Power Hammer vs Hydraulic Press (first, that is)

[nuge]

I still  disagree with the much respected Mr. Larson.  Check the pics.  (for reference, I have the 15 kw machine, the smallest one,  which is single phase)

 

#1 is a piece of 3/8 square that doesn't match my coil at all.  37 seconds later, after "scanning" it through the coil (much like waving your torch), about a 3 inch length is orange.  Another 10 seconds and I could have it yellow.  If the coil matched (was smaller) the heat time would be about ten seconds total and then the material would be burning.  Even at the higher length of time this heat cost me less than 3 cents in electricity.  

 

 

John does bring up a good point indirectly, my biggest gripe with the process, changing coils is a pain.  Even though it takes less than a minute, somehow you don't want to do it that often.  Must have something to do with being spoiled with the insta-heat.  So you tend to build up piles of work for different coils.  No big deal.

 

Pics  2-4 are of a beat up ring from the scrap pile.  I think its 3/8 round.  It doesn't even fit into the coil.  You can take advantage of the eddy currents and still get efficient heat.  16 seconds later a goodly section is yellow.  The final form took under 5 minutes to complete.  Not the prettiest thing but you get the idea.  

 

 

Pic 5 is a handle I made from 1.5 inch round bar.  Thats pretty much the top end in size for my little machine.  My gas forge would have to run for ten - fifteen minutes from a cold start to get the first heat on this, by that time the piece is done with the induction heater.  

 

 

I work on a big variety of  different stuff any given day, and I too would surmise 90% of the forgework rolls through the induction.  To re-emphasize one of the many virtues YoungDylan brought up, my time is everything to me.  Don't really care how much the material cost or the fuel cost or how much I paid for the  drill press,  I only care how long its gonna take me.  Thats the big #1 rule of running my clown show, er, i mean business.   

 

 

 

[John Larson]

I have seen one copper tube shaped as a wavy pattern as viewed from on top and totally flat as viewed from the side.  This was used to heat a piece laid on a fire brick with about a 3/4 inch air gap between the brick and the tube bottom.  It may have been Grant's picture/video.  That idea comes as close to general purpose as I have seen.  It is on my to do list.

 

I believe that my advice for a test drive before buying is sensible.  Had I done so in the presence of an experienced user I would have purchased a far more powerful unit.  I still would have acquired an induction heater and by being much bigger I would now use it a lot more.

 

Every heating method known to blacksmiths has pluses and minuses.  I use coal and propane and also an electric tempering oven with higher temperatures possible for heat soaking.  Die makers use computer controlled electric ovens to achieve temperature vs time profiles needed for metals such as S-7.

 

For what it is worth, urban environments are difficult for smithing because of effects on people close by.  That is why QUIET processes such as induction heaters, fly presses, and hydraulic presses are needed.  Complaining neighbors can really dampen enthusiasm.

[nuge]

Yeah, I wish mine was bigger too! :)

 

The pancake coil you describe is useful but the ones I've made don't seem to pump out the heat.  It's tough making good coils, kind of a dark art, exiting when you roll a good one.  I have also seen a multi-purpose coil with two different sized openings  in one.  Have yet to try it. 

[youngdylan]

[youngdylan]

[basher]

sooo...an induction coil is an amazingly versatile tool if you have 4 power hammers!!

 how much is a bigger one and where would you get one in the UK  ( I currently have 4 power hammers working and want to sell one to release money for an induction coil set up.)

 

by the way I vote power hammer.

 Letting your muscles build up whilst waiting for a power hammer is a sure fire way to a life long aversion to heavy forging due to shoulder injury caused by forging heavy stock in your early 20'S and thinking yourself invincible........... 

 

 oops I resemble that remark!!

[youngdylan]

... and some more induction versatility is because the heat is so intense, rapid and local, you find yourself holding little itsy bitsy little bits without tongs .... more control and faster work

[youngdylan]

... and some more induction versatility is because the heat is so intense, rapid and local, you find yourself holding little itsy bitsy little bits without tongs .... more control and faster work

[youngdylan]

by the way I vote power hammer.

So do I but an induction heater is very close second. Just wanted to take issue with the idea that they aren't versatile. Three years of use and I'm still finding uses for it .... all sorts of shapes and sizes

 

 

it's especially usefull for making jigs and tooling up for a project on the fly. Also very useful for bronze work when seeing the colour is oh so important

[Harris Snyder]

Some nice examples of both setups and smithing work here!

 

As for the versatility of induction, Mr Larson is technically correct. Induction heating is a careful balance of skin depth and resonance. The circuit needs to be in resonance (to keep the power transfer decent), but the frequency has to be such that it starts to heat the core of the metal too and not just a half millimeter around the edge. Of course, multiple coils can alleviate the issue to a great degree, but not entirely. That said, I do think that in practical terms, an induction heater can have "versatility" within a range of activities and types of stock, especially once someone gets familiar with how to pick the appropriate coil geometry. Ultimately you're both right. A given induction heater, due to frequency range and capacitor bank size, might be unsuitable for certain kinds of stock, but of course it looks like in practice most smiths find this particular range of heaters to work very well for most of their day to day smithing activities. 

 

That said, if I were going to go induction, I'd either test drive a unit, or design and make one myself. Ideally, I'd find a way that the unit can vary the capacitor bank to find a better match for a given piece of metal. The issue there is mostly the time involved to do it, which would be substantial. 

 

Owen, I appreciate your warnings. I do not think I'm invincible though, on the contrary I'm a bit scared of my propane tanks to be honest! I've tried bashing heavy stock, and that steel is tough to move. I think what I meant was that if I went induction I'd spend more time forging overall, even if I had to limit the heavy stuff I could do without help. Not all my work is larger stock, its just that I started this thread out of a desire to acquire a tool which would help me to forge large stock effectively. I know that before I can make bigger stuff on my own I need one of these tools. The induction heater addresses a separate issue, really. As I said I don't love using compressed gas, and I spend much of the year in the city where charcoal isn't available (for free that is) and coal smoke is a problem. Going induction would capitalize on my hammering time, and build my skill as a smith (I'm fairly junior as you know), before jumping into the bigger stuff I'd ultimately like to be making. 

[SJS]

As for the potential to damage yourself... Nothing can replace good technique, and good judgment! An iron will, and a body of flesh and bone don't mix well in my experience. You are only young and invincible for a short time. When I was your age my favorite hammer was an 8# hand sledge, then in my late 30's after not forging very much I lite up my tendons with several 4-6 hour sessions with a 4# rounding hammer and a gasser loaded to the gills with stock. The tendonitis and carpal tunnel crippled me for nearly 6 months. Now I prefer a nice 2-2.5# hammer for almost everything. I also have arthritic changes in my hands, wrists, and shoulder, and those pesky tennis elbow tendons still get inflamed easily. It is surprisingly easy to give yourself a repetitive stress injury. Damage you don't heal up, doesn't get any easier to live with as you get old! On the contrary it gets more painful and testy. Take very good care of anything you want to keep, such as: your hands, your eyes, your hearing, your knees and your back. My old standby definition of Wisdom: is the ability to learn from someone else's mistakes without making them yourself. Sadly most people don't learn from their own mistakes, let alone someone else's. You want to be able to see and hear your children, and it is nice to be able to pick them up and hold them...

[Harris Snyder]

Yeah. I'm going to look for someone reasonably local to have a look at the hammer technique I've developed, and get some advice on that. I don't feel that I'm hurting myself, but honestly, who knows.

[youngdylan]

 how much is a bigger one and where would you get one in the UK  ( I currently have 4 power hammers working and want to sell one to release money for an induction coil set up.)

Owen, with John N's help we imported two from China. The idea was that if they proved reliable he would think about selling them. We'll, its got so much built in protection and it's never missed a heartbeat .... I've not spoke to John for a while but he has an advert in the BABA magazine that mentions induction heaters so it might be worth giving him a ring.

 

If you want to see one in action you're welcome to test drive mine if you're ever near Manchester

[Senft]

Was wondering, does anyone know of a good source in the US for these now?

[Will. K.]

Monstermetal 

 

http://blacksmith.org/forums/threads/1967-Grants-Induction-forges-now-sold-by-Monster-Metal

[Lamey]

2 completely different tools that occasionally cross paths.