Star Drag Basics

Started by uman, April 16, 2020, 09:16:32 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

uman

Have you ever wondered how a star drag work?  I will try to explain and use the Shimano Torium 16 to illustrate; refer to the picture below.
The star drag works by creating drag between the fixed drive shaft and the rotating drive gear using the drag washers [291] and [288](x2) when one cramps down on the drag star [605].  Starting from the drive gear which is allowed to rotate as line goes out, let's move up the drive stack.  We first concentrate on the metal washers [290] and [289].  Notice that the key washer [290] rotates with the shaft due to the square key.  The eared washer [289] rotates with the drive gear due to the ear in the drive gear.  Finally, we have the key washer [929] which rotates with the shaft due to the anti-reverse bearing [493] grabbing the ARB tube [494] keyed to the washer.  The drag washers are sandwiched between the metal washers to provide the drag.  This arrangement of drive gear, key washer, ear washer, and key washer is basic for all 3 drag reels (and applies to single drag and other multiple drag stack reels).  Guided by this principle, one should be able to put a reel together without referring to a schematic.
Most modern reels use a handle ball bearing [486] to ensure smooth cranking. The bearing thrust washer [269] only contacts the inner race of the ball bearing so as not to interfere with the ball bearing rotation.  The tube [494] also doubles up as a thrust washer for the other side of the ball bearing. So if you find a thin washer with a big hole, it is placed next to the handle bearing.
Next up the stack are two drag spring washers [268] and [267] in a () orientation to keep tension on the drag washers as we crank down on the drag star. What if you use the washers in the )) orientation? When you change the orientation of the spring washers you change the tension adjustment characteristic.  When the drag star is crank down completely, the tension on the washers are the same since both are flattened completely.  However, notice the difference in stack height of the () and (( orientation.  With each full turn of the drag star, each configuration is compressed the same amount.  But the compression relative to the fully compressed amount is less for the ().  Hence the () orientation has a wider range for adjustment.  Therefore most factory schematics show the () orientation.
Many reels have 4 spring washers in this factory orientation ()().  One can play with others orientation like (()) or ())) to their liking.
In the diagram, [270] is a thin plastic water shield for the handle ball bearing and has nothing to do with drag adjustment.

Alan, I have learned a lot from you and your website.  Thank you.  This is my humble way of repaying a little bit of my indebtedness.  Hopefully some beginners will find this information useful.







alantani

very nice!  i've got to figure out how to paste in diagrams like that.  it never seems to work for me.   ;D
send me an email at alantani@yahoo.com for questions!

BocaSnook1

Thank you for this tutorial.

Very interesting and informative.

Tad

uman

Quote from: alantani on April 17, 2020, 12:30:36 AM
very nice!  i've got to figure out how to paste in diagrams like that.  it never seems to work for me.   ;D

I start with the schematics pdf file.  I blow up the page, centering around the area I want to copy.  I then copy the area in the Acrobat reader and paste it in a new file in a picture editor like PAINT. I save it as a .png file.  When I post, I just attach the .png file.  A piece of cake! Now I wonder how do you guys do a big tutorial with many pictures.