Thread: Bandsaw blade position on wheel

yes

If it is a crowned wheel and European saws usually have a flat wheel then the centre of the blade should ride on the centre of the wheel, if a flat wheel then the teeth should hang off the side if the wheel. Set the blade correctly then set the table & fence to suit the blade.

Hello
The six refers to the wheel size in mm, and you will find it more common if you search for 600
for quite similar machines that will have the same parts, Italian saws all made in closeish proximity and share logistics
It's very likely that identical machines to yours are under a different Italian name aswell, maybe Sipa?
These saws do not like any camber, my used saw needs a new tire really...
I dressed it as much as I can go, and I have a spare tire that I've been meaning to install, but have got decent blades now and its working well.
It doesn't like thin gauge blades.

The teeth should be off the tires on 3/4" blades, I have never put anything else but wider or a much narrower blade that I centred in the middle and worked well, about the only thin gauge blade that I could get to have predictable sawing.


The more tension you apply to the blade adjusts tracking of the blade forward towards the user, so it might take some time with a strange new blade to predict where you tracking adjustment screw should be set.
You stand a good chance of stripping threads on that bolt if your adjusting that bolt whilst the blade is tensioned. DAMHIK.

If your still having trouble I suggest you change supplier of blade, the difference it made from going from thin gauge to a reasonable gauge made a huge difference to
the saw, the table had to be set for drift by a mile and thankfully my table is bang on centre now,
I once made a nice composite ZCI for it and had to make the kerf wider with all that faffing before with the thin gauge.
I'll have to make another someday, but I hate the smell of the stuff.

All the best
Tom

Thanks to all. The blade that I am using is a Lennox Woodmaster A.
As you said Tom, the model is very similar to others and I have found a manual for a SCMI SP600. It appears identical.
The wheel is crowned and I set the blade with the tip of the teeth just on the edge. I am ripping some 50yr old hardwood 90 x 35 (down the 90mm) It seems to be doing it easy. I made a spring loaded roller to keep the wood pressed against the fence as some of it is not square. I may also at some stage, see about upgrading the guide system. I noticed, when adjusting for the new blade, that the guides were not completely parallel to each other and when touching the back of the blade they were not quite touching on the front. Eliminating this small gap meant putting too much pressure on the
blade. Thanks again
Guides.jpg

That guide looks like a fairly standard euro guide setup.

If you have crowned tires, You need to set the blade up so that there are 2 points of contact (because obviously if it is balanced on the crown without a 2nd contact point, it will waggle back and forth on the crown ridge).

The point of advancing the blade gullet forward of the crown's ridge is to reach a point where the whole blade points parallel to the way the machine points (or the axle,or perpendicular to the spine... whichever way you want to look at it). The spine of the blade will run on the ridge/crown and the teeth will contact and balance the blade lightly somewhere in front of the crown.

The procedure is:
Once you have the blade tension correct, track the blade so it points where you think it should, then bring up the guide carrier block so that the side guides are behind the gullets, then bring up the thrust support guide behind the blade to make sure it doesn't deflect the set on the teeth back between the side guides... then bring in the side guides towards the blade while hand rotating the wheel, till the guide starts to spin. Then back the side guide off 1/16 of a turn and lock it down. It should not now rotate when you rotate the wheel.

The effect of this procedure is to make sure the thrust bearing supports the blade correctly and to ensure that neither of the side guides is deflecting the back edge of the blade (which would cause it to point in a slightly different direction to where you tracked it).

Get a piece of 3/4" scrap (500mm or so) with a straight side. Mark a line parallel to the straight side. Power up the machine & cut freehand down the line. When you get to 1/2 way stop the machine ensuring you do not move the back edge of the workpiece left or right. Stand back and have a look because the straight edge will tell you where the machine cuts naturally, with this blade tracking adjustment. If the wood is pointing toward the spine, the back of the blade is pointing towards the spine and the teeth away from the spine, so you want to move the teeth to a lower point on the rubber (possibly off the rubber). To bring the blade around to a more parallel track, bring the blade forward a smidgen on the crown.

Following the adjustment, do the test cut again, then re-adjust as necessary, rinse and repeat.

The basic rule is if the blade stays on the wheel under hand rotation, it will stay on under power. If you need to advance the teeth off the front edge to get the blade aligned, then that is what you need to do, but make sure the back of the blade has clearance from the thrust guide and that the side guides are also clear.

The point of putting the back of the gullet just in front of the high point on the rubber tire is that this is a pretty good place to start 9 times out of 10. Of course that must vary if you change the ratio of the teeth as a percentage of the width of the blade, but its a good general place to start.

When you get the thing cutting in the direction you want, then you can line up the fence with the straight side on the test work piece, so then you know the fence is aligned with the blade under a cutting load.

I perform this little ritual every day and I always back off all the guides and set up the lower guide first. I have never had it let me down.

Best of luck

Hello again
That's a lot of wear on that thrust guide, I had the same with my ACM machine, and welded a big face on.
Luckily your side rollers are pristine!
As you may know those GL guide rollers are expensive, look up ScottandSargeant if you don't know.

Are you having to baby the saw looking at that thrust guide always?
Does the blade flutter or twist?

I have my money on the crowned tires are making this happen with your thrust guide
Believe it or not!


Are both tires crowned? I am guessing so by the fact you're not mentioning the saw's performance.
If not, and only one is crowned,
Do not try and do the other one..

The only reason for anyone to crown tires on these machines would be if a blade snapped and took lumps off the tire, or if someone was running narrow bands
and they wore a track in the middle of it.
Maybe a bit of both is very possible/likely.

How much meat is left on the crowned one?


If you're not having any issues as in not babying the saw, and being able to run narrow bands.
In that case it might be worth maybe making a different thrust to fit those euro guides to allow for the camber difference in blade geometry.
If you do this,
Is the guidepost going to be of concern though, as in parallel with the blade...
If your going to be setting those side rollers close, then you may have to be aware that you may move the guide block back and forward
if you raise/lower the post.
Might be an alright trade off though, depending on what you want.


All the best
Tom

This truly is a great forum. My simple question of, 'where should the blade sit on the wheel?', has been answered and much, much more.
Several things have been brought to my attention which could possibly need fixing. The pic of the guides was taken when I bought the machine and I have cleaned them up somewhat. As you mentioned Tom, I was thinking of making/changing the thrust guides to bearing type. Are the bearing type side guides better than the one that I have? I also notice that when I change the height of the guidepost it doesn't slide up and down perpendicular and can be tightened up slightly rotated so needing the guides set each time. I never noticed this before. Now I hold it tight to one side before tightening. I tested cutting with parallel freehand cut as suggested, T91, and it appears to be cutting slightly 'toe in' or the back of the test piece is slightly to the left towards the spine. Does that then mean that the blade teeth need to be more towards the back or centre of the wheel? At present they are just protruding over the edge. Is it common practice that the fence has to be adjusted regularly? (I noticed it has been mentioned in several posts). And is that the reason for there not being a cross slide guide, machined into the table? Both tyres are crowned and in good condition. I have not used this saw a lot but I can see the value in having it set up correctly, therefore making it 'user friendly' (safer). Yesterday I ripped some 250mm thick, well seasoned, Red Mahogany. The new blade (care of Henry Bros) made light work of it.

If the back of the test piece is pointed "slightly" to the spine, and not causing you problems, might as well leave it alone. If it is more than "slight" it will tend to lift the blade away from the fence, if the fence is aligned to parallel to the axle, which might cause thickening in the work piece towards the end of the cut. This can be dealt with by aligning the fence to point slightly to the spine (adjusting it to parallel the straight edge on the test piece) or by adjusting the blade tracking, till the test piece is cutting straight fore and aft.

IF you want to try aligning the blade more accurately to the axis of the wheel, you would move the blade slightly forward on the tire. This should cause more of the set to be over the edge of the front of the rubber while maintaining the back of the blade up on the crown of the tire. What this should do, bearing in mind that the blade is coming off the side of the wheel not the top, is to change the angle of the blade to be slightly more teeth_in.

The best way to learn is to get a few pieces of scrap, turn the tracking knob 1/8 of a turn anti clockwise, do a test cut and note the result. The test piece should cut slightly more clockwise. Then turn the knob 1/4 turn clockwise, do a test cut and note the result. The test piece should revert to pointing in the direction of the spine. You will soon get the hang of the procedure, and get to know how your specific machine cuts with the blade you are testing, and get familiar with how it reacts to the control knob. Small movements can have surprisingly large consequences. Just remember to re-check & adjust the guides and hand rotate the wheel.

have fun with it

QUOTE slim . As you mentioned Tom, I was thinking of making/changing the thrust guides to bearing type. Are the bearing type side guides better than the one that I have? /UNQUOTE

I don't think so, the GL guides are the industry standard and have been for probably 40 years or more.
The side rollers look perfect so why would you change them, you need the handiest tool free guides to setup if your guidepost isn't parallel.

Your thrust guide is all that I was hinting at changing out to a possible cheaper setup.....That's only if a new thrust guide wouldn't be parallel with the blade, and would wear prematurely, as these are pricey to buy.

When using these saws, the 3/4" and above say 1" blades, should not be rubbing against the thrust guides constantly.
Maybe close to capacity more frequently touching, but not constantly.

My comment about about babying the saw was referring to the thrust guide.
I have my machine setup to a bunch of the same blades I have now.
If I push too hard and rub against the thrust guide, the saw will veer off the line slightly, away from the line, and definitely not the other way round, as
I like most keep my surfaced timber to the fence,
The thrust guide is another indicator of things.
My machine really needs a tire replacement, as my lower one is flat for the most part now.
I cambered it as there was a few chunks near the front that was missing that would have been better filling I guess.
I scraped down to the bottom of those craters as so one could set the side rollers close, lumps missing make this impossible.

After some good advice on SMC I decided to dress it again flat and combined with a normal gauge blade it runs well enough.
The edges of the tires are not crisp, so I treat the end of the flat as the edge.
Maybe not as reliable resawing at near full depth, but for what I do, good enough.

Before with that camber combined with using really thin gauge blades was never ending torture and loads of rabbit holes was entered.
The saw was really bearing on the thrust and it could go any side of the line, probably because I had to set it back further as there was a bit of dancing
from the blade, I needed to keep the blade away from the thrust, and use it as more of a device that would stop the blade walking off the wheels.



I'm not sure if it would be the same with your machine though with more pronounced camber on both wheels.
A picture of your tires, and answer as to if you want to use your machine for curve cutting/and possible worry you may have if maintenance or replacment
is of concern may be the most helpful.


I don't know how your machine is running though, but that thrust looks like its in constant use...(it could be just old, but I've seen some old machines with much better
condition GL's)
I don't know if you are planning to run narrow bands on the saw, you maybe happy with not having to worry or look for wear on the tires
every now and again.
I can't say anything about the lifespan of having narrow bands on these large Italian bandsaws, you would get a good few answers on Sawmillcreek about that.
I presume the folks might move the tracking to account for wear after some time, you would get a more definitive answer there.
Plenty of folks like Van Huskey, or Erik Loza would know best.

It maybe also a case of whether your tires are vulcanised to the wheels, or if they maybe the same as on the Minimax with stretched on rubber with a tongue and groove to allow quick tire change.

Basically if you're not having issue with cutting thicker stock,
If thrust is rubbing and is not parallel with the back of the blade, but the noise isin't a problem, whilst
You are also wanting to use a narrow blade the other half of the time...

Then a fabricated bearing on a shaft to fit into the euro guide thrust hole might not be so bad.
You might as well buy a box of them as you might be swapping them fairly quick and wash a few of them at a time.

I hope this makes sense
Tom