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Advice sought - dedicated slabber chain speed

Started by scsmith42, February 17, 2012, 05:31:16 AM

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scsmith42

I'm about to start assembling a dedicated slabber, that will be operated by a 40HP electric motor.  As I'm figuring out how to build the slabber, one question that is still puzzling me is what is the best chain speed that will provide the fastest ripping in oak?

Can anybody advise me as to where I can find information related to the ideal speed for for ripping chain?

Thx.

Scott
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Meadows Miller

Gday Scott

Im not that advanced with the slabbing tech i have just keep them sharp n used them  ;) with 40hp pulling it your going to have a hell of alot more toque and power there to pull it through the cut  :o :) I take it you are using a 14 tooth harvester sprocket Mate ?? Ill get hold of Warren Lucas and pick his brain and see what he thinks for you Mate ;) ;D

Regards Chris
4TH Generation Timbergetter

scsmith42

Quote from: Meadows Miller on February 17, 2012, 05:51:41 AM
Gday Scott

Im not that advanced with the slabbing tech i have just keep them sharp n used them  ;) with 40hp pulling it your going to have a hell of alot more toque and power there to pull it through the cut  :o :) I take it you are using a 14 tooth harvester sprocket Mate ?? Ill get hold of Warren Lucas and pick his brain and see what he thinks for you Mate ;) ;D

Regards Chris

Howdy Chris - thanks for checking with Warren.  I have not yet selected a sprocket, so that too is on the research list.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

hackberry jake

I had a large log slabbed And it had a 18hp Briggs on it. He said any bigger and you could start snapping chains. And please keep us informed. I would like to build one in the near future as well
https://www.facebook.com/TripleTreeWoodworks

EZ Boardwalk Jr. With 20hp Honda, 25' of track, and homemade setworks. 32x18 sawshed. 24x40 insulated shop. 30hp kubota with fel. 1978 Massey ferguson 230.

terrifictimbersllc

I will be very interested to hear whether there is an "optimal" chain speed, or is faster always better.  There will probably be a point where either chain snapping, or tooth breaking, or maybe just available power will be limiting.  Scott's got a dedicated slabber planned, but everyone else needs to keep in mind if one changes the speed of a swing mill it won't be suitable for the circle sawing aspect. 

Some of my observations so far.  My WPF has 30 HP and there's no danger of snapping chains.  In use, I believe I'm no where near limited by its power, but by chip clearance.  There is a sweet spot for pushing pressure, beyond which the cutting speed is actually slower.  Correct pushing pressure is "letting the saw do the work".   As the chain dulls, higher pressure is needed, and eventually this sets up a vibration which seems to come from looser chain slapping on the back of the bar.   That is, overall, the chain is tensioned correctly, but during sawing, as the chain dulls,  the difference in tightness across the front vs. across the back increases.  The front is being pulled tight against the wood, and the back is loose because it is being pushed somewhat by the sprocket in addition to being pulled around the roller.  Eventually the difference becomes enough to derail the chain on the back side with the pushing pressure which is necessary for  optimal sawing rate.   

I am experimenting with a smaller pulley on the input shaft of the gear box, with hopes that faster chain speed will lead to faster sawing rate.  It is essential for fastest sawing, to keep the chain very sharp which means for larger logs i am changing it every 3 or 4 cuts.
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

scsmith42

I just got off of the phone with KC at Bailey's, and he recommended the following:

27RX chain (my bar is .063 guage, .404 pitch).  This chain has fewer cutters, and more room for chip removal.
A 14 tooth sprocket for faster chain speed.

He recommended a chain speed in the 3200 fpm range.  The 14 tooth sprocket, direct fed by a 3600 rpm motor, achieves this.  I'll need to figure out some type of jack shaft arrangement to gear up the rpm from the electric motor.

He also recommended that I look into harvester sprockets for driving the chain.  Oregon makes them for a keyed 25mm shaft.  Now I need to figure out all of the shaft / bar / motor mounting.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Norm

Wow that sounds expensive....sure you want to keep bidding on that stool.  ;D

terrifictimbersllc

You can buy regular ripping chain (Carlton/Woodland Pro 43RP) and cut off 5 cutters after every pair of cutters you leave on, and have the same thing for about half the cost.  Use a .045" thick wheel in a 4-1/2" grinder and cut them off from the side.  Not the same as grinding them off, that can overheat the links.
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

scsmith42

Quote from: terrifictimbersllc on February 17, 2012, 06:55:38 PM
You can buy regular ripping chain (Carlton/Woodland Pro 43RP) and cut off 5 cutters after every pair of cutters you leave on, and have the same thing for about half the cost.  Use a .045" thick wheel in a 4-1/2" grinder and cut them off from the side.  Not the same as grinding them off, that can overheat the links.

Great advice - thanks!
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

scsmith42

Quote from: Norm on February 17, 2012, 05:48:39 PM
Wow that sounds expensive....sure you want to keep bidding on that stool.  ;D

:D  I sure did a "gulp" when you bid it up two hundred bucks in one whack...  My piggy bank is starting to squeal a bit...  :D
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

fuzzybear

Quote from: scsmith42 on February 17, 2012, 05:22:12 PM
I just got off of the phone with KC at Bailey's, and he recommended the following:

27RX chain (my bar is .063 guage, .404 pitch).  This chain has fewer cutters, and more room for chip removal.
A 14 tooth sprocket for faster chain speed.

He recommended a chain speed in the 3200 fpm range.  The 14 tooth sprocket, direct fed by a 3600 rpm motor, achieves this.  I'll need to figure out some type of jack shaft arrangement to gear up the rpm from the electric motor.

He also recommended that I look into harvester sprockets for driving the chain.  Oregon makes them for a keyed 25mm shaft.  Now I need to figure out all of the shaft / bar / motor mounting.
I agree on the chain speed. My mill is direct driven by a Honda 11hp motor, 3200rpm. I can push the head through dry 22" spruce with ease.
  I would advise NOT using a skipped tooth chain, they are designed for high speed. It will leave a VERY rough finish.  I have been using standard 3/8 chain that I have slowly decreased the angle on the cutter until I now have them at about 5deg. This has left the smoothest finish so far.
  I have ordered a carbide impregnated chain to try on the mill. A lot less sharpening.
  If you build a head frame for the slabber you will actually sharpen less than with an Alaskan. Make sure you add two oilers for the larger logs, and don't be stingy with the oil, the chain will get hot and dull faster.
FB
I never met a tree I didn't like!!

Ianab

Cutting 22" you probably will get better speed and smoother cut with full comp chain. The Peterson / Lucas slabbers are designed to cut up to about 60". At that width the chip clearance and number of cutters actually "in the wood" at any one time make skip or "super skip" chain work better.

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

customsawyer

Keep the advice coming as I have had this thought as well. With the number of big logs that I seem to attract I have given some thought to making some big slabs to sell as table tops and such.
Two LT70s, Nyle L200 kiln, 4 head Pinheiro planer, 30" double surface Cantek planer, Lucas dedicated slabber, Slabmizer, and enough rolling stock and chainsaws to keep it all running.
www.thecustomsawyer.com

scsmith42

Update.  I've been corresponding with Oregon about recommendations regarding chain speed, and they have referred me to some documentation regarding harvester chains.

They have some great information in their documentation, including recommendations regarding power, force on the bar to tension chain, feed load on the bar, chain speed and bar adjustment ranges.

This is where it gets interesting.  According to their literature, for a .404 pitch chain the recommended min/max chain speed is between 3000 - 8000 fpm, with 8000 the recommended speed.  Now this is for a harvester, and not necessarily a ripping setup, but it makes me think that I'm going to slab more quickly if I go faster than the 3200 chain fpm range that the Lucas slabbers operate on.

One thing that also became clear is that I'm going to need to build some heavy duty guards around the ends of the bar to protect both operator and assistants in case the chain breaks.  I'm also going to need to figure out how to build some chain oilers, most likely for each end of the bar.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

shelbycharger400

any updates?

i was out playin with mine again today.  with the cheapy drive belt on mine,  pulleys comes out to being 4 1/2 to 2 1/2 where the belts are riding.   briggs 12.5 hp. I sawed a single slab off a 10 in ? dia  ash.  Took forever, i had to push super slow.  killed the motor a few times when the chain slowed down and bound up from me pushing too fast.
basically chain speed is at 6000 rpm.   too slow.  goin to get a different belt tomorrow so i can run it at the outside on the 6 in pulley to get it up to 7200 rpm on the electric clutch.   Im running a full skip chain on it currently, bar is at an angle. the sawdust comming out is rather fine but not too fine.    surface finish is actually very NICE  and smooth minus a few spots that i bound up.

Ironwood

There is no scarcity of opportunity to make a living at what you love to do, there is only scarcity of resolve to make it happen.- Wayne Dyer

Dan_Shade

My only experience with a slabber can only be described as aggrivating, and I felt like it was very dangerous.

I was thinking about building one once, but decided against it because I have no equipment to handle the slabs (which are very heavy).

I was going to make a feed option on mine so that I could be away from the chain when in operation.  Also, I think guards to catch a broken chain would be a very good idea.

I was planning to use a large harvester bar, and a high chain speed.

I am under the impression that the commercial slabbers are cobbled together without much optimization for efficiency in cutting.  I could be wrong, though.



Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

beenthere

QuoteI am under the impression that the commercial slabbers are cobbled together without much optimization for efficiency in cutting...

The Peterson used to slab up the huge redwood log in Madison a few years back wasn't "cobbled up". Not sure where you would get that impression, if not having used one. ??
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Dan_Shade

The one I worked around was a commercially built unit.

It's been several years since I helped saw up some large oak logs with one.  I didn't think the chainspeed was high enough, I also remember the oiler could have been better designed.  In addition to that, I also thought the bar should have been wider than a regular chainsaw bar.

When I was doing some preliminary design work, I was going to use belts/pulleys or chains and sprockets to get the chainspeed up high enough to be useful.  I was also looking at oiler options to keep the bar and chain cool.  I figured a wide bar with a "belly" on it would work well, because it would cut a "curve" rather than straight across the grain.  I gave up on my designs when I realized that moving the slabs, and getting them to dry without splitting up would be a challenge.

Another design concern is too much power to the chain may stretch it too much and/or break the chain.  That's why I was looking at harvester type chains and bars, some harvester's have a lot of HP compared to a chainsaw.

At any rate, using a saw chain to make boards or flitches is not really going to be efficient no matter how you go about it.

Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

logboy

I have a Lucas 827 Mill and a Dedicated Model 8 Lucas Slabber I run in my custom sawing business. For the guards, I wouldnt get too excited.  If a chain snaps or comes off during the cut, it will mostly grab in the log or fly off opposite the engine sprocket. So unless you're standing where you shouldnt be (on either end of the bar, instead of behind it) you'll be safe.  Fitting a metal splitter bar behind the chainsaw bar will help guard your legs for a just in case scenario.  Ease into the log when you start cutting, and do not shove it through the end of the cut, and your chain should not derail.  Usually the chain ends up inside the log and goes nowhere.

As far as differences in chains go, sharpening angles, etc, the topic has been covered thoroughly on www.woodworkforums.com/f132/ where most guys run a swing blade mill or slabber (they are "down under") instead of band saws on the forum here.  But to summarize, the super skip chain 27rx is typically better on anything up over 24" wide, but you can get away with the standard ripping 27r on stuff smaller. You will not get a better performance with standard 27r on the wide stuff, but you'll have a lot more teeth to sharpen.  The reason is how fast the chain can clear the chips.  Like I tell my customers on the wide stuff over 40", when the chain is cutting it has to clear the chips cut on the left side all the way through the log before they are ejected on the right side.  Simply put, that can take a fair bit of time and slow down the cutting speed.  You can add all the teeth you want, if the chain cannot clear the chips you not going to cut any faster. Again, I am greatly summarizing here as it has already been covered thoroughly on the other forum.

Contrary to what was said, you will not get a rough finish with the super skip, nor will you ever get any wavy cuts, unless you're trying to cut with a dull chain.  Before cutting, take the rakers down to .050 from the factory .035 or you'll wear your arms out pushing.  And sure, you can cut the teeth off and make your own super skip, but your total savings will be a whopping $20 bucks or less for an hour spent with a die grinder.  It's not really worth it.

I'm interested to see how your mill operates with the extra added horsepower.  I have the 16 hp Briggs & Stratton on my model 8 and there have been few occasions where I wish I had more horsepower.  Usually the limiting factor for cutting speed is the chain, not the engine.  Sure, I could push the saw harder and get into the governor more, but I would get a lot more heat buildup on the chain and the bar, prematurely dulling out the chain so I need to stop and sharpen.  Something I tried over the weekend with great success was dumping water on the bar to mitigate heat buildup.  There is already an oiler on the bar, but unless you're bathing the chain in oil, it can only do so much.  I was amazed at how much easier and how much longer I could cut between sharpening by dribbling a little water on the bar as I was cutting.  This also helped prevent the chain from gumming up like it normally does on the really wide slabs (50"+).  This week I plan on building a simple watering system to supplement the bar oiler.

A lot of my customers own a sawmill already but cannot cut the large logs into flitches.  Last weekend I cut for a forum member who owns an LT40.  This weekend I'm cutting for a commercial sawmill.  For a guy using a mill "cobbled together without much optimization for efficiency in cutting" I must be doing something right, because its not cheap to bring me in to slab.






I like Lucas Mills and big wood.  www.logboy.com

shelbycharger400

with logboy on above!
im running 12.5 hp briggs,  plenty of power.
i ran factory grind stihl  "full house"  on a 36 inch bar on my mill,  put on a full skip,  both cut rather smooth,  but slow,  as im running standard chain. I have noticed even with regular chain, it seems I need to drop the rakers on mine to take a bigger bite. my chain is running at 6k  wheras a standard chain saw is running 12k.  Havent had time to do any tweakin and playin , been too busy with Work, school, and cuttin firewood.  I want to find a happy medium, so i dont have to use ripping chain, i have a lot of 20-28 in dia "cookies"  to get done :)

sgschwend

Why not setup a dedicated slabber as a band saw? 

Take advantage of the thinner kerf, sharpeners and other parts like guides.  You would really need much for setworks.

Might provide you with other possibilities too.
Steve Gschwend

sjgschwend@gmail.com

shelbycharger400

a chain is a lot more forgiving/repairable to a degree if you hit something vrs a band!   very little if any bounce/wave if you hit a knot, or a nail. I know theirs more advantages, cant think of them right now.

logboy

You get no wave in the wide cuts, even up to 60". The thinner kerf argument doesnt carry as much weight when you get dead flat slabs 60" wide with no dressing necessary to get them to dimension.  If I want 10/4 slabs, then I saw at 10/4.  Knots, tight grain, twisty stuff, it doesnt matter, it will still be flat.  Know anyone with a 60" wide jointer or planer to dress a slab that big?  I dont.  Somewhere here on the forum are some stories about folks ruining 48" wide Walnut slabs with a wide cut band saw.  Slabbers are also portable and can be set up anywhere.   I can have the mill off the trailer, assembled, and ready to saw in 30 minutes all by myself.  The heaviest log I ever slabbed was around 4 tons. I dont care how good you say you are with a LogRite, you wont be moving a log like that without some serious equipment. 
I like Lucas Mills and big wood.  www.logboy.com

Ianab

Woodmizer do make a BIG bandsaw for slabbing up large logs.

But it's a beast. The heavier band increases the wheel size and tension that you need to maintain to keep a wide cut like that straight means it's not a portable machine. Cost is about $50,000, compared to $10,000 for a fully portable dedicated chainsaw slabber. Then you have the log handling issues to consider. Carry the portable slabber to the log is easy. Moving a 4 ton log generally isn't..

Now a slabber on a swingblade mill, now that makes sense.

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

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