Sealey SM5, blades snapping

[stevieh17]

Hi All

Got a sealey sm5 bandsaw given to me, been using it for a while now cutting 50mm box section etc.

Seems to be working the best but I have now snapped 2no. blades. The last one being a axminster blade that cost £30 and lasted about a day of steady cutting.

Does anyone have any ideas on what tension etc. to set the blade too or what else could be causing the blades to snap?

Thanks

 

[cumbriasteve]

Are the blades wearing out before snapping or still sharp when snapped?

On my Clarke saw I just used to tighten up until it felt fairly tight and then another turn, not very technical I know but my blades lasted for ages, I also used cutting oil..just a jar and small artist brush to dab before and halfway through the cuts.

I had the arm adjusted to a fairly light down pressure, that helped the blade life but made no significant time difference on the cuts.

I did once buy an expensive blade and that snapped within a few days, went back to Machine mart cheapies and no problems.

 

[stevieh17]

Na they are still fairly sharp. I could maybe try some cutting oil! I know in the sealey manual it says the blade should only move 1mm when you try to flex it but I can't seem to get close to that!

 

[cumbriasteve]

So are you saying with the tensioner fully adjusted up the blade still has a lot of flexing?

You should be able to get full tension on a new blade and still have some spare travel on the tensioner left for when the blade stretches after initial use.

 

[Wendelspanswick]

I've always found Axminster bandsaw blades pretty crap myself. Axminster Machinery invested in a bandsaw blade welder as a sideline when I worked for County Hardwoods about 20 years ago so we started to get our blades from them but they snapped for a pastime. The trouble seemed to be the blade snapping on the weld, the grinding around the weld always seemed over enthusiastic.
Your better off getting blades from a saw smith or welding your own loops up if you have a TIG.

 

[bletchmonster]

I ran a similar saw for years using the M42 bimetal blades without problem. I would only tension up enough to stop the blade wandering in the cut. Coolant tends to only help with avoiding blunting.
Excessive speed can cause cracking between teeth that will lead to breakage.
But having said that I always ran it at full chat on mild steel and the blade would keep going till it was hard to tell which side the used to be on, often same blade for 12 months.
Is the blade straight when its broke, if its curved you could have wheel misalignment issues.
All assuming its not to much downforce in thinwall box

 

[wristpin]

May be worth talking to these people - I've found them very helpful.
http://www.bedfordsaw.co.uk/