MC Hammer Posted July 9, 2018 Share Posted July 9, 2018 Piggy backing on my post regarding the Fisher anvil I recently acquired (didn't want to make the Fisher anvil post a mile long), I had some thoughts on rebound and the ball bearing test. Up until now, the hammer test seemed to be sufficient enough for me to determine if an anvil had sufficient rebound or not. I still think it's a valid test because anyone who has forged long enough can tell a lively rebound with a hammer, hear consistent ringing vs. a buzz that would indicate a delamination or crack in the face or under the face, or any other major problem. In a pinch, I'd still go with the hammer test. Here's where my thinking has changed though. When I hammer tested the Fisher before buying I knew it wasn't as lively as my Trenton but had no way of knowing just how much. Here's really where the ball bearing test helps. After buying the Fisher for $50 I located my ball bearing and realized what I detected in the hammer test actually equated to a 20%- 25% rebound difference when compared to my Trenton. On a 10 inch drop, the Fisher only returned 6.5 -7.0 whereas my Trenton gives me 9.0 - 9.5 inch returns on the same 10 inch drop with an inch diameter steel ball bearing. So my point is, I could not determine the fine difference in rebound until I did the ball bearing test. I think it's definitely worth it to do the ball bearing test before purchasing an anvil. I realized I didn't have the ability to determine an 80% rebound vs. a 90% or even a 70% with just the hammer alone. I guess for me, the best testing of a prospective anvil to be purchased would first start with a hammer test of the entire face. If all appears well and the face rings consistently / seems to have good rebound, then I'd fine tune things with the ball bearing test. Though this seems like "Duh" observation, I still think many of us in a pinch accept our observation with the hammer test alone. I used to, but my ball bearing has been relocated to a spot that I can find it now and have it with me when needed. Quote Link to comment Share on other sites More sharing options...
JHCC Posted July 9, 2018 Share Posted July 9, 2018 Well, one advantage to going straight to the ball bearing is that it's portable, discrete, and accurate. As for the greater accuracy, this highlights two important aspects of any test: isolating the variable you want to measure, and having a scale to measure that variable. For the latter, even if you don't have a ruler on you, it's fairly easy to eyeball the percentage of rebound when the bearing is dropped from a fixed height. As for the former, there's no chance of either adding or subtracting any force to a dropped bearing as there is (even unconsciously) with swinging a hammer. Quote Link to comment Share on other sites More sharing options...
Anachronist58 Posted July 9, 2018 Share Posted July 9, 2018 Very well said, JHCC. Hammers vary in hardness, ball bearings, not so much. The uniform distribution of mass in a sphere provides a default control for the test, as opposed to having to compensate for interference from the elongated head and the handle. My favorite four ounce ball pien would tell me what I need to know for this type of test, but only because I have swung it so many, many, times. Robert Taylor Quote Link to comment Share on other sites More sharing options...
JHCC Posted July 9, 2018 Share Posted July 9, 2018 22 minutes ago, Anachronist58 said: Hammers vary in hardness, ball bearings, not so much. Hadn't thought of that detail; good point. Especially if you always use the same ball bearing. Quote Link to comment Share on other sites More sharing options...
SLAG Posted July 9, 2018 Share Posted July 9, 2018 Oops wrong thread Quote Link to comment Share on other sites More sharing options...
MC Hammer Posted July 9, 2018 Author Share Posted July 9, 2018 Well said everyone! I also hadn't thought about the variable of the hammer steel face. Something I did note also was when I used a 1/2 inch ball bearing that someone gave me I got much poorer drops on both anvils. I'm thinking they were made of some kind of mild steel whereas the 1 inch bearing I used was made of hardened steel. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 9, 2018 Share Posted July 9, 2018 If it was mild it wasn't a ball bearing! HOWEVER not all steel balls are ball bearings---you can buy mild ones at many ornamental iron suppliers. Quote Link to comment Share on other sites More sharing options...
JHCC Posted July 9, 2018 Share Posted July 9, 2018 To continue our scientific exploration, using a mild steel ball will decrease rebound percentages (since micro-deformation of the mild steel absorbs a certain amount of the force imparted by gravity), but you'll still get a decent comparison of the difference in rebound between anvils. In other words, testing one anvil with one ball and another anvil with another ball (two variables) does not give you an accurate comparison, but testing two anvils with the same ball (one variable) does, even if it doesn't allow you to get an accurate measurement of the rebound percentage itself. Quote Link to comment Share on other sites More sharing options...
1forgeur Posted July 9, 2018 Share Posted July 9, 2018 And-----does whatever the anvil is sitting on when tested have how much to do with rebound depending on what it was tested with? Just wondering. Quote Link to comment Share on other sites More sharing options...
JHCC Posted July 9, 2018 Share Posted July 9, 2018 No. Rebound is a function of the energy returned by the continuous mass of metal directly under the hammer blow (or in this case, under the dropped ball bearing). Any interruption of that mass will reduce rebound, whether an internal discontinuity (such as a crack or a delaminated face) or an external limit (the bottom of the anvil). Quote Link to comment Share on other sites More sharing options...
MC Hammer Posted July 9, 2018 Author Share Posted July 9, 2018 I really think the 1/2 inch metal ball bearings given to me were probably out of a board game or some Foosball table or something. My guess is that they sure where mild steel, and yes the difference would technically be proportionate to the one inch in the way JHCC described. I believe that JHCC is right in that what is under it should have no bearing on the drop, but I can test that theory as I will be getting a stump soon for the new Fisher and can give it a try. I should get the same result. Quote Link to comment Share on other sites More sharing options...
tanglediver Posted July 11, 2018 Share Posted July 11, 2018 A ball bearing dropped from ~ 10" should not mar the anvil face, in which case, your anvil might be made of cheese. Quote Link to comment Share on other sites More sharing options...
JHCC Posted July 11, 2018 Share Posted July 11, 2018 Well, we do know Gromit is a welder. Quote Link to comment Share on other sites More sharing options...
ianinsa Posted July 12, 2018 Share Posted July 12, 2018 and Wallis invented bouncing bombs? not bearings Quote Link to comment Share on other sites More sharing options...
MC Hammer Posted July 13, 2018 Author Share Posted July 13, 2018 Here's an update on this situation: I had all but decided to just start using this Fisher, but I had some free time last night and decided to try an experiment. I took a medium grit carborundum stone and water and lightly worked it in circular motions across the face of this anvil. Having used water to sharpen metal blades with sharpening stones I know that the resulting color is usually grey. What I found was an oily murky brown and this is after the wire cup wheel and angle grinder had removed anything it could remove. I think this was a stubborn layer of garage grim that had worked into the small pits and abuse marks over the years. Once I saw shiny metal emerge and a good solid grey coloring to the water I stopped. No need to go any further as I was to the true metal surface of the anvil face. I wiped the face clean and did a ball bearing drop test. From 10 inches I got 7.3 - 8.2 drop returns. The highest returns were areas where there were not any abuse marks and the surface was smooth. Yes, yes, never grind the face and I agree 100% to never use power tools or take it to the mill to have it ground flat, but what little I removed with light work wasn't even measurable but the improvement in performance was noticeable. I hesitated to post this result because I didn't want some newbie to take a carborundum stone and work 8 solid hours polishing his or her anvil face as that would be a waste of time and good face material. So let me be clear, I spent all of 10 minutes working that stone around on the face with water - nothing crazy to create heat and any loss of metal on the face was not measurable. I'm also happy with the results and will not do a single more thing to the face of this Fisher other than work hot metal on it which I think over time will continue to improve the face surface / rebound. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 13, 2018 Share Posted July 13, 2018 Yes you were not grinding the face; just cleaning it. Quote Link to comment Share on other sites More sharing options...
SLAG Posted July 13, 2018 Share Posted July 13, 2018 Good job. An alternative method get rid of the grunge is to soak some paper toweling (many layers thick), with a strong lye in water solution. Drape the toweling over the anvil face (top of the anvil), overnight. Examine the anvil mid morning. The lye will attack the oily grime. If some brown-grime still remains repeat the procedure. Lye is sodium hydroxide (NaOH),. It is a powerful, corrosive chemical. So use eye protection, an old long sleeve shirt and full pants. (not shorts). Also,wear rubber gloves. No grinding nor polishing is required. When done flush the anvil with regular strength vinegar to neutralize the lye. then flush the anvil with a lot of water. You can then let it dry in the sun or wipe said anvil with paper toweling and an old towel. If you are still concerned with residual water and rust. You can rub the anvil with any type of alcohol to mix with the water. That solution will evaporate much more quickly. SLAG. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted July 14, 2018 Share Posted July 14, 2018 Similar to MC Hammers method, I have used a pumice stone to clean anvils and cast iron cook ware. No harsh chemicals involved. Quote Link to comment Share on other sites More sharing options...
MC Hammer Posted July 16, 2018 Author Share Posted July 16, 2018 I think this worked out great for the face of this anvil but I wouldn't recommend it for someone with a decent face with just some minor pitting as that will work off and polish up with use. Quote Link to comment Share on other sites More sharing options...
iron woodrow Posted July 17, 2018 Share Posted July 17, 2018 On 7/14/2018 at 3:14 AM, SLAG said: full pants. (not shorts). Lucky you clarified because working after you have filled your pants is uncomfortable to say the least Quote Link to comment Share on other sites More sharing options...
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