Why are my Bandsaw blades breaking

[bert]

I have a Clarke CBS45 bandsaw and I have been using clarke blades with a pitch of tpi24, the blades dont seem to be lasting very long.

I would say I am getting about 100 cuts of various thickness metals but mostly 1" tube and 5mm thick bright steel plate before the blade cracks from the back of the blade then fails.

Does this sound like the blades being rubbish or could it be a machine set up issue?

Thanks
Darren

 

[Wallace]

Have you adjusted the guide rollers since buying the machine and how tight do you tension the blade?

 

[bert]

I bought the machine second hand and not adjusted the rollers apart from getting it to cut straight.

The blade is not tensions too tight just nipped up until it feels right.

I have noticed on the top of the most recent blade a ridge where the rollers have been.

 

[mike os]

Are all the rollers turning?

Depending on what you are cutting that is not too bad

Better blades will/should help too

 

[bert]

Yes all the rollers are turning and are regularly cleaned off.

 

[Wallace]

The guide rollers should have 0.001" clearance to the blade, if they are creating a ridge on the blade they may be overtightened.

 

[Tigman]

do you let the blade down slowly ? are you using suds ?

 

[bert]

I'll check the tightness of the rollers when the new blade arrives.

Yes very gentle when letting the blade down, learned that lesson the expensive way.

No suds cutting dry.

 

[the artfull-codger]

They'll last longer if you use cutting oil,having said that m.m. blades are not the top of the range but definitely use cutting fluid,I make my own blades up scarfing the joint & silver soldering them,I made my own jig but "dropped across" a wadkin bursgreen bandsaw brazer which I now use, just keep my eyes open for 100ft coils at autojumbles,or longer blades than required & cut them to my size [if the price is right!!]

 

[desmo11225]

Hi Bert
I have a similar saw also second hand, I have spent quite a bit of time sorting it out too, try to get the saw back to how it was made in the first place, I have also changed to Starret blades, with very good results. Hope this helps a bit!!! All the Best desmo11225

 

[cumbriasteve]

I had no problems with the MM blades, in fact a bi metal blade I paid a lot more for did not last anywhere near as long.

By your description I was running mine with more pressure on the blade than you may be doing, in fact I had it wound up fairly tight.

I also used cutting fluid, only a small drop on the cut line but it made a massive difference all round.

 

[bert]

Thanks everyone, will have a tinker when the new blades arrive.

Found 4 broken blades in the shed and on closer inspection all have multiple cracks in them.

 

[waldershelf]

I have the same problem with my Clarke band saw, mine always break on the weld. is it me? am I doing something wrong?

 

[ford34/2]

We only ever used Starrett blades, eventually break after loads of cutting. But never experienced a major problem with premature breaking, It was however a damned big bandsaw. 1/2" blades though. Should try the re-saws!!!!!


Stan

 

[Wallace]

The joint is the weak point in the blade so the most likely place for it to break. A few methods of improving blade life......

• Slackening the blade tension off when not in use.
• Having the minimum distance between each set of guide rollers to clear the work.
• Coolant.
• Correct cutting speed and feed.
• Correct TPI for material thickness.
• Work held correctly.

The blades on spring balanced 6x4 saws such as the Clarke etc can benefit from a reduced cutting feed on box section and tubing as the sudden drop into the thinner wall section can shed teeth, a damped feed controller helps alleviate this happening.