John Larson

I suspect that the Nasmyth machine is set up as a drop hammer, steam being used only to raise the tup.

I converted my steam hammer today to pneumatically actuate the main valve's 3-position spool valve. You can read my blog here on IFI and see several photographs. I explain how the hammer behaves. Today I'm doing the happy dance.

I did the change in steam hammer linkage twice, over two days. The first version failed to account for the cam surface fall away as the tup descended and it would not reciprocate. The second version completed today does account for the cam fall away as the tup descends and reciprocates. Traditional steam hammers use spiral-shaped spears to account for the fall away. I still have to mess with the connection point for the vertical tie rod a bit more to tune for reciprocation as opposed to single blows. I am losing my patience with fully mechanical linkages.

I am going to change the design of my steam hammer linkages, as seen in Sam Salvati's photograps and videos. I am going to make the jackshaft for the roller lever movable as is the case with steam hammers like Mike Dillon's Chambersburg. It, like similar hammers, uses the motion control lever (hand or treadle controlled) to move the jackshaft of the spiral wiper up and down. The jackshaft extends through an enlarged hole in the machine frame. On the end of the shaft is a lever that connects to the motion valve via a near-vertical tie rod. Today's critical observational recollection and deduction was that the jackshaft's lever has the same length as the motion lever's leverage on the jackshaft. This means the constant length tie rod is not moved by the motion lever adjustment, but rather it is the wiper's rotation from contacting the cam in a different spot. And this is why an old steam hammer's slop in the wiper jackshaft bushings has to be minimal.

Today I tried a special inflow hand valve with more linearity than a ball valve. Virtually no improvement, so I went back to the standard ball valve. For the reciprocating mode I set the valve wide open and I control speed substantially with the air pressure regulator. I find this quite acceptable at this time. I did a couple of hot rr spikes and found the hammering adequate. Still not in the same league as my utility hammer, but over time I will learn to make the machhine a better pounder. Where air in-flow throttling makes sense and works is when the machine is set for treadle hammer behavior. But a fancy valve is not needed for that. Therefore, I am comfortable with the treadle controlling the motion linkage and the air flow being under hand control and basically held constant during a forging session. It is possible to lift the treadle to achieve lighter blows so that precision hammering is possible. As I've gotten the linkages improved, especially over the past several days, i've become more confidant about what is going on. I have a shortening to-do list of refinements. I'm ending my week in a very good mood.

Today I did a bit more experimentation with cam lift. To do so required that I use my plasma cutter to remove a bit of the cabinet floor for clearance, and while I was at it I removed more than necessaryso as to allow wrenching of the jack shaft levers from below. Crude, but I'll clean up the jagged edges when I eventually tear down the machine for finishing. I opted to re-drill the brackets for the jackshaft to move it away from the bottom of the cam. Back together it ran as it had yesterday. The added cam llft tried today was not of benefit. I noticed that the lever for the springs was slipping on the jackshaft and no amount of tightening helped. So I took a break to mull things over. When I got back from my machine shop store I inverted the lever, tack welded it to the lever controlling the horizontal push rod, and mounted the tensioning springs below the cabinet floor. Though temporary, this had a really good effect in that the machine would stay in tune during longer duration reciprocation tests. The cfm inflow throttling via a hand operated simple ball valve worked better than yesterday. For the time being, I suspect I'll keep the treadle acting as a motion control and keep the air flow hand operated.

Mad Mike and Iron Woody, I think there is definitely renewed interest in the versatility of steam hammers relative to any other style of hammer. Mike Dillon and Ken Zitur have me inspired that's for sure. When I launched into my hammer I was pretty sure I knew what I was doing. Not so. Lately I've been learning what does not work--not very pleasant. If it wasn't for info from Ken and Mike my project would have crashed and burned by now.

Whereas I was pretty depressed last night, that is not the case now. Today I attained reciprocation on the "steam" hammer and it is repeatable, predictable, and tunable. Hurray! Basically I doubled the cam lift and reduced the jackshaft radius of the roller so as to increase movement of the vertical pushrod per inch of tup travel. This took the bulk of my work day. When reciprocating I was getting full stroke and the stroking would slow down from air pressure and cfm reduction. By changing to another hole on the T-lever with less lift for the vertical pushrod and spool, I achieve single blow treadle hammering without reciprocation. The T-lever's array of holes for connecting the bottom of the vertical pushrod is analogous to Ken Z's slotted lever. The next stage of work is to refine all the pieces including the cam. More rigidity is needed to eliminate lost motion. No evaluation of reciprocation blows quality will done until I'm satisfied with the cam, levers, tie rods, and motion geometries.

Danger, thanks for correcting my thinking. Your video on p. 6 has been duly reviewed. I'm trying, but I must say I feel like the DUH man right now. I am encouraged by Ken's video today that I will be able to achieve reciprocation mode.

Thanks, KZ.

Continuing, Ric, it is worth saying that Danger Dillon recently provided some info from an old Chambersburg air driven steam hammer manual and it used a traditional lever on the cam wiper and a treadle on the air valve (so that a smith could use it without a "driver" helper). My existing hammer design runs like that, perhaps even better with my stroke tuning feature, however my single blow feature does not provide the tup-follows-the-treadle provided by the 3-position spool valve (as shown in Sam's video). When Grant Sarver mentioned in his video of his Bell steam hammer that some steam hammers did not idle very well I believe now that such hammers had fairly wide boundaries on the center position of their spool valves and I believe that the Chambersburg engineering drawing shows that spool valve to have very narrow boundaries such that stepping on the treadle would elicit reciprocation (wide boundaries lead to steam locking). If my sense of the Chambersburg is correct, it wouldn't easily provide tup-follows-the-treadle behavior. In that case its behavior would have been pretty much like my exisiting Octagon series of hammers. My lever sets the air space like the Chambersburg and my treadle controls the air flow (though I use back pressure control). In short, the exisitng Iron Kiss design is highly refined and very sweet to use. It just doesn't do double duty as a treadle hammer. That is what I am seeking.

Judson, I don't understand. Help me out a little bit. Rich, no it won't supplant what I now do. It is a research project with much left to learn. Ken Zitur has apparently succeeeded in eliminating the dump valves on his rebop[ of a Bull hammer according to his post today. That is the carrot in front of this old donkey's eyes.

Super news. Look forward to the video material. Congratulations. :-)

Sam Salvatti presented some video material of my hammer on the steam hammer thread here.

Thanks for posting these. It is amazing to me that he used his telphone to do them. I'm so stone age.

Thanks for answering my question. I certainly look forward to your findings. I want to achieve sustained reciprocation without the dump valves but so far have not been able to. Single blow treadle hammering is very nice without the dump valves. I'm using the setup pictured on my blog here at IFI.

Ken. you have stopped using the dump valves. Why?

Ken, that machine style is perfect for your conversion kit. I look forward to its completion and hopefully a video.

I have presented a number of photographs in my blog today, and indicated what they are showing.

Again, thanks Danger. I appreciate your generosity and interest in my flailing. I studied the Chambersburg cutaway drawing and the page of text that you provided. The machine was meant, I believe for running without much chance of steam locking at rest, that position where the spool covered both the top and bottom cylinder ports such that stepping on the treadle would not put air into either port. For this to be the case, it is only necessary for the spool to be a wee bit short so that couldn't happen. Though the cutaway does not show how the top of the treadle tie rod is connected, the air throttle valve cutaway shows both a hand lever and a tie rod lever that is likely connected to the treadle. The full document probably makes this clear. Because of this, if I have it clearly understood, the lever controls the middle of the reciprocation height of the tup and needs to be reset if thicker or thinner than usual stock is hammered. This is how my utility hammers work. Inherent stroke length increases with hammering speed and inertia. I believe that the spool's length relative to the ports' separation is either a tiny bit short or so precise as to be knife-edged sensitive such that the probabilty of a treadle depression not yielding tup movement is near zero. It is operationally like a 2-position spool rather than a 3-position spool. On the 3-position hydraulic spool valves like I am using based on Ken Zitur's work, the center position cannot be so knife-edged because of the high hydraulic pressure. More later.

Thanks, Mike. I will be studying it. I've been lax about picture taking so far because the hammer anvil and frame etc are routine. Now that I'm fussing with the linkages and valves I'll be taking a few snaps. The treadle was fab'd today and I had a few minutes to try it out. It became apparent that I need to change the lever ratio a bit on the treadle-to-throttle shaft a wee bit. Involves a bit of disassembly so I will do it tomorrow. I'm going one step at a time right now to reduce the number of degrees of freedom (joints) in the linkages. The amount of movement in the spool is quite small and so controlling it by joint treadle and tup movements requires precision. The build process in the recent days has involved revising parts a wee bit here and a wee bit there. No big deal except, just as with utility hammers, R&D in steel requires oodles of time and patience. In short, it is too early for brag snaps.

Thanks for the fun, John. :)

I haven't fallen off the edge of the flat earth. I am working on the "steam hammer" and am making headway.

Thanks. I have the chance of building another one for an artist awaiting word on a commission. I recently sold an older unit built in 2002 and rebuilt last summer to octagon configuration.

I am glad to hear your parts arrived. My worst case with customer cylinders from Norgren is 8 weeks, however once they have the original modifications set in their how-to-do-it files the wait can be much less. If that cylinder is a custom, I am not sure what has been made special. The probability of getting a reply to a question is low, but worthy of an attempt. Any customer would like to know what to ask for in the future, right? It could be seal material, it could be air cushion size. Other things are standard call out options.