Bandsaw tyre crown

[roombacurious]

I've recently bought a used bench bandsaw in reasonable condition. My first move was to completely disassemble it down to the last screw for cleaning, lubrication and tuning (and partly just for the fun of doing it :wink

I noticed the following interesting issue with the wheel tyres. The rubber seems ok, the tyres are not flat, the crown is still present but it's not in the middle of the tyre's surface, rather it's off towards the edge all around. I don't know how this may have happened, I suspect bad tuning, but do you think it will affect the bandsaw's function? Should I rather replace the tyres?

 

[Woody Alan]

Hi without seeing your wheels it's difficult to comment, but at some stage this link may be useful to some looking for replacements, they do other sizes. Also a good local rubber supplier should be able to help. I think the rubber required is "shot" bought in a length and scarfed together using superglue.
http://www.rutlands.co.uk/cgi-bin/psProdDet.cgi/DK1013

Alan

 

[CHJ]

George, does the blade track OK when adjusted and does it drive without any slipping?

If so then why touch it, don't fix what is not broken.

You don't say if the rubber 'crown' is to front or the rear of the wheels, if it is to the rear for instance it may be that the machine has been run with the blade offset to the front and it is just natural compression over time.

 

[roombacurious]

I think you're right about not fixing what isn't broken... I've reassembled and adjusted the machine today and seems to track ok without slipping. I'll leave it as it is for now.
I've now got an idea about what has cause may have been. It's a three-wheel bandsaw and uses the drive belt as second wheel tyre. The wheel is aligned to the motor's shaft so the belt runs smoothly but because the saw is el-cheapo the other two wheels are not co-planar to it any more and as a result the blade runs towards the front of the tyres - thus a crown near the back.
Interestingly enough the saw works well despite it's bad engineering. I had heard horror stories about three-wheel bandsaws but my test cuts have been pretty good so far.

Changing subject, I'd like to ask something about the blade guides. This saw does not use a standard side block/thrust bearing combination to guide the blade. Instead, there is a single wheel with a deep groove just behind the blade which envelopes approximately half of it at the back and thus supports it. Seems to work though I'm sure it increases friction (and heats up th blade). I could probably drill a few holes and make replacement guides but is it worth it? Should I expect problems if I keep the same ones?

Thanks, George

 

[CHJ]

.- thus a crown near the back.

Thought so, it's most likely just the compression of material over time, not wear.

.- .....blade guides. ..... Seems to work though ..... Should I expect problems if I keep the same ones?
George

The friction will be insignificant compared with that generated in most woods, and for such short periods anyway, Once again if it is working as manufactured leave it alone is my advice.