4 Stroke CSM

[banderso]

can anybody download the schematic to that thing? I would love to try it.

 

[Brmorgan]

Well here goes... I don't have any pics and unfortunately it's been disassembled now (the engine is on the aforementioned CSM). I got the idea from guys that go 4X4ing - some of them have secondary alternators on their rigs dedicated to welding just in case they break something important out in the bush. Do a google search for "weldernator". The best thing about them is that alternators are by design capable of a 100% duty cycle. They output three-phase AC power by default, but have an internal regulator and diode stack to convert it to DC, so in theory you could also use them as a three-phase power generator if you were to regulate the voltage properly.

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. I also ditched the diodes and replaced them with two parallel three-phase to DC rectifiers as they were much easier to work with. I re-configured the windings from a Wye 3-phase to Delta to give it better power output at lower RPM. Amperage control is achieved by varying the input voltage to the field coil of the alternator. If you use the diodes in the alternator, the case ends up being Negative and the output stud is Positive. My leads came off the rectifiers so that wasn't a concern for me.

You WILL need at least a 10hp engine for this to work well. I tried it with a 5hp and promptly blew the rod and crank from overspeeding it to get enough power when I put a load on the alternator. The instant you strike an arc it completes the circuit of the main coil, which then is fighting against the field coil (basically two electromagnets), so I also would suggest an engine with a good governor like one from a lawn tractor or genset, one that governs the RPM UP instead of down. Without a governor you have to have the engine just screaming so it has enough power to overcome the load of striking the arc. Once you're welding it evens out OK, but a governor really helps. Come to think of it, I actually did move that alternator to my old 18hp lawn tractor for a time so I had a truly mobile welder. It worked quite well on there too. Got some laughs from the neighbor anyway. Of course if you're going to put it on a vehicle and have 150-plus horsepower to work with none of these concerns apply anymore. 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.

That's basically it... It's what I learned to weld on and actually produced a beautiful weld, but it was hard to control the current because it was a mix of field voltage and engine RPM and of course I didn't have a 150A ammeter ($$) so I never really knew how much it was putting out; it was basically a trial-and-error thing. From what I've read the higher frequency three phase being converted to DC agitates the weld puddle much better than old 60hz 240V being converted to DC, and I would have to agree. I also got tired of interrupting a welding project to go and replace a thrown belt on the welder or whatnot, so I decided to drop the cash on a proper unit. Like I said though, my skills are a lot better now so I might rebuild it with improvements. Right now I'm working on my other welder to give it TIG capability so that's my focus ATM.


INFO I USED TO BUILD MINE

 

[harrygrey382]

GREAT stuff, I'm out of rep right now, but they'll be some coming your way. I'm definitely gonna build me one of them... I already have a ~90A arc but a portable one would be useful, and a good project. Could do with a few more amps sometimes too! Thanks

 

[Zodiac45]

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

+1 Absolutely right Slab,

Your gonna have to gear that baby for some chain speed Banderso. Most times I've seen the 4 stroke apps, it's been a band mill. No reason why I wouldn't work though properly geared for decent chain speed. You'd also gain in the fuel usage dept (as Slab mentioned) and should have longevity over the 2 stroke head. I'm going to follow along with this one as I mentioned I have the Briggs 11hp motor sitting on a shelf. They have great torque due too the fact that it's a slow reving large displacement engine. I think mine's a 480cc single or something close to that. Kind of like piston powered airplane engines. The props lose effeciency at too high a speed so the motor has to make it's power at 2500rpms or so. They accomplish this with large pistons. My old Piper Warrior had a 360 cubic inch 4cyl! Pistons the size of paint cans.

BrMorgan,

Thanks for the welder info! How cool is that!

 

[Brmorgan]

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 HERE 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.

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.

Also, has anyone tried using an electric clutch to power the jackshaft, much like the ones on car air conditioning compressors? They're 12V and you could start and stop the chain with the flick of a switch. I have one that should work but it's got a 1-1/4" shaft diameter or something like that, and I was using a 5/8" jackshaft. Never found a way to adapt it down yet, though I guess I could have a machine shop make me a bushing and then weld it on or whatever. Another thing I thought of was using a little servo motor like the ones used to control the innards of model airplanes and cars to control the engine throttle. Just use a variable resistor or automotive headlight dimmer to vary the voltage to the servo to pull the throttle pin back or forth. Whaddya think?

 

[harrygrey382]

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.

Thanks for all that - it's defo going to the top of my to do list. Well, maybe parallel with the compressor... I wonder what my spare 051 motor would be like. Governed too.

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 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..
You can get sprockets with many teeth. I think I've heard of up to 12, but 10 or over start to get hard to find I thin. Try Madisens, I hear they have them all

 

[TNMIKE]

There are one or two Briggs CSMs on this site

http://www.diybandmill.com/

 

[Lloyd H]

electric clutch

I once scrapped a lawn mower with an electric PTO clutch mounted right on the engine shaft, would work slick for CSM

 

[TNMIKE]

The e clutch is the way to go

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.

 

[Lloyd H]

electric clutch

Checked prices on those, wish I would have saved it now. Not sure but I think its gone. I will search the attic though.

 

[Brmorgan]

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.

Don't you have a battery to start the engine anyway? Even a small utility battery will work fine. You might be able to run an electric clutch straight off the charging coil of those larger engines, but without a battery as a charge tank you might burn it out.

 

[banderso]

I have one on a 14 horse Briggs. I was thinking of just popping this whole unit on my mill but It adds alot of weight with the battery and all.

 

[user 19670]

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.

 

[TNMIKE]

My engine is manual or electric start

The engine I have is manual or electric start but since I dont have a clutch I wasnt going to mount a battery. Now if I had the clutch it would be great but they are pricey new.

 

[Brmorgan]

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.

Well, my Lincoln buzzbox AC welder's open-circuit voltage is just under 80V across the +/- of the DC rectifier I put on it, so I dunno. And I know that most MIG machines go above 30V. I certainly won't disagree with you that the higher voltage from the alternator could be more dangerous though. But just try welding at 12V sometime - it's damn near impossible to start a good bead without the electrode sticking. Also, it's much harder to maintain a constant voltage with a rotary coil power source rather than a fixed coil transformer, so it's nice to have that higher voltage to start with.

Not to worry though, I'm building a High Frequency Arc Stabilizer for my welder - 15,000V, 30ma, 300 KHz. It will start an arc at about 3/4". Once I get it built it's time to TIG.

 

[urbanlumberinc]

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.

 

[Brmorgan]

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.

Hm... all your problems seem contradictory. An 8hp four-stroke, especially a Honda, should have WAY more torque than ANY chainsaw head, even an 090 which has a similar HP rating. Mine with the 10hp didn't even noticeably drop any RPMs when sawing a 12" D Fir cant with .404 full-comp chain. FYI, there's no need to gear the engine-to-chain ratio such that the chain is running at the same speed as a 13K RPM chainsaw. I think mine was around 2.5:1 or 3:1. Those big 4-stroke motors are so torquey that if you run the chain a little slower, say similar to an older high-torque low-RPM saw like an 090G, the engine won't even skip a beat and you will be able to just muscle through anything. This is the advantage of a big, heavy crank and flywheel. And way better on fuel too!

I also don't really understand your chain problem either - skip chain usually requires more power to pull since each tooth is grabbing a lot more wood. Providing you have the power though, it will cut WAY faster than full-comp chain, but the cut will be much rougher. No big deal if you're going to plane the wood afterwards anyway. Granberg (makers of the Alaskan mill) make a chain where two teeth are all but ground off so there is only a 1/16" wide "scratcher" on each side - this scores out the edges of the cut - followed by a full chipper tooth that cleans out the middle. I've never used a chain like this, but I have an old milling chain that I think I'll spend some time modifying to try it.

If you're finding skip chain SLOWER than full-comp, I suspect that your sharpening technique needs some adjustment. I'm not sure, but the fact that you say it's cutting slower while not bogging the engine down as much suggests that your depth gauges need to be lowered a bit to let the chain bite in a bit more. Milling chain is super sensitive to sharpening. I thought I was doing a good job hand filing by eye, then I bought a good sharpening jig and my cut times were improved by at least 25% if not closer to 40%. And I'm sure my chain would still garner scoffs and funny looks from the pros here using grinders and the like. But for the amount I mill for personal use it isn't worth it.

For more on milling chain technique try to find a copy of Chainsaw Lumbermaking by Will Malloff. He pretty much pioneered the entire chainsaw milling "industry" and that book is jam-packed with useful information. But it's pricey now and hard to find.

 

[banderso]

Here is an example:

 

[slabmaster]

skip tooth chainvs regular

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

 

[Zodiac45]

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

+1 yep skip was designed too allow saws too pull longer bars than they normally could. Better chip clearance too. The price is slower cutting than full comp at same chain speed.