Bandsaw mill info needed

[koosdup]

I am in the planning stage of building a sawmill enabling me to cut stumps up to about 710mm(28") in diameter so this is what I have in mind;

4 post steel frame, 30mm(1.18") shafting with pillo block bearings, 450mm(18") plywood wheels bolted to 8mm flange welded to 30mm shaft. Wheel center to center 117cm(46") depending on standard size blades available, I think about 148" to 150" blade, not sure about standard blade size yet. I have a 4 stroke petrol engine from a Ryobi RG-6900K generator with a rated output of 5,5KW and 6,9KW max output. Not sure if that refers to the generator or the engine.
Now my questions; 1) What is the ideal blade FPM speed on these mills. 2) Will a bicycle tube work as wheel tyre on the drive wheel and is it necessary for a wheel tyre on the other wheel. 2) I need some help on a simple wheel tensioner system, the drive wheel will be fixed so the other wheel will have to do all the adjusting and tensioning. 3) Blade info like width and TPI.

This mill will only be used to do the occasional slabbing of tree stumps, mainly hard woods, so speed is not very important as it is not a heavy production operation. The average tree stump is about 25 to 40 cm(10"-15") dry hardwood. Any info about the Ryobi engine will help, I assume the motor speed is 3600rpm but could not find anything on Google. I plan on using a 60mm(2.36") double belt pulley on the motor, the drive pulley will also be from plywood attached to the drive wheel.
Any help and suggestions will be appreciated.

Koos du Preez

[suther51]

Looks like you have a good start. (I have an Easy Board Walk mill, 14' 6" blade, about 40 " between guides, 1 1/4" blade with 7/8 pitch teeth, 7/8" from point of tooth to point of tooth if I remember correctly on the pitch) first I would take a look at the info from timberwolfblades.com. They have much good info on blade speed and other adjustments such as tensioning of the blade. I would not be worried about the power of your motor from the sounds of what you posted. What little experience I have with other mills (my mill has plenty of power with a honda gx670 motor) the less power you have the slower you feed the blade through the wood. With occasional use this should not pose a problem. The band wheels on my mill are 19" v-belt pulleys with a v-belt as a tire. Sounds like with wood band wheels better safe that sorry, I'd put a tire on both. If I have a chance I will try to post some pics of some details of my mill, adjustments ECT. Band mills are simple in concept but attention to detail is needed for functional safe operation.
A question, will you be ripping with the grain or crosscutting? You may need a non typical blade to crosscut, a rip blade may be to "grabby".
What attracted me to the Easy Board Walk was the simplicity of design and execution of the build so it may be a good reference point to base your design off of.
Happy building.
Eric

[suther51]

Went at it but first as usual. Looked a web site, down load the pdf catalogue, the info is there.
Eric

[Moby Duck]

I have seen pictures on the web of walk-along bandsaw mills using a pair of car tyres/wheels. It didn't seem to matter that the tyres were much wider than the blade and the hubs, stubs and axles can be part of the design.

[suther51]

Taylor mills are built near me, know some one with one (They use car tires), the tire pressure is CRITIAL to keep from throwing blades, talk about being chased by a spring loaded grizzly!

[koosdup]

I have seen pictures on the web of walk-along bandsaw mills using a pair of car tyres/wheels. It didn't seem to matter that the tyres were much wider than the blade and the hubs, stubs and axles can be part of the design.

Yes I saw plenty of those on Google, no need for tensioner as it is achieved by deflating and inflating tyre. Initially I planed on going the car wheel route but the end of the day cost dictated. The nearest town is 85km from where I live and the scrap yards(car breakers) are quite expensive and then I also have to pass a very expensive toll gate. Return trip to Mbombela( Mpumalanga, South Africa ) will cost me about R350.00(30US) so I decided to use what I have lying around. My biggest expense will be the blades, motor pulley, pillo bearings and one sheet 19mm plywood.

[Hoosiersmoker]

When you get this built you will be the envy of the region! Your Ryobi motor is approximately 13 hp. so it should be enough to cut through most lumber. cutting lumber with it will definitely be a possibility. Wood gears has a shop built band saw and, although it's not to the scale you are talking about, it might give you some ideas on the build.

at about 5:02 he shows how you can cut your own pulleys. If you make them you can make multiple sizes to see which works best for different applications. Hope something here helps!

[Hoosiersmoker]

Parts of this were not posted with the last post. When you get this built you will be the envy of the region! Your Ryobi motor is approximately 13 hp. so it should be enough to cut through most lumber. cutting lumber with it will definitely be a possibility. Wood gears has a shop built band saw and, although it's not to the scale you are talking about, it might give you some ideas on the build. Woodworking plans half way down the page the page. You'll find a tension adjusting idea there too. You can buy the plans but they won't be to your scale and you can see how he did it from the pictures. I also like suther51's idea of the V-belts as tires, it would just require notching the wheels to recess them and they would last a long long time. They're fairly inexpensive and it would also give you the little crown you'll need to keep the blade centered on the wheels. Cut the grooves for them and install the belts before you laminate the wheels together and it should work well. There is a possibility the drive pulley might not be as expensive as you think.

[koosdup]

@ Hoosiersmoker; You just derailed my thoughts, now I am torn between building a band saw or lathe

[Hoosiersmoker]

@ Hoosiersmoker; You just derailed my thoughts, now I am torn between building a band saw or lathe

That lathe is in process in my shop with a few modifications of my own! Great way to cut pulleys though, right?