Band tightning range

[sawdust]

Well, I am about to start building my bandmill! Question is, how much travel (adjustment) should I allow for tightning the band?
I am using those real hard spacesaver spare tires for the drive and idle wheels as they have lots of crown.
I am not looking for high production. I would like to use this for my shingle mill and for cutting beams.
It will be driven by a Honda 450cc motorcycle engine.

I have not started cutting steel so please speak up if I am about to Dang it up!

Sawdust.

[Tom]

I did a search on Band Tension on the forum and got 5 pages of hits.  Not that I'm trying to curtrail this thread, there will be info here to, but there is a lot to be learned by searching the old threads.

Measuring Band Tension link

I remember a good deal of conversation about trying to control the tension on a band when using tires.  Automobile tires make it difficult to control tension because the tire walls collapse.  You can move the wheels apart or use more air in the tire.

Dead-header wrote some pretty good posts on this way back.

Now, if it were me, I would allow myself a lot of travel between wheels.  This might be more important on a home-built than a manufactured mill.  My reasoning is that I might get myself in a position that I could use several different lengths of  bands.  This could come in handy if I came upon someone else who had bands for sale, or if I broke bands and had them rewelded shorter.   It might not be cost effective, but I've always thought of this. 

It seems that everybody has to have a band that is "exactly" the right length.  It seems to me that the more versatile you are able to make the mill, the more independent you become.    Realistically, 6 or 8 inches would be a lot of difference in length to most mills.  Once band length is determined, I think most manufacturers are concerned with loosening the band just enough to get it on and off of the wheel.  Most will collapse enough to get your finger between the wheel and band and some a little more.  I guess the wheel is being moved 2 to 4 inches.

[sawdust]

Thank you Tom, I like the idea of different length bands. Little more choice that way. I also saw a thread about welding repairs to bands, good idea. I think I may allow for a couple feet, easy to do at this point and does not get in the road of anything else.

sawdust

[Modat22]

I liked the idea of loads of slack and adjustment so I built mine to use ether a 258 inch band or a 264 inch band.

Though I'll probably not ever use a 264 inch band unless I find some at a yard sale  :D

[jpad_mi]

I'm running temp spares. The tensioner was originally built with 4inches of travel and tensioned with an acme threaded rod. It never took more than 3 or 4 turns to go from loose enough to remove the band to fully tensioned. I think that was 6tpi rod, so figure we used about 2/3 of an inch of the travel. This spring we upgraded to a hydraulic system with 1 1/2inch stroke cylinder and it has provided sufficient travel.

A couple of other things to consider:
1) 24in of adjustment equates to a 48in difference in blade length (it's a 2 to 1 relationship)
2) the more travel you allow on the idler wheel, the larger your guards have to be to accomodate it. It's not a big deal, but could come into play if you already had something in mind to use for the guards.
3) you are not limited to "stock" lengths of blades, you can order them in any length you want (to the inch).


Tom - I like your idea of being able to accomodate a shorter length for re-welded bands.