bradleywellsoff

Check this mill out. Just getting into milling. All I've really been doing is slabbing, and getting tired of the chainsaw. Seems like this would be a little easier to build than a band saw mill. Has anyone had any exp. with one of these?
http://www.youtube.com/watch?v=r2SaQu-t8aM

mics_54

hmmm
It is a chainsaw. Except this one has probably got all the disadvantages of a regular chain mill with a few more added to boot. Longer chain. Longer bar. What were the advantages you were thinking?

bradleywellsoff

MICS 54,
Has a more powerful power head. Looks like it could be 10-12 hp. I see the longer bar and chain as an advantage to cut larger material. Looks more stable and alot easier on the back than the alaskan mill that I am currently running. The Alaskan Mill is nice, but requires a straight edge for the first cut, then an adjustment to the mill with a knuckle busting wrench for additional cuts. Being on a budget, (like most) could be built with alot less $$$ than a band saw mill. Just a few of the advantages I was thinking of. Looking to purchase or build my first mill. Width capacity and cost are major factors.
Any advice would be helpful.
Thanks, Brad

TexasTimbers

It's a nice slabber. Made by Peterson in new Zealand. They make swing mills. I plan to get one of their swing mills whenever the wife turns her head long enough.

I'd love to have that slabber for a weekend. Have about 20 crotches I'd like to take apart. Some too big even for that slabber.

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Daren

. There is not even anyone close to me with a Peterson or Lucas swing mill, Id'a hired/helped them on a few. I too have almost pulled trigger on a swinger with the slabbing attachment more than once over the years. But they really shine on LARGE logs. For small-medium logs you just can't beat a bandmill. I have had opportunities to slab out big logs (and crotches) 60"-70"...100" across, but not the equipment. The thing about those swingers is you don't have to move the biggies, set the mill over it and saw away. But they are expensive . Having said that so is a hardwood slab 4'-6' wide . IF I had access to the big ones all the time I would have a swing mill also no question.

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dirtclod

I've been wanting a slabber (or the use of one) to break down some large logs. Even considered building one on tracks. But it's just thinking.

Like TT, doing some big crotches would be handy. I have some 3-5' diameter trees to do. Too big for the mill. Can't even budge them from where we'll drop them. So breaking them down into quarters will make them easier to move to the mill for even easier board making. We'll be in quarter-sawn heaven. And dreaming of some 4-5' wide slabs 20' long.

Here's a 5' dbh red oak we were given 3 years ago. I just noticed how big that crotch looked (7' across?) a couple weeks ago. It's still waiting for a plan.



I don't know about Peterson specifically, but I've seen some that offer several different engine options. You've got to admit. 4-stroke engines are not as loud as 2-stroke.

slabmaster

I've thought of using 4-stroke engines for milling, but they just don't have the rpms to drive a milling chain with speed.And if you gear them for speed , you lose too much power.So for a bar&chain mill, i would use a big 2 stroke engine.Just no way around the rpm/weight advantage of a 2-stroke engine.

TexasTimbers

slabmaster, I have been "dreaming" with a couple of other dudes on other forums about building a 4 stroke slabber. I have all the parts necessary to do it including an 18HP Briggs.

The thing about the 4 stroke that we believe is, with enough horses you don't need RPM's. There are 3 rules when using 4-strokers you need to remember:

I. Torque is King.
II. Torque is King.
III. Torque is King.

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Daren

Just like drag racing... RPM is nothing if you cannot put it to work.

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dirtclod

I may not know enough about these conversions and fall flat on my calculations. But here's the little I understand and the results of my calculations when comparing a Husky 575 XP chainsaw engine to Briggs 18 hp engine.

Briggs 18 hp verticle shaft Vanguard: torque = ~35 ft.lbs. @ 3600 rpm. Source = http://www.jimsrepairjimstractors.com/torque-specs.htm

Husky 575 XP chainsaw: 5.8 hp @ 9000 rpm. Source = http://www.usa.husqvarna.com/node3100.aspx

I couldn't find Husky's torque ratings. So using the formula hp = torque x rpm / 5252 I should be able to figure it out since Husky did show the rpm rating at max hp.

5.8 x 5252 / 9000 = 3.3846222222222222222222222222222 or around 3.4 ft.lbs.

As I understand it, when a given amount of horsepower is put into a gearbox the same amount will come out, less any friction. So the main change through the gearbox will be torque and rpm.

Assuming you wanted to compare both engines using the same sized sprocket/bar combo at the business end, then you need a gearbox ratio to convert the Briggs' 3600 rpm to the Husky's 9000 rpm.

9000 / 3600 = 2.5

So the Briggs' 18 hp with 35 ft.lbs. @ 3600 gets converted to 18 hp with 14 ft.lbs. @ 9000 rpm after going through the gearbox. (35 / 2.5 = 14 and 3600 x 2.5 = 9000.) This still doesn't include any frictional losses in the gearbox...but they should be minor.

So the results of the comparision of the Husky being used as-is -vs- the Briggs going through a gearbox is:

Husky = 5.8 hp and 3.4 ft.lbs @ 9000 rpm
Briggs w/gearbox = 18 hp and 14 ft.lbs. @ 9000 rpm *

* does not include gearbox frictional losses.

That was fun! But now my head hurts.

Does it look right to you?

Daren

If you say so . The math I think about in these type of situations is length of service. A Briggs (or Honda or Kohler or...) at 3500 rpm will run for years, decades. Change the oil and feed it gas. A 2 stroke engine by it's very design (no oil bath, the oil is mixed with the fuel) simply will not last as long as a 4 stroke I don't care what anyone says.

There is the weight to power ratio advantage a 2 stroke has. But we are talking mounted on a mill head here not carrying it around in the woods. A 4 stroke hand held chainsaw would be impractical.

Mixing (and burning) oil the whole time does add to the cost of operation. They are noisy (2 stroke) my little 13 HP Honda purrs like a kitten, I sawmill in the middle of town-no complaints.

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dirtclod

One error I spotted was I took the wrong torque rating from the Briggs chart. Here's what it should be:

Briggs 18 hp verticle shaft Vanguard: torque = ~25.25 ft.lbs. @ 3600 rpm.

So the Briggs' 18 hp with 25.25 ft.lbs. @ 3600 gets converted to 18 hp with 10.2 ft.lbs. @ 9000 rpm after going through the gearbox. (25.25 / 2.5 = 10.1 and 3600 x 2.5 = 9000.)

And the final output ratings end up:

Husky = 5.8 hp and 3.4 ft.lbs @ 9000 rpm
Briggs w/gearbox = 18 hp and 10.1 ft.lbs. @ 9000 rpm *

* does not include gearbox frictional losses.

Even using the proper torque rating I'm still not able to get the output of the gearbox to equal 18 hp when taking the calculated torque and rpm output through the horsepower formula. But it's close at 17.3 hp. Close enough for me.

Hey I couldn't agree more Daren...definately the lesser of two evils.

TexasTimbers

clod that was some fancy calculatin. I am seasick now though and the room is spinning.

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dirtclod

Ok, ok!. I see the little error that kept it from perfectly balancing. The torque on the Briggs from the chart s.b. 26.26 not 25.25. So the final results should be:

Briggs w/gearbox = 18 hp and 10.504 ft.lbs. @ 9000 rpm

That's ~ 3 times the hp and torque of the Husky. I'd say she'll do a good job.

TexasTimbers

So I guess torque is king after all.

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bradleywellsoff

I would most likely use a 15 - 20 hp vertical shaft engine. There dosent look to be a gearbox on the mill in the vid. Looks like an extention off of the shaft to a clutch and sprocket assembly. Not a real good shot of that area though. Where could I source a gear box? Mabey an rideing mower trans? I could have a 5 speed slab mill! Some type of direct drive system would be alot less complicated to set up.

dirtclod

A right-angle gearbox for a horizontal shaft engine. Or for a verticle-shaft engine, an in-line gearbox, or two different sized pulleys/cogs and a V-belt/chain... There's more than one way to skin a cat. Just watch which way you point that exhaust.

I wouldn't use the clutch from a standard chainsaw head - too whimpy. Get a heavier clutch like's used on bandsaw mills.

I'm liking the verticle shaft engine and two pulleys and a v-belt. There's more than enough power left over to overcome the power loss of a v-belt. The parts are less expensive and easier to get.

TexasTimbers

Great minds ....... because that's exactly what we decided some nearly 3 years ago. I am not running behind schedule. I never do.

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bradleywellsoff

Yea. I think I'm going this route. Simple to build and less moveing parts to break down.

Thanks for everyone's input, Brad

slabmaster

I see alot of errors! I was talking the same hp. of both and then compared. Ans as for the small husky you compared it to, that's not a milling saw.Try a 395 compared to a 7 hp briggs.At 12,000 rpm not 9,000. See who wins then!