1/4" bandsaw blade troubles

[pops92]

What model have you got?

 

[pike]

Record BS400.

I've been doing a bit of googling and it seems pretty common for tracking problems to appear with narrower blades.

Also I found a thread on this forum for the same bandsaw with a similar problem:
bandsaw-bs400-problems-t94411-30.html

Starting to worry this expensive machine is duff. jmac80 James seems to have had a very similar problem with the blade wandering from front to back and the blade sitting middle on the top wheel and nearly off the front of the bottom.

I think the problems I'm having would have been apparent in the first couple of months when I bought it a year ago but I hardly use it so am only just discovering.

 

[pike]

I spoke to the Record staff at the Harrogate show and he just suggested using a light abrasive pad to clean the tyres. So I've done that. I also picked up a new 1/4" blade just in case.

I can get it to track roughly center which is good. It is still very sensitive and prone to move all the way forward or back with the slightest tracking knob adjustment, but atleast I think I might be able to use it.

What all this fettling has confirmed however is the quick release cam causes the tracking to change if I detension with the cam then retension. After doing that, the blade moved forward quite a lot, almost coming off. Any chance someone else with a BS400 could check if this happens to them? Ideally with a 1/4 or 1/8 blade.

Cheers,
Carl.

 

[Alexam]

Carl, your tuning seems to be causing you a problem and shouldn't if you have followed the advice given before. Do not use the detension leaver as that is only to slacken the blade when you remove it, or are leaving it for a long time so that it does not remain under pressure.Once the tension has been released, it may move the blade slightly, but the same blade should return to it's position once it is run again.

Just to refresh............., all guides and the rear thrust bearing should be well away from the blade until such time as you have the blade running under power and remaining with the lower part of the blade gullet in the centre of the wheel. The adjustment comes about with a combination of correct tension and position of the blade on the top wheel determined by the tracking control on the back. That tracking knob IS very sensative, but each time it is moved (at 1/4" intervals) you need to run the power and see if it remains steady. Only when it is staying put under power will it be ready to bring in the side guides and the rear thrust bearing, non of which should be actually touching the blade when it is not actually cutting. Pity you ar not nearer or I would come over and help you solve your problem.

Take another look at the Alex Snodgrass video, which should help.

Malcolm

 

[pike]

Thanks Malcolm, I know the quick release is just for when the bandsaw is not in use, but I would not expect it to knock the tracking out when used and retensioned later. Maybe it does and thats normal? Seems odd. If that's the case it would be just as easy to just turn the tension knob a few times instead of having a quick lever at all?

The general tracking issues I originally described are not quite as bad now so it was either a damaged/messy blade and or dirty tyres.

Carl.

 

[CHJ]

.....I know the quick release is just for when the bandsaw is not in use, but I would not expect it to knock the tracking out when used and retensioned later. Maybe it does and thats normal? Seems odd. If that's the case it would be just as easy to just turn the tension knob a few times instead of having a quick lever at all?....

Personally I would suspect that there is too much play in the location of the upper wheel support mechanism, you could then have the problem of the wheel axis and fore-aft position choosing its own position every time you tightened up the tension.

For those old enough to have done their own front wheel tracking on old bangers it would be a bit like trying to track the front wheels with the tracking rod length with excessive play elsewhere in the steering linkage it ain't going to happen.

 

[pike]

Any idea how I would confirm that Chas? When the blade is tensioned, the wheel is fairly fixed. When it's off tension it's all very loose but thats normal.

 

[sunnybob]

With the blade tensioned, grab the wheel each side and try to pull it towards you. Then try to push it away from you. Try hard, right up untill the machine starts to rock. If you feel any movement, thats wrong.

Then try to rock the wheel side to side, up down, left right. any movement is wrong.

 

[pike]

Ah ok I'll try that thanks. I only checked without tension which I realise now was not much use.

 

[CHJ]

Ah ok I'll try that thanks. I only checked without tension which I realise now was not much use.

Not so, the upper assembly should be 'contained' in its slides loose enough to facilitate sensible adjustment but you don't want it to tip and twist too far under its own volition and possibly take up a different alignment within the guides when you tension it.

Think in terms of your bench vice, would you be happy if the movable jaw was free to move excessively from side to side whilst tightening it.

 

[davem62]

Hi Carl
If you have the time and want to look at my saw I'm only just down the road from you, and yes the top wheel mechanism does move left to right and for and aft if pulled , even the new ones at the show have that same feel and movement. At the moment my legs in plaster so can't easily get in the workshop but your more than welcome to call down and I have a 1/4 blade we can fit and set up if your not in too much of a hurry
Regards David

 

[pike]

I'm in contact with Record about this too. A new blade and cleaned tyres has helped but I think I may still have something fundamentally wrong with the upper wheel assembly.

The shaft can be pulled out of the block it is in. I'd have to check how much but it's 10mm or more I'm sure. Not sure yet if that's the problem or how it comes apart for me to check.

 

[pike]

Thanks David, I might take you up on that. Much appreciated but I'll see what record think about the loose shaft and slide mechanism first as maybe I just need to replace that.

The wheel feels reasonably in place under tension.

Carl

 

[pike]

Just to update on this. Richard at Record helped explain to me how I go about tightening the shaft to the slide mechanism (block) which I've now done. I had to remove a locking pin to take things apart, get at the shaft and block then tighten a grub screw. I don't know if this is what has been causing my erratic tracking issues but it certainly is good to know a little more about the bandsaw and fix one possible problem.

Cheers,
Carl.