Thread: Saw bench motor HP

A 16" blade will need 7-8HP electric or 10-15 HP petrol.

I reckon a sharp chain saw is quicker and safer for cutting fire wood than a saw bench. Manoeuvring large long branches around a 16" spinning blade is a right PITA and asking for trouble.

Thanks BobL. I agree, those saws have a good reputation for unplanned amputations, but don't worry all the limby pieces I have are only about 6 foot long and about 3" diameter. Plus I had to justify the need for another saw. I plan to stay well to one side of the blade. Or as you suggested, I'll make up a frame to hold several branches and cut them with the chainsaw all at once. I have a fold-up saw buck that's handy for holding smaller diameter stuff for cutting up with a chainsaw, but that can get a bit dangerous too if you are working by yourself.

On the saw bench side of things, sounds like I'll have to start looking around for one of those 13HP Chondas or something similar.

Simon

15 HP sounds about right provided the blade is sharp and you don't push things too hard. I rekon you need some sort of clutch or belt tensioner so that you can disconnect the motor from the saw when you start the engine or is something goes drastically wrong, plus you also need some sort of emergency stop switch that is easy to find in a hurry!

Originally Posted by XJ9OX

Thanks BobL. I agree, those saws have a good reputation for unplanned amputations, but don't worry all the limby pieces I have are only about 6 foot long and about 3" diameter. Plus I had to justify the need for another saw. I plan to stay well to one side of the blade. Or as you suggested, I'll make up a frame to hold several branches and cut them with the chainsaw all at once. I have a fold-up saw buck that's handy for holding smaller diameter stuff for cutting up with a chainsaw, but that can get a bit dangerous too if you are working by yourself.

You can greatly reduce your risk when using a chain saw by wearing chaps, maintaining a sharp chain and not getting over tired.

A hardwood branch 6ft log and 3" in diameter will weigh about the same as a Stihl 660/1 but you won't need that big a saw to cut a 3" log.
I reckon lifting and manoeuvring even those size pieces past a 16" blade will get more tiring that using a CS.

A Chainsaw enables most of the branches to be cut while they are still on the tree after it is felled so there's reduced double handling of material. Then all you have to pick up are the smaller lighter weight pieces.

In terms of ripping boards those big circulars are dangerous as in terms of kick back you would be better off getting your self a decent bandsaw and make up a set of in and out feed rollers.

Is this saw one of those cross-cut saws where you slide the log along a frame and then swing the blade across the log to cut it or a small sawbench where you rip the log down along it's length? The ripping process uses real horsepower when you get into larger lumps of wood and can pose some real safety problems, not that the cross-cutting process is all that much better but at least the swinging blade is in a housing for part of the operation.
Kick-back can be, literally, a real killer when it comes to larger saws. You definitely need a "splitter" (riving knife) fitted properly behind the blade and some sort of cover over the top of the blade to catch stuff that the blade may throw towards you. You also want to make certain you don't "bury" the blade in the log, unpleasant things can happen if the blade stops cutting and starts throwing lumps of wood around.
Oh, a final word of warning....Don't work a sawmill on your own. Mobile phones are really hard to use to call for help if you only have one hand.

Old Hilly, the saw is a table saw arrangement, not one of those tractor swinging saw table setups. It needs some modifications to make the table part bigger etc to do what I want to do. My Jet 10" table saw (under the ply here somewhere: http://www.keypoint.com.au/~sab/construct/ribsa.jpg ) is able to make 80mm deep cuts. This is a bit shallow for some of the stuff I want to be able to do. I have made deeper cuts by cutting one side of a piece and then inverting it to finish the cut from the other side. This works, but is pretty dangerous since the saw blade is buried and difficult, especially with odd shaped pieces - like salvaging some nice timber from a piece of firewood. Also,any jigs made up to help generally steal some depth of cut.

Regarding kickback, I collected a piece of flying timber years ago that turned 90 degrees to get me while I was standing to the side of the saw. I got a really nice bruise on my arm and dislocated a finger or two. Luckily the fingers snapped back in place easily and there was no broken skin to speak of. There should have been, considering the force and speed that the timber projectile came for me. That was a buried blade operation and I was being especially careful about it, but obviously not careful enough. Another few inches higher hit would have been my neck - much harder to snap back in place once dislocated! It just goes to show how easily things can go bad when fast moving sharp things are around. I still have all my fingers and I plan on keeping them.

My plan with the saw is to extend to carriage rails to allow me to rip longer material safely and the bigger diameter blade will give me a bit more depth of cut in one pass. A good length of out feed table/track is a must have. The safety features definitely need beefing up, including guarding, a splitter and way to hold the piece being cut to the carriage as well as a way to hold the carriage down to the rails maybe - depending on weight. It would even be possible to add some spring-loaded anti-kickback spikes without too much trouble. Of course, for docking up some small pieces of firewood, it should work relatively safely without too much modification. That is what the saw was used for by the previous owner and his father powered by a small electric motor. Judging by the size of the electric motor that now resides in the guy's concrete mixer, it may have been slow work

Saw1.jpgSaw2.jpg

BoblL bring your splitting axe!

Firewood.jpg

I'll just add these couple of small jobs to my growing list of projects.

Simon

Just an update on my saw bench project. I have ordered a 16HP Chonda engine and a 3" double belt pulley to go with the 3 1/2" double pulley fitted to the arbor. I am hoping that combination will give me some flexibility with regard to blade speed and size without needing to run the engine flat out all the time. The engine is rated at 13HP / 16HP peak, so I think that should be plenty of power for what I want to do, which is to make essentially a mini circular sawmill for re-sawing slabs into boards. My 10" tablesaw has a maximum depth of cut of about 80mm (approx 3 1/4") so I am limited fairly well in the board width I can cut without having to do double cuts.

I am trying to design a small "log" carriage that will carry, maybe 3.6m timber to be resawn into smaller boards. I have an old tractor swingsaw that someone has butchered with and angle grinder, including cutting the thread off the end of the shaft, that might yield some parts for my carriage. It has a rack mechanism mounted under the swinging table that I may be able to be adapt to advance the cut on carriage. It's probably a good thing that the old tractor saw has already been vandalised or I might be tempted to use it to cut firewood.
Swingsaw.jpg

I could do a mini-sawmill build thread if anyone is interested and not too impatient.

Simon

A bit sort of off topic, but someone might be interested.

I generally do what some other people have suggested with the smaller limbs on fallen trees and that is to cut them to firewood length while they are still attached to the trunk. Because I push the envelope too much as far as the thickness of sticks I try to cut with the chainsaw, I have a few derailments. Here's what I came up with to settle the OH&S squad down and hopefully to help keep the chain on the bar:

Sawbuck.jpg

Cut between the wooden uprights for 15" long wood. It seems to hold the limbs much better than my X-style saw buck and takes quite a bit more to fill it. It can be used single handed rather than needing someone to hold the pieces down while they are cut as is often required with the other saw buck.

Simon

If you wish to rip with it you want 3 - 5 Hp for inch of saw in the wood. So thats 15 to 25HP, and when it comes to saws bigger is better and safer.

Looking at the photos in #7 there is no way that I would add a 15-20hp motor to drive that contraption, certainly not as is. The frame requires some serious beefing up and a lot more mass if you plan to break down / rip / re-saw billets.

Just looking at those photos......well, you need infeed and outfeed tables at either end. A sliding trolley on rails would be nice but if you want to cut 3.6M logs you will need someone (they were called a "tailer-out" locally but the Yanks seem to call them "off bearers) to handle the other end of the log as it goes through the saw. You can't just let go of one end of the log and walk around the bench and grab the other end of the log and keep pulling it through the saw. Well, you can but you probably won't do it very often, not after the log jams the saw blade. And you need an adjustable fence so you can set the width of cut.
The blade needs a riving knife that will hold a blade guard, that will make things a bit safer and keep some of the sawdust out of your eyes.
Basically the device has potential, it just needs some refinement. Things like a remote throttle and emergency stop switches spring to mind. Try to think of all the things that can go wrong and then tale steps to prevent them and you will have a heap of fun!

Plenty of valid points there Old Hilly. I have thought about the in-feed and out-feed tables and my initial thoughts are some pieces of angle iron that I can run some grooved bearings along for the wheels of a trolley. I have some ideas about a couple of your other points too. The plans are still forming and will probably take a while yet to get to something usable. First off I need to get my workshop extension finished first so that I can have some room to move. I can barely get between the piles of projects and potential projects in my workshop now and it is 12m X 6m plus a skillion piece on the side.

I really wanted the saw mainly for the arbor parts and the rest of it is spare pieces of steel that can be re-arranged, so I am pretty well situated to incorporate all of your suggestions. Thanks for the pointers.

Simon

The little old mills that used to abound in this area (Wauchope and the Hastings Valley used to have about 50 sawmills, some only employed 2 or 3 people), the main saw bench was an "island" with tracks in the floor at either end for wheeled trolleys to run on. The saw bench often had a powered roller on the feed-in side to help push the timber through the saw and then pull the billet back ready for it to be moved across to the fence ready for the next cut. The "sawyer" and "tailer-out" did a fair bit of walking in a day!
Some of the small mills got their material as waste from the bigger mills, they may specialise in tomato stakes, oyster sticks, fence palings, or, if it was a Brushwood mill they were getting their stock from, they might do furniture moldings. Apart from sawdust, there was little waste. This process of using small sections from logs already broken down elsewhere meant that some mills didn't have to worry about having a big "breaking-down" saw which saved money and the big mills didn't have to worry about getting rid of the core of the log.
The downside of having the saw stationary is the length of track needed for the in and out-feed rails (log length x2 plus the size of the saw). On the mill I built for cutting Paulownia logs we went for a bandsaw that runs on tracks. The log is stationary and the mill moves on rails (log length plus twice the size of the saw base) . We still get plenty of exercise in a day though!