Wavy cuts and burning out blade guides on homemade bandsaw mill

[JohnnytheFish]

Hi - I am new to this forum and am looking for advise. I have built a bandsaw mill that is loosely based on the Linn Lumber mill - similar system for mounting the band wheels, but using a boat trailer winch for raising and lowering the carriage head. It has 4 legs so is fairly sturdy. The rig runs on angle iron - in a similar manner to the Crosswood mills - which I have plans for.

My blade guides are the Crosswood style - with 2 bearings together that push down on the "fat side" of the blade and one at the back that the back of the blade pushes against. The mill has a 10 HP diesel engine and I am using Woodmizer silver tip blades.

I feel like my rig is as good as many homemade mills - and yet I am really struggling with a few things:

I am trying to cut Blue Gum (which I know is very hard) and I am really struggling to get straight (not wavy) cuts - do I need a blade for hardwoods and if so any advise which ones; or is this an issue with setting up my blade guides. (The blades are brand new and sharp).

In addition, by blade guide bearings do not seem to last more that half an hour or so. I have tried both high quality Japanese and cheap Chinese bearings and they both wear out pretty quickly - even if I have a heavy water flow on them to keep them cool. In low light conditions, I can even see sparks coming off the bearings - and the bottom bearing develops a groove in it very quickly from the back of the blade.

Should I have different blade guides - any advise on good ones? I have see that the Woodland Mills use bearings - so can't understand why mine are dying so fast.

Many thanks in advance,

Best wishes

Tom

[Grizzly]

Welcome to the Forum Johnny! The smart guys will be along shortly.

Lyle

[Den-Den]

The guide design is valid, bearings should last much longer than that.
Two things:
* How fast are your guide bearings turning?  If they are pretty small, they may be spinning faster than they are designed to, which will make them wear out quickly.  The rpm of those bearings can be calculated by dividing your blade feet/minute by the circumference (in feet) of the bearings.  Check that number against their rated speed.  If this is an issue the fix is larger bearings or slower band speed.
* Wearing a groove in the bearing that supports the back of blade tells me that there is too much pressure on that bearing OR the groove is developing after the bearing has begun to fail.

[Kbeitz]

Does your band wheels have a good crown? If not then your guide bearings is doing all
the work of trying to keep the band on.

[drobertson]

yea, it sounds like an  alignment issue.  Thinking your build is close to the Linn, there has to be a reason the bearing are going out.  Clearly not normal.  Sounds like you are in store for some serious bed rail inspection as well as blade alignment.  Set back and take a good look at it from all angles, move slow in making adjustments.

[Kbeitz]

If your saw is working right then you should be able to
make a slow cut without the guide bearings on the machine
or touching the blade.

[bandmiller2]

Tom, my homebuilt band mill used the three sealed ball bearings you describe and I got long useful service from them. The back of the horizontal bearing behind the band should not be touching the band all the time, when running free their should be a gap something like 1/8". How much does the two bearings push the band down should only be 1/4" or a little less. Sounds like their being overloaded. As the guys have stated alignment is critical. Hard wood is easier with less than 10 degree hook usually 7 or 4 is recommended. Don't get discouraged you are close. Frank C.

[JohnnytheFish]

Hey Guys

Please forgive the delay in answering. I went ahead and bought so Cook's Saw Standard Complete Guide Retrofit to see if that makes a difference.

I am still getting wavy cuts with the Woodmiser Silvertip blades on Eucalyptus saligna (Sydney Bluegum).

Do you think it is time to try different blades? (I live in Africa so hard to come by a different type). Or should I adjust the set? Or is it more of an alignment issue with the mill and the guides?

Generally the blade has a tendency to dig down into the log and sometimes if I back off it goes straight second time round.

Finally - what are thoughts on running water lube with this setup?

Thanks 

[willowbender]

JohnytheFish 
 
You should have came back way back and posted what was up.
people here gave you great advice and you wained for a long time without a word and came back with the same ? and have not even recognized the answer is already answered.
If your going to ask a ? at least come back and thank the people that gave a good answer.
Good luck it sounds like you need it.

[starmac]

I am betting you do not have enough blade tension, and the back of your band should not be touching the guide, like mentioned above.