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Posted: Tue Apr 13, 2010 3:23 pm
by dusty
JPG40504 wrote:A possibility!!!! Suggest you measure the distance between the wheels. If the blade is too long it will be too far apart by 1/2 the 'extra length'. Mine measures 7 13/16" from wheel(not the tires) to wheel at the back edge of the aluminum table. By eyeball they are about 1/16 + 1/16 closer at the axis position. The tension was set 1 turn BELOW 1/8"(loose).
However the calibrated arm moves with the wheel(up/down) so the tension MAY be independent of the blade circumference(within reason).
Do tell what you 'discover'.
Theoretically, (my theory) is that the Shopsmith Bandsaw has sufficient adjustment to permit the use a blade that ranges in length (circumference) any where from 70.754" to 73.254".
This is based on the measured performance of my two bandsaws. The axles of the upper wheel is movable so as to vary separation of the two axles from 18" (absolute minimum tension) to 19.25" (absolute maximum.
separation).
The separation of the axles when tension is adjusted properly for a 1/8" blade is 18.75". This equates to a 72.254" blade.
Note: Circumference of the wheel plus 2x (axle separation).
Posted: Wed Apr 14, 2010 12:01 pm
by heathicus
dusty wrote:Theoretically, (my theory) is that the Shopsmith Bandsaw has sufficient adjustment to permit the use a blade that ranges in length (circumference) any where from 70.754" to 73.254".
This is based on the measured performance of my two bandsaws. The axles of the upper wheel is movable so as to vary separation of the two axles from 18" (absolute minimum tension) to 19.25" (absolute maximum.
separation).
The separation of the axles when tension is adjusted properly for a 1/8" blade is 18.75". This equates to a 72.254" blade.
Note: Circumference of the wheel plus 2x (axle separation).
I measured last night and with both the 1/4" and 1/8" blades, when adjusted to a tension that felt right (tight, but not too tight), my wheels were right at 19" apart. I could easily deflect the blade at least 1/4" or more right above the table. And my tension gauge was well beyond the appropriate blade marking. I tried readjusting the indicator, but I can't move it any further in the correct direction.
Posted: Wed Apr 14, 2010 12:46 pm
by JPG
Add a pix of the upper left of the band saw including the upper wheel, arm, tension spring, adjustment 'screw' to the wheel/tire collection. Maybe we might 'see' something to explain all this!
Posted: Wed Apr 14, 2010 1:05 pm
by heathicus
Will do when I get home tonight.
Posted: Wed Apr 14, 2010 7:50 pm
by heathicus
Blade tight to operating tension:
1 -
2 -
3 -
4
Blade loose
5 -
6 -
7 -
8 -
9
Gauge set for 1/8" blade
10
Posted: Wed Apr 14, 2010 8:21 pm
by nuhobby
Hmmmm... I wonder if your red tension spring has deformed a little, like you said? I would think that this type of tension gage, if working right, would indicate blade tension correctly even if the blade-length was a little different from 72" nominal. Can the red part be reversed and re-installed for an experiment?
Posted: Wed Apr 14, 2010 8:42 pm
by heathicus
nuhobby wrote:Hmmmm... I wonder if your red tension spring has deformed a little, like you said? I would think that this type of tension gage, if working right, would indicate blade tension correctly even if the blade-length was a little different from 72" nominal. Can the red part be reversed and re-installed for an experiment?
I did that. I turned the tension bar around and noticed no difference.
Posted: Wed Apr 14, 2010 8:44 pm
by JPG
heathicus wrote:Blade tight to operating tension:
1 -
2 -
3 -
4
Blade loose
5 -
6 -
7 -
8 -
9
Gauge set for 1/8" blade
10
All looks 'normal' to me!:)
STOP 'tightening' it all the way!!!!!!!!!!!!!!!!!:eek:
My 1/2" blade deflects as much as your 1/4" in '#10' when set as yours.
Metinks ya need to just set it and use it and quit pushing on the blade with yer pinkie. i.e. Fergit what ya red elsewhere!!!!!]
Posted: Wed Apr 14, 2010 8:53 pm
by heathicus
JPG40504 wrote:All looks 'normal' to me!:)
STOP 'tightening' it all the way!!!!!!!!!!!!!!!!!:eek:
My 1/2" blade deflects as much as your 1/4" in '#10' when set as yours.
Metinks ya need to just set it and use it and quit pushing on the blade with yer pinkie. i.e. Fergit what ya red elsewhere!!!!!]
Maybe it's my technique, then. But it just "feels" loose when set to the right spot on the gauge. It's harder to keep a straight line, it's harder to control curves, etc. It just feels like the blade moves left and right a lot more than it should.
Posted: Wed Apr 14, 2010 9:02 pm
by JPG
???Blade guides. ???upper guide adjustments proper. ???lower blade guide position relative to both wheel and upper guide.
FWIW The blade should move in an absolutely straight line between the tangent points common to both wheels. Getting there is difficult(especially the upper blade guide 'post').
BTW are you attempting too small a radius cut for a 1/4" blade?(<3/4")
