Re: Propane forge

Hello Arnar, I liked seeing your "trip hammer" design. Simple and elegant. How does it perform? Do you have any plan sheets for it?
Glen Gardner, Pittsburgh, PA
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The trip hammer perform great. Yes, I have plans and more pictures of details. The motor speed is controled by a frequency converter.
If you or others are interested, please contact me. ( The hammer is also for sale)
Arnar Haugedal snipped-for-privacy@broadpark.no
This is my new propane forge se pictures at http://www.eurofoto.no/fotoalbum.php?aid "3730&portal_language=no_NO
Arnar Haugedal (Norway)
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I thought I would add that there is a lot cheaper, and in my opinion, better, way to control the motor speed, other than frequency converters. I set my power hammer up with a variable speed drive using an adjustable "Hi-Lo" spring tension pulley on the motor. There is a hand crank motor bed that moves the motor in or out for speed changes. It costs a small percentage of a variable speed drive, and is more reliable....nothing electrical to fail, and is just as quickly adjustable as a frequency converter. Another nice thing about this method is the motor speed stays at its rated run speed. I describe the construction and operation of the power supply on my Forge and Foundry Page if interested. Here is a link to an image of the finished variable speed power supply I built for my power hammer.
http://www.reil1.net/motor.jpg This is a 1-1/2 hp system, but you can set one up for just about any horsepower you might need. This system has an output rate for the hammer of 125-325 hammer cycles per minute, but you can shift that to whatever range you want by simply changing the fixed pulley size. Here is a link to an overall picture of the hammer prior to it being moved into the shop.
http://www.reil1.net/easyham.jpg This is a 35# rated Little Giant "Easy Hammer," but it has the striking energy of at least a 50# hammer due to the helve action.
Ron
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Golden Age Forge
http://www.reil1.net/gallery.shtml
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Arnar Haugedal wrote:

I don't have a link but snowmobiles use them so you might check with a dealer.
Ted
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wrote:

I don't believe that any variable ratio pulley made of springs and sliding parts can be as reliable as solid state electronics. That's the most reliable thing we know how to build. It seems the machinery manufacturers largely agree, since most have abandoned mechanical variable speed drives for solid state inverter drives.
Gary
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On Tue, 05 Aug 2003 19:16:47 GMT, snipped-for-privacy@swbell.net wrote:

True, the main one is availability of spare parts. Electronics technology moves rapidly, so parts don't stay current very long. But the parts themselves are very reliable, much more so than moving mechanical parts. They don't wear out, they only fail if overstressed.
BTW, the problem with electrolytics was solved a few years ago. You can now get large value capacitors with basically indefinite life.
Gary
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Apparently you have not used variable pulleys. Look at the "Hi-Lo" page, http://www.hi-lo.com/pages/prod_DCv_2.html , and you will see a device that is pretty much proof against failure. You only need the part that is shown in the picture in the center right of the page, and a carrier to move the motor, http://www.hi-lo.com/pages/prod_motorbases.html . You could get ten of these for what a frequency converter set-up costs, and it will last as long or longer.
Ron
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wrote:

I've used, repaired, and replaced more than my share of variable diameter pulleys. The problem is always the undamped spring allowing the cam followers to chatter on the cams. That causes excessively rapid and *uneven* wear of the cams. Then the sheaves start to wobble, and wear accelerates exponentially until the pulley disintegrates.
There are no moving parts in a VFD to wear. The electromigration problems of 30 years ago have long been solved. The components won't fail unless you feed them too large a voltage (lack of proper power conditioning), or allow component temperature to exceed its rated maximum. A well designed VFD has spike suppression, over voltage shutdown, and over temperature shutdown built in. It should perform the same as new for many many years.
I didn't find a price on the variable speed pulley and motor platform you mentioned, but a 2 hp VFD from Dealer's Electric is $170. I doubt the Hi-Lo pulleys and platforms cost under $17 each (you said I could get ten of them for the price of a VFD).
Gary
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I'll throw in with Gary Coffman on this one. I use a lot of VFD's at work. Currently, I have 21. I've installed others in the past. Before that I used DC drives. several decades ago, I used Reeves (variable pulley) drives. I have not had a vfd failure yet. I did have a few failures on DC drives, and the Reeves drives required a quite a bit of periodic maintenance. The variable speed drives were considered latent mechanical hazards due to the springs employed.
In addition, the vfd's and DC drives give me the precision I need (variable speed pump drives for precise flow). The Reeves never did due to belt wear. They drift.
In my home shop, vfd's give me 1 to 3 ph conversion plus the speed control. I do have several variable pulley drives. The one advantage of the variable pulley drive (as pointed out to me by Leigh Knudson) is that they serve as torque multipliers while decreasing speed. This is useful for manually controlled machine tools. VFD's are constant torque. However, you shouldn't run them at tremendous turndowns unless the motor they're driving is designed for it.
I prefer VFD's. My experience is the reliability is second to none, and the price has come down tremendously. The variable pulleys will work, too. Just be aware of the maintenance.
Pete Keillor
On Fri, 15 Aug 2003 11:18:49 +0200, "Arnar Haugedal"

the advantage with a VDF is that you can start and run the motor very slow, and with full power even if it is just moving. The drawbacks are that it is very expansive, and also a little complicated to adjust (for me?)

vary the speed from 0 to full rotation and with full power? However, of cause the construction I think is more rugged and simple, and much cheaper?

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Here is interesting link about DRAX Propane burner that preheats air and propane to get hotter flame.
http://www.maran.co.uk/drax.htm
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Hmmm, it says that "Everyone knows you can't melt steel with an ordinary propane burner." Wonder where I have been, because I didn't know that. I guess I best e-mail Dave in Florida that his tool steel making furnace can't melt the iron, chromium, tungsten, and other alloying metals, he uses to make his steels. It is done with nothing more than a blown "Reil burner." I have pictures posted on my site.
You don't need to spend $$$ on patented technology that doesn't do anything more than you can already do with the technology freely available to you on my web site. If you need those kinds of temperatures they are easily available without messing around with recuperative burners.
I am not taking a shot at you Mr. Duncan, the link is appreciated. I just hate to see guys spend money for technology that isn't any improvement over what is available for free.
Ron
Golden Age Forge http://www.reil1.net/gallery.shtml E-mail: snipped-for-privacy@reil1.net Boise, Idaho
R. Duncan wrote:

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