Record Bandsaw BS300e top wheel end float.

[pops92]

Was changing the blade and was wondering why when I have set the blade as per the blade gullet in the centre way that I have been getting some movement in the blade position.
I nolticed that there was 0.5mm end float in the top wheel. The bearings are set in the wheel housing solid. It's end float of the wheel assembly to the circlip.
I have now made a 0.5mm shim to remove any float,will see if this eradicates the movemnt.

 

[Alexam]

............. some movement in the blade position...... which way is it moving. I don't understand. Moving back, sideways, ??? Once set up, it should not move out of line other than a few thou between the guides and bearings and before they are moved in, the blade should be running true in one position.

Malcolm

 

[pops92]

This photo should show you what I mean?

 

[Alexam]

Thanks, I thought that was probably what you meant. I dont believe that the wheel movement of 0.5mm should affect a blade bthat is set up correctly. the guides and bearings would be about that far away from the blade and are for the purpose of 'bumping' the blade back to where it should be, so that variation would probably be normal with many bandsaw wheels. If you have managed to improve that with shimming, then all the better, but do check from time to time, on any friction heat that may build up by tightening it. The wheel needs to move freely and not 'catch' on anything.

Malcolm

 

[Eric The Viking]

It shouldn't be a big issue. The wheel's shaft pivots to adjust the blade tracking. On mine (SIP, not Record) there's a hinge about 3" up from the shaft, and a bolt that pushes against the shaft, so it both tilts and moves in-out at the same time. The tensioner lifts this entire assembly on a screwthread. And I've always had some float as you describe - probably not quite as much, say 0.3mm, but it's definitely there.

The bearings settle in a pair of locations on the shaft (there's a pair of bearings for each wheel, I think to keep costs down) and are kept there by friction caused by the blade tension. Down at the table, the back guides (top+bottom) hold the blade against the pressure of the stock, so there is very little effective pressure to make the wheel move on the shaft, and anyway the blade would have to climb up the crown of the wheels to be a problem - I'd expect you to set it so that the meat of the blade goes over the crown and the set teeth ride off the crown to the front (obviously it's different for very small blades).

I had an annoying drift issue over the w/e, but almost always I find it's not actually drift (the blade not wanting to cut straight) but something else, for example if I've damaged a blade by dulling one side more by cutting circles.

In this case, I'm pretty certain it was the fence twisting in use (off square, vertically), and an awkward bit of design on the table, which often gives problems. That was exacerbated by me ripping fluffy, damp wood with teeth that were a bit too small (still for ripping, but too-small gullets probably), and a ZCI that kept blocking with tearout splinters that were pushing the stock around.

I should know by now: don't skimp on the setup! With the wrong blade, or an asymmetrically-worn blade, or the wrong ZCI, or in my case also not properly checking the table "halves" were level with each other properly, or not checking the fence is secure and square, I get bad behaviour. If I'm systematic and religiously careful, one pass with a hand plane after the saw is usually enough for spot-on dimension (even that is unnecessary for tenon cheeks). It's an old saw, with bits modded, replaced, and repaired, but I still get good results.

I think you're worrying unnecessarily, unless you're getting obvious issues with new middle-sized blades of good quality.

E.

 

[CHJ]

End float of the upper wheel 'could' influence the behaviour of the blade when adjusting the top wheel angle to get the blade to run appropriately, I can envision a sudden shift 'over the top' as the blade slides sideways due to the tilt of the spindle. But I suspect the chance is going to be very minimal in comparison with 'loose' tracking adjustment linkages found on many of the cheaper machines.

Without being fanatical with the fettling I think any small elimination of excessive play is to be encouraged as it can only lead to smoother working and less wear and tare such as loose bearings sliding about on their support shaft.
In the pops92 instance above, if the two bearings are fitted correctly with their inner races against shoulders within the wheel or have a central tube spacer on their inner races then even clamping the inner races tight on the shaft would be good practice so no need to worry about any clearance between circlip and bearing as long as any spacer washer does not impinge the outer races. (clamping a pair of inner races without internal spacers between the races is a no-no however)
In fact on my machine that's exactly what I did after I had the first bearing seizures on the lower wheel due to dust contamination, I killed two birds with on stone and fitted a wider diameter 'shield' washer on the inner side of the wheel to stop dust collecting in the wheel shaft cavity coming into contact with the bearing shield inner gap.