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I Forge Iron

KMG grinder clone


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Hay good luck with your bild I hope it goes well. I welded mine insted of bolting together to save time. I got the plans off Don fogs website. I bought my contact wheels frum usa knife supply they where the chepest I could find. I used a 10" contact wheel frum grizlee and had a machine shop put bearings in it. I alson converted the platten and tool arm like Ed Caffery. You can see his tool arm mods on his web site. I also made my own small wheel atachment. I used a 1 1/2 horse with a step pulley set up and it had plenty of power. I monted my motor underneath on a hinged platform that could be rased with a foot pedale on an ecsentric. I am curentley changing to a 2 hp with a vfd.

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Looks great. I will be welding mine as well, and I thank you very much for the info. The contact wheels seem to be about the most expense from what ive seen so far, but after seeing one of these at work durring a hammer-in this summer I beleive they are well worth the time and money

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Yes speed control is very good to have if the motor has the hp you need. You will need 1 1/2 to 2 horse at least anything less will bog dawn real bad and over heat the motor. Varyable speed is best but a three speed step pully set up is ok. I just switched frum step pullys to a vfd infanet speed controler on a 2 hp motor and love it.
Steve.

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It is a two horse motor, I was kinda thinking of putting a step pulley system in play as well, the combo of the pulleys and the speed control should make for a pretty adjustable machine I think. I cant wait to start building it, but alas I have a few loose ends on other projects to tie up first and the annual spring cleaning and yearly equipment maint. knocking on the door so id say i have a few weeks to think on it before I get started. Thank you very much for the info its been very helpful, and great pics of yours as well. Ill get some pics of mine up as soon as I get started on it, well if the gallery deal is working by then anyway

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Fosterob, i have a 1- 1/2 dc motor with a dc speed control and it is supposedly constant torque. doesn't flinch at all when i'm doing heavy grinding. Of course i bought the dc motor new and the controller new. Nathan here is a link to a good source for parts and such: http://www.beaumontmetalworks.com/
I started with a treadmill motor, i fried it, ordered a new motor (went with a dc motor because i had a dc speed control) got the new motor, hooked it up and realized it was the controller. since i already had the dc motor i had to buy a new dc controller. If i were to start from scratch i would buy a vfd with an ac motor.

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  • 6 months later...

Fosterrob, I believe you're thinking of one type of AC motor. DC motor torque curves are VERY vertical meaning they start with high torque at low revolutions. Locomotives are Diesel generators running a generator to power DC motors. DC motors have a few advantages and several disadvantages. The advantages are they have low rev torque, high power to weight, and precise speed control. AC motors are less expensive because with a few exceptions, they don't have commutators, brushes, or diodes to worry about. With the advent of Variable Frequency Drive, industry largely moved towards AC motors to save costs on applications previously dominated by DC motors. There is a hybrid design called a universal motor which is a combination of a DC and and AC motor. These are frequently in power tools and bench mixers. While limited in horsepower and torque, they make up for it in versatility and reasonable cost.

The least expensive option is generally to use a simple AC motor of sufficient horsepower. One idea that hasn't been mentioned is to add a flywheel. This would tend to counteract bogging down without requiring greater horsepower.The down side is that it won't help you for a sustained hogging out operation. When it comes to grunt, regardless of speed, the AC motor must have higher horsepower ratings. With higher HP ratings come thicker winding's which can handle more heat. Heat breaks down the insulating varnish which leads to winding failure.

If you can afford it get a TEFC which means Totally Enclosed Fan Cooled. These have sealed bodies that don't allow debris or dust to enter the housing and break down the bearings. They have cooling ribs on the exterior and a shaft mounted fan that blows along the exterior of the housing.

Look for electric motor rewind shops. Often motors under 25HP are simply replaced because Chinese imports are less expensive than paying to rewind them. Since most folks don't know that, the shops end up knee deep in dead motors. Often they'll take quality motors like Baldor and rewind them for resale. Generally they price the re-winds on par with the new Chinese. Depending on the shop, they're a better deal if they've got new bearings in them.

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