Bandmill Design / Ideas thread

[Brmorgan]

Since I'm going to be working on building a bandmill for myself in the very near future, I've been trying to collect as much information as possible regarding designs and features. YouTube has been a great resource, but the resolution of the videos is limited and it's sometimes hard to really tell what's what. I'd like to have a thread here, much like BobL's CS Milling tips thread, that just contains photos, videos, drawings, and other ideas from the bandmill users here on this forum. Stuff like carriage raising/lowering mechanisms, carriage power drive systems and guides to hold tight to the bed rails, log securing methods etc.

I just want to build it as "right" as possible the first time so I don't end up realizing I could have done something much better a week into using the thing. Any information at all will be much appreciated.

 

[DRB]

http://www.diybandmill.com

Have you seen this site?

 

[Brmorgan]

You know, now that I see it again I think have been there before, but if so it was years ago. Thanks for refreshing that in my mind. Looks like a lot of reading to do tonight.

EDIT: Upon further inspection I must be thinking of a different website. The one linked above is great though.

 

[gene1605]

past threads

for pictures check out my past threads
gene1605

 

[Brmorgan]

In trying to save as much money as possible in the engine department, I've been rolling a whole bunch of options around in my head for the last few days. Here's what I'm leaning towards right now:

I have an 18HP vertical shaft Briggs & Stratton tractor engine that's in excellent condition and has very low hours on it. If I use that I'll replace it with the 10HP Tecumseh I have. Not as much power, but at least the tractor will still be driveable. I also have a 5:1 gear reduction box that I could use to convert the vertical drive to horizontal. Assuming a ~3700 RPM engine speed, the 5:1 reduction gives about 750 RPM at the bandwheel. The circumference of these 26.5" wheels is about 83", so the band speed would be somewhere around 5200 feet per minute. That's not a bad ballpark to be in without having to start playing with pulley combinations - I could just make everything 1:1 to begin with and then speed the final drive up a bit if the engine and blade can handle it.

If that'll work, I pretty much have everything I need to start building the carriage. I've been drawing out some rough ideas on graph paper, and I think the only fairly major components I have yet to buy are the small gauge sprockets for the carriage lift mechanism I want to build.

I want to build the mill to fit a commonly available band size. Right now it looks like that might be the 17'1" band that the bigger WoodMizers use. If I put a 34" gap between the 26.5" wheels, that gives me a band length of almost exactly 17' even, and a log capacity approaching four feet if it's milled right.. It also puts the upright posts of the carriage and the bandwheel centers at pretty much 5 feet apart dead-on. So I'll just build for 17' and have it adjustable 2-3" in each direction.

Since I do want to go fairly large with it, I think I might use the 4" squaretube from the original unit for the main carriage uprights. I do have enough 2" lying around to do the job too, so I'm not quite sure yet. I think I'd benefit from the extra 2", especially when it comes to the method I'm considering for raising and lowering the head. I have about 6' of rack-and-pinion toothed track that I plan on bolting to the sides of the main uprights, and then I'll have a small gear on each one with a loop of chain connecting them, driven by an electric winch. After my first drawing, I realized that I had to have the track on the same side of each post, not both on the inside or both on the outside, or else the two drive gears would be pulling in opposite directions unless I did some extra work with the drive chain routing.

The design is starting to come together in my head, now I just need some time to get some of my more pressing projects out of the way. It's keeping me awake at nights though. But, that's how I am - when I have a project or problem the solutions almost always come to me after my head hits the pillow.


Oh, and while trolling YouTube for bandmill vids, I came across this one:
http://www.youtube.com/watch?v=Q3QnuxJhTU4

Safety first, eh! Apparently those guys have never seen what happens when those big bands fail and fly apart sending square-foot-sized shrapnel flying.

 

[Backwood]

I built my mill. I have plans to make another one before to much longer, many things I would do different next time.
I built a 2 post mill that uses a winch that lowers and raises the head. My next one will use a different method for moving head up and down. Will be watching this for ideas.
I welded some short pieces of 1" pipe to the frame to hold my dogs which I made by welding some 3/4 pipe off centered to some steel plates approx 1/4 x 6"dia. and use a bungee cord to keep the dogs tight. Until I switch to hydraulic clamps these work ok.
I found out its no big deal trying to make it to fit standard size bands, The places I have bought bands from say they can make one size just as easy as any other. They charge by length though. (mine's 180")
I am using a 10hp electric , which if I remember right should be close to a 17.5 hp gas motor. Not sure what kind of motor I will use for the next one but it will have more power ( I hate 4 clyinder cars too )