can the band on a bandsaw have pressure applied by the roller guides?

[weisyboy]

iv been thinking more about a horizontal resaw bandsaw.

pic 1


would there be any problem with running the bad like this?

if not then could the cut be angled for making weatherboards etc by lowering one of the rolers?

[bandmiller2]

Weisy,thats pretty much how it works only not so much deflection from the rollers .Usally one roller is stationary the outher moves in and out to support the band when your making a narrow cut.Your second drawing would probibly work but would be hard on band life, better to tilt the base for the clapboard effect.Frank C.

[weisyboy]

how mutch would it shorten band life, at $25 for a 1 1/2" 1tpi blade its cheaper for me to throw them than sharpen. so how many hours do you recon id get out of a blade?

the problem with tilting the bed is i would have 20' of rollers either side for in and ou feed that would have to be tilted also.

[weisyboy]

if they just pushed down on the blade, say 1/8" of less when in horasontal

then to cut a weatherboard the down side would need dropping 3/4".

or would i be better just buildign a dedicated angled machine.

the otehr option would be to have the wheels individuality movable up down?

[bandmiller2]

Weisy,hard to give bandlife estimate as I have never tried to vary roller hight.In your case a better solution would be to tilt the whole band and wheel assembly,three positions with level in the middle.Make a cut tilt head the outher way for the next cut. Frank C.

[ladylake]

 I'd guess the band life would be short bending quite a bit around a 2 or 3 inch guide wheel. Steve

[weisyboy]

it wouldnt need to be tilted for each board.  id cut 7x1 1/8" bards on the mill and reaw them in half.

will have another think, this idea jumped into my head this arvo.

[Banjo picker]

I'd guess the band life would be short bending quite a bit around a 2 or 3 inch guide wheel. Steve

dito....Tim

[Ironwood]

Weisy,

Are you trying to make tapered siding? or just figure out blade dynamic, your one reponse has me beleiving the siding is you goal. ???

Ironwood

[sgschwend]

The guide bearing would not likely last very long.  The bearing has a fairly low load specification for the rpm they are used at.

[kevinlt15]

if it siding you are trying to make ? just make A jig that rocks back and forth  the main pert of the jig clamps to the deck I think I have some pics in my gallery of one I made

[Tom]

Band deflection by the roller guides is the way that the roller guides obtain control of the band.  It is also a part of the tuning of a  bandsaw to insure that the band is in the same plane as the bed of the mill.   If the band is not square (in plane with the mill), the lumber will not be square.

Your drawing #1 is the way that a bandsaw is tuned and works properly.
Your drawing #2 is a configuration that would lead to many problems, running the gamut from longevity to out-of-square.

There are many applications where a piece of lumber is wanted that is out-of-square.  One is known as a clapboard.

Designers have determined, over the years, that the best way to get deliberately slanted lumber is to adjust the cant, not the band.   When you adjust the band, you lose the one, single, known entity in the process.

Even bandmills with diagonal or vertical bands retain the relationship of the band to the bed.

[Brucer]

Further to what Tom said, the WM specs call for the band to be deflected downward 1/4". Any more than that and you over-stress the bearings.

[redbeard]

The more pressure on the guide rollers the hotter they will get, with that much deflection you will be starting a fire in no time! But you might be on to something I like your drawing!

[weisyboy]

weather boards are a tapered board used for exterior clading, they are 3/4" at one edge 7" wide and 1/4" at the other edge.

tehy are normaly cut on a bench saw with a bevel fence, you have to use a 1 1/4" x 7" board to cut them because of the kerf loss, with a bandsaw i could get them out of a 1" board. meanign i can get more from a log.

i dotn need to change the angle between cuts, i would mill out 7x boards in the mill and resaw them on a slant.

i am doing up to and over 20' lengths o to tilt 2 setes of rollers 2' long it a big task, it seams changing the blade angle seame easy.

as for bearings i would get something that could take the load an speed thats easy.

so the biggest problem with my design would be band life?

would the bearing pushing down make the band twist and misalighned?

[Meadows Miller]

Gday

Carl i would just build in the ability to set the whole head to to suit the angle of cut you want that way you can get your head and guide system tuned in just rite Mate you will want to add a guide plate for about 2 to 4' each side of the saw the longer the better too   ;)

also I have a bandsaw sharpener sitting in the shed but you would have to sett the bands a handsaw setter Mate  ;) I never got to high tech on My bandmill  ;) :D :D ;D 8) 8) 8)

Regards Chris

[weisyboy]

guide plate?

[Meadows Miller]

Fence just a lenght of angle or steel welded vertical to make sure your piece being resawn or split stays in the rite place Mate ;)

[Tom]

I'm never hoping to be one to stop someone from reinventing the wheel.  Who knows, perhaps we'll end up with a square wheel one day.   Still, there has been a lot of work done on this subject. 

WoodMizer has a jig that was originally meant for shingles, but works for siding.  A search for shingles, resaw and things of that sort will find that several folks have developed jigs to make siding.  Here are two that go to Arkansawyer's home-made siding jig.

https://forestryforum.com/board/index.php/topic,38180.msg550131/topicseen.html#msg550131

https://forestryforum.com/board/index.php/topic,11160.msg154508/topicseen.html#msg154508

I'm not in favor of using the guide wheels to make adjustments on the band because of longevity issues.  Doing the manipulation with the band guide is mis-using the purpose of guide and leaves nothing to do the guide work.  I doubt that there would be a twist put in the band, but there would be a sharp corner it would have to turn and that will work-harden the band.  It's the same kind of problem the engineers ran into when they devised the three-wheel shop bandsaw.  It was eventually made to work OK, but it has never worked as good as the old two wheel saw.  It's purpose was to provide a wide throat with smaller wheels and shop space saving.  They spent years trying to keep a band on the thing and never got them to last as long as the two wheel design.

So, don't let me stop you from inventing.  That's how new ideas come into production.  But take heed that the engineering that has gone into the existing configuration wasn't developed over-night on a whim. There has been a lot of thought and many hours put into making the band run straight.

If you are planning on using the saw for your own production, you might be better off using something that is already proven and work on your ideas on the side.

You wouldn't believe some of the wild contraptions I've seen people put together over the years, and they usually all come back to the old stand-by's.

[band-it lumber]

the one thing i did not see mentioned is that you would need to keep the moveable guide roller in the same spot ,if you don't it will change the angle of the cut

[Slingshot]

         I have one of the Woodmizer lap-siding/shingle jigs and have only used it once to
 try it out. It does work, made a few beveled siding boards from cedar. It is easy to use
 and is adjustable. For lap siding the cant is held with pipe clamps and the handle/lever
 on the right is pushed down for a cut and pulled up for the next cut. Rocks the cant up
 and down on one side. Never used it for shingles but looks like it would work OK for
 them also. It will hold 6 blocks and the same lever tips the blocks up and down on one
 end to make 6 shingles each run. The beveled edge can be made thinner than the 2
 boards shown.



















______________________________-
Charles  
 

[Brucer]

Had a friend who owned one of those WM jigs. He wanted more bevel on his siding so I made him a couple of steel shims to go under the two tilt cams. I just epoxed them down and they did the job.

Personally I like Arky's setup.

[mrcaptainbob]

How about changing one of the wheels to a different diameter? Not sure how difficult that would be, but if doing enough sawing it could be justified...

[weisyboy]

1. i dont have a saw i am going to build one.
2. it would be a resaw with fixed head and the boards just power fed threw it.


i know what you are saying about the band life, any ideas how a band would last in this setup.

at $30 each if i had to change out a band after 4 hours run time it would be no big deal. it would be well blunt by then anyway i would imagine.

i would put a threaded rod on the roller to push it up/down.

if you think its not gunna work i might be able to make a saw head that is tuned and have it on 2 posts and wind one side down separate to the other. keeping the saw the same but throwing it out of square with the bed.

i would like to keep it adjustable otherwise i would just mount the wheels set onthe ange and be done with it, but as soon as i do that someone will want a custom width or something stupid.

all advice has been taken into acocunt and is currently being filed in the storeroom - or bouncing around in a big empty space depends who you talk to.

[sweetfarm]

Weisy
     Do a search for MSG ind (http://www.msgind.com/).  I have their video and they make a tilt exactly as you are describing.  Depending on the thickness you want, and the width of your cutting head, you may only have to move the guide down a 1/4 inch or less.