Thread: What is causing this

It looks like you are cutting very very quickly. Each tooth, between entry and exit, looks to be cutting about an inch of material. Slowing down the feed speed gives a better surface finish. But slow cutting makes more heat, and makes more cuts/inch which reduces the lifespan of that blade's sharpness.

As Kuffy says try some slower feed rates and see how that goes. I sometimes get a bit of that ripple effect in hard woods but don't mind it as long as the thing cuts strait. Really sharp is the only way to go for resawing.
Regards
John

I am cutting very slowly.
Ted

Is it a skip tooth blade?

Recheck your drift, use a pointed fence rather than a long fence to see if it makes any difference

Have you got a bent or broken tooth?
It only needs to be slightly out of whack to do something like that.

3TPI blade is for fast rough cut, if you want a fine cut, increase the TPI & slow down the feed rate.

This is a pic of some resawn blackwood. I think the boards are about 100mm wide. It was cut with a 1/4" 4tpi blunt carbon blade. It's about as good as I can get with these blades. Cutting super slowly, you can see the ripples are basically vertical. If I had to measure the feed speed, it would be about 1.5meters/min. These lengths were about 750-800mm long and it would have taken me about 30secs to do it.
SAM_0263.jpg

Looks like the blade has a bad join

My money is on the blank is contributing to or causing the problems! Then there are the matters that Cliff addressed. The second photo shows both faces of the blank square to the cut face are not flat and are slightly curved, certainly irregular. As the blank is being fed through the bandsaw it is walking from side to side causing the blade to bite and fill the gullet between teeth causing the pattern. I'm sure you would have felt the vibration through the blank as you were cutting.

Ted I've had same problem from time to time with Henry Bros blade yet others from them have been brilliant. I had noticed kerf difference, I also sharpened one blade and depped the gullet took care of that one. Feed rate as other have said. Check the back edge also I found one so sharp yet with a scraper like edge I had to run a stone across it. I fugured as the timber was being cut and the back edge being caught/dragged through it was causing chatter and blade twist.

Thanks for all the suggestions . I'll go and play some more.
Acco - I am using a skiptooth blade . Not sure what you mean by a pointed fence . I am using the fence that came with the saw , about 300mm and on the other side I am using a magnetic feather board.
Bobl - I'll check the blade again but I am getting the same effect with a blade that has seen some use and with a brand new blade.
Kuffy - Your cut surface looks heaps better than mine . I'll stick a 1/4" blade on and see what happens .
Ted

Thanks to the combined wisdom the problem is solved .
I discovered that the cut was just as bad when cutting freehand so that ruled out a problem with the fence .
I then fitted a 1/4" 4tpi blade and found that gave a much better cut but not very straight .
I then bought a 4 tpi 12mm blade and that gave me an acceptable cut .
Thanks
Ted

Originally Posted by turnerted

Thanks to the combined wisdom the problem is solved .
I discovered that the cut was just as bad when cutting freehand so that ruled out a problem with the fence .
I then fitted a 1/4" 4tpi blade and found that gave a much better cut but not very straight .
I then bought a 4 tpi 12mm blade and that gave me an acceptable cut .
Thanks
Ted

Ted I would not call that resolved if you out the other blade back it will still happen. Check both rear blade guides make sure blade has not cut into them I went to bearings on my Bissato 4 If you can't get someone to machine the bits I'll gladly do it for you.


Ray

Ray
My top rear bearing was also scored although not as badly as yours . I got a couple of replacements from H&F but that did not fix the problem . After reading your fix I might go that way next time I need to replace them . Thanks for the offer to machine them but I have a couple of contacts .
I am not concerned that the original blade gives a rough cut as I just needed to get a reasonable cut for a one of job .
Ted