Blade Guides

[zathras]

I was hoping somebody may be able to provide some advice for me.

I've been looking at bandsaws and I have noticed that there seems to be two camps when it comes to bearing guides i.e. the thrust(?) bearing is mounted so the blade rubs against the side of the bearing http://ubb.ubeaut.com.au/ubb/confused.gif or the blade runs against the edge so the bearing can actually roll as per normal.

Surely running the thrust bearing in the second way would be better as the bearing can just then roll freely as the blade gets pushed back ?

Cheers Ray

[Tim the Timber Turner]

Hi Ray

I know just what you mean, it looks to be wrong with the blade running against the side of the bearing instead of the outer ring. However running the back of the blade against the side of the bearing is the system most commonly used and works fine. I had a Woodfast that worked this way and belted it for 10 years without any problems.

My current Sheppach works the same way.

Any wear on the bearing is even around the whole bearing but with the blade running against the outer ring would tend to wear a grove.

Cheers

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Some days I turns thisaway, somedays I turns thataway and other days I don't turn at all.

[zathras]

Ah yes, I didn't think of the possibility of wearing a groove into the bearing's face, although I should imagine that would take some serious work to achieve being hardened steel http://ubb.ubeaut.com.au/ubb/biggrin.gif

I suppose it now makes a bit more sense why they now look wrong at first glance.

Thanks

Cheers Ray

[soundman]

There has been a number of articles and various after market systems to address exactly what yo are interested in.

The side on bearing thing seems to be an american thing.
The argument is that it supports the blade better.

The european style seems to use the bearing in a more conventional way.

Check out the current carbatec catalogue, there is an after market system in there.


To cut to the chase the considered opinion of the articles I have read is that the side bearing with two blocks style is better for scroling & thin blades and the all bearing system for ripping.

If using the us style replacing the blocks with aftermarket lo friction blocks is considered the best move ( cool blocks.)

Cheers

[ubeaut]

Think you'll find the side on bearing comes from the use of a similar thing in big bnadsaws (the real oner). Many use a flat circular disk that revolves on a bearing hub and sits behind the blade, the side bearing is a cheap way of producing a similar effect.

I think you will find a blade running on the the edge of the bearing would be inclined to make the blade skid from side to side. However, I just happen to have one with a groove cut into the rim for the blade to run in. This was designed initially for use with very fine 1/16" & 1/8" blades used for fine detailed scroll work where side guides could not be used.

By the way you can wear a grove into the hardened face of a bearing from the side I did it when (unbeknown to me) the lower bearing seized.

Cheers - Neil