Dan P. Posted May 3, 2015 Share Posted May 3, 2015 My hammer only has one face. Do I win a prize? Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted May 3, 2015 Share Posted May 3, 2015 (edited) Just in case anybody is confused by SmoothBore's interpretation of Newton's 2nd law or the physicists' illustration of billiard balls I posted. I sketched up what I think is happening…and why I think the crowned punch head better directs the energy to the workpiece and the crowned or round face of a hammer may help with reducing roll and pitch of the hammer head. When both systems are perfectly in line they are obviously equally effective. It is when the hammer strike point is offset that the crowning comes into play. When the crowned face hammer strikes off centre, the energy is not directed to the centre axis of the tool (it continues via the "normal reaction" in line with the acceleration vector as I interpret Newton's observation) and the off centre blow tries to bend the punch. The same forces as make it difficult to drive a bent nail, I remember the unpleasant tingle in my fingers from a flexing punch when it is hit off centre. Wasted energy and sore fingers! When the flat faced hammer is offset it still strikes the centre line of the punch and the energy travels directly to the working tip via the "normal reaction force". But the hammers centre of mass carries on and tries to rotate the head around the strike point. If you tilt the flat faced hammer relative to its direction of travel so that the strike point is offset, the energy is still directed via the "normal reaction force" to the working tip of the tool. The amount of pitch or roll of the hammer head will be determined by the degree to which the centre of mass is offset from its direction of travel to the strike point. Whilst as SmoothBore said this is relative to a gently rounded hammer the same applies even more so to a round faced hammer. The energy transfer issue is interesting to muse on but not the main reason I use flat faced hammers for punches and chisels. The overriding disadvantage of the round faced hammer for me is just as VaughnT originally posited…the likelihood of the glancing blow. I would rather have something I can control; like the hammer twisting in my hand, than something I can't; which is the punch flying off across the room. Even though I completed my first 10,000 hours of hitting things with hammers nearly forty years ago, I still want to give myself every opportunity to make every blow count and not have to rely solely on my hammer skills. Why make it any more difficult than it need be? It is much more important to be concentrating on the effect the working tip of the tool is having on the workpiece, rather than hitting the tool-head in just the right place. Alan, who has drunk too many mugs of coffee this morning and must now go and mow the grass… Edited May 3, 2015 by Alan Evans delete doubled up image Quote Link to comment Share on other sites More sharing options...
arftist Posted May 3, 2015 Share Posted May 3, 2015 Alan, by flat face do you mean truly flat? I have always been taught that hammer faces should be slightly crowned. Never did understand the exact physics behind it unfortunately, but it made sense at the time. (I do understand why a perfectly flat hammer would leave marks in a forging)Second, are you trying to say that a rounded punch end is the exception rather than the rule? Again I have always rounded my punch ends and also advocate fiercely that others do so as well. Seems like you are making a case for mutual exclusivity. The exception to the above of course being stone carvers chisels with a hard struck end being struck by a soft hammer. Different dynamic as the stoneworkers chisel actually takes a bite into the hammer face with each blow.........but this is a blacksmiths forum. Quote Link to comment Share on other sites More sharing options...
arftist Posted May 3, 2015 Share Posted May 3, 2015 My hammer only has one face. Do I win a prize? You can have a badge, assuming Sweany is done with it. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted May 3, 2015 Share Posted May 3, 2015 Alan, by flat face do you mean truly flat? I have always been taught that hammer faces should be slightly crowned. Never did understand the exact physics behind it unfortunately, but it made sense at the time. (I do understand why a perfectly flat hammer would leave marks in a forging)Second, are you trying to say that a rounded punch end is the exception rather than the rule? Again I have always rounded my punch ends and also advocate fiercely that others do so as well. Seems like you are making a case for mutual exclusivity. The exception to the above of course being stone carvers chisels with a hard struck end being struck by a soft hammer. Different dynamic as the stoneworkers chisel actually takes a bite into the hammer face with each blow.........but this is a blacksmiths forum. The only hammers I have which are truly flat (or at least as flat as I can get them) are my chasing hammers which are used with my chasing punches and hammer gravers. All the others have some degree of crown as you say.I and everybody that I know also have crowned end punches, drifts and chisels. Whether they grind them as I do, envisaging the working point as the centre of the crown's arc, I do not know. So no, I am not claiming anything exceptional.My posts in this thread were directly in response to the comment by SmoothBore when he corrected VaughnT's post...and then subsequently corrected mine. I agreed with VaughnT and not the corrections by SmoothBore. But as I also indicated above, I think the energy transfer issue is fairly inconsequential…but having my statement questioned/refuted is not!Someone disagreeing with you always wakes up the brain, I have never really considered the effects theoretically before, just accepted the results as observed. So it has been a good exercise.I really hope he can prove me wrong. I think any discussion like this has a win win result. If I win the argument okay..but if I lose the argument by being proved wrong then I win by learning something new…a new knowledge and insight to add to my experience! Happy either way.Alan Quote Link to comment Share on other sites More sharing options...
ianinsa Posted May 3, 2015 Share Posted May 3, 2015 Alan, have you thought about going into politics? You have really put the win, win in such a glowing light! to the point of the other party looking forward to the trip.We love you Alan you're a star! Quote Link to comment Share on other sites More sharing options...
SmoothBore Posted May 3, 2015 Share Posted May 3, 2015 I think the difference of opinion on this issue, results from viewing the Hammer blow as the result of travel in a straight line, ... rather than an arc.The example of the Power Hammer, ... and Billiard Balls, ... illustrate this quite well.But the essence of my original point, is that the geometry of a FLAT Hammer Face, striking a Punch, ( WHILE TRAVELING IN AN ARC ), ... has more of a tendency to transfer that energy radially ( glancing blow ), ... than axially.I agree totally, ... that the pragmatic result, is often inconsequential. Others have commented on Hammer Control being useful in mitigating these issues, ... and I find that to be true in many cases, ... but when it's necessary to really 'bear down" on the punch, ... my "control" is seriously diminished. . Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted May 3, 2015 Share Posted May 3, 2015 smooth bore, i belive that to be true for all of us, lol. but practice and the amazing machine that is our body can make for a near perfect swing every time. The truth is, we use diferent "swings" all the time, in my case it is most evedent wen drawing clips, in that case the arc is used to push the meatal I am drawing in one direction. This is a fast hard blow as the thin stock lossed heat and the higher energy from the blow translates in to a momentairy flash from black to orenge heat.i certainly don't pretend to understand the physics of curved serfaces impacting on another and what direction energy travels. But I know a flat hamer will bend nails, and I know it will "jump" in your hand when striking steel on the anvil (as the hammer attempts the right it's self I assume) as I mentioned before, many comertialy made rounding hammers are very flat faced and must be dresed. Most other hammers have suficient crown but need the face polished and the edges blended (a 45 degre champher?! Really?!) Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted May 3, 2015 Share Posted May 3, 2015 I think the difference of opinion on this issue, results from viewing the Hammer blow as the result of travel in a straight line, ... rather than an arc.The example of the Power Hammer, ... and Billiard Balls, ... illustrate this quite well.But the essence of my original point, is that the geometry of a FLAT Hammer Face, striking a Punch, ( WHILE TRAVELING IN AN ARC ), ... has more of a tendency to transfer that energy radially ( glancing blow ), ... than axially.I agree totally, ... that the pragmatic result, is often inconsequential. Others have commented on Hammer Control being useful in mitigating these issues, ... and I find that to be true in many cases, ... but when it's necessary to really 'bear down" on the punch, ... my "control" is seriously diminished.Maybe, maybe not. I don't think our difference of opinion is relative to considering or ignoring the arc…Both the hammers are travelling through an arc whether flat or round faced. The off tool-centre strike point effect I sketched still applies whether to front and back (generated by an inappropriate arc) or side to side. I confess I did not pick up that essence from your posts...I didn't get past your contention that the round hammer face directed the energy to the axis of the tool. But in which case why did you quote Newton at me if you were in agreement with my statement that a curved hammer face was likely to reduce the pitch and roll?I think our difference could be more to do with the degree of strike point inaccuracy we are each envisaging. But...even when the offset is so great that one cannot prevent the hammers from rolling and knocking the tool sideways (you obviously have a lot more leverage with the handle to control the pitch, which I assume is why punches always seem to fly sideways) the round faced hammer would have still have the additional sideways forces generated by the curve and knock the punch further across the room! Alan Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted May 3, 2015 Share Posted May 3, 2015 Alan, have you thought about going into politics? You have really put the win, win in such a glowing light! to the point of the other party looking forward to the trip.We love you Alan you're a star!Ian, I may appear calm, serene and philosophical on the surface…but SmoothBore is making me paddle furiously underneath! Alan Quote Link to comment Share on other sites More sharing options...
Dan P. Posted May 3, 2015 Share Posted May 3, 2015 I did read about using the round end of a typical rounding hammer for using on tools in a copy of "Anvil" magazine years ago.I don't see how in practical application it makes a blind bit of difference. Quote Link to comment Share on other sites More sharing options...
americansckcmo Posted November 21, 2015 Share Posted November 21, 2015 Ethan BB is not the only game in town. Listen to the experience and skill represented in these responses. Good topic. Quote Link to comment Share on other sites More sharing options...
yesteryearforge Posted November 21, 2015 Share Posted November 21, 2015 I just love it when Y'all use big words Quote Link to comment Share on other sites More sharing options...
LawnJockey Posted November 21, 2015 Share Posted November 21, 2015 9 minutes ago, yesteryearforge said: I just love it when Y'all use big words The way I see it is if you can't say it with four letters it probably isn't worth saying. Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted November 22, 2015 Share Posted November 22, 2015 Then we get nasty grams from the moderators, LG. I for one dont want to end up in time out (-D the truth is I get lazy and hit with wich ever face is present when striking tools with my rounding hammer. Quote Link to comment Share on other sites More sharing options...
David Einhorn Posted November 22, 2015 Share Posted November 22, 2015 My forging hammers are for forging. I use brass, wooden mallets, and fleamarket ball-peens for misc. cold hitting of stuff. A friend used a brand new yet unused Hofi hammer (acquired through IFI) to bang on a guillotine tool before I could stop him, and I almost had a heart attack. Fortunately, the hammer appears to not be damaged. Quote Link to comment Share on other sites More sharing options...
TechnicusJoe Posted November 23, 2015 Share Posted November 23, 2015 AARRGHHH!!!!!!!!! !@(#$)(*)(*_@()%#% Stupid disappearing posts!!!!!!!! Curse you! #$()*_ This really annoys me....... there's a lot of typing gone to explain why I use my forging hammers to strike my tools and the round face on the rounding hammer. Maybe another time... Sigh........................................................... Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted November 23, 2015 Share Posted November 23, 2015 You may have some luck if you use your back button to go back to the point before you posted, your text may be there and and you can copy it then paste into a new thread and ask the mods to add it to this one. Alternatively try opening up the reply to thread text box and see if the system offers to fill in the text from the auto-saved repository...then copy and post as a new thread again.... Alan ps you are aware this is a 7 month old thread aren't you? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 23, 2015 Share Posted November 23, 2015 David; and did the friend end up damaged? I've learned taking forges on campouts to have all the hammers hidden away save for a couple of "loaners" until I am ready to work the forge and so be watching over everything. Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted November 23, 2015 Share Posted November 23, 2015 Let me take a stab, one less hammer, no "oops wrong hammer" and one less thing to wory about when the steel is hot. As for hiting with the round, it works, less off side hits sending high speed tooling across the shop... Alen, I think Tech is the original OP, school may have cut into his forge and in ernet time Quote Link to comment Share on other sites More sharing options...
Kozzy Posted November 24, 2015 Share Posted November 24, 2015 This conversation shook loose a rusty memory of something I read in the long ago times (so don't take it as fact). Someone mentioned that an old timer had chided him about not sharpening his hammer. The guy, of course, thought he was being punked so wouldn't play along until the oldster boss grumpily insisted. The old guy had the whippersnapper rough up the surface of the hammer just a little with coarse sandpaper: not smooth but a little "grippy" and it actually worked better when driving nails. It's sort of a smooth hammer version of a waffle-head where you get less slip from the slight misdirect of the blow. It does help....some...in some cases. Nice polished face looks good but a little rough IS good. Of course my hammer work is impeccable and I NEVER have a misdirected hit so it's hard for me to do a proper test Quote Link to comment Share on other sites More sharing options...
TechnicusJoe Posted November 24, 2015 Share Posted November 24, 2015 What the............ I can't post what I wrote!? But this does come up, is it too long? I have it saved, but I can't post it on here. What is this nonesense, while this bit of text CAN come up here. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted November 24, 2015 Share Posted November 24, 2015 As I suggested.... paste it into a new thread you start with something along the lines of "disappeared using a rounding hammer for driving punches" as the title. When you have posted it open it up and report your own post to the mods asking them to add it into the original thread. Alan Quote Link to comment Share on other sites More sharing options...
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