Second hand bandsaw, new blade won't stay on!!

[TheBeeBoyKid]

Hi team. Recently bought a little bandsaw off eBay (kity 413), it won't seem to keep a new blade on; the only way it held the old blade on was when the top wheel adjustment was tilted way back so the back of the blade was hanging off the back of the tyre and still the blade was only just hanging on to the bottom tyre. If I run the wheels backwards it travels backwards on the bottom tyre and when I run it forwards it travels forwards and eventually pings off. Feels like a bent wheel to me, any ideas off anyone else?

 

[Ttrees]

You would notice big time a wheel that was bent, likewise more likely a wheel shaft that was bent.
I wouldn't say that was the issue.
What kind of tires is on the machine...rubber tires? and are they crowned?
Are both wheels crowned?, ....
And are they the same thickness of rubber...could one have been dressed possibly/probably
unlikely on a smaller machine.

Any signs of wear from a narrow blade?...
I would keep the sawdust on the tires for observation, just as long as there's no mad amount of crud.

Step 1 get the wheels coplanar, with all guides backed out, so there's no possible contact with blade
no matter what position of the blade on the wheels is..
When set up properly, it should be able to run without them touching.

Is there any twisting when you hand turn the blade?
Have you tired a different blade turning by hand, tensioned a bit on the light side of things.

So, say the tires have no wear cut into them, and no lumps missing or lumps of timber resin either.
I would think if you cant get the top wheel tracking to sort things out, which is what you have been adjusting,
that the bottom jacking might need to be adjusted.

The machine can be tested fairly well turning by hand without throwing a blade.
If the tires are crowned I would shoot for having the blade centred on both wheels.

Dressing is the last straw and should not be done without trying all else first with new blade,
as everything else can be repositioned.

I strongly advise getting a new narrow blade, and a wider blade for tests...both have their place when testing.
It may take some fiddling to get the bottom wheel right, take a picture of the position of the bottom wheel shaft placement for reference, incase you wish to start again in troubleshooting.
There is a guide for adjusting the bottom wheel jacking screws/bolts on Rikon bandsaws which may help..it explains what effect each adjustment has, and the counter adjustment following.

That is about as helpful as I can be until you get back to us.
I wouldn't look at the Snodgrass video until you get the saw running.
It will confuse matters, and you might find your saw works coplanar like with bigger machines...
which I get the feeling with, which these saws are more based on.
There should be some archives on your machine on here somewhere, that would be a go to also.

Good luck
Tom

 

[TheBeeBoyKid]

So the wheels have tyres and aren't crowned; they're flat on the kity machines and are supposed to run with the teeth just off the rubber.
I've been running all tests with the guides out the way and with multiple blades.
This might give an indication of the problem: when I wind the blade forward it wanders off the front of the drive wheel and when I reverse it, it tries to wander off the back.
Can't find any adjustment on the drive wheel and the tyres don't look in bad condition. Bearing feels solid and there's no play to speak of.
Pretty stumped by this one.

 

[MikeJhn]

Just a thought, does the bottom wheel have any adjustment in and out to line up with the top wheel, usually on the back of the casing, just four bolts and move the wheel shaft? Use a straight edge to line them up and try again.

Mike

 

[Ttrees]

Flat tires can be troublesome as I have had experienced some of the same issues with my Griggio saw what you describe.
Mikes suggestion is what needs to be done next.
I would set a plum line, or good long level, to level up the machine, and as said place a straight edge on the wheels in the middle.
If you have a good chunk of timber jointed on 3 sides accurately, you will be able to rig/clamp it up against the wheels
and place a square against each side of the beam to true up the yaw angle .
Here is a 20" machine being tested for coplanar

You might find you need to place a washer behind a wheel possibly, as I've heard about folks
doing this on other saws in the past.

Would there be any side to side movement in the blade, so you wouldn't be able to set the guides tight (omitting the thrust guide), if the blade actually stayed on the wheels?

So there is no visible damage to the tires, are they both the same thickness?
How much meat are we talking here?
If you can take the wheels off easily, I would look to see if they are an even thickness throught
and not just seemingly even on the front of the tires looking at the wheels from inside the cabinet...
This fooled me and the only way I will make sure of this anymore, is by taking the wheels off...
or at least sliding them out, protruding from the saw cabinet so you can check them with a straight edge and a square which I can do with my heavy Griggio wheels.

I might ask how is the belt doing also?
These can be bought for very cheap.
Tom

 

[Ttrees]

I have more on this in depth, but I suggest you see how you get on with troubleshooting these things before trying any further
steps.
Good luck

 

[Yorkshire Sam]

I had a similar problem with an older machine I used to have . I eventually found that there was some slight play in the top wheel bearing ... (can be felt if you grasp the wheel top and bottom and try to 'rock' it ) it was very very slight but replacing the bearings solved the problem.

 

[Sideways]

It doesn't sound like it but I'm throwing this in the pot just in case you are completely new to bandsaws like I was when I bought my used kity 613.
Blade tracking is affected by the blade tension as well as the tracking control. There's a bit of a dance balancing the two to get tracking right. I didn't find it quite as straight forward as dial up the tension then dial in the tracking - maybe I should have ?
If you haven't already, start with tension roughly correct, try to track it then see if adjusting tension up and down helps you to get it in range.

I think I remember the lower wheel adjustments on the 613 being inside the enclosed rear of the machine with the motor. A couple of bolts with locknuts into the collar that holds the bearing. I'm guessing Kity would use the same basic design on all their machines if you do need to change it. You need access to the bolts while the wheel is in place and it is a rarely used adjustment so it makes sense to do it like this.

 

[TheBeeBoyKid]

Guys, thank you for the info, you're legends!! there's loads of things to double check and re-try now, I'll get back to you in a bit when I've gone over some stuff.