes and lawnmower blades on my cheap belt sander in much shorter a time than I ever would on a Tormek. Not to mention adjustable convexity by playing with the slack of the belt.
If the Jig on the Tormek is that good at convexing, I don't see the point in the "broader angle" workaround. And I'd rather discuss whether or not (or when) convexity actually matters, rather than "yes we do convex, but you don't actually need it that much, right ?"
Once again, the Tormek excels at precise, slow, wet, constant-angle hollow grinding. A belt sander excels at less-precise, fast, dry, somewhat-constant-angle convex grinding. One could also mention bench stones, rod sharpening systems, bench grinders. They are built differently and that's the only thing that matter to physics, so they perform differently and one should choose one over the other based on that.
Bending over backwards to pretend otherwise reminds me of the debate we had on the AngleMaster for knives where the error "didn't really matter" before the AngleSetter was introduced.
Quote from: Ken S on September 20, 2024, 10:39:44 PMI will also anticipate your thoughts on flat grinding with the AX-40
I'm not sure this is relevant to the issue of how well the SVA-170 can convex a blade. But here goes : my thoughts are that it is a much more sensible way of sharpening a blade than the convexish-able thingamajigs mentioned above... If one can afford an additional multibase and diamond wheels. Sparing a diamond wheel (let alone two) will pay for a nice belt sander, so flat-grinding with a SVA had better not be the reason behind the purchase.
In a nutshell : I'll gladly sharpen a ceremonial Viking-style axe on a Tormek with a SVA-170/SG/SJ combo, and not care about Convexity. If I did care about convexity (and probably also speed especially when repairing a worn out axe), I'd stick with my belt sander.
TGBTO,
Your posts are both logical and diplomatic; I appreciate both.
When the KJ-45 was first introduced, I was pleased to see Tormek finally producing a self centering knife jig. The convexing and ability to handle cleavers struckme as after thoughts. Not bad thoughts, but not main attractions. I admit I may be biased by sharpening conventional kitchen knives almost exclusively And by already having a US-430 support bar. In my opinion, the US-430 is the better tool for cleavers. However, the KJ-45 seems an adequate tool for these functions.
I have been surprised with the small number of posts about convexing with the
KJ-45. I am pleased with the increased holding power and flexibility of the AX-40 and somewhat surprised by the lack of forum chatter about convexing with it. Time will tell if interest in convexing picks up.
Ken
Quote from: Ken S on September 23, 2024, 04:26:55 PMI have been surprised with the small number of posts about convexing with the KJ-45
When I sharpened my hatchets and axes by hand I would always convex since it was really easy, not for any other reason. I know professional competitors will hone their axe face to ultimate precision but for me it is pretty much "get it cutting". I got to the point where I could shave with the axe pre Tormek but that took so long. Now I can get the same result in a fraction of the time and am soo looking forward to trying out the new jig.
For me the idea of concave vs convex vs flat is a moot point.
Well said, John.
Ken
I've tried AX-40 now for a few days, it's really a gamechanger when it comes to axe grinding. The jig is so secure on the head, and pivots and tilts with ease on the universal support. Splitting axe up to 20 cm/8 in was no problem at all and produced a very solid result. Another win for the Tormek team :)