DIY Scrap Iron Bandsaw Mill

[Magicman]

Don't be concerned with them, just do whatever you wish.  They will exit as the lumber dries leaving a small pyramid of sawdust.  They can not infest anything.

[RetiredTech]

I have found the 10 degree blades to be the worst ones I use.

Wow, I hate to hear that, but I only ordered 5. The first blades I ordered were from Sawblade.com. I'm not really happy with them. They cut fine, but from the marks on the wood it looks like they have a problem with consistent set on the teeth. I thought it might just be the first blade I tried, but the second blade left the same marks, right up until I tried to saw through a side stop. I can't say that helped it at all. I'm on the third blade now and it's just like the other two. So I ordered 5 of the 10 deg blades from WoodMizer. We'll see how it goes.

[RetiredTech]

They can not infest anything.

 Thanks, I had written that stack off. I just threw it on some pallets in the edge of the woods and covered it up. I'll have to go back and move it to the shed where I have a flat spot for it to dry on. 

[Magicman]

Most of the interior finish lumber in our cabin had ambrosia beetles.  Nothing was kiln dried.  After I finished occasionally I would notice a pyramid on some flooring somewhere and I would vacuum it up.  After the lumber finished drying the ambrosia beetles were gone.  They can not live in dry lumber, but PPB's love it.  Tim-Bor, etc. will prevent PPB's from entering the dry lumber.

Conversely, Ambrosia Beetles usually enter the log while it is still a log.

[RetiredTech]

  I started a new thread here Band Blade Drag Sharpener with band sharpening questions. Somehow I let it devolved into another discussion of my mill so I thought I'd try to bring it back here and try to get the other thread back on topic too. 
  We were talking about engine speed and sawdust. I had a couple flitches still on the mill bed so I edged them just to generate a little sawdust at a reduced rpm.

This is a picture of the sawdust the mill generates at full speed. This batch was from some Cedar but everything I've run through was about the same. I wanted something small to put in the picture as a comparison. All I could find was a piece of .035 welding wire. It's smaller than cornmeal.




This is what it looks like at about 1/2 throttle. I'm fairly sure it was Elm.




Here's a shot with both piles.




I'm thinking the sawdust should look more like the lighter colored pile.

[Magicman]

ERC sawdust will have a different look & texture from anything else that you saw.

[RetiredTech]

Point taken. I went back and reset the motor to full speed and ripped a section of the same piece of wood for comparison. Here's a new look at all three.
The top pile is the same piece of wood as the lower left except it I sawed it at full engine speed. I'm going to order a tach just so I know how fast the engine really is running. If I can run it around 2800 that should put me in the right ball park with my current pulley. That would also let me know for sure what size pulley I need for full throttle sawing.

[Old Greenhorn]

Essentially, what you are looking at here is 'chip load per tooth'. Instead of changing the pulley size to reduce the band speed, you could also increase the federate down the log to get the same load per tooth.
 Just a different perspective to consider.

[RetiredTech]

  I've had some questions about the blade speed on my mill. It cuts OK, but it leaves a lot of sawdust on the log and the sawdust it makes is really small. I've also read that too high a band speed can cause excess wear on the band and take the set out of the teeth.
  Not having any reliable data on the little kubota I didn't know what the actual engine speed was. So, I bought a $20 magnetic pickup tachometer off the web and mounted it in a small plastic box with a 9 volt battery so I can use it as a portable Tach. I epoxied one magnet to the engine pulley so I could get the actual engine RPM and another to the pulley attached to band wheel. Full throttle with the band engaged gives me 3260 engine rpm and 1120 rpm at the band wheel. This works out to be 5868fpm at the band. From the information I found at Cook's maximum fpm for a 30+ hp mill should be 5500. From information I've found online I believe my engine is between 16-20hp. Cook's suggests a maximum of 4500fpm for 16-18hp engines. I can lower the engine speed to 2500rpm and hit the 4500fpm recommendation, and I'll probably try that for the short term. Long term I want to get a 14" to 16" pulley so I can raise the engine rpm. The 14" pulley would put me just over 5000fpm with no load, the 16" just under the 4500fpm. Either would probably work better than the 12" pulley I'm using now. They would allow me to get more torque to the blade, hopefully prolong the life of my blades and leave less dust in the cut and in the air. Time will tell and I'll post results the results when I figure it out.
  Does this sound reasonable or am I going about it wrong?

[Crusarius]

I have 4" centrifugal clutch on engine and 14" drive pulley on bandwheel. Works very well. band wheels are 19".

[Ljohnsaw]

Yes, you're on the right track. I switched mine for 12" to 14" with my 19" wheels. I'd have to remeasure the engine pulley but 14 is as big as I could fit. I had to cut into a cross piece as it is! A good jump in torque.

[RetiredTech]

I'm using trailer tires for band wheels. With 65lb of air in them they are 21" before I tighten the band. after the band is tight they're closer to 20". The little diesel has cut everything I've put on the mill, but on the bigger stuff I do have to go pretty slow to keep from bogging the engine down. Going by Cook's guide I should probably go with the 16" pulley, but I haven't made my mind up yet. I think I've got enough room to fit either one.

[Joe Hillmann]

I also have a trailer tire mill.  It runs somewhere around 4200 fpm.  With a 13 hp engine I cant push it fast enough to bog down the engine.  The blade will start to rise and dive before it bogs down.  When I built it I was aiming for around 5000 fpm but I used what I had.

I think mine would cut better if the blade was moving a bit faster.

[RetiredTech]

I also have a trailer tire mill.

Have you had a problem with your tires going out of round? I trued mine up with a 4" angle grinder and a carbide carving disk when I built the mill. I noticed today that one wheel is out of round a good bit again and the other one is slightly out of round. I wonder if it's because I've been leaving the band on the machine?

[RetiredTech]

  I finally got a chance to put a piece of the Pecan I've been saving on the mill. I think I almost waited too long. I had a happy accident happen while sawing it. I've been playing around with building a diesel band lube setup. My goal was to have it supplied from a very small auxiliary tank that constantly refills from the engine return line. Right now I just have a gallon jug for a manual drip. I got a little too much diesel on the band and band tension squirted the band off the front of the tires when I engaged the blade. It made a terrible racket and damaged a couple teeth on the band but no real harm otherwise. That gave me an excuse to open the box of WM 10° blades I had ordered. What I found was a pleasant surprise. I didn't see any difference in the ease or speed of cut, but the quality difference was amazing. See below.

Short 7'4" section of pecan log.




This is the cut quality using the Sawblades.com 7° blades. This was the third blade from the box. All three blades left this pattern on on everything I sawed.




The new Woodmizer Blade looks like this.







You can still see faint teeth marks on the wood, but they are so small you can't really feel them when you run hand over it. I wish I would have ordered the WM 7° bands now. That will probably what I go to long term. I didn't have any problem with the 7° sawblade.com blades cutting. They just left the boards looking so rough. I'm thinking a good re-set and sharpening will make them cut a lot better. I see more WM blades in my future. Come to think of it, MM told me to buy WM 7° blades to start with. I think maybe experience has taught him a thing or two.
smiley_turkey_hide

[Joe Hillmann]

I also have a trailer tire mill.

Have you had a problem with your tires going out of round? I trued mine up with a 4" angle grinder and a carbide carving disk when I built the mill. I noticed today that one wheel is out of round a good bit again and the other one is slightly out of round. I wonder if it's because I've been leaving the band on the machine?

No.  And my mill is left with a tensioned blade all the time.  The first couple years I released the tension when not in use.  But for the last 7 years or so it is left tensioned 24/7.

[RetiredTech]

Don't be concerned with them, just do whatever you wish.  They will exit as the lumber dries leaving a small pyramid of sawdust.  They can not infest anything.

MM called it again. I just finished sawing the first pecan log yesterday. Took 2 days due to multiple interruptions.  I flat sawed it into 1/2" boards and stacked it on the end of the mill as I went. I moved it today to a temporary pallet because one end was in the afternoon sun and I didn't want it to warp if I can prevent it. I wont have time to spray it and properly stack it until probably Wednesday. But this is what I found today.




  The wood is drying out fast and they don't like it.

[RetiredTech]

Due to some less than optimum weather I had a chance to make a much needed upgrade to the mill. My old magnetic mount lumber scale proved to be almost useless. I spent a lot of time measuring down from the cant top to get a halfway accurate cut.  Hopefully the new scale will be much better. All that's left is a little paint, the final adjustments and a couple good clamps. The lower pointer will be set to the distance to the bunk +1" That's my bottom board thickness at the mills lowest setting. The gray indicator will have a handle or knob on it so I can easily move it to an eye level mark and calculate my cuts from there. My new ruler is wide enough that I can add marks for common cut sizes. A cheat sheet with common cut drop distances will also help once I get it done. If I get really ambitious I can order one of those Fancy Dan magnetic lumber scales just like real sawmills have. But the little bit I cut I think this new setup will make sawing my lumber much faster and more accurate.

Here's a couple photos of my old setup and a few of the new one.

[Crusarius]

First measuring device. One was set from the bed so I always knew my exact location from the bed and the other was floating for random cuts.



 


new version with all the scales I usually use on it.

 

I do have an even more upgraded version with a fixed pointer for exact location and a movable pointer for random cuts. I do not have a picture of that one.

[Ljohnsaw]

I used a pair of dividers set to a size like 1" + kerf and scratched my way up my aluminum scale. Then I scratched the marks deeper with a chisel. After I completed all the scales including numbering them, I sprayed paint. After it dried, sanded it down. That just left paint in the marks. Later I added dots midway on the larger scales. I use those when I want to center the pith on a timber. I can slide my scale to reset my starting point. I also stamped but not painted the scale number up the scale for ready reference.

My first scale.



Rare earth magnets prevent the scale from dropping when I release the clamp.

 

 
Added a laser to eliminate the parallax errors.

 

[RetiredTech]

  Those are great. Some of the vertical lines look like they are etched into the aluminum. How did y'all accomplish that and keep them so straight?

[Ljohnsaw]

The first (neat) one I used a straight edge and a box knife. The other I tried to use a v chisel. Didn't work so well.

[Crusarius]

I used a mill and a V bit

The aluminum is 1/8" thick I think I went almost 1/16 deep with my cutter. I thought about painting it but instead I just used a sharpie and darkened the lines. Worked just fine.

[RetiredTech]

  I may have to try ljohnsaw's method on my old ruler. I don't have a cnc. I used to use an awl to scratch lines on sheet metal when building duct work back in my HVAC days. Aluminum is much softer so I guess a couple passes with anything sharp would give you a nice line. I just never thought about it. I tried using a sharpie to mark a ruler but that made the lines too thick.

[Crusarius]

I didn;t have the CNC when I made mine. I just used my manual bridgeport.