The metric nomenclature is quite simple,but it doesn't use metric... One has to convert it into inches and multiply by blade's TPI to get the number of teeth in the cut.
How fast is your saw cutting BTW? For example a 1in solid round, or a half inch thick plate. Can you see the blade moving down through materiał when looking closely, or is it imperceptible? Today I think I found a good rate for half inch plate where it cut a mm a second. Let's call it a 32nd of an inch a second in imperial units.
On the half inch plate, provided it was being cut on the half inch direction, you can see it move down. I think it might be a little slower than you say, but again, I keep mine on the low belt speed, so my misuse of the blade (and general lazyness about it) makes the blade much more tolerant of uses that are not quite right. I've never timed it, but I'd speculate it's more than half a millimeter in a second, but not near a full one. On a one inch round it cuts quick at the beginning and the end, in the middle I guess you can "percieve" that it's moving, it feels like watching the minute hand move on an analog clock. Or like watching water boil. It takes forever, unless you step away to do something else, in which case it doesn't take much time at all.
The issue with using too high TPI blade is that spaces between teeth(gullets) get filled with chips before they exit the material and teeth can brake off. One can just slow down the downfeed to compensate, but at some point downfeed becomes too low and the blade is just rubbing and not cutting.
You are quite correct. I choose to use that blade for "everything", and if I have no choice but to cut with a longer engaged length, that can sometimes take a while. Technically, that is wrong. In practice, the saw runs it's self, so once the cut is established, I don't need to be there. There's always something else to do... I'm sure it shortens the blade life some, but compared to changing the blade and fooling with the tension and tracking enough to get a different blade to run right in the same guide wheel setup.... I look at it like this- If the chips pack the gullets enough to stop the cut, then it stops cutting, and will drop as soon as the "full" portion of the blade is past. (No, it doesn't work like that....). But so long as I keep the blade speed low, it seems to set it's own feed rate, and the blade life is yet to be determined, but it's still going strong. It's been there long enough and cut enough metal for me that if I needed a new one tomorrow, I would replace, I'd still feel ahead for making the compromise in "correctness".
Yes, it does it when I just try it with no material and no motor on. Today I let it downfeed like that fairly slowly, but visibly, and I went for lunch. When I came back it moved an inch then stopped. It is interesting yours does so too, but the mechanism is likely different. I would grease/wd40 your pivot point. That's what I did first on my saw as I thought it must be this initially.
That's why I tossed out both things I was thinking... I have seen it, which makes it easy to think you have the same issue I've encountered, but at the same time, it didn't quite fit. Something has to be stopping the fluid. I've never had one of those apart, so I won't be a huge help there.
I do make the bolt loosen slightly before tapping
I found it to be the only way to move a very small amount. To me tapping it (not necessarily with a hammer, but even with a wrench, those are not strong taps) is easier to control. I guess it doesn't matter which exact method we use as long as it ends up where it needs to be. However, I can't seem to set it properly with a square.
Nothing wrong with that if it's working. I don't actually use the square to "square" the blade (except initially, in a very coarse adjustment). I use it for a visual reference to see how much I've changed the blade position. The adjustments are kind of archaic, so I'd say any way it gets done without breaking something, is probably a good way.
It was said in this thread one should be able to achieve a cut that wanders by no more than 4 thou. My cut, after setting it right by the square moved about 60 thou inwards on my 4in long, half inch thick plate.
It's a band saw. I'm sure it's possible to get that result, but in practice it is not a precision tool. If you're looking for that accuracy, you're going to have to take more than that off of the end of the part anyhow to finish it. Besides which, these little light saws are hard pressed to get "identical" results in different shape materials. One place mine falls a little short is like your example, cutting half inch plate. If I'm cutting plate, stood up, so there's not much length engaged, it will wander way more than it will in a more solid section like round or square. That "might" be reduced with a hydraulic feed, but I have no experience.
Regarding that speed adjustment. I figured out a way to make is "sort of" work for cutting fairly thin material like this half inch plate. I did it by lifting the saw and letting it downfeed with no motor. Setting the speed, waiting for it to stop, crack the valve a tiny but open, wait for it to stop, repeat, until it doesn't seem to stop anymore.
Then lift the saw few inches too high for the actual cut so when it starts going down way too quickly it slows its descent before it gets to cutting. When it gets to touch the material it slowed down sufficiently to make the cut.
That sounds reasonable.
This works fine for fairly thin material. I gave some really thick metal to cut (that's why I'm trying to fix that saw). I wonder if this method works with its much slower descent rate.
having never used your saw to know it's character, I think you would set it up just as you would for a narrower cut. Set it to feed about the maximum that each tooth wants and let it go. So long as you have several teeth in, the work will slow the decent, but as it comes out the bottom and the cut gets shorter, the hydraulic fluid would still prevent it from accelerating past where you set it. Maybe. I'm out of my depth, so that's more food for thought than it is advice...
