New DIY stationary bandmill

TMalone240 · July 20, 2022, 11:15:06 PM

howdy DIYers

Im currently building a stationary mill that will be ran with 14" trailer tires. the frame design will be changed as the motor doesn't allow frame to raise to my desire cut height. I have a 1" spindle that will be mounted in pillow blocks sitting on a 1/4 plate resting on two 1-3/4" inserts which will slide in the 2" carriage rails which will tighten by a threaded t-handle..im still cautious about using a 1" axle with the thought of it bending due to force but these are things I hope to learn.

My questions for y'all:
will a 1"x18" axle stay true with two spaced out pillow blocks for the weight and tension of the wheels?
what is a good size drive pulley for a 440cc engine with 3600rpm?
how do I know what size belt+blade I need?

pictures are on my profile as I gave up trying to load them up to this

thank you!!

fluidpowerpro · July 20, 2022, 11:28:16 PM

I have heard of people using 1" but that sure sounds small to me. I would go bigger. Say 1 1/2". @Cornerstone just built a band mill. I forget what he used.

Den-Den · July 21, 2022, 01:48:47 PM

You could probably get by with 1" shaft IF there is a bearing on each side of the wheel / tire AND the bearings are close to the wheels. With the more common set-up having two bearings and the load on one end, I would consider 1-1/2" shaft a minimum.

The drive pulley question requires more information for a reasonable answer

blade length calculation is not complicated assuming the two wheel / tires are the same but even so, it is easier to wrap a tape measure around the wheels

V-belt length calculation is more complicated but on-line calculators are available, you will need to know the center to center distance and the pitch diameter of both pulleys

barbender · July 21, 2022, 03:56:00 PM

There is a band speed calculator in the forum toolbox. For instance when I plugged my numbers (3600 rpm, 4.5" drive and 12.5" driven I believe it gave me a blade speed of around 6400 fpm. Mast advise around 5500.

Crusarius · July 22, 2022, 11:11:09 AM

With a 1" shaft you are going to want the axle as close to the hub as possible. I would go with a larger shaft if possible. I put 2500 psi on my hydraulic tensioner to get the blade tight enough to cut well. That is just an example for how much stress will be on that shaft.

for blade length calculation, I highly recommend you go to woodmizer website find a stock length blade then adjust your mill to match. Place I worked at just happened to use 1.25" banding for shipping. I had a 158 and 176" loop made up and I used those as dummy blades. made setting everything up quite a bit safer and easier.

My sawmill is setup to run those 2 blade lengths. The longest blade allows me to cut 41" between the guides. using 19" band wheels.

jpassardi · July 22, 2022, 02:27:24 PM

Yes, as BB says: stay under 5500 FPM. Note that's blade speed measured in feet per minute, not RPM.
With lower horsepower you may want to stay closer to 4500 FPM.

You may want to consider the standard 19" pulleys with belts rather than tires. Tires can be too compressible preventing adequate tension on the blade.

TMalone240 · July 26, 2022, 03:38:21 PM

love all the info fellas!

I am just going to order a bigger shaft to be safe. ill keep the FPM in mind and thankful y'all mentioned that and figured I will run the tires since it would be easier/cheaper to complete the build now that im changing the axle size but will eventually make the switch to the 19" pulley wheels. I mean shoot its like $400 just for them wheels and $300 for blade guides alone! I still need to figure out what type of blade guides will work with a 1-1/4" blade. I was reading another forum and they were saying blade guides needed to provide downward pressure and be 1/4" away from the blade? most mills I've seen have the blade on top of the rollers and I sure don't recall a distance between the guides and the blade.

JoshNZ · July 26, 2022, 04:18:24 PM

What they mean is the guides need to pull the band 1/4" downwards from where it would naturally want to sit, under tension. Roller guides support it from top only so you need a force pulling the band into them to get the support from the bottom.

Do a bit of google searching on cooks roller guides or woodmizer guides etc look at some photos and get an idea. It's pretty well the accepted design now. You don't want any components below the band as it would hit the bed when you were cutting close to it. Picture your last cut, when sawing 3/4" boards.

kelLOGg · July 27, 2022, 09:00:56 AM

Quote from: Den-Den on July 21, 2022, 01:48:47 PM
V-belt length calculation is more complicated but on-line calculators are available, you will need to know the center to center distance and the pitch diameter of both pulleys

I can do that calculation if needed. PM me and I can do it or make the long equation available in an excel spreadsheet.

thecfarm · July 28, 2022, 06:19:52 AM

Welcome to the forum.
I always say make it long!! ;D
I have a mill that can get 20 foot logs. Gives me lots of room when I put a 16 foot log on. Gives me four feet of room instead of inches. Also helps to get the head out of the way too.

Crusarius · July 28, 2022, 09:06:11 AM

I thought about adding a flip out section of rails to mine so I can get the head completely out of the way and allow me to cut 24' I have not done it yet but might someday.