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Chain saw bars

Started by shelbycharger400, September 01, 2012, 12:17:20 PM

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shelbycharger400

After reading stihls webpage about the rails hardened, and center of the bar flexible, now I understand why my bar on my mill bends some  sometimes but springs back.

Anyone know of solid bars that dont flex?  Anyone try to make their own and use a factory tip ect.  I have access to a bridgeport or several  ;D .  My csm uses a 36 in bar, for 80 bux but If I dont have to spend $600 for a big bar (84 inch) Id rather take a few hours and a few nights and make my own.  I do have access to centerless grinders and a big oven to harden it.     

tyb525

Is your bar supported on the tip? If it is flexing sounds like you might have an alignment problem.
LT10G10, Stihl 038 Magnum, many woodworking tools. Currently a farm service applicator, trying to find time to saw!

shelbycharger400

It flexes in the middle.  Only really happens when the chain gets dull, or if I push the mill too fast in oak.   I have a 5 ft dia cotton wood comming, gets wider as it goes up, over 6 ft dia at top,  but have a few 3 ft maples, 2-3 ft dia red oak,  and a few 4 to 5,  and one 6 ft dia maple ,   one section of a silver maple that i want to slab with crotchwood that is over 6 ft at just 8 ft from the ground.   I need a 8 ft bar at minimum, and I dont want any bowing.

tyb525

Sounds like you figured out your problem, chain dull and/or pushing too fast.

You won't find any kind of steel as thin as a chainsaw bar that won't flex over a span of 8 feet, and if you somehow do, it will will be brittle as all get out.
LT10G10, Stihl 038 Magnum, many woodworking tools. Currently a farm service applicator, trying to find time to saw!

Clam77

I would think titanium might be better for a bar that long...  expensive as it's going to be..    :-\
Andy

Stihl 009, 028, 038, 041, MS362
Mac 1-40, 3-25

Devon

I have had the same problem.  I think any long bar is going to sag in the middle when it is horizontal and supported on both ends.  I have toyed with the idea of using one of those super-duper magnets to mount on the mill above the bar (and above the log).  This would negate some, if not all, of the gravitational pull.  It would add weight and the magnet would need to be sized properly.

Al_Smith

Those old Mercury /Ditsons from the the late 50's  had about an 8 foot bar that was 7-8" wide .I doubt they bent too much .Cannon could probabley build you a bar that won't bend .It would cost a kings ransom though .

Now a Bridgeport milling machine is the icon which every other one tried to be .I own one myself albeit a small model M. I've seen a lot of them but never one large enough to mill out a long chainsaw bar .

shelbycharger400

Yea, Al..  its going to be fun setting it up in the bridgeport. .. 2 vices dialed in to one tenth. Buddy's mill has a 60 inch table I believe.  So it will be a mill, slide it down, mill, ect .  The machining shouldnt be too big of a deal. He said he has done something similar to it before.  Just looking out for ideas and tips.  Anyone know the alloys ?

Al_Smith

Say what,1 ten thousandths of an inch over 60 inchs of travel ?

Al_Smith

While not being able to find exact specifics a Google search found the general concensus as infering most bars are made of O1 steel .

It seems knife makers are fond of recycled bars for knife blanks .

Now this stuff is pretty hard even before it's hardened so how a person would cut it on a milling machine even with carbide tooling remains a mystery .Even more so would be how to groove it .

I'd venture a guess if it was machined without the use of coolant the steel would work harden and thus in short order it would get so hard you couldn't do anything with it .If you then anealled it you're right back to square one and spend hours just getting the set up back to where you started .

Keep in mind also that should you have good luck machining the bar then it has to be heat treated .Then comes the challange of keeping the part from warping .After that it has to be tempered back because O1 will fully harden to around 65 Rockwell which would likely be brittle like a file .So what I'm alluding to is this project will be quite a challange .Best of luck .

tyb525

I think there is a reason we pay good money for the companies that have figured out how to make good chainsaw bars :)
LT10G10, Stihl 038 Magnum, many woodworking tools. Currently a farm service applicator, trying to find time to saw!

John Mc

Quote from: Al_Smith on September 09, 2012, 09:38:35 AM
While not being able to find exact specifics a Google search found the general concensus as infering most bars are made of O1 steel .

...

I'd venture a guess if it was machined without the use of coolant the steel would work harden and thus in short order it would get so hard you couldn't do anything with it .If you then anealled it you're right back to square one and spend hours just getting the set up back to where you started .

I'm not familiar with O1.  Is it an air-hardening tool steel?

Regardless, this is going to be quite a project, for all the reasons you mentioned.  Keeping steel from deforming when heat treating can be very tough, especially for the shape under consideration here.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Al_Smith

O1 is oil quench tool steel .I forget the exact content obviously enough carbon to harden ,some vanadium ,maganese probabley ,probabley some silicon .

I wouldn't doubt the bar makers might have some specialty stuff .They might use induction hardening also rather than soak heat from a furnace .

Not claiming to be an expert on bars I have noticed they seem or at least some of them to be harder on the rails and less so on the main portion of the bar which leads me to believe induction hardening .I do know it just about takes a solid carbide drill bit to punch a hole in one .High speed steel you might get lucky and get one hole .

shelbycharger400

4 tooth carbide endmills that are tin coated will bore a hole ,  also they work awsome in "drilling" out broken off grade 8 head bolts in engines.  Only in a bridgeport tho.

I was thinking setting the 2 , 6 inch vices about 3 feet apart.   I have  done a 6 in vice, on one side then in line a few feet over, a 24 in rotary table.  I milled something straight line,  then took the bolts out of the vice, then rotated the table.  I cant remember what  I did make.

hmm... looks like the alloy is going to be a challenge.

shelbycharger400

this just let the wind out my sail.  a piece of o1, at 8 in wide , .375 thick,  36 in long .  is $275    3 in wide is bout $96.   Havin a hard time finding a 8 footer piece... gunna make a phone call tomorrow and see how much it is.   

Al_Smith

I didn't want to bust your bubble but I knew a piece of tool steel would be costly .Every so often a big giant bar pops up on flea bay .

On one of the forums somebody built a big slabbing mill with a giant bar and I think an 18 HP Briggs engine with a big sprocket so it had some chain speed .I'm not certain exactly what they used for a bar but with a big sprocket it about had to be custom made .

shelbycharger400

I have a 17 kohler on my 36 in bar, running 6000 rpm chain.. seems just bairly big enough.

My next slabber is going to be a hydro drive motor on the saw. No more slippy clutches/ belts.

I already have the pump, in and out are 3/4, and have 5 ports out (toro reel mower)
can you say Hydraulic creep drive and dual clamps  8)
If that dosn't do it, I have an even bigger pump with One inch in, one inch out, 2 stage, and an Onan 19 and bellhousing.
I need to research my drive motors yet
and see what I can find for harvestor sprockets and stuff for the correct speed
I want PRODUCTION :)

Al_Smith

If you're going to run big harvester chain do they make a long bar for a harvester ?

Robert Andrews aka Rotax Roberts runs a big harvester chain on his aluminum block Buick hotsaw which is the fastest in the world .Now somebody had to make that bar .Who I have no idea or how .

Now it's completely different as far as what you are doing .His chain speed is around 200 MPH which is 4 times faster than the average saw .However if that bar can withstand aprox 300 HP at that speed it can certainly take the average chainsaw speed of 55-60 mph with 20 HP I should think .

While I'm thinking about it somebody makes a big slabbing mill with a 10HP 3 phase motor .I'm thinking 5 or 6 foot of bar .That could be an option rather than making one but I assure it will cost-a- plenty .

Another thing crosed my mind .If that bar were to be supported on the far end and kept under tension by some method it should act like a band saw blade to some extent with regards to not sagging .

Hilltop366

Heat build up will be the big difference between a 3 second cut and slabbing, I did like Al's idea of putting the bar under tension.

I was wondering that instead of fighting gravity that it might be easier to mount the bar vertical, this might cause a whole new set of problems to solve.

shelbycharger400

hilltop.. ..   NO peavy in the world and my 240 lb body leaning against it is going to move a 5 ft dia log at 14,000 lbs..  LOL   verticle unfortunatly wont work.

also part of the reason why im thinking making an 8 ft bar is the biggest ive found is an 84 inch,  ( 7 foot ) .   I dont think I will be able to make it less than the $600 it costs.     

Al_Smith

Cannon is about the only one I can think of besides a specialty machine shop that can furnish a 7 foot bar .

There isn't any cheap way out of this one .

I have no idea what a person could do with a 5 foot slab anyway but I guess that's not the question at hand .You'd need a crane to lift the darned thing .That pot licker could pinch your fingers like a bear trap if it got away from you . :o

shelbycharger400

Ya got that right!

I want to do some premium market stuff, where  I can potentially make some money.
I come across lots of big trees  due to the fact NO one wants to even touch them period!

Its a shame they go to firewood or just torched in the field.

Hilltop366

Quote from: shelbycharger400 on September 10, 2012, 08:59:54 PM
hilltop.. ..   NO peavy in the world and my 240 lb body leaning against it is going to move a 5 ft dia log at 14,000 lbs..  LOL   verticle unfortunatly wont work.   

That would be one of the "whole new set of problems to solve" I was talking about, though I'm sure someone on here can tell you just how long this peavy should be.

Al_Smith

In this area we call a peavy like that by it's first name "Case " as in front end loader . ;D

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