Band wheel crown and edge sizes/dimensions

[chisel]

Hello everyone,

I've been wanting to build my own bandmill for several years, and I finally decided to do it! I lurk here nearly every day picking up good info. I picked up two 24" diam. wheels yesterday at the local surplus place, but the rim is 1 5/8" wide. I'm planning on taking them to a machine shop (if it's not too spendy) to have  the rim narrowed and a crown ground on the wheel.

If I want to use 1.25" or 1.5" blades, does anyone know:
how wide the rim should be and how much of a crown should be ground on the wheel? I think if I just had it crowned without narrowning the rim it would mash the set out of the teeth.

Thanks for any help or ideas.

P.S. I haven't found any keyed bushings to fit the center hole yet, so the above may be moot if it costs to much too have the bushings made.

https://forestryforum.com/images/03_21_04/index.php?image=24inchwheel.jpg

[Danny_S]

Welcome to the forum chisel, youll learn lots here, we hope!

Are they cast sheaves? ie: like a pulley?  Sounds like they are solid wheel that would accept a flat belt or something. Mostly the ones like on a Norwood are sheaves with a belt in it the same curcumfrence as the sheave and the blade rides on that. You probably know this allready but incase you didnt that is the scoop on that... ;D

I bought a 1½" taperlock for a wheel one time and it wasnt that bad, something like $20

[slowzuki]

I followed the link to your picture and I've never seen a wheel like that, almost looks like it has a wheel bolt pattern on it.  Is it off an amusment park ride?

I hope you learn a lot while you're here!
Ken

[Danny_S]

DUHHHH....  didnt see the link!!!




That does look different than what I have regularly seen on bandmills. I am sure it will work, but like Slowzuki said it has a different looking hub to it. It kinda looks like a Baker bandsaw wheel.

[D._Frederick]

Chisel,

Check with Cooks Saw, they machine, grind, and balance wheels like that for their mills. They are nice looking wheels if they will stand the speed, if they are cast iron you may have a problem.

[Bruce_A]

In this area goodyear rubber will laminate rubber to bandsaw wheels for about $50.00 per foot of diameter, say $175.00 for a 42" wheel. After this the crown can be cut with a very sharp knife and turning the wheel much like turning on a lathe. This price is from 2001.  

[chisel]

The are for a Dake bandsaw, and yes they are cast iron. Is that a problem? Will they fly apart? I didn't think about that.

I'm sure the Dake bandsaw is a metal cutting one, so the speed would be lower than a bandmill.I figured max rpms should be about 800 to get 5000 fpm. The wheel currently has a '"tire" on it but the rim itself is flat. After reading an article at Cook's Saw, they use metal wheels with no tire or v-belt between the blade and the wheel.

That's why I was asking about how much crown I'd need. I figured I could get it crowned and do away with the old tire.  

Thanks for the welcome. (sorry, I didn't know how to include the pic in my post, just the link)

[FeltzE]

I've seen cooks setup for "true-ing" band wheels. It consists of a stand which supports a band wheel which mounted and  driven nest to which is a grinder which can be adjusted to contact the wheel as it's rotated ... the result a grinder that will contact the revolving band wheel creating grinder based lathe simple and effective.

balance I don't know about.

a note a 5000 linear feet per min blade speed, on a 24inch diameter wheel is 796.178 rpm so RPMs aren't too high for most wheels.

Eric

[Neil_B]

Isn't that 800 rpm the shaft speed for the wheel? The outside of the wheel would be going the 5000, wouldn't it  ??? Would that make much difference??

I think most cast wheels/ sheaves have the max rpm stamped on them. At least the v belt sheaves I have did.

[Danny_S]

The shaft speed and the wheel turn the same rpm, the sfpm would be greater as the wheel gets bigger. Those wheels probably allready have a crown on them maybe. If not I wouldnt think it would take much to track a blade.

[chisel]

I just did a magnet test and it did not stick to the wheel, so the wheels must not be cast iron. Oh well, live and learn. I'll put them on eBay and see if I can get my money back.

I'll be better prepared next time.

Thanks for everyone's help. I'll be back.  ;D

[Bruce_A]

I must have missed something.  Alot of bandsaws were built with aluminum wheels or magnesiem or mag iron and or steel with and without spokes, I even know on at least two built with wheels made of plywood. At least two others I know of have auto wheels with the tires on them.  They all worked according to how they were maintained.  Sloppy workmanship and or poor maintainence create more problems than the material used.  You may have a very high priced set of quality wheels there.  Don't dispose of them too soon.

[Danny_S]

You would have a hard time convincing me that there would be a problem with those wheels, unless they are plastic, I think you could use them. Now I am no genious but I am with Bruce, I would certainly be using them.....

[chisel]

I'm going back and forth in my mind...I thought I had a great deal yesterday when I bought them, and got a bit scared when a magnet wouldn't stick (I thought they were steel since they are so heavy...20# each). I'm 99% sure these are for a metal cutting bandsaw which would run much slower than a bandmill. I'm going to try to contact the mfr. and see if I can get any more info.

I'm sure the wheels are a high $ item even if I can't use them, but if they won't work for me, the trick is finding the person that needs them.

Everyone's post helps me clarify what my next step is.

You all are great!

[Danny_S]

Here is a blurb that was stated on several different sites..

There are two factors that limit speeds. First, the materials used must have adequate tensile strength to withstand the centrifugal forces due to the rotation. Cast iron is limited to a maximum peripheral speed of 6500 feet per minute, and ductile iron to 10,000 feet per minute. Caution: Exceeding these speed limits may cause a sheave to burst and any persons or objects in the area will be subjected to extreme danger.


Peripheral Speed (FPM) = .2618 x Revolutions Per Minute x Sheave Outside Diameter (in.)

Hope it helps..

[MrMoo]

chisel,
I was all set to get the info you wanted from my machine tounight but it sounds like you have changed your mind. If you decide you still want wheel crown & dimension info I can get it from my machine. Just send another response to this topic.
Mike

[chisel]

MrMoo,

I'd really appreciate any info you can provide, esp. rim width and the amount of crown and what blade width you use (1 1/4 or 1 1/2 etc.). I took the tire off and the wheels have a very slight crown, but I'm curious as to whether it's enough to not ruin the set on a bandmill blade. Maybe I should keep the tire and not fool with grinding the wheel as it may upset the balance?

I'm leaning towards using the wheels now.. ;D  Let me explain...a few hours ago I found the parts and user manual for the saw that uses the band wheels that I have. "In high range, the max speed for the saw is 5000 fpm, and if it runs faster then excessive vibration and damage to the guides may result." Also, max blade width is 1" for the saw that uses these wheels, but I think that's because of the blade guides, etc., not because of the wheel width. This saw weighs over a ton and looks VERY industrial and overbuilt, so I think it's safe to assume that the wheels are very sturdy also.

So it seems these wheels should be ok. But I'm going to contact the mfr's tech support to be on the safe side.

One more thing, for all of you out there with bandmills that uses a bushing in the center of the band wheel, do the bolts that go through a shoulder-type bushing screw through the bushing shoulder into the wheel, or do they bolt through with a nut on the other side of the wheel? The wheels I have would need to have a bolt go all the way through the bushing and wheel with a nut to tighten it. Does that make sense?

(sorry to ramble so much, but I'm excited about building a saw!)

[chisel]

Maybe these wheels are aluminum as Bruce suggested. These 24" wheels weigh ~ 20 # each. At the Cook's Saw site a 19" wheel weighs 28# and a 26" wheel is 70# !

Is there any easy way to test to see if they're aluminum? I know there are many AL alloys, but in general, is the tensile strength higher than cast iron or steel? I just don't want them flying apart when they're up to speed.

Ok, I've asked enough questions. I'll leave you all alone for a while until I get this figgered out.

[Danny_S]

Give it a rub with a coarse file someplace and see if the filings are shiny and if it files easily. I think if it is only 20 # then its probably alumium.

[Bruce_A]

Aluminum is going to to be a whitish color when you scratch it as will magnesium.  Regular white vinegar will cause mag to turn a dark grey.

[slowzuki]

Tensile strength can be higer than some cast irons, but less than steel.  If I remember right the internal stresses when spinning are less due to the lower mass.
Ken

but in general, is the tensile strength higher than cast iron or steel? I just don't want them flying apart when they're up to speed.

[chisel]

I tried the vinegar test and it didn't turn color. Also filed it a bit and it's soft, so must be aluminum.

[chisel]

For anyone that's interested, here's a refresher: I have 24" aluminum band wheels 1.5" wide at the rim and was curious about how much crown I'd need in the wheel. I was concerned about mashing the set out of a 1.25" band running on a 1.5" wheel.

I just called Suffolk Machinery and spoke with Art, who was very knowledgeable and helpful. He said no problem, crown it .005 to .007" (if it's not crowned that much already) and go to Carter Products and buy their tires (3/16" thick) and glue (Suffolk only makes tires up to 20"). He explained how to prepare the wheel for gluing and how to glue the tire on, etc. I'm glad I talked to him.

Now the next step is what kind of spring do I use for the tensioner? I'll have to do more research on that one.

chisel

[Larry]

Sounds like a good plan to me Chisel.

True your wheels up and put the tires on after you get them on the arbor shaft.