Trying to find source to replace a bolt on sliding compound miter saw

Hello:
I have a TSS121 12 in. Sliding Compound Miter Saw and the plastic ‘head’ on the bolt that locks the slider on the extension arm broke.  It is p/n TTI089041038052

and can be seen here: https://ryobipower.ordertree.com/model?modelId=62637&brandCode=RPT   It is part ID #10

 

The part is cheap at $1.76 but add s/h and the cost is over $10. 

The part is simply a hex bolt but has a ‘winged’ piece of plastic formed over the hex head so it can be tightened/loosened by hand.  The plastic broke and it is a pain to carry a wrench everywhere with the saw.  Anyone have suggestions of an alternative bolt w/ a thumb screw type head? 

Thanks

J