Tight or not tight enough

[antifoul2020]

Snapped three NO5 blades sawing 6mm birch-ply
Blade doesn’t pull out the clamp it actually snaps
Certainly not pushing to hard
Getting a good tone of the blade when tension is set
But is it the right tone

 

[TRITON]

Blade for what ? Bandsaw ?

 

[antifoul2020]

Apologies
Hegner multi cut 2 scroll saw

 

[bodgerbaz]

What make of blade?

If you’re getting a good ‘ping’ the tension sounds okay. Cutting 6mm ply shouldn’t be a problem either. I’ve cut 25mm hardwood without issue if you take your time.

Are you overly pushing the ply through instead of letting the blade dictate the pace?

 

[clogs]

try another blade manufacturer.....
teeth count.....?
a lot of so called Euro manufacturers/dealers just re package the Asian stuff....
which can be good if not made of cheese Gromit.....

 

[AES]

1. Were the 2nd and 3rd blades that broke new? (I'm assuming that the first blade was already in the machine when you started that job).

2. Was the tension OK (a "ping" as you pluck the blade with a finger while making sure the blade wasn't touching anything)?

3. What brand was/were the blade/s, all the same?

4. Were the blades mounted the right way round (cutting on the DOWN stoke)?

5. Was the ply pre-used (e.g.with any nasties on the surface/hidden inside)?

6. Have a look at the sticky on top of the Scroll Sawing Section here - lots of info on what blade to use on what sort of job, PLUS where to buy blades.

I would have thought a No. 5 blade would be fine for 6mm ply.

HTH

 

[antifoul2020]

Olson NO5 reverse tooth
I will try to put a wee video of the tension up next post

 

[antifoul2020]

Wee video

 

[bodgerbaz]

That sounds a bit too tight to me. I always get a ping but it doesn’t sound as high a note as that. Try slackening it off a bit.
Olson reverse tooth #5 should eat a 6mm piece of ply.

 

[AES]

That sounds a bit too tight to me. I always get a ping but it doesn’t sound as high a note as that. Try slackening it off a bit.
Olson reverse tooth #5 should eat a 6mm piece of ply.

Agree with bodgerbaz on both counts - blade tension sounds a bit too high; AND it sounds a bit "dead" (more of a "clunk" that a musical "ping"). And agree, Olson No 5R should "eat" 6mm, ply without breaks.

If a bit less tension doesn't cure the problem try another blade make or tooth type - e.g. I like Pegas (RGT - "Revised Geometry Teeth", or something)!

But all these things are a bit subjective, and difficult for others to solve at a distance.

At the end of the day a lot depends on "the operator" and his/her personal preferences. I think that most on here have developed the "right setup for each job" by a bit - a lot? - of "try this, try that". Certainly in my case anyway.

So try a few different things - ONE AT A TIME PLEASE! - to find what works best for YOU. E.G's: blade No; tooth shape (Reverse, Skip, etc); manufacturer; machine speed; tension; etc.

AND are you quite sure the ply you're cutting is OK? E.G: no broken staple hiding in the core, or something like that?

 

[bodgerbaz]

All good advice there from AES.

Certainly reduce the tension then one step at a time to change material and blade selection. I’m sure that soon get the results you want … and please let us know how you get on.

 

[antifoul2020]

The ply is laser cut A4 from amazon
I will do as you suggest with the tension then
Let you hear it again
Is there a certain way that the reverse tooth blade fits
Or just teeth pointing down

 

[bodgerbaz]

Yes. The teeth will be pointing downward and, as it’s a reverse tooth blade, the last couple of teeth will point upward to trim off the “furries”

 

[AES]

The ply is laser cut A4 from amazon
I will do as you suggest with the tension then
Let you hear it again
Is there a certain way that the reverse tooth blade fits
Or just teeth pointing down

Well not ALL the teeth point down (NOT being sarcastic, 'onest), just the majority! By that I mean that the first few teeth (at the BOTTOM of the blade) point UPWARDS. The purpose is that when cutting something like thin ply, especially when the laminations are VERY thin/delicate, you CAN (sometimes) get splintering of the "bottom" lamination (i.e. the lamination resting against the machine table) or even the upper lamination (again, it's rare, but CAN happen).

Personally I seldom bother with Reverse tooth blades, but as per my last post, "different strokes for different folks".

 

[AES]

Ah, posts overlapping sorry, not trying to confuse the OP. I need to be offline for a while anyway (bb, good to see you back).

 

[bodgerbaz]

I have a Hegner too and the little jig where you fit a new blade (on the right of the table) shows the direction of the teeth

 

[bodgerbaz]

(bb, good to see you back).

nice to BE back. Thank you.

 

[antifoul2020]

Altered the blade tension

 

[bodgerbaz]

That sounds much better. Have you tried cutting the 6mm ply yet?

 

[antifoul2020]

Yes cuts it fine at the moment can only do rounded 90degree turns
Not got the confidence or experience to turn the workpiece quick
Have tried it but still get an awful fright when the blade breaks