Duncan M Posted March 31, 2022 Share Posted March 31, 2022 I was cutting an axle today to make a hammer and I noticed some strange patterns on the cut faces. The pattern appeared on both ends of the hammer billet and I cut the axle with a horizontal band saw. If anyone knows what would cause this I'd be curious to know. Quote Link to comment Share on other sites More sharing options...
George N. M. Posted March 31, 2022 Share Posted March 31, 2022 My SWAG is that it is some sort of artifact from the rolling/extrusion process at the steel mill. If you had access to a metallurgy lab it would b e interesting to do a chemical analysis of the different zones. "By hammer and hand all arts do stand." Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 31, 2022 Share Posted March 31, 2022 That's what I was thinking George. I'd be tempted to cut a thin slice grind smooth and acid etch it. I'd keep the etched slice as a souvenir for sure. It suggests a catchy brand name too. "The Pattern Welded Axle Hammer." Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Goods Posted March 31, 2022 Share Posted March 31, 2022 I’ve seen that before and I took it as an effect of the actual saw cut, kind of like tooth chatter. Try making two cuts rotating 45 degrees between cuts to see it the pattern alway follows the cut direction. David Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 31, 2022 Share Posted March 31, 2022 That's not the pattern we're talking about David. Look for the lighter colored sort of football shaped semi circles in the steel itself. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Duncan M Posted March 31, 2022 Author Share Posted March 31, 2022 I had been wondering if it was caused in the production process, and was curious because I had never seen that before. would sticking a slice in white vinegar work to etch it, or would I need something stronger? Quote Link to comment Share on other sites More sharing options...
Randy Griffin Posted March 31, 2022 Share Posted March 31, 2022 Actually, I think that is called ghosting. It’s caused by the harmonics of the tool. In this case a saw. I’ll try and find some info. Edit-found this. Good explanation of what’s going on. If you measure the distance from the edge of the material to the edge of the "eye" along the cut lines, you will find that the distance is always the same. You will also find that this distance is also the same as the tooth-to-tooth distance on the blade of the band-saw used to cut the material. Essentially, the "eye" is just a "ghost" of the material edge shifted along the cut by one blade tooth and will match the shape of the material. Hex stock will make a hexagonal "eye", octagonal will make a octagonal "eye", and square will make a rectangular "eye". The teeth on the band-saw blade are slightly offset, in alternating directions from the center line of the blade. This is done so that the kerf (width of material removed) is larger than the thickness of the main part of the blade so that it does not (ideally) rub on the material and build up heat. The ghosting happens because as each tooth enters or exits the material, rather than cutting slightly to the side of the previous tooth due to its offset, the side of the blade not it the material flexes to the side causing the kerf to be narrower. On the entrance side of the cut, when the next tooth enters the material, the blade flexes to the other side giving the previous tooth sufficient support to cut offset from the blade center-line like it is supposed to. Once the tooth ahead leaves the material the blade outside of the material again flexes to the side such that the following tooth again rides it the center of the cut. If you were to carefully measure the faces of both sides of the cut, you would find that the kerf in the "eye" area is wider that the kerf near the edges. If it is really and issue, less cutting pressure (and/or slower down-speed) will also reduce the side-load on each tooth, reducing blade deflection and "ghosting". Quote Link to comment Share on other sites More sharing options...
Goods Posted March 31, 2022 Share Posted March 31, 2022 Randy, that is exactly where I was coming from. (The “eye” would rotate with the cutting direction…) Quote Link to comment Share on other sites More sharing options...
JHCC Posted March 31, 2022 Share Posted March 31, 2022 10 hours ago, Duncan M said: would sticking a slice in white vinegar work to etch it, or would I need something stronger? The usual acid for etching steel and iron for grain examination is nital, 2-3% of nitric acid in ethanol. That said, you're not doing a microscopic examination of the individual grains, so start with white vinegar and move on to something stronger as needed. Just make sure to polish your sample first. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted March 31, 2022 Share Posted March 31, 2022 It is an effect of the bade cutting it. I have seen that with a lot of stock over the years. Quote Link to comment Share on other sites More sharing options...
Duncan M Posted March 31, 2022 Author Share Posted March 31, 2022 Thanks everyone, I looked up ghosting and would definitely agree that that's what the cause is. I guess that means there would be no point in trying to etch a piece then. Goods, I am sorry that i misunderstood your original post. Quote Link to comment Share on other sites More sharing options...
George N. M. Posted March 31, 2022 Share Posted March 31, 2022 Cool. This is a phenomenon of which I was unaware. "By hammer and hand all arts do stand." Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 31, 2022 Share Posted March 31, 2022 DANG! Learned something new AGAIN! There goes another memory from my overcrowded and dented brain. Oh well, Deb doesn't really expect me to remember anniversaries anyway. Thanks! Thanks for the original question and pics and thanks for the answer. Much appreciated. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
JHCC Posted March 31, 2022 Share Posted March 31, 2022 19 minutes ago, Duncan M said: I guess that means there would be no point in trying to etch a piece then. Just because it's pointless is no reason not to do it! Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 31, 2022 Share Posted March 31, 2022 Frosty are you *sure* it was a tree that hit you? I didn't know that term but was familiar with the cause. Quote Link to comment Share on other sites More sharing options...
Randy Griffin Posted March 31, 2022 Share Posted March 31, 2022 Frosty, you didn’t lose a memory. It just went on microfiche. You’re too old to have a hard drive. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 31, 2022 Share Posted March 31, 2022 No, I don't REMEMBER the tree hitting me, all the evidence is circumstantial but I'm pretty sure anyway. You're TRYING to get me in trouble aren't you Randy? Don't make me get even. Truth is my memory filing system got scrambled so all the memories are hiding in the wrinkles and start moving around if I search very hard. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
JHCC Posted March 31, 2022 Share Posted March 31, 2022 As personal computers were starting to become a thing, my mother decided that "Random Access Memory" was about the best description ever for her own thought processes. Quote Link to comment Share on other sites More sharing options...
Anachronist58 Posted March 31, 2022 Share Posted March 31, 2022 10 hours ago, Randy Griffin said: Actually, I think that is called ghosting. It’s caused by the harmonics of the tool. In this case a saw. Randy you have it. I have seen this pattern thousands of times in many different materials... As to microfiche, every now and again I pull up something that was "lost forever". May we only remember that which can be therapudic, cathartic, edifying, or necessary... Robert Taylor Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted April 1, 2022 Share Posted April 1, 2022 I can remember things from years ago going back to my childhood. Just don't ask me about what I had for lunch or breakfast today. As far as ghosting is concerned, I also learned something today that I have never heard of. To be honest, I've never looked at the end grain of stock that the bandsaw cut, as long as it was the correct length and square it's good to go. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.