Bandsaw Tyre Repair

[OPJ]

Just spoken to Sika and their only suggestions is a "fairly stiff windscreen adhesive". Again, that's a polyurethane, similar to what others have suggested. That seems to be the way to go... I am a little concerned that car body filler would not bond properly, could come lose and, because it dries rock-hard, could damage something or someone... :? I also wonder whether it would be so hard that it wears the set on one side of the blades?

 

[Steve Maskery]

Olly

I would bet a pound to a penny that that little bit of damage is not your problem at all. Your problem, I suggest, is tracking. Tracking of the bottom wheel.

You say that the the blade jumps off when the saw is stated. As soon as the saw is started? If so, that is a classic symptom of East-West tracking of the bottom wheel. It means that the two wheels are not in the same plane, twisted in respect to each other, so the blade is shrugged off, like slipping off your jacket.

To correct this, adjust the bolts which hold the bottom axle in place. There are four and normally you would adjust just the N-S pair, leaving the E-W pair alone. But if the wheel is in the wrong plane, then you need to adjust the E-W pair until it's right.

You've got my DVD, watch it!

HTH
Steve

 

[OPJ]

Yes, Steve, that is also what I had suspected first of all (and I will check it all, later on). Though, it seems strange that this has only started happening since the wide blade snapped, which is why I've stuck with the tyre-theory so far...

I just can't imagine that one blade jumping off is enough to upset the tracking of the lower wheel though? :? I do trust the guy who sold me this saw but, alas, I'll have a proper look when I finally get off this sodding PC!

 

[Steve Maskery]

Well how about this for a scenario?

Blade breaks and gets mangled up inside saw.

Wheels get jammed with knackered blade.

Wheel is removed to extricate blade.

Wheel get replaced but not adjusted properly.

I'm not saying that's what happened, but if it looks like a duck and quacks like a duck.....

S

 

[kasandrich]

I'm not saying that's what happened, but if it looks like a duck and quacks like a duck.....

S

......if it looks like a duck and quacks like a duck........then it could be a chicken in disguise :lol: :lol:

I agree, start with setting up from scratch in accordance with Steves DVD then try different widths of blade, if it will run a 3/4" blade but not a 1" blade, considering the cost of a new wheel, can that be justified for an extra 1/4" blade?

 

[promhandicam]

I don't know what is suggested for the 401e but in the manual for my 502e it says to position the blade so that the teeth are on the edge of the wheel - presumably so that they don't damage the tyre. If it is the same for yours, this may be why it is difficult to get the blade to track as the damage is on the front edge by the looks of it.

Steve

 

[Steve Maskery]

That's OK for a wide blade, but not practicable for anything below, say, 1/2". It's also much more difficult to track straight and true in that position.

I go for central with good tracking every time. Damage to the tyre is minimal and performance is max.

S

 

[wizer]

My bandsaw always tracks to the front. I tend to get a crowned cut then re-sawing. Is that the same wheel adjustment Steve? i.e the four bolts. Yes, Yes I've seen the DVD. I might watch it again this afternoon actually

 

[9fingers]

My bandsaw always tracks to the front. I tend to get a crowned cut then re-sawing. Is that the same wheel adjustment Steve? i.e the four bolts. Yes, Yes I've seen the DVD. I might watch it again this afternoon actually

The position of the blade for cutting purposes should be completely controlled by the guides and not any crowning of the wheel.

My BS manual even shows a guide system that puts a 45 degree twist into the blade to enable crosscuts of long items. Not tried this I must add though. Seems a bit extreme :shock:

Bob

 

[Steve Maskery]

Crowned cut as in not flat top to bottom?

That is probably insufficient tension. The blade is being pulled down by the bottom wheel, so the section of blade underneath the table but above the wheel is in greatest tension.

However, the workpiece offers resistance, so the section of blade above the workpiece but below the top wheel is in least tension. The workpiece is, effectively, pushing the blade up. And if you push anything that is not rigid, it buckles.

The answer is to use a blade specifically designed for resawing and tension it properly. I've go one of Ian's that is 2 TPI plus a raker in between. It looks the bee's knees but I haven't actually tried it yet. It's 3/4" wide though, so it will put my machine to the test as I'm usually up to nearly max on a 1/2" blade. I'm hoping that its thin-kerf nature will allow me to tension it properly. (Less steel = easier tensioning).

HTH
S

 

[Jake]

Mine's a 401 as well, and I always run with the teeth on or just off the front edge even with thin blades. Tracking is never a problem in the slightest.


I'd suspect like Steve that the wheel has been shoved out of whack to screw the tracking up that badly that the blade jumps - unless some of the rubber is sticking up rather than just missing (in which case sand/grind/cut it down).

 

[Steve Maskery]

The position of the blade for cutting purposes should be completely controlled by the guides and not any crowning of the wheel.

Ooh, I don't agree with you ther, Bob

My BS manual even shows a guide system that puts a 45 degree twist into the blade to enable crosscuts of long items. Not tried this I must add though. Seems a bit extreme :shock:

I've seen metal-cutting bandsaws like that, but never used one.

 

[OPJ]

I don't know what is suggested for the 401e but in the manual for my 502e it says to position the blade so that the teeth are on the edge of the wheel - presumably so that they don't damage the tyre. If it is the same for yours, this may be why it is difficult to get the blade to track as the damage is on the front edge by the looks of it.

Steve

Steve, I think you've got it! :wink: My manual says the same.

I've been out there this morning, cleaned everything up (didn't need a lot of work) and have fitted a 1/2" blade centrally on the wheels - it seems fine. I had to re-adjust the tracking on the lower wheel slightly but, it's not moving and it's certainly not going to fall off.

At the moment, I'm only able to rotate the wheels by hand as I'm not yet wired-up for 16amps. But I'm doing this for at least thirty-seconds, as the man from Startrite advised.

If you look again at these photos:

It looks as though he might have been doing the same with narrow blades as well (I could be wrong and that could just be where the teeth were running on blades of varying width).

I haven't yet tried the big 1" blade I've got because I need to practice coiling a long blade again before I let that one out! I can't imagine any of the other blades having any trouble with this, though.

It might be nice to try and fill it one day but, I agree with kasandrich; you can do a lot with narrow blades and they're a bit cheaper to replace.

Well, it looks like I could be worrying over nothing although, we won't know for sure until I get some power running in to it.

Why would you run a 25mm blade with the points protruding over the tyre though? Is it to do with the camber of the tyres?

 

[9fingers]

The position of the blade for cutting purposes should be completely controlled by the guides and not any crowning of the wheel.

Ooh, I don't agree with you ther, Bob

Perhaps I should have said the guides should control the side to side position and angle of the blade. The crowning and tracking will affect the front to back blade position but the guide should then be adjusted to compliment that.

Bob

 

[OPJ]

Just a quick note to say that I tried fitting the 25mm blade over the weekend and it's fine. You can see below that it just misses the damaged part of the top tyre, when tracked centrally.

I don't see any reason why thy would "have" to have the points overhanging the front edge so, I'll continue doing it like this. I've now got power running to the saw and I have to say, what a joy it is to have this machine in my workshop!

I'll probably stick with 3/4" blades as my widest so, I doubt that tyre will ever get repaired (unless it gets worse).