Sawmill Blade Guide Rollers

[steveh2112]

hi all, i'm planning to build my own sawmill and have been watching many youtude videos, reading article and this forum so i feel like i've got a good plan. it will be 18" wheels, 7HP gas motor for 1" blade, cut up to 24" logs or so

the only bit i'm still unsure about is the blade guide rollers. i've seen 2 types, the WM/Cooks type which i would describe as a single v-grooved flange bearing (one per side obviously), and something more like you would see on a bandsaw, 2 roller bearings, one vertical, one horizontal (no need for the bottom bearing if the guide is pushing the blade down 1/4").

to me it seems the 2 bearing system would give less friction because it turns in both vertical and horizontal plane independently.

with the WM/cooks type flange bearing, sure the blade is supported vertically on the roller, but horizontal, if the blade is pushed back and touches the flange which is spinning perpendicular to the back of the blade, would you not get massive friction?

i guess the idea is to set it us so the blade never touches the back flange, is that the idea?

thanks, steve

[gms1911]

I built my own rollers guides to begin with. They ended up failing pretty quickly. Maybe I used the wrong bearings. Or maybe my design was faulty. I ordered a set of cooks and fabed them in. They work great. Lots of adjustment. Cooks has a video on alignment of their guides. YouTube It, it will answer your question. Best money I spent on my mill.

[Kbeitz]

Why not use the standard 1-1/4 or 1-1/2" wide blades ?

[Den-Den]

I am using bearings and not had an issue with them.  An important consideration is the speed the bearings turn.  Ball bearings have a maximum rated speed and if that is greatly exceeded, they won't last long.  Obviously larger bearings turn slower than small ones with the same blade speed.

[Cutting Edge]

with the WM/cooks type flange bearing, sure the blade is supported vertically on the roller, but horizontal, if the blade is pushed back and touches the flange which is spinning perpendicular to the back of the blade, would you not get massive friction?

i guess the idea is to set it us so the blade never touches the back flange, is that the idea?

The blade does not make contact constantly with the flange.  The flange does provide support to the back edge of the blade, and Yes, it can/will cause friction.  The blade will contact the flange, especially if it is getting dull, knots, etc.  Just don't want it to do it constantly.

This contact is not so much an issue with heat, but is it detrimental to blade life.  I've done service work on mills where new blades were breaking in the first run because the mill had bad alignment and tracking issues.  So the owners were relying on the flange/backup bearing to keep the blade where they wanted it.

For what you are looking to build, you may want to consider going with a 1-1/4" blade. 

[Ljohnsaw]

I, too, upgraded from dual bearing homemade guides to Cook's.  They work great.  I also vote for you to look at 1¼" blades since they are a more standard size.  I'm not sure if Cook's makes a guide for 1" blades.  The 1¼" guides are actually 1" deep so the teeth don't ride on the guide knocking the set out.  A motor size of 7HP will be a good start but don't turn down a 15 or 20hp motor if you come across one! ;)  Especially if it has electric start!!

[AncientTom]

Dang! Your post looks almost like mine for engine mounting.

I too am new at this and have been spending several weeks now on Youtube trying to educate myself with the plan of building my own band saw mill. I have already picked up an engine that was on super Christmas sale at Harbor Freight and will start working on my build after the first of the year.

With everything that I have looked at on the Internet, there are 2 different concepts to what the blade guide should be like. One is stationary guides top and bottom of the blade about 1/32" away from the blade and only touching the blade when pressure is applied keeping the blade from diving up or down under heavy load. Also, a bearing is set behind the blade at the same distance from the blade that is there only to keep the blade from being forced backward when cutting pressure is applied. It will not normally touching. In this scenario, the trueness of the blade is dependent on the alignment of the 2 wheels and sufficient tension to the blade to keep it stable.

The 2nd rule of thought is the Cook's method of a flanged hardened steel roller with deep grooves in it to handle the excessive buildup of sawdust on the blade. The roller is positioned back from the blade so that it will not contact the blade unless sufficient pressure is applied when cutting that forces the blade back against the flange. Also, the guide rollers are positioned just below the normal blade travel enough (I forget the actual suggested amount) so that the pressure downward on the blade is sufficient for the guides to control the blade's stability.

Everything else that I saw was a mix of, or somewhere in between, these two concepts. I personally, will be trying both and expect to be doing a lot of experimenting till I have something that works well for me.

[Magicman]

Also, the guide rollers are positioned just below the normal blade travel enough (I forget the actual suggested amount) so that the pressure downward on the blade is sufficient for the guides to control the blade's stability. 

Use ¼" downward pressure.

[AncientTom]

Use ¼" downward pressure.

Thanks.