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Why the gap by the back guide bearing on a bandsaw

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Why the gap by the back guide bearing on a bandsaw

Postby RogerS » 02 Aug 2016, 16:37

Why do we have this small gap ? It doesn't make sense to me. The ball-bearing rotates. So why not have the blade touching it at all times ?

And a supplementary question. Why do these so-called sealed bearings on the guides on a bandsaw go all graunchy very quickly ?
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Re: Why the gap by the back guide bearing on a bandsaw

Postby Mike G » 02 Aug 2016, 16:56

They stop working because bearings aren't supposed to take load on one side of one face, but uniformly distributed around the rim. I think the gap is unnecessary.
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Re: Why the gap by the back guide bearing on a bandsaw

Postby RogerS » 02 Aug 2016, 18:05

Mike G wrote:The stop working because bearings aren't supposed to take load on one side of one face, but uniformly distributed around the rim.....


I agree with you if the bearings are configured in Diagram A (which I think is how you are envisaging the layout) but mine are as per Diagram B. But then it would only be the back bearing. My bearings are the two side ones that always seem to go.

Image

I could be misunderstanding your post ...more than likely !
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Re: Why the gap by the back guide bearing on a bandsaw

Postby Rod » 02 Aug 2016, 19:04

No bearings on my old Startrite 352 only blocks.

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Re: Why the gap by the back guide bearing on a bandsaw

Postby Tusses » 02 Aug 2016, 19:27

anything "wears" with use

so if it's in contact all the time, it will wear more than if just when cutting

Thing how long the BS is running compared to when it's cutting.

The bearings could last twice as long ?
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Re: Why the gap by the back guide bearing on a bandsaw

Postby Mike G » 02 Aug 2016, 20:40

RogerS wrote:......I agree with you if the bearings are configured in Diagram A (which I think is how you are envisaging the layout) but mine are as per Diagram B. But then it would only be the back bearing. My bearings are the two side ones that always seem to go.

Image

I could be misunderstanding your post ...more than likely !


No, you got it exactly right. Mine is configured as per your diagram A.
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Re: Why the gap by the back guide bearing on a bandsaw

Postby Andyp » 02 Aug 2016, 21:01

I'd always assumed that he side bearings (mine are made of lignum vitae) and rear rolling bearing were there to prevent too much blade movement when timer is pushed up against the blade. If the blade were touching the bearings all the time then both the blade and bearings would wear out much quicker.
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Re: Why the gap by the back guide bearing on a bandsaw

Postby Rod » 02 Aug 2016, 22:57

What Andy has said - my blocks are as B.
It would only touch the rear one if too much pressure is applied rather than letting the blade cut without forcing.

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Re: Why the gap by the back guide bearing on a bandsaw

Postby RogerS » 03 Aug 2016, 07:10

Rod wrote:What Andy has said - my blocks are as B.
It would only touch the rear one if too much pressure is applied rather than letting the blade cut without forcing.

Rod


I'm not sure that that is the case. The gap is supposed to be set at the thickness of a £5 note which means that the blade is always going to touch that rear roller when it's cutting - unless it's a massive resaw blade and tensioned to within an inch of its life.

Regarding life of these bearings...given the amount of run time that the bandsaw has, maybe a few hundred hours if that, then if wear was a problem then surely most cars would be immobile ? Maybe the bearings are cheap'n'nasty and not sealed very well and fill up with sawdust?
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Re: Why the gap by the back guide bearing on a bandsaw

Postby kirkpoore1 » 04 Aug 2016, 06:03

I'm convinced that the very fine dust that bandsaws produce gets into guide bearings and kills them. I had to replace the rear thrust bearing on my old Jet BS at least 3 times in the 20 or so years that I owned it.

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