Newbie Questions on Milling with a Chainsaw Mill (homemade)

[n8ghz]

Hello, as a complete newbie to Chainsaw Milling (never even saw one except in pictures), I have been reading here and elsewhere for ideas.

I have read about ripping chain & the values thereof.
I have read about the high HP required for non-boring performance.
I have also read where alot of folks use regular chisel-chains where size of the kerf is not a concern.
I have read about narrow-kerf chains for those that do care.
I have read about auxillary oilers for long bars..or for any bar? (too much oil not being a bad thing?)

My main Q's right now, having just started building a carriage to run on a ladder:

Is it possible or not desirable to mill in both directions ie: cutting off of the top of the bar as well as the bottom? My bar will be supported in all directions near the roller-tip rivet (chainable tip bar)
This would allow changing depth of cut after first cut and going back the other way cutting off of the top of the bar.

This is a question that I guess even pertains to hand-held sawing.......say you put a 36" bar on a fairly powerful saw, but only sawed say 22" logs that were a PITA for a 18 or 20" bar.....is the HP requirement of the 36" bar in that useage any more of a power-hog than a 22" bar or smaller?
I realize that there is more bar-to-chain friction, but it can't be that significant can it?

I will probably set this thing I am building up with a 20" bar, but am making it so the bar support can work with a 24",28" or maybe the 36". Even with those bars, I doubt if I will ever cut anything that those would allow for width. I figure about the biggest logs I have would be 18".
Unless I really get a kick out of doing this, it is only for hobby use....and mostly because I enjoy building things and simply want to see Me making a board or a post.....ha ha

I am sure I will have more questions if anyone cares to comment.....all comments will be welcomed.

Thank You

 

[sachsmo]

Take your time, milling ain't cookie cuttin'.

You can use regular full chisel chain, but I would re-file to a 8 to 10 degree top plate angle.
I have only used semi-chisel for milling.

 

[n8ghz]

Another question

I thought of another tidbit I've been wondering about.

I am planning on power advancement using a small gearmotor that is 2.9 RPM @ 120vac.
I have played with the math on different diameter winch spools to wind 1/8" cable (or smaller) in a controlled single wrap as to speed.

My initial calculation is 1/8" cable on a 1" spool @ 2.9 RPM (120vac)...that is 10.5 minutes to cover 8'.

Is that about right for speed thru a log with a chainsaw mill?
I know the type of wood & it's dryness, etc. are big factors.

I have played with my little gearbox and have run it via a variac....I can go slower
and I can go faster if I use a larger diameter spool.

I have looked at U-tube videos of a few CSM's and they are walking...kinda....slowly pushing the rig....I think I can match that with this winch....but have not built it yet

 

[mtngun]

My initial calculation is 1/8" cable on a 1" spool @ 2.9 RPM (120vac)...that is 10.5 minutes to cover 8'.

I don't think power feed is a good idea on a chainsaw powered mill. It would stall if you pushed too fast. Or waste time (and over rev) if pushed too slow.

Perhaps you could get away with it on a 4-stroke CSM.

10.5 minutes to mill 96" = 0.15" inch/sec, very very slow. Real life CSM speeds will be 0.25" - 1.0" inch/sec depending on log width and chain sharpness.

 

[BobL]

Is it possible or not desirable to mill in both directions ie: cutting off of the top of the bar as well as the bottom? My bar will be supported in all directions near the roller-tip rivet (chainable tip bar)
This would allow changing depth of cut after first cut and going back the other way cutting off of the top of the bar.

Yes it is possible but the operator will have all the sawdust squirting out all over them, also the controls/handles will need to be set up for use on both sides. It's actually no big deal to pull the carriage back and I prefer that more than have to operate it from each side.

This is a question that I guess even pertains to hand-held sawing.......say you put a 36" bar on a fairly powerful saw, but only sawed say 22" logs that were a PITA for a 18 or 20" bar.....is the HP requirement of the 36" bar in that useage any more of a power-hog than a 22" bar or smaller?
I realize that there is more bar-to-chain friction, but it can't be that significant can it?

Chain friction is in the noise for a well adjusted well oiled bar. Of course if you try and cut with it that's different
I saw everything down to about 18" in diameter with a 42" bar

I will probably set this thing I am building up with a 20" bar, but am making it so the bar support can work with a 24",28" or maybe the 36". Even with those bars, I doubt if I will ever cut anything that those would allow for width. I figure about the biggest logs I have would be 18".

That's what everyone says :smile2:

 

[BobL]

I thought of another tidbit I've been wondering about.

I am planning on power advancement using a small gearmotor that is 2.9 RPM @ 120vac.

Power advancement would be OK on a CS mill where the powerhead is big and the logs are small but otherwise I agree with mtngun that it could too easily bog the saw.

I'm a fan of sloped versus any sort of winch assisted Alaskan CS milling. If you get the log up on a slope using a hi-lift jack there is no need for a winch as the weight of the mill and saw provides plenty of forward pressure. This is why I have never explored building a carriage style mill.

 

[rock]

If your near medina ohio you can pm me
i will be milling between the rain next few weeks
Track mill 20" bar and granberg 36" to 60"

 

[n8ghz]

On the power feed idea, I think I will re-think that after I see for myself what kind of advancement speed I can achieve by pushing by hand with my setup.

I hope to get some pics posted soon, as I have enough of it built to show it.
I made the outboard bar support and tip guard with the oil needle-valve on the guard right above the sprocket roller. I have read about the oil flow from various aux oilers changing as the reserve's level drops. I am going to pressurize my tank with air. That will allow me to not mount it high above the machine, and should solve the irregular flow thing.

Thanks for the basic speed guidelines. On the comment about getting chips all over the operator if cutting in both directions....with a power feed, you don't have to be near the chips being thrown on either side. I'd be sitting near the speed controls of the winch watching. But as I said, that may or may not even get attempted....gotta see it cut a little bit first.

 

[BobL]

On the power feed idea, I think I will re-think that after I see for myself what kind of advancement speed I can achieve by pushing by hand with my setup.

A wise choice.

I have read about the oil flow from various aux oilers changing as the reserve's level drops. I am going to pressurize my tank with air. That will allow me to not mount it high above the machine, and should solve the irregular flow thing.

Same thing will happen - the pressure will drop as the free air volume changes and less oil will run out. One way to reduce this effect is to have a large high pressure chamber containing a small amount of oil so the relative change in free air volume does not change much but the amount of oil would run out quickly and I don't know If I would like a container under high pressure attached to the mill. I've found the simplest way to get around this is to have a manually adjustable flow so as the oil level drops the valve can be opened up. Of course this requires the operator to be up close and personal and pay attention at to what is going on.

On the comment about getting chips all over the operator if cutting in both directions....with a power feed, you don't have to be near the chips being thrown on either side. I'd be sitting near the speed controls of the winch watching.

I misunderstood what you meant, it won't be a problem because on the way back most of the sawdust will be thrown off at the nose. I'm not sure how significant this will be but some power might be lost on the nose by cutting on the back side of the bar.

 

[TMAR]

Is it possible or not desirable to mill in both directions ie: cutting off of the top of the bar as well as the bottom?

I have a Procut setup and I always saw with the top of the bar. Like Bobl said- the saw dust all flies away from you.
Another thing is that the oil rides over the top of the bar first and the bar and chain are well oiled during the cut. I have never used an auxiliary oiler.

 

[bigjohn1895]

it may just be me but when i tried to mill backwords mi will always tried to cut up leaving me with wavy boards or thiner on one end then what i started cutting

 

[n8ghz]

The oil tank I'm making will hold .3 USG. There won't be much room for any apprecable volume of air @ that level, I guess I could fill it half way...for 50-50 oil to air? I have tested it under water to 120 PSI, but have to add a couple of bungs yet. I don't intend to run that much pressure, but it is nice to know that I could. I'll try it here tonite, dribbling into a tin can...playing with the needle valve.....probably start with a full tank and 40 PSI. I will adjust the needle valve for a guesstamate of what might help oil the bar and see how long .3 gallons last and what happens to the air pressure and flow rates as the pressure drops,etc. I will have a pressure gauge on it for monitoring pressure.

I had to take a buddy to the doctor this morning, so am getting a late start on the build.

 

[WadePatton]

running the mill both ways would be a major pain if one slopes the log for gravity feed...:hmm3grin2orange:

(but i have pushed a few wet ropes uphill in my time-or tried to.)

if you must attempt power feed, you might consider a slipping mechanism-clutch of sorts to maintain proper feed pressure (which might vary by cut) w/o bogging thesaw. A torque limiting device-yeah, tha's the ticket.

carry on.

 

[n8ghz]

i like the clutch idea, that is do-able.

 

[WadePatton]

i like the clutch idea, that is do-able.

certainly. i'm not all hot-air and sundrop. :msp_thumbup:

i'm a/k/a w1ade. 73

 

[n8ghz]

Another reason I am interested in power feed, is now that I have built a roller table to run on a ladder, I intend to add an additional bolt pattern to allow me to bolt on a support post with lateral adjustment for a machine cutting torch. All of the saw stuff is removable, and I can use part of it's mount for the outboard bar support to hold the torch bar. I have other ways to cut steel, but on occasion I have wished that I had a track torch. I have had the torch for years, just no track or motor drive. Now that I am getting interested in the CSM, I can have both.

To W1ADE, 73 to you also.

I have been thinking about the clutch idea. Right now I am leaning toward making my little gearmotor on a slide with an adjustable over-center lever so I can move it toward the winch spool with varying tension and latch. I am thinking of machining a disc-brake pad round like a puck and putting it on either the spool or the output shaft with a plain steel plate opposite it.
This would allow me to control the slip somewhat. It will also allow me to free-wheel the winch spool and roller table to wherever I want it along the ladder track and then latch the gearmotor pressure plate into mesh.

I did some more calculations on the gearmotor RPM's thru the variac. I misread the label on the gearmotor to be 2.8 RPM, and what it really says is 2.8 FL and 9.0 NL. So running that info thru an excel sheet I made, gives me just what the fellow gave for approximate feed speeds... .25-1.00 inch/p/second from 2.25 RPM to 9.0 RPM. I can get 2.25 RPM with the variac and these calcs come out perfect for that speed range using a 2.125" spool.

I am now going to build the winch, even if I don't like it for the saw, It will work for the torch.

 

[john taliaferro]

If you could use a small nylon rope or maybe put a bunge coard in the system it might provide slack to pull the mill backwards if it did stall the saw . Ive been thinking after pushing up hill yesterday for two hr on some small pine for a friends bird house projects . A rope over a limb with a weight attached would work for every one but Daninvan on the Beach .

 

[n8ghz]

i'm going to use 3/32" SS cable on the winch, but am also thinking of using a spring on the connection to the slide, if for nothing else, but to maintain taughtness in the cables. It will add some additional 'give' if it's not too strong. My plan is to have two cables on the spool, one coming off the top of the spool and one coming off the bottom, so as to be able to run both directions, with the spring as a tensioner.

 

[Talltom]

Not sure why you're focusing on a power feed rather than a simple hand crank that you can control. Feed rates will vary by a factor of 10 or more based on width of cut, type of wood and sharpness of chain. When I'm edging boards at 4" or less I don't even use the crank because I can't crank it fast enough. When I'm cutting a 24" hickory, I may take a minute to cut a foot. A hand crank can exert plenty of pressure - enough to really bog the saw if you're not careful, so it will more than meet your needs for feeding the cut. The best clutch to use for CSM feed rate is your brain.

 

[n8ghz]

That is good advise and the speed thru hardwood along with the health of the chain,etc are good info. As I said when I started this thread, I have never ripsawed anything with a machine-held saw. Doing it will be new to me.

Also, as I said, having built a workable slide that holds a saw and runs along a ladder for a track, if I use the slide as a track-torch too, motorized is a plus for that app. We'll see if it is an exercise in futility with the saw......?

BTW, on your example on hickory, @ my slowest speed It would be .8 minutes per foot, not counting any slipage or if I lowered that speed control so it actually stopped advancing.

Not being a knot-head, and a dummy to boot, I will certainly run some of my first cuts by hand.
I have no idea how my saw will handle ripping. I have hand-cut thru some crotch logs to be easier to log-split, and that was impressive.

I use hydraulic saws.

I have a double-ender bar if I think I want to try 2 hydraulic saws on one bar.
If so, I would have a 36" width cut capability. I have read about balancing 2 gas saws on such a bar, and for the most part, it sounds like a tough thing to do....ie: waste of money?......however, balancing 2 hydraulic saws would be rather simple ...the fluid would do it? But that remains to be seen.....if I get this going, I may try it....i have enough parts to do it.