The h.p. gives you power ,not speed.A 4 stroke won't have the rpms that a 2 stroke has,so a gearing would be in order for this kind of mill.The gearing on the jack shaft would determine the speed on the chain.Just my thoughts on this kind of mill which is a great idea.Would save on oil and gas. I've thought of building one myself.As i prefer csm over bandmills. Mark
Thanks for the welder info! How cool is that!
No problem, though it feels like I ended up hijacking this thread. My design was for all intents and purposes the same as the one http://oak.cats.ohiou.edu/~weinfurt/gaswelder.html with the exception that the fuel tank was part of the engine on mine. I would honestly prefer a horizontal shaft engine because it's much easier to build a belt tensioning mechanism that works WITH gravity instead of against it. The main problem when I built mine was that I had no welder at the time, so it was all bolted and/or clamped together and then welded up while running, and I dunno if you've ever tried welding something that's moving, but...:censored: :censored: :censored:
One thing I forgot is that you MUST make sure that the alternator case ground is electrically isolated from the battery negative and (preferably) the frame it's built on. Otherwise when you strike an arc it's possible to feed a few dozen if not hundred (positive) volts at high amperage into the negative terminal of a 12V battery.
Another tip is to build a good choke coil and capacitor line filter - this will greatly help reduce any voltage or current drop-offs that occur as a result of striking or changing the length of the arc. The initial arc causes the engine to bog down for just a second, but this of course changes the voltage of the alternator output so it's easy to lose the arc or make a messy weld.
I guess it depends on belt tension/size... I wouldn't have thought 325 would be such a good idea. I guess you could take the rakers down but I'd stick to 3/8... Much more common, stronger, bigger bite, less sharpening etc..To get this thread a bit back on topic, do you think it would be unwise to use .325 chain with an engine like this? Mine had .404 but that's just what I had lying around at the time. .325 would HAUL A$$, and with a belt drive, I think the belts would slip a lot faster than a large saw's clutch would, so maybe it wouldn't break as easily as if, say, on an 090? While on the topic of chain, you may as well get whatever sprocket you can that has the most teeth. Do they make more than a 9 tooth? That's the most I've seen.
I would love to find a junk one for my band mill. Solves a few problems with belt tension etc. The only draw back is you have to mount a battery.
Brmorgan; I ripped out the regulator because it's near impossible to weld with only 12V - without the reg it put out almost 175V which draws a nice arc. . . . Something I've seen other guys do as well is use a small aircraft generator. They're bigger but some can put out 250-400A if you need it and most are 24V I believe.[/QUOTE said:Egad! One thing you will learn in welding school is that most home welders are limited to 24 volt max. for safety reasons so you don't fry yourself. 175 volts is downright lethal with those amps.
Egad! One thing you will learn in welding school is that most home welders are limited to 24 volt max. for safety reasons so you don't fry yourself. 175 volts is downright lethal with those amps.
I tried just what some of you guys describe awhile back - a geared up CSM that used an 8 horse honda for power. Found out pretty quickly that the 8hp lacked the torque. I thought about trying to find a small diesel, but even used ones are too pricey for this outfit. At present I'm working on a design that uses a hydraulic drive unit I salvaged off of a wrecked walk behind mower. As you would imagine these wheel drive units dont turn at the ideal rpm's for chainsaw milling, however, they've got loads of torque, and I'm thinking It'll probably pull the chain with plenty of torque.
One sidenote- I did have some sucess with the honda powered unit by modifying the chain. I ground off every other set of cutters. It cut well, and definetley solved the torque problem to some degree, the unintended consequence was that it cut slow, really slow in fact.
Skip chain requires less power to run because there is half as many cutters cutting.They don't cut any deeper than regular chain because the rakers won't allow it.I use skip chain because it's easier on the saw.If it's sharpened to 10 degrees or less,it leaves a nice surface as well.Mark
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