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Cant be true - how to?

Started by Sprucegum, June 15, 2009, 11:59:14 PM

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Sprucegum

I have been fiddlin' with my mill again.
The boards are coming off pretty good now but the cant left is never the same size at the back end as it starts out to be  :(  A 10 foot 4x4 is only 3 1/2 x 3 1/2 at the other end  >:(

My track is almost 1/16 inch closer to the back of the sawblade than the front and the blade appears to run true, no rub on the guides (which I have reset in their proper location  ;D ).

I found some side play in the back end of the carriage and tightened that up.

Finally I measured the headblocks. They are in the original configuration so I never suspected them  ??? What I found was 1/4 inch set back. That is: if the front block is at 10" the eight foot block sits at 9 7/8" and the twelve foot block is at about 9 3/4" from the sawblade.

So when I flip the log 180 the cant loses 1/2" off the back end and if I flip to 270 every board is 1/2" narrower at one end. When cutting through and through the thickness is good all the way.

This appears to be an intentional setup. How would you work with it? Or would you rebuild to make them even? Its got something to do with log taper, eh?

Jeff

You don't have adjustment in the headblocks?  They should all be adjusted exactly the same distance form the saw.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

DanG

Just a quick, bleary-eyed shot at this before I go to bed;  are you sawing parallel to the bark on all sides?  If so, the cant will be tapered the same as the log is tapered.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
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coastlogger

If I understood you right you have your saw leading "out" not "in". Directions for setting up my long since sold M14  called for saw to be closer to carriage at front,not further away. I had to adjust a couple of times over years as wood frame of mill deteriorated. Does this help?
clgr

ladylake


If this was a bandsaw the only way that could happen is if the log bed and the tracks were not even with each other.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Ron Wenrich

Another question would be if you turned the piece over 180°, are your boards tapered?  If they are, I would suspect the lead.  If not, then I would suspect your mill alignment.

It doesn't seem that your carriage is perpendicular to your husk.  It needs to be sawing in a straight line.  And it needs to be level.  You have to get that 1/4" out of the rear headblock.  There should be some sort of alignment on the headblock.

Have you checked your saw lead?  To do it, unloosen your saw guides so they aren't rubbing or pushing the saw.  Mark a tooth and measure the distance from the headblock to the tooth at the guides.  Move the carriage to the back of the saw, and measure the distance from the headblock to the same tooth.  
Never under estimate the power of stupid people in large groups.

bandmiller2

Spruce,do you have a rt. or left hand mill.If you have taken the play out of the carriage probibly you just have to adjust your headblocks.I mark one tooth on the saw and move the carriage making a accurate measurement to each headblock they usally have a little wiggle room when you loosen the bolts.Sometimes on older mills that are a little loose especially if the lead isn't right they will move going through the cut.Most have provisions to take up wear.Frank C.
A man armed with common sense is packing a big piece

Sprucegum

The boards are all uniform thickness so I think the lead is OK.

I don't have individual adjustments on the headblocks. I will try loosening all the bolts and giving it whack with a hammer to take up any slack  ???  I guess my goal is to get all the headblocks equal distance from the saw rather than deal with that strange taper all the time.

Jeff

The adjustment would not be in the headblock per say, but in the knees, or in the mechanism that drives the knees.  There must be some sort of adjustment there. 
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

sharp edge

I would make sure the saw isn't laying over the log when cutting. The blade should tick the log the same amount all the way back. But do make sure the head blocks are all even, like said above. Some times thier are two or more things wrong. >:(

SE
The stroke of a pen is mighter than the stroke of a sword, but we like pictures.
91' escort powered A-14 belsaw, JD 350-c cat with jamer and dray, 12" powermatic planer

JSNH

It is possiable to knock the drive gear off a tooth on the end of the carriage, if you have enough play in the bearing. Bandmiller's advice on adjusting is spot on. Do that to get the head blocks even. Then run a cut at speed check to make sure the cut is even. You will have to adjust the scale a bit since you make your adjustment not running and check it running. There is just a bit of a diffrence with the saw standing up at speed.

bandmiller2

Spruce rereading your post sounds like two problems the headblock adjustment,all should be the same distance from one point on the saw.Also your lead comes into question,as Coast logger noted,sounds like its the wrong way.Front of the saw should be a little closer to the headblocks than the rear[to counter the saws tendency to run out of the log.As stated by Sharp Edge the teeth should just tick the log/cant on gigback,if they don't too much lead,if they try to cut at gigback too little or the lead backwards.Probibly an older mill 1/16" lead in would be about right.Frank C.
A man armed with common sense is packing a big piece

Sprucegum

Yeah, the saw rubs pretty hard on the log when I gig back - that's an easy fix.  :)

Getting the headblocks even may call for some new bolt holes - nothing a Saturday afternoon can't fix.

Is it Saturday yet?

beenthere

Before moving the headblocks, did you check out Jeff's suggestion?

Maybe check the backlash from wear in the knees. Measure, then reverse the direction and measure each again.  If that makes sense.  ::)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jeff

If the saw is rubbing pretty hard, so lead is probably part of the problem but you gotta get that differing distance from the blade to the knees fixed.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

Tom

QuoteThis appears to be an intentional setup. How would you work with it? Or would you rebuild to make them even? Its got something to do with log taper, eh?

I don't know what I'm talking about, but..

Things on my mill, that are board/mill relative, have to be square.
I'd say that the whole carriage was knocked catywhumpus.  Have you ever seen a truck with crooked axles, going down the road?  It travels in a straight line, but like a crab.  That would account for the mis-alignment in progression.

Ron Wenrich

The first thing you have to get corrected is that 1/16" that your track is closer to the mill at the back of the saw.  That's taking lead out your saw and causing your carriage to run in an angle.  You will get tapered cants even if your headblocks are straight. 

Have you run a string line down your guide track?  Any bow in your guide track will cause your carriage to move and will taper a cant.  If you can't use a string line, you probably can do something with a small laser.

Headblocks are also part of the problem.  The poor alignment may come from the track.  That has to be parallel to the saw.
Never under estimate the power of stupid people in large groups.

Sprucegum

All good advice (as usual  8) )

I will adjust the lead first thing. I built in some threaded adjusters so its easy to do and precise.

I am starting to think the front headblock may be 1 cog out of sync with the others so I will check that and get them all square and equal to the blade - when I get there  :(  It sure seems like a long time between weekends  :(

backwoods sawyer

You got some good advice on how to get every thing back in adjustment. However to get to the root of the problem you may want to find out why it is out of alignment, other wise you will have to revisit the alignment issue on down the road. The first thing I would check would be the main frame and supports to see if they have settled or shifted. Firm them up, or replace them then realign the mill as described above. If you are setting on a wood frame that has seen its better days, then you should expect it to move even more then it has as you add the weight of logs. If the wood in your frame work is solid, it may have been bumped out of alignment when loading logs.  
Backwoods Custom Milling Inc.
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