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Motor for Appalachian style hammer.


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Hello everyone. First post here on this forum. The last time I visited IForgeIron was back when the site was new. WOW! It has came a long way. Great site.

Anyway, my name is Chris Simmonds and I am from Fall Creek, Oregon and have been blacksmithing for about 5 years. I recently have been acquiring quite a few commissions and some are pretty big jobs. I have decided to build a power hammer for my shop and have decided on the Appalachian style hammer. I hope this is the right place to post questions about this but if anyone knows of a forum specific to these hammers please let me know.

My question is regarding the motor to power the hammer. I have an old air compressor that seized up and it has a 1 1/2 horse Dayton motor that runs great. My only concern is that it turns at an RPM of 3400. This seems fast compared to other motors I have seen posted on the net used on these hammers. Also, any ideas on pulley size for this RPM would be great. If someone who has built one of these hammers has any pointers to help me out that would be great also. Thanks so much. Chris

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I built a Rusty-type hammer with a 34 pound ram, and it runs at 220 beats per minute. My flywheel is a 13-inch two-groove cast iron pulley, and the motor has a two-inch pulley that has the grove cut wider so that the belt rides a bit lower, more like a 1-3/4 inch pulley. My motor runs at about 1750 RPM.
1750 x 13 / 1.75 = 237 RPM

My measurements are not exact, but close enough for this.

The motor shaft is 5/8 inch, and the smallest pulley I could find was 1-1/2 inches, but the hammer ran a bit slower than I wanted with that size of pulley, so I modified the 2-inch one to fine tune the speed.

If your motor runs at double that speed you would need a large flywheel pulley in the order of 26 inches if your motor pulley is 1-3/4 inches in diameter.

If you used a 1-1/2 inch pulley, the large pulley would have to be roughly 24 inches in diameter.

The exact speed does not seem to work out because it depends on how deep the belt rides in the pulley - especially the small pulley.

I am running a 1 HP motor, and one thing I have noticed is that the small pulley gets quite hot even if I don't "slip" the clutch very much. There is always a bit of friction in that tight bend that the belt makes in going around the small pulley, and not much surface area to radiate the excess heat. I am a bit worried about overheating the motor shaft seal on the TEFC motor. If you go to a 1-1/2 inch pulley and have it deliver 1-1/2 HP, you might also find that it gets quite hot. That's why I would suggest a bit larger motor pulley ( and the resulting larger flywheel / pulley or the jack-shaft idea that was mentioned earlier).

I also think my "flywheel" is a bit light and/or my spring is a bit too stiff. When I ran it at 240 rpm, the current spikes on the 1 HP motor were twice the rated current of the motor- that's why I backed it off by turing down the motor pulley a bit. Now the peaks are only a bit higher than the rated curent (measured with a clip-on ammeter). The motor works hardest at the top of the stroke when the ram suddenly changes direction. A softer spring would make it a lot easier on the motor, but if it is too soft, the maximum speed of the hammer has to be reduced. If you exceed the resononant speed of the hammer as determined by the mass and the spring constant, the ram will tend to float or hit erratically.

I did put a counter-wieght on the flywheel equal to about half the weight of the pitman arm and bearing to reduce vibration.

If you can't come up with a reasonable pulley combination for that 3450 RPM motor, try scounge a 1760 RPM motor and use that high RPM motor for a belt grinder. That size and speed of motor would be great for a belt grinder if you don't already have one. I built one and don't know how I got along without it for so long!

I hope that helps a bit.

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Thanks for the formula Jr. That will be sure to come in handy.
jj2k - How would I construct a 'jack shaft'????
DonS - Thanks for all the great information. I am sure I will have alot more questions as I start this project. Do you have any pictures of your hammer? How did you construct your flywheel? Ha Ha. See I am asking more questions already! I do have another 1 1/2 horse motor that turns 1760 but it is currently on a compressor that works even though it is very old and I never use it. I am thinking about scrounging that motor. It also has a double belt 14 inch cast iron pulley. I was just hoping I could use the faster rpm motor so I wouldnt have to disect my old compressor.

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Simmonds, a Jackshaft is just an intermediate shaft set in it's own bearings running between the drive, and the driven pulleys. I.e. a belt goes from your motor pulley(A) to a pulley(B) which is key'd into the jackshaft. Motion is transfered through the free wheeling jackshaft to another key'd pulley© on the jackshaft, and from there through another belt to the driven pulley(D) on the hammer.
In effect giving you four pulley's to adjust your speed with instead of just two. and avoiding such large jumps in pulley size.

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Johnny99 - Thanks for the reply. That makes sense. Hmm, not sure if I want to go that route or not. I just found another motor I have - a one horse craftsman motor that turns 1750. It is half a horse less but that seems to be what most use anyway. The problem is the motor has been outside hiding in the blackberries for the last year through rain and all. I just dug it out and I can even see a wasp nest inside the motor. Do you think this motor can be saved and used? Guess I should take it apart and clean it up before trying it out. Chris

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Simmonds, I just posted some drawings and pictures of my power hammer. I built it about 2 years ago. It works OK, but is not spectacular, probably because I made the springs a bit too short (due to limited space). I used a relatively short anvil and initially had it on a trailer so I could move it out of the way. That did not work out so I placed it on a heavy bench, high enough so that I couls park the lawn mower under it, again due to a space problem. Have a look in the Gallery under recent uploads or under DonS.

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A 3400 rpm motor is going to need some serious jackshafting. On my mechanical hammer, I was able to just get by without a jackshaft by making my own small motor pulley, and because I found a rare 1100 RPM motor. I helped get a friends 35# Champion hammer running with his 1725 RPM motor. We used flat belt pulleys he had scrounged, plus one I made (see Blueprint BP0245), with the formula Irnsrgn posted, and got the hammer to run 275 BPM. I'll try to stick on a pic of the Champion jackshaft set-up.

2621.attach

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If you have access to a 1/2 hp 1750 rpm motor, I think you should go for that. That's what I run on mine and it does fine. What you'll save in bearings and stuff for a jackshaft would offset the cost of a new 1/2 hp motor. harbor freight offers an inexspensive one to get you sytarted if you are strapped for cash. Junk yard hammers are great and they have thier place but don't scrimp on the power train. In the long run you will be happier with it.

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DonS - Thanks so MUCH for the great pics and the drawings. That hammer looks really well made. When you say it works 'OK but not great' what do you mean? does it not hit hard enough or ??? Thanks again for the reply and the great info.

jj2k - I found a 1750 rpm motor but it is 1 hp. That should be a great motor if I can clean it up and make it usable. From what I have read the one horse motor is better than the 1/2 unless you are building a 25 pound hammer or less where the 1/2 horse will be plenty efficient. I will play around with the motor in the morning and see if she is going to work.

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I set up my Rusty style hammer drive with a 24" doughnut tire & rim--1 hp 1750 rpm motor & a 6" shop made oak drive wheel. The hammer is 28 lbs. and the speed control is great. A picture is in the gallery. It took a little effort to get it adjusted (throw length, clamps on the stacked leaf springs for flexing mainly) but it runs smooth. My Grandsons love it!

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Simmonds, you can make a jackshaft very easily by scrounging up an old motor that doesn't work, and stripping all the guts out of it. Whats left is a shaft, mounting brackets and bearings. CUt the casing in two, add a couple of pulleys and Bob's your uncle.

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JerryCarroll, Thanks for the pictures. That helps alot and gives me another option for the construction of my hammer. I wish I could see some video or something of one of these hammers in use. I will have to fix my profile and add my email address.

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JerryCarroll, I also really like the way that design eliminates the need for a v or flat belt. The only advantage I can see in having a belt is it can be made to slip with lighter pressure to adjust the speed of the hammer.

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Simmonds,
I think what Don Means about the hammer being "ok but not great", is a pretty fair assessment of this hammer. My hammer is a 25 pounder. And like Dons it is ok but not great. However it is a bunch better than nothing which is what I had before I built it. Mine was cheap to build and only took one weekend to construct. But it did sit there and didn't get used very much for about the first 3 months. I didn't know how to use a power hammer. There is a learning curve involved here. Take your time and think about things a lot before jumping in to heavily. Talk to some folks who have and use power hammers. Get some opinions and instruction. No sense in re-inventing the wheel, right? I use my little hammer for for texturing mainly. I have made a lot of homemade dies for doing random impression work. I use a quick change die set up on all my hammers. These hammers will move metal ok. But not like a 50 lb Little Giant. My 50LG made a big difference in my shop. But my "Rusty" Hammer has made me a lot of money also. Each hammer has their place just like a coal forge and a propane forge each have their place. Build your hammer, play with it, and enjoy it. They are fun to build and fun to work with.

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simmonds, in this area there is a lot of metal working been going on for a long time. The Garey Ind. mills are only an hour away and a lot of smithing stuff in the past has been made in this area. Chgo. Hgts. is south of Chgo. a short distance and has had manufactors of forges--blowers & other tools. There is several spring shops, some you can deal with and others that only cater to the big guys. Here in Momence there was a spring factory named Tuthill. When they closed there was a lot of flat stock stacked back in the corners and I was lucky enough to know the new owners of the building. A lot of things went quick--like the power hammers and tooling for them. If I had known then that I was gonna get hooked as hard as I have been on beating hot iron I would have gathered a bunch more than I did of the good stuff. Check your phone book for spring shops and with luck you can probably come up with a supplier. Good luck!!

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