Blade tension question

[OCtoolguy]

And I thought I had this thing figured out. Well it seems I don't. I have, up to this point, pretty much used Pegas #5MGT blades for most everything but I decided to branch out a bit and try some smaller blades. So, I dropped down to a #1 and #2/0. My problem is in tensioning. I can't seem to find that sweet spot with the tension on my Ex 16. I first tried it at the same point on the big black knob that I use for the #5. Well that proved to be way too tight so I backed off. Way off. Almost a full turn off. Once I got to a point where I wasn't snapping the blades upon applying the tension lever, they become "un-steerable". Lots of wandering. So, I tried tightening back up just a smidge. Back to breaking the blades. So, I guess I need some help from those of you who pretty much always use those tiny blades. How do you keep from breaking them? I'd like to hear from folks who have either a Pegas, Seyco, Excalibur or similar types of saws so we are talking oranges to orange. But any advise would be greatly appreciated. 

Edited November 21, 2022 by OCtoolguy

[don in brooklin on]

Are you talking about the big black knob at the back.  It should not really have to be touched.  

It is to keep the arm parallel to the table and then does not have to be touched.  It can come a little loose, so I just measure front and back and good to go.

I am currently doing a lot of 2/0 work and I have not had any problems on my EX-21.  I am a bottom feeder and I just have to make sure I don't get any kinks in the blade to change the tension. 

Also make sure the blade is going straight up and down. 

There are good instructions at https://sheilalandrydesigns.com/free-pattern/tuning-your-excelsior-or-excalibur-scroll-saw/

[TAIrving]

I have also had a problem with the 2/0 blades breaking under normal tension.  My fix, which works well for me, is to press on the side of the blade when clamping, putting a little bit of slack in the blade.  Then when I flip the white tension lever, the blade has slightly less tension.  It takes a little practice to get it just right.  

[Joe W.]

1 hour ago, TAIrving said:

My fix, which works well for me, is to press on the side of the blade when clamping, putting a little bit of slack in the blade.

I came across this suggestion from a previous post - used it a few weeks ago on a piece and it works for me.

[dgman]

Ray, I have always used high tension with all blades. Both on the DeWALT and now on the Pegas. The blade wandering is caused by not enough tension. Do as mentioned above. Use the black knob to make the arm parallel with the table only.

[kmmcrafts]

I've never really done any adjusting on tension for blades down to size 2/0... but anything smaller you might have some problems.. You didn't mention what brand or type of blade, spirals tend to break easier than a flat blade. I use 2/0 FD-NS blades quit often in my excalibur without any issue, BUT, I find the Pegas brand runs a tad smaller on the number sizes so a 2/0 is kind of more like a 3/0 and I have had some breaking issues with the Pegas sample spirals I tried.. I think if I remember correctly I kind of compare the #1 Pegas to the 2/0 FD spiral..

Unfortunately this style of saws don't really have a "variable" adjustment for tension.. But that's really the only flaw I've found with these type saws.. and as has been mentioned.. clamp it with a little slack and it should work.. I mostly use my Hawk when needing to use real small blades.. because once the tension is adjusted I should be able to just run it until I change sizes again.. and need to adjust.. The EX saws if doing fretwork with these blades can be a pain to get used to how to get the tension correctly set each time you go to the next cut out spot..

[hotshot]

A few years ago when I got my King 16, when i would try to tension Jeweler blades like I did on the 21, I would break them about every time.  The shorter arm on the 16 had less flex so created too much tension on very small blades.  About that back knob, If your saw has been tuned for minimal blade travel, you really don't want to use that to adjust tension as it will mess up that tuning.  I did this video a few years back to explain my approach to this issue.

I know you aren't using Jeweler blades, but see if this helps:

 

 

I'm not great in front of the camera, so sorry for the production quality.

 

----Randy

Edited November 21, 2022 by hotshot

[preprius]

Ray,

My machine is hawk. I do what you do.  Set tension enough not to break the blade.  In fact just a tad less. This was the fix #1. Fix #2 was use pegas mgt blades.

Observation of dull blades to begin with is also important.  Some blades just have differences. 

Different woods make blades do different things.

Purple heart cuts at different angles that yellow heart. 

I complained about blade wondering when I was cutting yellow heart 1/4 inch. 

I was using non pegas blades.  2nd quality down from top.  The blade just would not cut going right. The blade would twist but still not cut a curve. These were not tight turns. I increased tension it helped a bit. I still have 144 of those blades. But going to highest quality blades made more improvement. 

Any 1/4 thick wood becomes squirrely. Including BB ply.

When I cut 3/4" wood much less tracking issues.

Also cut slower, my speed knob is about 30%.

Ok that is what this village taught me.

Obviously you milage may vary.

Me.

Mark Eason

 

[BadBob]

I copied this from my ED-21 Manual. It seems to contradict itself.

Helpful Hints On Blade Tension

Determining correct blade tension is somewhat subjective. It is learned through experience and is somewhat dependent on personal preference. A properly tensioned blade will last longer and be much less likely to break prematurely. If the blade tension is too loose, you will notice that the blade will tend to drift or slip offline when cutting, and you may also experience excessive vibration or unusual noise. A blade that is too tight will break prematurely.

Assuming the blade has been properly installed in the blade mounts when the blade tension lever is pushed fully back towards the rear of the saw, the blade should be properly tensioned. Test the blade tension by lightly plucking on the blade, like you would a guitar string, with your finger. If the blade is tight and tensioned correctly, you will get a clear and even note. If so, you are ready to proceed to operating and cutting with the saw. If not, for some cases after double checking that the blade is properly installed in the blade mounts, further blade tension fine tuning can be made by adjusting the rear knob to raise the upper arm slightly. Note: this is not the main function of the adjustment knob (see the following paragraph) and using this knob as the primary blade tensioner will cause premature wear and damage to the machine.

This saw has an adjustment knob K in the rear that can raise the blade mount up to 1” (25 mm). This allows you to fine-tune blade tension when needed, as well as to reposition the saw blade at a point where you can use a different part of the blade in the cutting area. This also allows you to use a piece of band saw blade, cut to a length of 5”- 6” (127-150 mm) in your saw, and gives you up to 3 inch cutting capacity when needed.Note: Do not over tension the knob as this can cause premature wear and damage to the machine.

 

[OCtoolguy]

Let me clarify. I'm trying to use Pegas 2/0 and/or #1 mgt blades. Cutting 1/8" BB stacked 4 high. I know that the black knob is meant for leveling the upper arm and is not a tension adjuster. BUT, there is no other way to adjust the tension on these saws. I am using the Pegas clamps with the white flip lever. I bottom feed. I've never heard of leaving "slack" in the blade when mounting it. My method up til now has been to mount the bottom clamp first, feed the blade through the drill hole, and then mount the top clamp while pulling down on the upper arm to remove any "play" in the mechanism. Then flip the lever. So if I'm reading all the replies correctly, I'm doing it wrong by removing the slack in the mechanism causing too much tension. I will take all this advice and try to change my method. After re-leveling the upper arm. I appreciate all the help folks. I guess the wandering blade is caused more by operator error than tension.

[kmmcrafts]

1 hour ago, OCtoolguy said:

Let me clarify. I'm trying to use Pegas 2/0 and/or #1 mgt blades. Cutting 1/8" BB stacked 4 high. I know that the black knob is meant for leveling the upper arm and is not a tension adjuster. BUT, there is no other way to adjust the tension on these saws. I am using the Pegas clamps with the white flip lever. I bottom feed. I've never heard of leaving "slack" in the blade when mounting it. My method up til now has been to mount the bottom clamp first, feed the blade through the drill hole, and then mount the top clamp while pulling down on the upper arm to remove any "play" in the mechanism. Then flip the lever. So if I'm reading all the replies correctly, I'm doing it wrong by removing the slack in the mechanism causing too much tension. I will take all this advice and try to change my method. After re-leveling the upper arm. I appreciate all the help folks. I guess the wandering blade is caused more by operator error than tension.

Yeah it's kind of the only down point of a Excalibur or similar style saws as there is no ( what i consider perfect ) constant blade tension as there is on some of the other saws.. Even the DeWalt has a better set up.. Not sure how Hegner system works but the hawk you adjust it at the back once for that style blade and it's good to go until you change to a different size blade. Unless of course those Pegas MGT blades can't for some reason have them all the same length.. doesn't matter on most saws but the Hawk it does..

The older EX's had a tension lever that you slide over much like the DeWalt.. then you could adjust it as needed.. Not sure why the went with the flip lever.. The new Jet has a threaded shaft that will raise / lower the upper blade chuck to get that perfect tension similar to the Hawk but at the front and once set its good until you change size of blades... Anyway as you may have now learned.. for the most part it's not an issue unless you're a person that consistently uses the real small blades.. I know you mentioned you was just giving them a try.. but I typically use the #3 on a stack of 4 BB ply 1/8" thick.. so maybe that is somewhat a partial issue too? I don't use small blades often and when i do it's usually a 2/0 in a spiral.. never have had a need for them that small in a flat blade..    

[OCtoolguy]

Kevin, after reading many posts by others, I was realizing that many folks use the tiny blades. Now, maybe it's because they do primarily fretwork. I'm not a fretwork person but for what I'm making right now, I have to do some of it so I thought it might behoove me to give it a try. I think I will try what you say and go back to either a #5 or drop down to a #3. I've never messed around with the knob before and had no problem with the #5's. I was just wondering if it was something I was doing wrong. Now, I see that it is more of an issue with not knowing what I was doing and something that will require a bit more finesse when mounting smaller blades. I've always tried to take the slack out of the mechanism because this is usually quite a bit. But now, I know not to do that on the smaller blades. Onward and upward.