saw blade heating ?

[ArborJake]

 I recently bought another circle mill. I just got it set up and had the new blade and the old blade (I already had) hammerd to match my pto speed at 600. ( I had just recently checked the pto and realized it was at 600 and not 540). I milled a few spruce logs and had them to within 1/16 of an inch over 9 ft. Then milled  a small fir log, no problem. Next I started on a larger fir log 20 some inches. After slabbing two sides of the log the blade began to dish out away from the log. I left it turning for a while and when it straightend back out went to make another cut and the log stopped half way through the cut. I soon realized that the blade is dishing so far that the center part of the balde is making contact with the cant and the teeth weren't making contact wich put pressure on the cant enough to stop the hydrolics ( seperate system) from moving. turned the log same result. My next step will be to try a differnt log. My question is for anyone with a cirlce mill if they have ever seen or heard of anything like this. Could it be that the saws ware hammerd for a left hand turn istead of a right. I explained how the mill was set up to the sawsmith. Maybe a miss communication? any help would be appreciated. Oh aslo switced out blades and the problem was the same.

[Bill_G]

Sounds like you have a lead issue . This could be caused by alignment of the arbor or high corners on the slab side of the sawteeth . My experience is lead differs on every mill , trial and error until you get it dialed in for your mill .

[beenthere]

Might double check back with your sawsmith to be sure of the left/right hand hammering. Seems a receipt or his log notes should show that if he doesn't remember. Describing the results might also help him answer your question.
Also, you could do some checking  of the blades as there is some basic differences between a left saw and a right saw.

What is your history of sawing with this mill prior to sending the blades off for hammering?

[dgdrls]

Collar issue?  It affected both blades

appears more than one thing will cause dish in a circular sawmill

let us know.

DGDrls

http://www.sawdoc.com/troubleshooter.htm

[ArborJake]

 The 46in. blade is new to me. Came with the mill. The smaller blade "44in." was my original saw and worked good just wobbled a tiny bit cause it was hammerd for 540. now hammmerd for 600 , the correct speed it turns real straight until i set it into this fir log. But both act excatly the same. The lead seemed to be right when i sawed the spruce logs. Boards came out straight and square. Just started acting up on the larger fir log, thats what confused me. I double checked everything else i could think of as far as the blade is concerned its square to the carriage except for the lead of course I mean its straight up and down, the carriage is moving straight along the mill and everything. I have never sawn fir before and it is frozen just wonderd if that could possibly be it or if its something I have not thought to try or check. I am also using the old mandrel and collar from my first mill that cut pretty good.

[bandmiller2]

Kinda sounds like a lead problem heating the plate.I would not change anything and try a different log and species if that cuts fine the log is suspect.Sometimes a chip or something will rub unseen and cause all kinds of chicanery, heating the saw plate. What brand is your new mill.  Frank C.

[lyle niemi]

Before you get to changing stuff, check your teeth!  make sure they are sharp, a dull blade does funny things

[GeneWengert-WoodDoc]

A comment or two that might help or might not.  First, it is common in my experience to find that two things are not quite right, but each one is just a little bit off and by itself is not an issue.  Combined, we see bad stuff.

A saw can dish when the eye is heated.  So, check the bearing closest to the eye to see if it is heating.  In my experience, if we had heating of the rim of the circle saw, it got very wobbly, but not dished.  I saw the worst dish when we caught a piece of wood between the saw and the frame, heating the center of the saw but not the teeth.

Also, as I understand it, you have the log close to the eye of the saw.  Perhaps you already know this, but the saw plate is thicker near the eye, so you might need a bit wider tooth to have a wide enough kerf to avoid heating this thicker part.  This is especially true with frozen wood as the sawdust can refreeze on the log and lumber right after it is sawn, making the kerf narrower.  This means rubbing and heat.

With frozen wood, the sawdust can spill out of the gullet more easily and that means heating.  When I ran a circle mill with a 60" blade, we found the Standall bit really helped in winter.  That bit has a little protrusion in the gullet to help keep the sawdust spinning.  Today there are other suitable bits too, but this was over 20 years ago and we did not have as many options.

The idea of right hand vs left hand is good.  You can check by seeing which side of your saw has the most dish when stationary.  The flat side should be the log side.  Do not do this test with the collars being tight.

Also, check the collars.  When tightening the collar, the rim should not move.  One collar is usually perfectly flat.  You can check this by putting chalk on the face and then using a flat edge to scrape it off...it should scape the surface clean in one pass.  The other collar should be dished so that the outer rim contacts the saw, but not the inside.  Some saws use both collars dished.  In either case, the idea is that the saw is held by the outside rim of the collar and should not move the saw as the nut is tightened.

In case I have not been clear, have you seen the book on circular sawmills?
http://www.fpl.fs.fed.us/documnts/misc/circsaw.pdf
Check figure 5 for the Standall bit and page 15 for right and left hand info.  Saw collars are on page 64.

[ArborJake]

 Thanks Ill check those things mentioned here tom. Thanks for the links also.

[bandmiller2]

What has always impressed me about circular mills is is how critical seemingly small adjustments are.Everything looks so big and rugged but really needs fine tuneing.Doc is right sometimes small problems compound and cause misscuts and downright mayhem.In outher words little things mean alot. Frank C.

[ArborJake]

 I put a small spruce log on the mill today and didn't seem to have any problem with heating. But have seen that somehow the lead is off by quite a bit. I don't know what must have moved Ill have to check further tom. . Bandmiller ,  this mill was made by the guy I got it from and his father. He told me the made it from a Mack truck frame and parts from  other mills. here is a picture from this summer.

   I used my old mandrel and collars becuase I have a seperate hydrolic system and didn't need all the extra parts on the mandrel. 

   Here is a view of the whole mill.

  

  He also made the scale board. I realy just wanted the mill frame becuase my wood frame was gonna need rebuilding. Then I passed by this one and decided for the money, better than rebuilding and a spare blade is a good thing.

[bandmiller2]

Jake,sometimes the cheapest and best route is to buy the whole mill.Seems when you have one mill outhers just come out of the woodwork.I have had parts from as many as four mills around,picked and chose the parts to use on the mill I have now. Frank C.

[tgalbraith]

ArborJake-
The rotation the blade was hammered for, should be stamped on the saw along with the rpm speed.
I agree with the others that you may have a lead problem.
Hope you get it figured out--

[GeneWengert-WoodDoc]

Something just popped into my mind.  Is it possible that the collars are not holding the saw tight AND you do not have two pins to keep the saw from slipping under load?  If the saw slips between the collars, this would give eye heating and dish.

[Bill_G]

I always start with the basics , make sure everything is square , plumb & level . Then I tune in the lead , if there are still problems I start checking collars and bearings . Also feed rate plays a pretty important role . All this assuming the saw is correctly hammered , teeth are filed correctly and shanks are tight and not worn out .

[ArborJake]

 Ok. Today a milled some more spruce logs after adding a little more lead. 1/16 of an inch at a time. I also check the bearings and made sure all was secured properly and straight and even. Cutting pretty good again now. I think the lead was the main problem and "knife" if thats what you call it. The piece that holds the board away from the blade as it cuts was making a little to much contact with the cant. Think Im in good shape now. Bill G, I know now what you mean about the feed rate, it took me some time to figure that out when I first started. There definately is a feel for it that you only get with practice I suppose. Like was said earlier one problem not so bad add in another and then you realy see it. Thanks everyone for your suggestions. Gives me some other things to keep in mind should I have more trouble also.

[Ron Wenrich]

The "knife" is called a board splitter. 

[bandmiller2]

Troubleshooting a circular mill can be a real bear,because everything affects everything else.A slight dip in your rail especially near the husk,can cause no end to problems,you may try to change your lead and dig a deeper hole.Clamp a piece of sticken verticle to one of the headblocks and run your carriage from end to end,look for excess movement,do it again with a heavy log on the carriage.As far as lead if the saw just ticks the log/cant on gigback I consider it good,constant hitting on gigback,not enough lead.If the last couple of boards tend to pull away from the last headblock and you not getting any ticking on gigback you probibly have too much lead.Most everything on a mill is common sence if you sit down and think about it.Opinionated old phart. Frank C.

[scottmtfarm]

I was sawing SYP this weekend. After sawing about 15 logs without issue, the bladed got a wobble on the first slab cut of a new log.  Stopped the saw and it was warm in the center.  Ate lunch, touched the saw up with a file, turned the log and sawed rest of the day without any problems.  A slightly dull saw can combound other issues.

[ArborJake]

 When I first got a mill I thought as long as I set everything up level and straight that would be that. Then started sawing and found out that like everything else there is a lot more to it than you think. Its ok though that's what makes life fun. Learning about it. I got this mill and with the experience I had setting up the first one did a much better job. Then when things got "wierd" I was a little discouraged I only had to come back here and now I'm sawing away again. I also am better prepared to figure things out next time. It does get in your blood alright. Why is that?