Breaking blades

[martinka]

I'm having real difficulty figuring out why I am breaking so many blades. I broke about 10 today so far, all Olson blades. They mostly break in the middle though one did break at the bottom. At this rate I am going to be a nervous wreck as I jump about 3 feet every time I hear the dreaded 'bang!' It got to the point where I daren't use the Hegner so I set the Jet up again on the bench and did the job on that, without breaking one single blade.

I've tried tensioning by feel, and by ear. I've read that people tend to put too much tension on. Well, how much is just enough?

So, people, how do you go about tensioning yours? If you used to break blades when you were new, how did you overcome it? Or did it come with experience?

Martin, very despondent at the moment. But at least my quick clamp is on its way.

 

[stevebuk]

you need to pluck the blade and hear a note of about middle C to be tightened about right, i just need to find a music teacher now..

 

[Philjohn60]

Hi Martin - I emailed you earlier to explain that my hard drive gave up the ghost on the Sunday that I collected my saw, so I'm catching up with things and noticed you've been having a few problems with your Hegner. When you were talking about vibration on the other thread, how bad is it? As you know, my saw is on a Hegner stand and to be honest, I don't get any vibration whatsoever. I can stand a penny on edge on the saw's table and going from minimum to maximum speed, the penny doesn't move. I believe your saw is single speed but nevertheless should really perform the same. Do you have a wooden floor? If not and you've got it bolted down, I'm afraid I'd be bit concerned that something was not right. With the blades breaking too, I'm wondering whether one of the arms is out of allignment for some reason. Have you left feedback for it yet? PM me if you prefer.

Cheers

Phil

 

[martinka]

Steve, the wife has one of those electronic thingumajigs for tuning her guitar, I'll give it a try. Although I listen to music constantly, I wouldn't know a C from a saw.

Phil, the garage has a concrete floor and I have a piece of steel, which at a guess weighs about 50lb, on the stand cross pieces. I couldn't get that AND the bag of concrete to fit.
Removing the 6mm bolts and fitting 8mm ones to bolt it down did help a little. It makes quite a difference if I change it to the shorter stroke, but I doubt I could stand a coin on the table without it walking off. Don't get me wrong, I'm not going to get tingling fingers or anything like that, but sometimes when my hands are on the table, you can hear the ring on my right hand ticking away with the vibration. I've had the arms off to check the bearings and they are fine, and I can't feel any play in the link from the motor. The blade lines up smack in the middle of the slot in the table. Sooo, while it doesn't sound to be as smooth as your own, I'm pretty sure vibration isn't a problem. In fact I'm convinced it's to do with needing to find the correct tension and having the blade straight in the clamps. It takes me a couple of goes to get the blade straight in the top clamp because my very near vision is terrible. If my arms were a yard longer I'd be OK. I'm hoping the quick clamp will help with that.

Martin.

 

[Baldhead]

Hi guys

Don't know if this will help but I have an app on my iPhone called Cleartune, it's a tuner, and very easy to use, perhaps this will help to get the tension right on your scroll saws.

BH

 

[martinka]

Hi guys

Don't know if this will help but I have an app on my iPhone called Cleartune, it's a tuner, and very easy to use, perhaps this will help to get the tension right on your scroll saws.

BH

Sounds like a good idea, ('scuse the pun), but my phone makes and receives calls and does nothing else. Well, probably text messages too but I never used it.

Martin.

 

[mac1012]

Bit baffling really I went through a phase when I first was scroll sawing when blade kept breaking and I realised I was tightening the bottom clamp too much if breakage near the clamp it could be that ?

If your arms are out of line it could cause problems , but something not right , have a word with tech guys at hegner if still causing problems they really helpful

also you should have to really push over the lever really hard on the tension , it should be quite firm but not like using a lot of major force

mark

 

[martinka]

Bit baffling really I went through a phase when I first was scroll sawing when blade kept breaking and I realised I was tightening the bottom clamp too much if breakage near the clamp it could be that ?

If your arms are out of line it could cause problems , but something not right , have a word with tech guys at hegner if still causing problems they really helpful

also you should have to really push over the lever really hard on the tension , it should be quite firm but not like using a lot of major force

mark

Hi Mark, only one blade has broken at the bottom, they nearly always break in or towards the middle. A couple of times I have been cutting as light as possible and still the blade snapped. I'm thinking about what you say about my arms being in line because once or twice I have noticed myself trying to move around the saw. Maybe I should try sitting, although I like to stand because of back problems. Trouble is I jump that much when it breaks that I am likely to end up on my back on the floor. :mrgreen:

BTW, I am only cutting some crappy 3mm ply, so it's not like I am needing to put a lot of pressure on the blade.
The middle C idea is difficult to use because I am doing all internal cuts. Flick the blade when its in a 1/16" hole and it just clunks.

Martin.

 

[boysie39]

you need to pluck the blade and hear a note of about middle C to be tightened about right, i just need to find a music teacher now..

:shock: :shock: After all the strange things and methods I had to learn on the turning section :roll: Here on the scroll saw section I now have to take me saw to a music teacher :shock: :roll: .

So you want to join the music group what instrument do you play .**The Scroll Saw ** enter the men with the white coats ,AGAIN. :mrgreen: :mrgreen:

 

[martinka]

you need to pluck the blade and hear a note of about middle C to be tightened about right, i just need to find a music teacher now..

:shock: :shock: After all the strange things and methods I had to learn on the turning section :roll: Here on the scroll saw section I now have to take me saw to a music teacher :shock: :roll: .

So you want to join the music group what instrument do you play .**The Scroll Saw ** enter the men with the white coats ,AGAIN. :mrgreen: :mrgreen:

Creedence Clearwater Revival - Scrollin' On The River.

 

[Ian down london way]

I've been cutting thinish ply for my clock (see WIP and have to use a thin blade with a high tooth count per um cm. On thin ply, they are fine (using an old henger). When I needed to slice up some 1 inch softwood, the same blades were slow to cut, so one applies more pressure - and the inevitable result is low life for the blade.

So I find, the best thing is to ensure I change the blade to one appropriate for the thickness of the material. The blades with fewer teeth are much stronger, so you can tighten them more, (same middle C), and they last longer.

I must get my daughter's guitar tuner outside and see what I tune the blades to - as I do it by ear, and also I have no clue what a middle C is.

(You only need a couple of teeth in continuous contact with your wood - I think that's the rule)

 

[martinka]

I'm using Olson #3 Double tooth, 23tpi

I just spent ages setting a new blade up, checked it, checked it again, and just to be sure I checked it again. Literally seconds after I started cutting, the blade snapped in two places.

 

[Gary Morris]

have you checked that the blade is square all four sides. Are you feeding the wood in at an angle or pushing too hard into the blade? Is there sufficient tension? Is there a min and max tension setting, if so I'd try a blade at Max, half way and finally min, if all three break, it's probably not the tension that's to blame.

 

[martinka]

have you checked that the blade is square all four sides. Are you feeding the wood in at an angle or pushing too hard into the blade? Is there sufficient tension? Is there a min and max tension setting, if so I'd try a blade at Max, half way and finally min, if all three break, it's probably not the tension that's to blame.

Hi Gary,

With screw tension, the tension is infinitely variable. On the Hegner, you set the tension with the screwed rod, then you have on and off with the quick tension release lever for changing the blade. At least you do on mine. (Apologies if I am teaching egg sucking here.) BTW, the tension rod had a couple of slight bends which I straightened out, though I doubt very much that it had anything to do with the blade problem.

I am feeding in at an angle sometimes, but then that's when using spiral blades, though with flat blades, I am feeding from the front. The blades have broken at times with little to no pressure, so it's not from pushing too hard. In fact I've got so scared of the damn things breaking, I think I am trying to cut with no pressure at all now. :mrgreen:

Now the good news. My quick clamp arrived and is fitted. The bad news there is that the revolving part of the clamp still had a pip on from being turned in the lathe and I had to stone it off. Anyway, I changed to a different blade, fitted the quick clamp, and sat, instead of standing, in front of the saw. I've made about 6 internal cuts of the Tribal Kitten pattern with NO breakages! I'm still a nervous wreck, waiting for it to happen, and my shoulders hurt from being so tense, but I think there's light at the end of the tunnel.

Thanks for all the input. I'm convinced I will get there eventually, it's just so damn frustrating.

Martin.

 

[Ian down london way]

Having grabbed my daughter's guitar, I can confirm that middle C is the first note of Frère Jacques

 

[MIGNAL]

You can't tension a scroll saw blade (or a Bandsaw blade) to the pitch of a specific note - well you can but you would also have to know the exact type of blade as a reference. You would also have to know the exact distance between the clamping points, that might vary on pinless blades. It's basic Physics. Thinner, shorter blades will reach the pitch at a much lower tension than thicker, slightly longer blades and I strongly suspect that pinned blades will be different from pinless.
I just don't think it's a good method of determining correct tension.

 

[martinka]

You can't tension a scroll saw blade (or a Bandsaw blade) to the pitch of a specific note - well you can but you would also have to know the exact type of blade as a reference. You would also have to know the exact distance between the clamping points, that might vary on pinless blades. It's basic Physics. Thinner, shorter blades will reach the pitch at a much lower tension than thicker, slightly longer blades and I strongly suspect that pinned blades will be different from pinless.
I just don't think it's a good method of determining correct tension.

While you are correct, for a number of people it seems to be a good starting point, though maybe not for anyone who is tone deaf.

Martin.

 

[MIGNAL]

Yes but only 3% of scroll saw users are tone death, it rises to 4% for bandsaw users and 98.9% for table saw users. Table saw users just aren't that bright, sad to say.
More seriously . . . if one of the very experienced users gave a specific gauge/size of blade ( let's say Mr. average scroll saw blade) and the distance between clamping points that would then make determining tension by a specific note a useful method.
Of course we would have to use 'concert pitch' @ 440 Hz, none of that silly baroque pitch @415 Hz.

The other method that I've heard used for Bandsaws (I don't use Table saws, honest) is to apply just enough tension so that if cuts true and square. Obviously with a scroll saw that really limits it to the blades designed for cutting thicker wood. With 1 inch material it's fairly easy to determine with an engineers square.
Either that or keep using,trying, experimenting until you get a feel for the correct tension. My money's on the last method!

 

[Bryan Bennett]

Hi Martin over the years I have used different blades,only early this year found F/D blades.Thought that I had found the ultimate blade,then I have found P'egas blades ( swiss) and in my opinion are the best blade that I have had the pleasure of using.
The blade is a No 3 R ( Reverse Skip) ref 90.428 priced at £2 71 p a doz plus pp.I have using the blades now for four weeks and they follow the line well and do tight turns,and have done all that I could have asked of a blade.I bought mine from Workshop Heaven who are located at Banbury.

Bryan

 

[martinka]

Bryan, I got some Pegas blades with my Jet saw. I think they were left near the saw in the shop by mistake and I forgot to tell them. I found them to be good blades too but I was expecting them to be expensive so I have been saving them. Going on your price, they are actually cheaper than the standard Olson blades I have been using.

I bought some of the Olson PGT blades today after reading good things about them, and they ARE expensive at 4 quid for 6, but I wanted to try them out. They are ground carbon steel and they certainly look far superior to the standard ones, looking through a magnifying glass. In fact they look very similar to the Pegas ones. I'm hoping they will cut the old stool tops that I have been unable to touch with anything else so far.

Mignal, I don't know if you typed "tone death" on purpose, but it suits my missus' singing.

Martin.