The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: Dave VH on January 04, 2012, 01:23:15 PM

Title: cant seem to cut straight
Post by: Dave VH on January 04, 2012, 01:23:15 PM
  I've always dreamed of having my own sawmill. I kinda fell into a t.a.shmid.  I don't know how old it is, it has a 13hp honda on it.  I had to make my own track for it.
  My problem is it doesn't seem to cut very straight, it cuts up and down to freely putting a lot of stress on the blade.  My first blade snapped on my,(I think that I had it to tight, and was pushing it to hard).
  I feel that I really don't know what I'm doing, but this is the only way that I know to learn. 
  I'm cutting mostly oak and maple.  I would really appreciate any feedback or wisdom that you all might have.

southern michigan
Title: Re: cant seem to cut straight
Post by: Magicman on January 04, 2012, 01:41:52 PM
First, Welcome to the Forestry Forum.

The first question that I have is the sharpness of the blade.  Dull blades do bad things.  The next is blade alignment, being sure that it blade guides are holding the blade perfectly horizontal.
Title: Re: cant seem to cut straight
Post by: Dave VH on January 04, 2012, 01:53:01 PM
thanks for the feedback.
  I purchased 2 new blades from woodmizer. 1 .042 with 7/8 spacing @1 1/4", 1 .035 with 1/2 spacing @ 1".  I figured that I would try a couple before I bought a pack of blades. 
  I did have to mess with the alignment of the guides, but they seem to stay on the blade now. The thinner blade seems to have more of a problem than the thicker one does.
  The saw only has guides on top of the blade, I wasn't too concerned because I figured that the designer knew what they were doing.
Title: Re: cant seem to cut straight
Post by: terrifictimbersllc on January 04, 2012, 01:55:05 PM
Also enough tension on the blade, does your machine have a gauge on it?
Title: Re: cant seem to cut straight
Post by: Dave VH on January 04, 2012, 02:06:09 PM
no, I haven't found a tension gauge on it.  Blade tension is somthing that I've had a lot of question about.  Is there a rule of thumb in regards to blade tension?  (the first blade that I snapped was on the saw when I got it)
Title: Re: cant seem to cut straight
Post by: terrifictimbersllc on January 04, 2012, 02:12:03 PM
I'd have to look it up for the blades you mention coming from Wood-Mizer, you might find recommended tension on their blade website pages or call them and ask.  However you'll need to be able to measure it and accessory tension gauges are expensive (think WM is $300).  My WM LT 40 has a hydraulic tension mechanism with a gauge, right on the mill,  that reads out pressure, I think I'm running 2300 psi for 1-1/4" .045 bands.   Perhaps you can get the manual for your machine and see what they recommend or maybe someone here has an inexpensive work-around.
Title: Re: cant seem to cut straight
Post by: ladylake on January 04, 2012, 05:24:55 PM

As Magic said make sure the guides hold the blade level with the deck, guide wheels need to push the blade 1/4" down after they touch the blade, make sure it's important. The back of the blade should be 1/4 "(I run mine a bit closer for good blade life).   in front of the guide wheel flange or back bearing which ever is used.  Also don't lug the engine, keep the rpm's up if lugged down it will cut crooked. Steve
Title: Re: cant seem to cut straight
Post by: hbilly on January 04, 2012, 05:31:44 PM
I havent got much on wood cutting yet butt hopefully will be there soon. I do work with a band saw everyday, I wouldnt believe blade tension would cause that: to loose and your wheels would just spin and to tight cause it to snap or stretch. If you have to keep putting tension on your blade then maybe. IF it was me I would start with what magic typed then make, sure my head is staying stationary during the cut, also if your loggs are seasoned probably need to slow down. If they were yard trees sounds like maybe a little metal.
Title: Re: cant seem to cut straight
Post by: ely on January 04, 2012, 05:35:27 PM
not sure what size the band wheels are on a ta smimdh but you should maybe try the.055 thickness bands. the thicker the band the more leeway you have with other adjustments that are out of whack. IMO. bear in mind there is no replacement for a finely tuned bandsaw. more horsepower will help to an extent also.
but when the saw is out of adjustment you just have to back off and get the tools out.
Title: Re: cant seem to cut straight
Post by: LeeB on January 04, 2012, 05:40:47 PM
Blade tension can indeed cause some of tne problem. You can set the tension by doing the flutter method. Tighten the blade up till it is nicely snug, counting the turns on the crank. Start the blade spinning. If it is fluttering try tightening a little more, again counting the cranks. When it stops fluttering, the number of total cranks will be a good starting place. I would not recomend the .055 blades with a 13HP. A .042, 1 1/4, 7/8 would be my first choice.
Title: Re: cant seem to cut straight
Post by: cypresskayaksllc on January 04, 2012, 06:27:48 PM
A lot of detailed pictures of your mill might help. Close ups
Title: Re: cant seem to cut straight
Post by: ladylake on January 04, 2012, 07:12:30 PM
Quote from: LeeB on January 04, 2012, 05:40:47 PM
Blade tension can indeed cause some of tne problem. You can set the tension by doing the flutter method. Tighten the blade up till it is nicely snug, counting the turns on the crank. Start the blade spinning. If it is fluttering try tightening a little more, again counting the cranks. When it stops fluttering, the number of total cranks will be a good starting place. I would not recomend the .055 blades with a 13HP. A .042, 1 1/4, 7/8 would be my first choice.

Got to agree with you on blade choice, a .42 should be the max for a 13 HP.  I'd almost bet lugging it down too much is most of the trouble.    Steve
Title: Re: cant seem to cut straight
Post by: Dave VH on January 04, 2012, 11:52:38 PM
thankyou so much all of you,

after rechecking, no my blade guides were not as level as they could be

when it was cutting real crooked, yes I was pushing the mill to the point that the engine was bogging down, I didn't think that that would effect straightness. (apparently I was wrong)

thanks, I'll try again
Title: Re: cant seem to cut straight
Post by: tyb525 on January 04, 2012, 11:56:28 PM
You mill head might not be locking tight enough, allowing it to drift up/down.
Title: Re: cant seem to cut straight
Post by: paul case on January 05, 2012, 06:49:48 AM
Sounds like you have got it.

Dull blade+ pushing too hard= wavy cuts?

It isn't as simple as point and cut, but it is close.The saw needs not to lose many rpms when in the cut. Those bands do strange things when slowing down and speeding up in the cut. PC
Title: Re: cant seem to cut straight
Post by: slider on January 05, 2012, 07:40:47 AM
Dave ,woodmizer sells a tool that clips on the band that makes aligning the guides much easier.They are fairly inexpensive and easy to use.You would do well to purchase one.
Title: Re: cant seem to cut straight
Post by: customsawyer on January 05, 2012, 09:48:35 AM
When you lug the engine your blade speed slows way down and this will have an effect on your cutting. I would also not use over a .042 blade with 13 hp.
Title: Re: cant seem to cut straight
Post by: coastlogger on January 06, 2012, 11:06:39 PM
I run 13hp also,have good success with .045x 1.25 wm bands. Something Ive found helped me get cutting straight is keep an eye on the back edge of band at the guide roller.When its not in wood it should be say 1/8 or a bit more away from the back flange on guide roller.When you are cutting it should most of the time still be away from back flange,actually fluctuating in and out a bit as you cut thru  knots etc. If it stays on the back flange all the time you are cutting you are pushing too fast and or your band is dull.Slow speed feed is better till you get the hang of things. In a big cut this might be really slow.IMO you need to get the tension thing sorted. WH Conley showed me how to do this on this forum a few years back. Search my posts youll find it.You clamp a caliper to the blade and measure the stretch when its tight.
There are many factors that can cause waviness.The folk on this forum helped me get things on track,and believe me I needed lots of help!The above are a couple of things I had to get figured out.
Keep those blades sticky sharp,more set is way better than less. Etc,etc.
Title: Re: cant seem to cut straight
Post by: Dave VH on January 07, 2012, 11:07:26 AM
thanks coastlogger, I'll take all of the advice I can get!