Sawmill sawing hard

[Nsmiller]

Ok thank you. So I will have to feed slower at 550 rpm direct?

[beenthere]

Ok thank you. So I will have to feed slower at 550 rpm direct?

Did you read that in what Ron said, or in the link to the circular saw .pdf linked in Reply #6? 

Read about the tooth cuts per inch, in other words the bite of each tooth. Calculate no. of teeth and distance the carriage travels in one revolution to get that bite.

[Ron Wenrich]

Feed rates depend on the log.  A small log can be fed faster than a large log.  Softer woods can generally be fed faster than harder woods.  A sharp saw can be fed faster than a dull saw.  There are a lot of variables.  You'll get to know your saw feeds as you get more experience.  You want to keep the same sound through your cut. 

When I ran my mill, I had a 125hp electric running the saw.  I had to slow down on occasion.  You'll be running at half my horsepower. 

How about describing your operation to us.  Sometimes that will help us figure out what you're trying to do and how we might help.  I don't know everything, but I have learned a little bit over the years.

[Nsmiller]

Well my hydralic feed at the fastest is about a foot per second. That's slower than my old friction feed. But I did saw a lot of lumber running that fast. And yes I really couldn't hold a good bite with the set up. Now after like 5 years I have to make this work and fast because I'm running out of money and I need my mill to make some. I'm usually sawing say green 10" spruce. I have sawn juniper pine maple and dry spruce around 20". 
It's too bad I couldn't post pics.
I am planning to hook to direct pto shaft 60 hp at 600 rpm saw hammered for 550. Feed at fastest foot per second so this mite work I hope.

[beenthere]

If your pics are on your computer, and in .jpg format, there is no reason that you can't upload them.

Have you set up your own gallery in your profile?

Have you followed the primer in the "Behind the Forum" forum on the "Home" page?

Tell us how far you get, we'll gladly give you a boost at that point. Right now, we don't know what is hanging you up. ;)

[beenthere]

Well my hydraulic feed at the fastest is about a foot per second.

How many teeth on the saw blade?

[whitepine2]

  If you hook this up direct to PTO make darn sure you have a slip clutch or shear pin or you are looking for trouble gotta have give somewhere in driveling

[Nsmiller]

I have a blade with36 teeth. Also I have a 40 bit blade

[bandmiller2]

I hesitate to say anything as the water is so muddy. The advice given by Ron is  spot on, I wouldn't want to be in the same building with a 48" saw at 900 rpm. It sounds like this mill has lane fallow for several years if so everything should be checked especially the foundation, alignment and excess play. Where are you located does the NS stand for Nova Scotia, if we have a member with a circular mill near a second set of eyes won't hurt. Stan Lundstroms  booklet or internet rendition, Beenthere recommended, will tell you everything you need to know. When I got my current mill it was setup to spin a 50" saw at 700 rpm everything was happening too fast for this old phart set thing down to a more comfy 600. High speed is fine for production but theirs a price to pay in maintenance and power. Frank C.

[Nsmiller]

I am in Nova Scotia. On the 215 hwy like an hour from truro or Windsor.  I have been working at this mill and have replaced nearly everything. Bearings boxes shaft belts pullys cable drum shaft the list goes on. Identified several problems with help so far. Like the speed!! Also the belt pully set up. Need so much tension that it pulls one end affecting the lead! That's why I'm shifting the rpm to direct shaft to stop this problem. I would like to know someone near me tho to take a look sometime. Maybe I will soon just purchase another old mill skeleton for all my good gear after all this has become my livlyhood now. Off to work at it now.

[backwoods sawyer]

I am woundering if he is making the same mistake I made here in assuming each revolution of the tac is a foot rather then 1/2 a foot. It would explain a lot if it is the case ;)

The wheel on the tach is 6" in cir. So the blade is running about 4800 FPM.


 

Seems the reading would be the actual reading unless the book for the tack says other wise :P 

been a while but it seems like 3,500-4,500 is the ideal blade speed, to fast has as many issues as to slow.

that is the actual RPM but the cir of the wheel is 6" so each rev is 1/2 foot. So half of that would be the actual FPM. (I think)

[Ron Wenrich]

I'm going to put in a few more things for you to think about.  There is no reason for belt tension to be pulling out your lead.   We had our belts banjo tight on our mill.  It never pulled lead out of the saw.  How many belts are you running?  You know you can only transfer so much horsepower per belt.  If you don't have enough belts or they are too small, you may be trying to overcompensate that lack by adding tightness. 

I think there is a lot of wisdom to using your belts.  As pointed out, you will need shear pins or something in case you hang a saw or something else causes your saw to bind.  Those belts always act as a nice slippage area.  Would it make more sense to swap out your one of the pulleys so they're both the same size?  If you do that, you'll be able to keep your speed at 540 and still have the comfort level of knowing you won't booger up the tractor if you wreck the saw.

[Nsmiller]

4 b belts 122" long. I tried same size pullys before and had too much belt slap and slippage. So I guess I loose power from belts? Just tell me this if I hook up direct pto shaft to main shaft foe saw , 550 rpm I can still cut a decent log just feed slower ?

[beenthere]

Nsmiller

Well my hydralic feed at the fastest is about a foot per second

Are you looking to go this fast?

[Ron Wenrich]

I'd suggest that you look at Lundstrum's book that Beenthere has linked to.  It has all the information you're looking for.  Go to page 20 to find out about the belt sizes, and hp ratings.  Go through all of it and figure some of this out before you spend a bunch of time or money on something that won't work well. 

Slowing down will cause you to slow your feed.  That's covered in the book, as well.  For the type of saw you have and horsepower, it might be 2-3 seconds per foot.  That seems a little slow, and it would be faster for the small softwoods.  So, your hydraulic feed ought to be OK.  You always want your return to be faster than your feed.  So, your 1 ft/sec rate is for your return.   

I'm thinking you're not going to notice too much of a difference.

[Nsmiller]

Well my direct shaft on mill works great having the rpm slowed down. But,,, my lumber is coming out too wide after the first 6". So does this mean I need more lead??

[Ron Wenrich]

Do you mean too thick?  That means your saw is cutting in, and you probably have too much lead.  Your saw will follow the lead.

[Nsmiller]

I mean the cant on carriage should be say 6" but it goes wider. Measures 6" at both ends but over six In middle

[Ron Wenrich]

What's the board thickness like?  If you're getting a consistent board thickness, then your problems are in your track or carriage.  You would be getting movement there.  If the board thickness varies, you may not have the guides set quite right.  Or the lead might be a little light.  Check the board thickness first to see how uniform.  The wood has to have come from someplace.

[backwoods sawyer]

At the production mill we would run a test block a few times a day.
Start with a 12" pealer core from the venier plant. Paint half the end so the sawyer can orient the same as it was measured, measure it 4 points with large log calipers. The sawyer would scan the log and saw in test mode, down stream all the pieces were measure at the same four points using calipers with a memory bank. Then the measurements wire printed out. This gave us the ability to check where the two block chippers were setting in to as well as each of the four bandmills. When any measurements were over .005 off an off set was added to the computer that positioned all six machines and another test block was ran. We used the same process to check all five edgers and the resaws.

You can use the same principle by squaring up and measuring a cant and taking measurements at four points on the board and the cant after each cut. Use a pair of clipers as a tape measure will not give you the precision you need.   

[Nsmiller]

The thickness is off too. How close should the guides be? Thers also adjustment at tha back of the carriage , wonder if that has anything to do with it!?? I previously tried moving it some but didn't seem to make much difference. Other then on the return it would hit teeth more one way then the other.
I'm reading and taking it all in , a great thanks to everyone. I'm gonna work all day tommorow at it.

[Nsmiller]

Well I got my mill sawing right. It was a mixture of things. The blade I was using, the carriage adjustment and lead. Thanks