Power hammer mechanism choice

[EDL]

If you were to build your own hammer, which mechanism or style of hammer would you choose to build?

Which type mechanism lends itself better to damascus/knife making?  I've seen everything from air hammers (like the anyang 33lb), even home made ones made with an air cylinder powered by a compressor to slam the hammer down (it was quite compact and powerful), to what I assume is called a "tire" hammer with tire spinning an offset cam connected to the hammer via connecting rods with a spring of some sort between them, to longitudenally mounted leaf springs that rock front to rear.  I'm sure there are other mechanisms I'm not even familiar with.

Which type do you think is simpler to build, but provides the best combination of power and operability for a small home shop?  I guess one last qualifier is something I won't need to cut into the foundation and build some massive isolation block to use. 

A log splitter press is on the list too, and I realize this can make up for some lack of hammering power, but I'd like the hammer to do some of the work, it seems to leave a much flatter and consistent finish (planishing?) and a press isn't always the best for making damascus, at least for initial welding. 

[Frosty]

Simple or easy to build? They can be two very different things depending oh your shop skills and equipment. Simplest forging machine to build would be converting a log splitter, they can be sped up with a little more investment. 

Frosty The Lucky.

[EDL]

Press will be a converted log splitter.  Been looking at used ones in the various local for sale ads and Craigslist and man, people want new or near new prices for well used ones and ridiculous prices for those that are clearly clapped out.  I'll probably go with a new budget one in the 22-25 ton range (I found a brand new 25-ton unit for $899).  I'm mainly after the hydraulics and the steel beam/bed.  Of course, the gas engine will get replaced with an electric motor.  I first thought of just buying a pump, cylinder, etc and build from that, but dang, just a proper 2-stage pump with enough flow rate is nearly half the price of an entire new log splitter, so a conversion is the plan.

Anyway, my question was really about a power hammer.  I know how it goes with the power tools, bigger is always better, but perhaps not so much in this case.  Like I said, I don't want something so big and massive that I shake the surrounding country side like that Pilkington Alec Steele has.  I guess the best "requirement" that I could give is it needs enough oomph to set the weld on a decent sized damascus stack (say, 2" W x 2.5" thick x 5-6" long) and then perform the usual drawing, shaping and flattening on a piece that size.  I'm curious about the style of hammer that ya'll think works best for that sort of work.  I don't really have any sort of space requirement (I have a 10,000ish sq foot barn).  I guess I shouldn't have said "simpler to build" as complexity is not really a concern.   

 

[Frosty]

Have you checked into what you'll need in an electric motor to  make a 22+ ton log splitter perform even close to what a 5hp Honda will? Much more than a 3 HP motor wants 3 phase and new they're darned spendy.  Is that 22+ ton log splitter a 2 stage pump? 

Building a power hammer isn't a trivial project and please don't think you're likely to get away with a structural steel anvil, not if you want to forge stock the size you describe. That size billet would make a silly big sword, that'd be a billet more than 6 lbs. 

You could work that much with a 25 lb hammer but it'd a little under weight. A 50lb is more in the realm but I have to work that size material on my 50lb. Little Giant, it's not fast.

What kind of hammer do you want to make? If you want a modern utility hammer (external compressor) I suggest looking to buy one and then the compressor is going to cost. There are plans available though, the improved Kinyon plans have been around for decades and make fine machines.

Mechanical hammers are probably the most popular for home builds and there a bunch of designs and plans online. A proper anvil is usually the toughest thing to find or make. 

Probably the simplest power hammer design is a self contained fluid drive but you have to find the pre 1903 patent drawings as there were so many manufacturers getting to the market they all had to have legally unique designs or pay royalties so the valving starts getting crazy complex. Before I found my LG I was going to build one but about the time I was ready to start all the scrap yards went to single buyer contracts and I couldn't buy my anvil. <sigh>

I'd planned on using Rail car axles, they're IIRC 9 7/8" dia. 4140 and better than 4.5' long. I figured I could bundle and weld 3 lengths together for the anvil and have the drops for other various projects. 

Were I going as light as a 25lb. hammer then one axle would've worked a treat. 

Frosty The Lucky.

[EDL]

The log splitter I have in mind runs on a 5HP gas engine, has a 2-stage pump and a 9.5 second cycle time (that's full travel of the ram down and back up).  A 3HP single-phase 220v TEFC motor ($189) will operate it quite nicely (many such conversions on youtube of this set up and they function well).  I could spend $229 on a 5HP TEFC motor if I think I need the extra HP.  I could even possibly source a used motor even cheaper.

I understand about the billet size, but with damascus, since it typically requires a lot of heats, cutting, stacking, reheats, you typically lose a lot of material and end up with a fair amount less at the end.  I am OK with the hammer being slow initially.  My main interest is in setting the weld, doing much of the drawing and squishing with the press then return to the hammer, theoretically with a lot less billet mass at that point, to do final shaping/finishing/planishing.  That seems to be the basic sequence makers use when they have both tools.

Fluid drive sounds complicated and expensive?  Based on what I've seen, I'm guessing it's going to have to be something mechanical, although admittedly that air cylinder hammer I saw on youtube is intriguing.  It's very compact, and looks like it hits plenty hard.  I'm just not convinced the cylinder is going to take the pounding over a long period of time (they are cheap though, $60 for a 2.5" bore, 20" stroke cylinder that specs at 280Kgf (617lbs) of force and a max air input of 145 PSI.  Here's the link to the video I saw on youtube:  https://www.youtube.com/watch?v=hfJFDZTZTqc

Unless there's some specific type of steel for the anvil, my understanding is that it needs to be at least 10 times the mass/weight of the hammer, does that sound right?

 

[arftist]

Mechanical hammers are cheaper to build unless you already have massive air supply.

Mechanical hammers are much more efficient than air unless you buy self contained hammer.

Self contained hammer is much too complicated than most home builders can handle.

This question has been asked and answered here many times, search for more details.

Tire hammers, the tire is just a simple but IMHO poor clutch.

Spring helve hammers are simple to build, hit hard and are easier to tune.

As to the last of your ideals, if your hammer is big enough to weld up a 2.5 inch billet, it is certainly going to require a big foundation. I would want a 100 pounds or so.

On the other hand, a more right sized billet could be welded with a much smaller hammer.

As to your press ideas, you are way off in your estimations. 

More like minimum 10 horse electric. The die must move fast as the work quickly cools as soon as it contacts. 

Instead of recycling incorrect parts consider cheaper sources or forget the plan and just use the hammer.

FYI many folks are doing Damascus welding in a properly sized press.

[EDL]

Thanks arftist,

I've read discussions elsewhere that squishing damascus in a press to set the initial weld is bad.  I've also watched plenty of videos of smiths using a hammer to smooth/flatten a knife after it's been forged to shape and it seems this saves a lot of post heat treat grinding to final shape.  There's no hurry on this at all, just thinking about things and learning more about hammer types/styles and so on.  I'm not 100% committed to the idea of building a hammer at this point.

As for the press, I'm curious as to why you say I'm way off on my idea?  Here's a video of a channel I watch.  He converted a splitter that ran on a 5.5HP Honda engine with a 3HP electric motor.  Are the ram speeds on this conversion too slow?  Looks to me like it works pretty good, but I'm always open to learning.

 

[Judson Yaggy]

Youtube is not the best source of info.  

90% of knifemakers prefer a press.  Real blacksmiths can use either but find hammers more versatile.  Poke poke grin...  You can do serious work with either or preferably both.  Skills first, tools second.

[ThomasPowers]

Presses allow for less distortion when doing fancy pattern welded billets.

[arftist]

Big difference between what you said you wanted to do and what he was doing.

[Benona blacksmith]

What is the difference between what he said he wanted to do and what Big Dog forge did with his?

[EDL]

22 hours ago, arftist said:

Big difference between what you said you wanted to do and what he was doing.

How so?
 

[arftist]

You want to squish 2× 2 1/2

He was squishing 3/8 ×3 the easy way.

No comparison.

[EDL]

Um, did you watch the video?  The very first thing he presses is a 1 1/2"  diameter by about 6" long chunk of steel, end wise and turned it into a puck about 2" thick on flat dies.  The second thing was a leaf spring, looked like 3/8 thick, and he pressed a tang on the end of it pretty quick.   The third item was a 1 1/4 x 1/2 bar using a 5/8 bar as a kiss block to dimension the piece.  He dimensioned about a foot and half of it in less than 2 minutes.

I don't want to be argumentative, but a couple folks keep insisting this won't work.  Here is a video showing the guy doing the conversion with the details and showing it in operation on three different dimensions of steel doing three different types of operations.  If you still feel it won't work, then please tell me why, not simply that it won't.   

As far as squishing 2 x 2 1/2, that would be a damascus billet, obviously I'm not looking to mash it from 2 1/2" thick to knife thickness in a single press.  

[ThomasPowers]

Only time I've worked 2.5" sq stock it wasn't a pattern welded billet; I borrowed the use of another smith's 200# chambersburg (see photo under my name).

[arftist]

EDL, I did explain it and I stand  by it still. Not the same. I can't force you to understand.

[EDL]

Ok, done with this.  It would just be arguing at this point. 

[tylerdewitt]

I don't have any press experience, but I think what arftist is saying is that if you think about the surface area contact 2x2.5 is going to be pretty slow going. Yes in that video he squishes the round bar into a puck, but notice how little the metal moves near the end of the stroke as the surface area becomes larger. It would be even worse as the material gets thinner because it cools faster.
I guess narrow drawing dies will help but the point remains that 3HP log splitter will likely be underpowered for working 2x2.5 stock. The examples shown in the video are not representative of efficiently working down a billet of that size.
 

[EDL]

But that's not what was said.  He cherry-picked one of the three demonstrated press operations, specifically the 3/8" thick piece pressed on edge and proclaimed it not anything like what I wanted to do and then proclaimed he couldn't "force me to understand."

Of course, pressing 3/8" material on edge has nothing to do with what I asked about.

I did type out a much longer response and went over some details about hydraulics, electric motors, comparisons of such a press as this, to actual commercially available ones, and even the thoughts of people here (and elsewhere) concerning the subject of press power, travel speed, and the like, but I decided to just erase it and end here. I am reasonably confident that this press is adequate for the specific needs I am looking for (both in functionality and within the limits I have in my shop and in my wallet) with the express consideration and understanding that it is not perfect, nor the best.  I'm no longer pursuing the discussion as I don't want to get into multiple page length  posts on what I personally know or understand concerning the science and math behind physics, pressure, hydraulics, speeds, force, or interpretations of what the very people here say on the matter in other threads, etc, et al.  I really don't like the atmosphere that I feel I have to provide a doctoral dissertation on my full qualifications to convince anyone I have a modicum of gray matter lingering between my ears. 

I thank you for your input and addressing the question(s) directly.

 

 

 

[BIGGUNDOCTOR]

EDL, when you get it running, post a video of it in action. I would like to see how it turns out.

[EDL]

No need to wait for mine, here's a 25-ton log splitter forging a PW billet a fair bit bigger than I would do (and the individual layer pieces of the this billet are pretty chunky in thier own right).  After setting the weld and a little initial working on the railroad track dies he appears to be using, I'd change them out for some with a smaller radius to help in drawing.  Could a faster/more powerful press speed this entire thing up?  I'm sure, but it would also need more power than I can provide in my shop and more $$$ than I can afford.  This level of performance, for the cost, is pretty much the limit for what I can power and afford.   Outside the press itself, there are options for sizing the work and the dies to help speed things up.  End result:  I'll take this over attempting to beat a billet anywhere near that size by hand.

 

[basher]

The log splitter seems to work fine for what its is. smaller bites would make much faster working. I would be a little concerned about the frame flexing but really its soooooo much better than by hand.

[marcusb]

I'm kinda confused by this thread at this point, but I will throw in the random info I have gleaned over the years on presses. If your shop is limited on electrical service build a hammer, if its not build a press.