BANDSAW GUIDES - HOW CLOSE?

[samlarsen]

Watcha (No abreviations here.)

I'm just wondering how close a fit the roller bearing guides should be to the blade on a bandsaw. My manual is, of course, useless on this issue.

What is the consensus? Both up to pinch the blade, then back off a couple / few thou? leave them all-but-tight on the blade? leave a clear gap?

Cheers all, and any help much appreciated.

Sam

 

[Anonymous]

Hi Sam

I have pondered over the same thing from time to time. Mine is a Charnwood 720 and they told me tha the blade should not touch the guides in use and to set them about 0.5-1mm away on either side.

 

[Noel]

Tony,

I think the blade has to touch the guides in use. After all they do guide the blade. For me the guides and the rear thrust bearing (assuming you have this type of setup) should be as close as possible without touching. About a Rizzla gap.

Rgds

Noel

 

[Pete W]

A magazine article I read last year suggested the thickness of a banknote folded in two and able to slide smoothly between blade and guide.

 

[johnelliott]

How close they need to be can't be defined in terms of an exact distance, this is because bandsaws and their blades vary in their flexibility. I would suggest that you set the guides so that they are clear of the blade when it is running but not cutting, and so that they occasionally touch when cutting, especially curves

John

 

[Dewy]

I often worked on Startrite bandsaws as part of my job & always set the saw guides so that the blade passed through without binding. With every job needing a blade welded, you had to grind the welded part down so it was slightly thinner than the rest of the blade. We were sawing 3% & 5% chrome steel & thats far harder than any timber
We used coarse blades as the normal small tooth blades wore too quickly & took too long. Those blades were perfect for cutting wood though.

 

[Guest]

Do these suggested settings apply to roller guides as well as friction guides?

 

[Adam]

Having just come back from the Homewood Doscovery workshop - todays topic was bandsaw setup. The guy had run a saw mill for 10 years - and knew his stuff. He set set the guides about 1-2mm away.

He then demonstrated a 1mm veneer cut in mahagoney to prove this really worked. He was demonstrating on a "Draper" bandsaw.

He explained you can cut a grove in the rear thrust bearing if it's too close, and provided the blade is sharp and tensioned correctly, the side bearings don't actually do anything.

Adam

 

[Alf]

As I understand it, the rear thrust bearing should only come into play when the blade is forced back against it in the cut. At least that's how I set mine, by pushing back on the blade by hand (power off!) and setting the rear thrust bearing to just kiss the back, and I've had no complaints so-far-touch-wood. One of the advantages of good blades, such as the Dure Edge ones, is the back corners of the blade are rounded off to minimise wear on the guides too.

Adam, interesting that the chap had the side guides quite so far away from the blade. Fine for straight cutting but I wonder if it's ideal for curved stuff? I'm trying to visualise what might happen and failing... I think you actively need the guides in a curved cut, although I agree absolutely with them being pretty much redundant on a straight cut with a good blade. Was the workshop worth going to? Or wouldn't you bother again?

Cheers, Alf

 

[Adam]

Was the workshop worth going to? Or wouldn't you bother again?

Cheers, Alf

Very good. Snedger was there too - although SDA and Charley didn't put in an appearence.

Basically, the shop had brought it this chap who now demo's for Draper bandsaws having worked in cutting veneers/logs all his life. He said cutting softwood logs, on a bandsaw for cutting 5-foot diameter:shock: logs, they used to get through 1 blade/per day, but on hardwoods like mahogoney they used to get through 2/log. They has an onsite saw doctor fully employed.

He recommended a supplier in London, who was importing swedish blades I think - as the very best they had tried. I'll dig out the address. On small bandsaws (e.g. up to 16 high capacity) the rear bearing was set about 1-2mm back, like you said so when pushing wood through fast, it would just start to turn. The side guides were set 1-2mm away, and iterated over and over again, that if the guides are too close, they severly reduce the lifespan of the blade - and getting through 10+ blades a day in their mill, I guess he knows. He did mention that de-tensioning the blades when not is use also improves life. They used to de-tension all blades every weekend, but if in daily use, they would leave them tensioned. The veneer he cut was superb, really fine finish.

Adam

 

[Charley]

Was the workshop worth going to? Or wouldn't you bother again?

Cheers, Alf

Very good. Snedger was there too - although SDA and Charley didn't put in an appearence.

No I was away for the weekend and missed it

 

[Adam]

www.nlstools.co.uk

Adam

 

[Alf]

Yeah, but Adam there's a bit of a difference between sawing planks on a wide bandsaw all day and cutting bowl blanks f'rinstance on a narrow bandsaw. No? :? I have no doubt he knows his stuff within his field, but it's a bit of a different kettle of fish. I wonder what set up the likes of Craft Supplies and Axminster use to saw their bowl blanks?

Hmm, interesting link. I've heard of the Hakansson Silco blades before (was it DC again perhaps?) Tilgear stocks them IIRC. Trouble is I like the Dure Edge ones now...

Cheers, Alf

 

[Signal]

NLS Tools are a superb company, being just 10 minutes walk from my front door I would say that woulnt I

Seriously though they are a very helpful guys.

Cheers

Signal