Setting blade tension on a Jet scroll saw

[KCSteve]

So, on Saturday I will have had my Jet scroll saw for 6 months.

Today I suddenly realized I've been trying to set the blade tension completely wrong the whole time. 

On pretty much every saw the big knob at the back sets your tension.

Jet saws are different.

The Jet uses a lower blade holder and a cool upper clamp that uses a flip arm.  When you flip the arm the upper clamp closes on the blade and pulls it up into place.

So the big knob at the back of the Jet saw?  That's really just for adjusting the spacing between the arms.  It does affect the tension, but only in a crude way and if you try to set it too tight you can't get a blade in.

The knob is to get the arms parallel and to make sure that the upper clamp comes down far enough to grab the top of the blade.  You rotate the flip arm of the clamp to set your tension.

Once I realized it I was able to get my blade to the exact tension I wanted rather than just kind of close.

I'd say the realization made me feel stupid, but it's just one more thing on a long list. 

The manual does tell you all of this, it's just so different from other saws that it didn't sink in until today.

[lindafitznj50]

I also have a Jet and love it. I've had to adjust the tension to keep the arm up and in doing so the table and the arm are no longer parallel to each other. Back to the manual as I know there's a way to adjust that (but I'd rather saw than adjust ;-)

[KCSteve]

Use the knob at the back to get the arms parallel.

Turn the lever that locks the blade to adjust the tension.

If you try to use the knob at the back to set the tension you wind up with the arms out of parallel and other problems.  Plus it's a very crude way of setting the tension.  Just use the knob to get the arms parallel (reminder: you may have to push down on the top arm after loosening the knob).  Then put in a blade, flip the lever back and check the tension.  If it's too low, turn the lever one full turn to the right (I open the lever first).  Repeat as needed.

[harpolemond]

Yep..my new Jet was an experience. Found I had to read the manual since it was not like my Excalibur at all, nor my Delta.
      Hate reading manuals, but now after about six months, I found my Ex16 right next to to be the difficult machine.  I have increasing Arthritis in my hands and fingers from playing Guitar for years.  The new Jet solves that problem for me....So my new jet has turned out to be the most awesome machine I have ever owned.
      Not a spec of trouble and cuts the most serious works perfectly.  Of course the blades matter but I like so many others have my preferences.
   Same blades on my newer Excalibur and on my Jet,  well the Jet wins hands down,
but I do have to say that before the Jet the Ex16 did help me win first place at the IL state fair last year.
  Wanted to add that by adjusting the arm parallel with the back knob does indeed control blade rock back and forth on most  machines of similar design. Motor positioning and arm level to the deck are very important.  Place a piece of tape on the back knob and the arm to mark its position since that arm  does have a tendency to move. That will keep you in true if the arm drifts.

[KCSteve]

I'll have to add the bit of tape on mine - good idea to keep an eye on it because it does manage to sneak in a self-adjustment every now and then.