Thread: The missing bandsaw post

Happy birthday.
no idea where your thread went either.
Got a picture?
Does it always come off the same side?
Does it come off the top, bottom or both?
Whats the depth of the blade you are using?
Are you using the same blade for vert and hoz?

Stuart

1. Ummm, never taken any notice , Right side I think. Now that tells a story, I’ll keep an eye on that.
2. Top. Hmmm, same story…
3. 12.7mm
4. Yes, same blade.

Fresh eyes, that’s what was needed, I’ll check the bearing and associated parts again.

I bought this saw in Brissy where I also bought my blades (Starrett) never had a problem. I bought this lot of blades in SA, where I’ve just moved, different brand so could also be something to do with it.

Thanks Stuart, I’ll send a bottle for your blood…

I did read your original post last night.
I am not familiar with using a metal bandsaw but they work on the same principal as wood bandsaws.
Your problem may be caused by a number of factors.
You would need to ensure the top guide is lowered as far as possible so only the required amount of blade is exposed and also this gives maximum support to the blade.
You may not have the tension correct on the blade or there may be a problem with the alignment of the side and thrust bearings that support the blade.
Also be sure that you are not pushing metarial through too fast and putting too much load on the blade.
Finaly check that there is not a fault with the blade itself.

I reckon there is a chance your band wheels are not in co planar alignment. Illustrations below give you the idea.
The graphics are from vertical woodworking units but the application is still the same.

You will need to remove the saw blade to do this as on the 6 x 4 units the teeth of the 12.7mm blade overhang the wheel edges.

If the wheels are not both level at the outside edges,the low wheel needs to be packed up to match the other and the tilt adjustment manipulated as well, to gain co planar alignment.

Also check the blade for level ( across the top=where it pushes against the non adjustable roller) where it was welded. In my learning curve, I did the bloody alignment checks so many times I bought a piece of 25mm sq Aluminium box section and cut it to specific length dedicated to checking co planar alignment.

One blade I had made up commercially , was a bit out like this, and needed re doing and threw the blade off the wheel repeatedly. Do all these checks and get them them right, before any blade guide alignment or you will chase your tail.

Hope it helps,

Grahame

I doubt it Grahame, as the band would jump off the pulley first.

Also the side ball races (guide rollers ) are what keeps the blade centred on the rear pressure bearing/race.

IF the blade is centred and touching on the rear bearing, and IF both side rollers are snug against the sides of the blade, and NOT hitting the tooth set, then the only thing could be that the guide adjusting slide nearest the motor is loose/moving in the vertical position.

Check all of the above.

Rob

Is your blade tensioner spring, assuming you have one, in good shape?

It is probably worth watching the Alex Snodgrass video on you tube as is applies to any type of bandsaw.
Beleive it or not the wheels are not co-planar and should not be, the bottom wheel should be factory set and best not too mess around with it as your problem lies eslewhere and you may make the problem a lot worse.

Sounds like you should try more tension.

Originally Posted by sacc51

I posted this last night and Ueee answered, this morning I was greeted by a happy birthday sign and a missing post. Anyway my problem is the blades on my bandsaw keep bending. The bandsaw (Machinery House BS5S) has three bearings top and bottom which guide the blade. Two sit either side of the blade and are adjustable via the eccentric bolts that hold them in place. The third sits behind the blade and is not adjustable. I have set the bearing guides so the blade runs freely without any slop but the blade keeps running to the right of the rear guide thereby bending it and ruining it. The bearings are all in good condition and I have checked and rechecked the side bearing guides but still the blade keeps running off the rear guide and bending. This only happens when using the saw vertically and feeding material on to it. Anybody else have this problem or is it just a quirk of bandsaws?

I've a similar bandsaw, my fourth, (others were sold with businesses). I've found that if the bearings are tight against the blade it will create problems. Try adjusting the eccentric bolts so that the blade runs in the centre of the bearing, both top and bottom.
Where in SA do you live? If you are coming past Murray Bridge at any stage and able to, you are more than welcome to drop in, so that I can show you how to set it up. I was shown by the owner of Independent Saw Works, who has unfortunately retired. PM me if you are interested.
Kryn

Originally Posted by mark david

It is probably worth watching the Alex Snodgrass video on you tube as is applies to any type of bandsaw.
Beleive it or not the wheels are not co-planar and should not be, the bottom wheel should be factory set and best not too mess around with it as your problem lies eslewhere and you may make the problem a lot worse.

I watched the Alex Snodgrass U tube video and while his comments regarding woodcutting bandsaws have merit the notion does not cross over to metal cutting bandsaws .I completely disagree that ALL bandsaws should be set up without co planar alignment.
As was explained by Alex Snodgrass himself, the saw teeth must not touch the bare metal of the wheels as they soon will lose their sharpness.

This was the way the horizontal metal cutting bandsaw was designed - a factory setting, if you will. Given that the saw referred to by the OP is a 6 x 4 horizontal metal cutting bandsaw that requires the saw band teeth to overhang the front of the bandwheel and the opposite edge to run up against the a raised flange, the non co planar method does not work for me as the blade walks off the bandwheel after a few revolutions.

If you have had much experience with the sub $400 metal cutting generic bandsaws, you might notice the the factories had paid scant attention to any semblance of factory settings around the wheel areas. In fact, finding a bandsaw of this quality with wheels anywhere near to being circular or without axial run out was an event within itself.
Some reading through the instructions supplied by virtually every metal cutting saw band manufacturer fails to locate any preference for a Non Co=Planar set up.


Try running a fanbelt on pulleys that are not well aligned, ie, non co planar and you you can see why this is so important.

I tend to to go with consensus of opinion and at the moment do not see any one else promoting that way of thinking. I have been cutting with my BS4 saw for 12 months or more and find that the combination of the bi metal blade and co planar alignment give trouble free cuts to within a few thou of square each time.

Cutting without co planar alignment may work for Alex Snodgrass with a wood cutting bandsaw with rubber tyres ,but it does not work for me with a metal cutting saw that has no tyres. I ran an industrial sized metal cutting bandsaw for a year or two and the wheels on that $12000 saw were set up with co planar alignment.

Grahame

Thanks for the input fellas, some things to check tomorrow.
I’ve seen the Alex Snodgrass video, but really it doesn’t have much to do with the horizontal bandsaws metal workers use. The users manual even tells you to align the wheels, if you don’t, as Graham said, the band jumps of the wheel, that's the first thing I did when I got it home. Hopefully I’ll get to have a look at it tomorrow, been busy the last couple of days reorganizing my workshop, moving the lathe, saw, pedestal etc, trying to make more room..

I am left wondering if horizontal bandsaw operators/adjusters are aware of the primary adjustment that should be made in the bandsaw blade guides- BEFORE the rollers are adjusted- A lot of times, adjusting rollers won't give the degree of the arc movement required to pull the blade over.

Given that our horizontal metal cutting bandsaw are a bit different from the vertical woodworking types its easy to overlook by those familiar with the vertical type that the blade has to forced out of its natural alignment - parallel to the wheels - to cut perpendicular to the deck ,then guided back again to lay on the wheels.

Perhaps also not considered is the extra function available in the slide section of the guide. That is, not the arm that slides in/out of the frame to adjust the cut width, but the sideways movement of the said vertical slide action afforded by the slot machined into the two piece arm and roller components.

This slide also allows a twisting action affording a primary adjustment. What has worked for me was the big shifting spanner- 14" plus to get the jaw opening needed and the loosening / tightening of the bolt and leverage . The hex head bolt was changed out and replaced with a cap head socket screw to get quicker adjustment. The cap head is barely visible behind the hex head bolts in the photo below.The photo caption should read "Changing the bottom guide etc"- not the top - sorry brain fart! occurred.

Most are probably aware, but I thought this was worth throwing in for those that weren't

Grahame
Adjusting top blade guide block.JPG

I have had the exactact problem and it was caused buy Twp factors. 1 dodgy BLADES which were too soft and 2 was the driving wheel sliding off the shaft.

P

A couple of things came to light this morning whilst playing with the BS5S bandsaw: the band wheels can’t be aligned. With a straight edge touching the two inner circumferences the outer circumferences are clear of the straight edge by about 6mm (see drawing). As the distances are roughly the same I’m of the opinion this is how it was designed. I suppose some alignment could be useful, ie, making sure the gaps on the outer circumferences are identical.

I also played around with squaring the blade and found the quickest way to do it was to pull the rear guide forward until just behind the fence and then pull the front guide forward as far as it will go, place a square on the vice table up against the fence and just lightly touching the blade, then place a 6” rule on the other side of the blade (lightly) ,just clear of the teeth, and line up with the square, this gives a good starting point. Repeat for the front guide with the jaw opened to the maximum and the square just in front of the jaw. The guide nuts should be just snug so a light tap on a shifter spanning the guide will move it slightly. It only took a couple of minutes to do this.

For the test cut, place the stock against the rear fence, clamp, cut and then measure with a square, making any adjustments with the shifter. Movements from this point on are miniscule and best done with the guide nuts tightened a little. Once square, tighten the guide locking nut and repeat by making a cut with the stock about 6” in front of the fence (use packing).

You have to keep checking that the rear guide bearings are positioned correctly throughout so the blade is not forced forward.. All up it only took a few minutes but just to make sure it wasn’t a fluke I did it again and found the process just as quick..

I mentioned in a previous post that the table wasn’t square to the blade, I traced this problem to a slight curve on the top surface of the guide on which the table rests. The edges of the holes punched in the table were also protruding slightly, so after filing the underneath of the table flat and filing the top surface on the guide flat I put it back together and found it square to the blade. The table is only made of thin material and this combined with the blade slot means it distorts/twists very easily.