need experienced opinion on band speed

[fathead]

im starting to gather the parts to assemble the carriage for my homemade bandmill i purchased a set of quality 19in. wheels,2in.shafts,pillow bearings.Im not sure of the optimal blade speed for a 20hp mill with 19in. wheels so that i can look for the correct dai. drive pulley.also would you recommend a dual belt pulley

[Tom]

The forum is full of information from members who have built their own mills.  I did a search for "band speed" and got theses threads out of 9 pages.

https://forestryforum.com/board/index.php/topic,35444.msg512756/topicseen.html#msg512756

https://forestryforum.com/board/index.php/topic,25933.msg278170/topicseen.html#msg278170

https://forestryforum.com/board/index.php/topic,7207.msg99342/topicseen.html#msg99342

https://forestryforum.com/board/index.php/topic,15598.msg221767/topicseen.html#msg221767

Basically, you are looking for a speed that allows the blade to perform as much or more than you are matching it to the engine.  The more horses, the better the blade will perform, but blade speed may not be any different than on a mill with 10 horses.

[logwalker]

Double belt pulley and around 5500 surface feet per minute. Keep us posted. Joe

[fathead]

thank you Joe, does this sound right 20 maybe 24 hp motor 12in. double belt pulley 19 in.all steel wheels on a 1 15/16 shaft and a 4 in. pulley on the motor.also whats your recommendation on weather i should use a idler pulley on the double belts or a centrifical clutsh

[logwalker]

Woodmizer uses a over-centering lever to raise the motor to tighten the belts. This calculator is in the forum toolbox under Don's calculators.

https://forestryforum.com/members/donp/pulleycalc.htm

[fathead]

do you know were i can get look at that to understand what happens to the dual belts when they are slack

[pineywoods]

do you know were i can get look at that to understand what happens to the dual belts when they are slack

Side by side single belts is not a real good idea. They need to be perfectly matched to run properly, if one comes apart, the other one will get trashed, maybe other stuff too. Most industrial belt suppliers will have double or tripple belts made as one unit Woodmizer uses a double belt on smaller mills, tripple on the bigger diesel units.
Quick and easy check on bandspeed, a $10 bicycle speedometer from wal-mart, mounted on one of the bandwheels.

[fathead]

i have a lot to learn thanks, do you think with a 20 hp you need a double belt ,how about a24hp

[Larry]

Belt suppliers can tell you how many and what size/type of belt you need.  Grainger had a simple calculator which would give different choices...lost mind someplace when I moved.

Gog belts can transmit a lot more power than regular belts but they are dangerous to use on most clutched applications because they are grabby.

I'm thinking a single belt might barely work depending on type...again talk with your belt supplier.

[Fla._Deadheader]

We use a single belt on a 36" cut, 24HP Honda gas engine. It can hold the power of the engine without slipping, if we keep it tensioned correctly. It is a 5V Series from Grainger. It takes the same series pulleys. Says in the catalog it will deliver 20% more than regular "V"-belts. I believe it. I have dead stop stalled the engine at high RPM when the blade bound up. In over 200,000 bd/ft, we are on the 3rd belt.

  About your clutch deal, we use a reverse of WoodMizers "PUSH-UP" to engige. We pull the lever down, and a cam pushes the engine up. Works like a charm, and the loose belt runs right around the 4" drive pulley without moving the blade.

  Should be photos in my gallery. If not, I will post a couple for you. Let me know.

[D._Frederick]

with only 20 hp and a blade speed of 5500 fps, the saw dust will be a powder and can spill out of the blade causing sawing problems.

[fathead]

deadheader,thanks for your advice if you could post a picture of the pulleys and thier belt guides it would be very helpful. Iam still trying to visualize the belt slipping around the drive pulley and not flying off or grabbing the driven pulley

[Fla._Deadheader]

Here ya go, FH.
First is belt in slack position. Engine plate that engine bolts to, actually raises up tightening the belt.

 

  Second is Belt tensioned properly. Note the lever is broken "Over Center", to lock it in position, by pushing it toward the sawhead.
 
 

  Photo of Drive pulley. There is nothing to keep it from running off the pulleys. They are correctly in line to prevent riding on the inside of the pulley groove.

 

[Ironwood]

Good info/ dicussion.

Ironwood

[bandmiller2]

Jeez,I hate to call someone fathead.Their are always different ways to reach the same end.My engine is stationary and I have an idler and overcenter lever to tighten the belts.B series belts are most common but if one b won't hack it you could go to a bigger C series.I used" two matched set" B series on my homebuilt bandmill.Those spring loaded belt tighteners used on autos today are handy and not expensive,just use the pulley part.Frank c.

[fathead]

both deaheader and frank i appreciate you sharing your proven ideas, i this forum gives me confidence that over time i will be able to build a dependable safe mill

[fathead]

all the bandsaws i have studied either use a angle iron with one end up and a groved roller to match usually on manual ones.alot of the driven ones have the angle welded with the edges down and a v groove roller. has anyone tried 3/4 square stock with the top edges eased and rollers to match.Iam thinking with the two flat surface areas being  larger and less psi maybe they would push easier and have less wear.I would probably put brush cleaners in front of the rollers because the flat surface would collect dust does anyone think this would be ok